2-stroke diesel is the (near) future?

[Max Kallio]

Proposal for a future (helicopter) engine...

2-stroke diesel
2500cc two cylinder 45 degree V (120-150hp)
air cooled (cowlings)
common rail direct injection (high pressure)
supercharged (Whipple fixed displacement max. 25 psi twin-screw)
piston ported (or with LIM-type intake valve)

Links...

www.limtechnology.com
www.zoche.de

Has anybody ever tought of opening the intake valve (one ceneterd
valve) with (the high) diesel injection pressure?

Perhaps the valve and injector could be integrated. As the pressure is
released (at the exact right time) to the valve, it opens and lets the
supercharged compressed air rush in. As the piston rises past the
exhaust ports, the diesel fuel is injected and as the pressure quickly
drops (and simultaneously the cylinder pressure rises) the valve
closes tightly.

Could this be feasible? Unfortunately, I am no engineer. Just a
tought.

In a two-cycle engine the integrated pump nozzles and intake valves
could be operated directly from crankshaft with push rods and rocker
arms. This would still eliminate the camshaft and the high pressure
injection pump.

This type of engine could prove to reliable and economical...

- diesel fuel acts as a lubricant as well (reliability)
- low parts count (reliability, low and easy maintenance, light)
- sturdy diesel parts (reliability, low maintenance)
- economical on fuel(low consumption, the use of bio-fuels, possibly a
bi-fuel)

Is this the future engine for aviation (rotor aeroplanes and
helicopters), automotive, machines, marine etc?

Cars (trains and boats as well) should be full two-mode hybrids with a
mecanical planetary drivetrain or just the combination of a diesel
generator, batteries and electric engines (to make things simple and
economical).

You could (and should) recharge the batteries from AC mains during the
night, so they are at full charge when you go off to work. They are
charged with the diesel generator and as you apply the brakes.

[Chas Hurst]

Detroit Diesel has been producing 2-stroke diesels of this sort for 50
years. They recently changed to conventional 4 stroke engines. Guess why?

"Max Kallio" > wrote in message
om...
> Proposal for a future (helicopter) engine...
>
> 2-stroke diesel
> 2500cc two cylinder 45 degree V (120-150hp)
> air cooled (cowlings)
> common rail direct injection (high pressure)
> supercharged (Whipple fixed displacement max. 25 psi twin-screw)
> piston ported (or with LIM-type intake valve)
>
> Links...
>
> www.limtechnology.com
> www.zoche.de
>
> Has anybody ever tought of opening the intake valve (one ceneterd
> valve) with (the high) diesel injection pressure?
>
> Perhaps the valve and injector could be integrated. As the pressure is
> released (at the exact right time) to the valve, it opens and lets the
> supercharged compressed air rush in. As the piston rises past the
> exhaust ports, the diesel fuel is injected and as the pressure quickly
> drops (and simultaneously the cylinder pressure rises) the valve
> closes tightly.
>
> Could this be feasible? Unfortunately, I am no engineer. Just a
> tought.
>
> In a two-cycle engine the integrated pump nozzles and intake valves
> could be operated directly from crankshaft with push rods and rocker
> arms. This would still eliminate the camshaft and the high pressure
> injection pump.
>
> This type of engine could prove to reliable and economical...
>
> - diesel fuel acts as a lubricant as well (reliability)
> - low parts count (reliability, low and easy maintenance, light)
> - sturdy diesel parts (reliability, low maintenance)
> - economical on fuel(low consumption, the use of bio-fuels, possibly a
> bi-fuel)
>
> Is this the future engine for aviation (rotor aeroplanes and
> helicopters), automotive, machines, marine etc?
>
> Cars (trains and boats as well) should be full two-mode hybrids with a
> mecanical planetary drivetrain or just the combination of a diesel
> generator, batteries and electric engines (to make things simple and
> economical).
>
> You could (and should) recharge the batteries from AC mains during the
> night, so they are at full charge when you go off to work. They are
> charged with the diesel generator and as you apply the brakes.

[Don Stauffer]

Considering that the famous mfg. of 2-stroke Diesel locomotives has now
gone to 4-stroke because of better economy and lower emissions, this
seems to me like a step backward.

Max Kallio wrote:
> Proposal for a future (helicopter) engine...
>
> 2-stroke diesel
> 2500cc two cylinder 45 degree V (120-150hp)
> air cooled (cowlings)
> common rail direct injection (high pressure)
> supercharged (Whipple fixed displacement max. 25 psi twin-screw)
> piston ported (or with LIM-type intake valve)
>
> Links...
>
> www.limtechnology.com
> www.zoche.de
>
> Has anybody ever tought of opening the intake valve (one ceneterd
> valve) with (the high) diesel injection pressure?
>
> Perhaps the valve and injector could be integrated. As the pressure is
> released (at the exact right time) to the valve, it opens and lets the
> supercharged compressed air rush in. As the piston rises past the
> exhaust ports, the diesel fuel is injected and as the pressure quickly
> drops (and simultaneously the cylinder pressure rises) the valve
> closes tightly.
>
> Could this be feasible? Unfortunately, I am no engineer. Just a
> tought.
>
> In a two-cycle engine the integrated pump nozzles and intake valves
> could be operated directly from crankshaft with push rods and rocker
> arms. This would still eliminate the camshaft and the high pressure
> injection pump.
>
> This type of engine could prove to reliable and economical...
>
> - diesel fuel acts as a lubricant as well (reliability)
> - low parts count (reliability, low and easy maintenance, light)
> - sturdy diesel parts (reliability, low maintenance)
> - economical on fuel(low consumption, the use of bio-fuels, possibly a
> bi-fuel)
>
> Is this the future engine for aviation (rotor aeroplanes and
> helicopters), automotive, machines, marine etc?
>
> Cars (trains and boats as well) should be full two-mode hybrids with a
> mecanical planetary drivetrain or just the combination of a diesel
> generator, batteries and electric engines (to make things simple and
> economical).
>
> You could (and should) recharge the batteries from AC mains during the
> night, so they are at full charge when you go off to work. They are
> charged with the diesel generator and as you apply the brakes.

[Dan]

Diesel aircraft engines for certified and experiimental aircraft are here
now.

http://www.centurion-engines.com/c17/c17_start.htm

There are others also.

[John S.]

That's not a new design.

[Don Stauffer]

Dan wrote:
> Diesel aircraft engines for certified and experiimental aircraft are here
> now.
>
> http://www.centurion-engines.com/c17/c17_start.htm
>
> There are others also.
>
>

To prevent going to much OT in rec.auto.tech, if you wish to discuss
engines other than car engines, there is a Yahoo group called heat
engines, for discussion of any heat engine, IC, steam, or other.

http://groups.yahoo.com/group/heatengines/

You can access it as a web discussion group, or you can receive and post
via email.

We'd be happy to see more folks join, and liven up the discussions.

[Andrew P.]

Wandering aimlessly about the Web, I heard Max Kallio say:

> Proposal for a future (helicopter) engine...
>
> 2-stroke diesel
> 2500cc two cylinder 45 degree V (120-150hp)
> air cooled (cowlings)
> common rail direct injection (high pressure)
> supercharged (Whipple fixed displacement max. 25 psi twin-screw)
> piston ported (or with LIM-type intake valve)
>
> Links...
>
> www.limtechnology.com
> www.zoche.de
>
-- SNIP --

I've been watching Zoche for 6-7 years, and as far as I know, they still
haven't released anything to the market that you can buy. The material
on their web site hasn't been updated in three or four years. Their
aerodiesel designs look good -- excellent power/weight, fuel economy
significantly better than gasoline, use of more widely available jet
fuel or kerosene, projected high reliability and life due to much lower
component count than 4-stroke engines, compressed air starter eliminates
need for large, heavy cranking battery, etc., etc.

Unfortunately, Michael Zoche got wrapped around an axle in typical
German mindset by trying to get JAR-E and FAR-33 certification before
marketing the engines. That's kept them entangled in bureaucratic red
tape for years, particularly in Germany. (The bureaucracy in Germany is
phenomenal. It's little wonder Germans have been relatively
non-innovative in the world market, compared to Japan and the U.S.) It
would have been better to get some of their smaller, lighter engines
into the hands of homebuilders and experimenters on a non-certified,
use-at-your-own-risk basis to gain operational experience, while they
continued to work on JAR and FAA certification. After all, look at the
junk ultralight builders have been strapping to their machines for
years. A Zoche pre-production engine would probably be as good or better.

--
Andrew P.

[Post replies to this message on forum only]

[Sport Pilot]

You have most of it right. Some things you have wrong,

1. Desiel injection timing is differant than on an Otto engine. The
fuel is injected during the intake cycle on the Otto engine and the
fuel is injected during the ignition cycle on the Desiel. On the
Desiel the fuel injection cycle starts just before TDC and ends well
after TDC. The fuel ignites as soon as it hits the hot air.

2. The parts count is not less on a two stroke Desiel, It is higher
because of the need for a supercharger and a way to port the exhaust.

I don't think you would want a four stroke Desiel in an aircraft
because of the increased weight and low power. Desiel engines don't
really produce more torque as a gas engine, its just that the fuel
burns slower and thus the engine cannot rev as fast, but it can produce
the same or slightly more torque at lower speeds, and at much lower
fuel flow rates. Because of this they should be ideal for an aircraft
engine that doesn't need to turn at a higher speed.

You do lose one advantage of the Desiel engine on an aircraft. Because
of the lack of a throttle and the fact that they can burn extreamly
lean at idle, Desiel engines are extremely efficient in stop and go
traffic. But we don't idle aircraft engines that much.

[Andrew P.]

Wandering aimlessly about the Web, I heard Sport Pilot say:
> You have most of it right. Some things you have wrong,
>
> 1. Desiel injection timing is differant than on an Otto engine. The
> fuel is injected during the intake cycle on the Otto engine and the
> fuel is injected during the ignition cycle on the Desiel. On the
> Desiel the fuel injection cycle starts just before TDC and ends well
> after TDC. The fuel ignites as soon as it hits the hot air.
>
etc., etc. --- SNIP ---

It's Diesel, not "Desiel".

--
Andrew P.

[Post replies to this message on forum only]

[wingsnaprop]

Guess why?
*Duh* Pollution laws, and no need for the power to weight
requirements of Aviation! Duh... whats that got to do with this topic?
Other than to show that 2 stroke Compression ignition engines are a
proven concept?

[MJC]

"Andrew P." > wrote in message
ink.net...
> Wandering aimlessly about the Web, I heard Sport Pilot say:
> > You have most of it right. Some things you have wrong,
> >
> > 1. Desiel injection timing is differant than on an Otto engine. The
> > fuel is injected during the intake cycle on the Otto engine and the
> > fuel is injected during the ignition cycle on the Desiel. On the
> > Desiel the fuel injection cycle starts just before TDC and ends well
> > after TDC. The fuel ignites as soon as it hits the hot air.
> >
> etc., etc. --- SNIP ---
>
> It's Diesel, not "Desiel".
>
> --
> Andrew P.

Well if you're going to get picky, it's "Auto" engine, not "Otto" engine.

MJC

[Sport Pilot]

So what I often transpose letters. I don't spend time proofreading
something as trivial as a usenet messsage.

[Sport Pilot]

Sooo. I oftern transpose letters, I don't proofread something as
triavil as usenet messages.

[N8N]

MJC wrote:
> "Andrew P." > wrote in message
> ink.net...
> > Wandering aimlessly about the Web, I heard Sport Pilot say:
> > > You have most of it right. Some things you have wrong,
> > >
> > > 1. Desiel injection timing is differant than on an Otto engine.
The
> > > fuel is injected during the intake cycle on the Otto engine and
the
> > > fuel is injected during the ignition cycle on the Desiel. On the
> > > Desiel the fuel injection cycle starts just before TDC and ends
well
> > > after TDC. The fuel ignites as soon as it hits the hot air.
> > >
> > etc., etc. --- SNIP ---
> >
> > It's Diesel, not "Desiel".
> >
> > --
> > Andrew P.
>
> Well if you're going to get picky, it's "Auto" engine, not "Otto"
engine.
>
> MJC

Actually, it is Otto, as in 4-stroke spark ignition.

nate

[Don Stauffer]

N8N wrote:
> MJC wrote:
>
>>"Andrew P." > wrote in message
ink.net...
>>
>>>Wandering aimlessly about the Web, I heard Sport Pilot say:
>>>
>>>>You have most of it right. Some things you have wrong,
>>>>
>>>>1. Desiel injection timing is differant than on an Otto engine.
>
> The
>
>>>>fuel is injected during the intake cycle on the Otto engine and
>
> the
>
>>>>fuel is injected during the ignition cycle on the Desiel. On the
>>>>Desiel the fuel injection cycle starts just before TDC and ends
>
> well
>
>>>>after TDC. The fuel ignites as soon as it hits the hot air.
>>>>
>>>
>>>etc., etc. --- SNIP ---
>>>
>>>It's Diesel, not "Desiel".
>>>
>>>--
>>>Andrew P.
>>
>>Well if you're going to get picky, it's "Auto" engine, not "Otto"
>
> engine.
>
>>MJC
>
>
> Actually, it is Otto, as in 4-stroke spark ignition.
>
> nate
>
A 4-stroke diesel is still an Otto engine. An Otto cycle engine is one
with four strokes, intake, compression, power, and exhaust. Doesn't
care whether SI or CI.

[Don Stauffer]

Don Stauffer wrote:
>>
> A 4-stroke diesel is still an Otto engine. An Otto cycle engine is one
> with four strokes, intake, compression, power, and exhaust. Doesn't
> care whether SI or CI.

Whoops

Before everyone jumps on me, I left off an important qualification. I
was specifically talking about cars, airplanes and highway trucks.
Large Diesels, (stationary, large ship, etc) do run a different cycle-
the true Diesel cycle.

However, even the true Diesel cycle of larger engines is not the true
cycle Diesel really wanted. He couldn't develop the true cycle he
wanted (constant enthalpy), and a large Diesel comes somewhat close. A
high speed (vehicle) engine doesn't even come close with even today's
technology. It is pretty close to an Otto cycle, though still not
exactly. Otto cycle has infinitesmal fraction of cycle for ignition and
burn, while even a high speed Diesel (and even the SI engine) still
ignites and burns over a finite angle of crank rotation. Still, the
result, as I say is MUCH closer to Otto than the cycle Rudy had
intended. Still makes a good engine, however :-)

[Don Stauffer]

Bryan Martin wrote:
> Not so. In the Otto cycle, the fuel and air are introduced to the cylinder
> during the intake stroke. In the Diesel cycle only the air is introduce to
> the cylinder during the intake stroke, the fuel in injected at the end of
> the compression stroke.
>
> in article , Don Stauffer at
> wrote on 5/13/05 10:47 AM:
>
>
>>A 4-stroke diesel is still an Otto engine. An Otto cycle engine is one
>>with four strokes, intake, compression, power, and exhaust. Doesn't
>>care whether SI or CI.
>
>
>
>
In terms of the thermodynamics the fuel is immaterial. It is only a
source of heat for raising temp and pressure. The AIR is the true
Carnot working fluid with either a CI or SI engine. In an indicator
diagram of the SI engine, one would be hard pressed to see the
difference even if fuel were shut off during the induction stroke.

The reason a Diesel is not a true (though close) Otto cycle is that in
the true Otto cycle the burning is instantaneous (or at least an
infinitesmal number of degrees of crank rotation or percentage piston
motion.

[Steve]

wingsnaprop wrote:

> Guess why?
> *Duh* Pollution laws, and no need for the power to weight
> requirements of Aviation! Duh... whats that got to do with this topic?
> Other than to show that 2 stroke Compression ignition engines are a
> proven concept?
>

As already stated, 2-stroke diesels really don't have a power-to-weight
advantage over 4-strokes. They still have to have a camshaft and
exhaust valves (they aren't like weed whacker engines, you know), so
they don't save that weight. Plus they have to have a blower for
scavenge air. The only area where they save weight is in that the
connecting rod and crank can be lighter, and that only helps offset the
added weight of the blower.

[Steve]

MJC wrote:

>>
>>It's Diesel, not "Desiel".
>>
>>--
>>Andrew P.
>
>
> Well if you're going to get picky, it's "Auto" engine, not "Otto" engine.
>

No, the spark-ignition cycle is the Otto cycle. Yes, most Auto engines
are Otto engines, but don't let that confuse you.

[Steve]

>> Actually, it is Otto, as in 4-stroke spark ignition.
>>
>> nate
>>
> A 4-stroke diesel is still an Otto engine. An Otto cycle engine is one
> with four strokes, intake, compression, power, and exhaust. Doesn't
> care whether SI or CI.

No, it really isn't, at least not in common usage. If you want to be
ridiculously pedantic, then the "Diesel cycle" is an Otto cycle with
constant-pressure combustion under varying cylinder volume, whereas what
is commonly just called the "Otto Cycle" is a spark-ignited Otto cycle
with constant-volume combustion under varying cylinder pressure.

Neither cycle attains that ideal, so there's some overlap, but if you
look at real-world pressure-volume diagrams for Diesel and
spark-ignition engines, the difference is obvious.

[Steve]

Don Stauffer wrote:

> Don Stauffer wrote:
>
>>>
>> A 4-stroke diesel is still an Otto engine. An Otto cycle engine is
>> one with four strokes, intake, compression, power, and exhaust.
>> Doesn't care whether SI or CI.
>
>
> Whoops
>
> Before everyone jumps on me, I left off an important qualification. I
> was specifically talking about cars, airplanes and highway trucks. Large
> Diesels, (stationary, large ship, etc) do run a different cycle- the
> true Diesel cycle.
>
> However, even the true Diesel cycle of larger engines is not the true
> cycle Diesel really wanted. He couldn't develop the true cycle he
> wanted (constant enthalpy), and a large Diesel comes somewhat close. A
> high speed (vehicle) engine doesn't even come close with even today's
> technology. It is pretty close to an Otto cycle, though still not
> exactly. Otto cycle has infinitesmal fraction of cycle for ignition and
> burn, while even a high speed Diesel (and even the SI engine) still
> ignites and burns over a finite angle of crank rotation. Still, the
> result, as I say is MUCH closer to Otto than the cycle Rudy had
> intended. Still makes a good engine, however :-)

I pretty much agree, although today's high-speed diesels are doing a lot
better at approchin the constant-enthalpy cycle than they used to,
thanks to being able to divorce the injection profile from crankshaft
position via electronically-controlled injection systems.

"Steve" > wrote in message
...

> I pretty much agree, although today's high-speed diesels are doing a lot
> better at approchin the constant-enthalpy cycle than they used to,
> thanks to being able to divorce the injection profile from crankshaft
> position via electronically-controlled injection systems.

Now that you mentioned it, what sort of rpm ranges are the high speed
diesels capable of?

You may remember that some years ago (just after the Arabs shut off the oil)
AVCO showed
a rather smallish (V8?) diesel that you could swap into just about any
American car of the time.
Cost was about $5000, estimated.

They claimed some rather high RPM capabilities for this engine.

[Sport Pilot]

Don Stauffer wrote:
> Bryan Martin wrote:
> > Not so. In the Otto cycle, the fuel and air are introduced to the
cylinder
> > during the intake stroke. In the Diesel cycle only the air is
introduce to
> > the cylinder during the intake stroke, the fuel in injected at the
end of
> > the compression stroke.
> >
> > in article , Don Stauffer at
> > wrote on 5/13/05 10:47 AM:
> >
> >
> >>A 4-stroke diesel is still an Otto engine. An Otto cycle engine is
one
> >>with four strokes, intake, compression, power, and exhaust.
Doesn't
> >>care whether SI or CI.
> >
> >
> >
> >
> In terms of the thermodynamics the fuel is immaterial. It is only a
> source of heat for raising temp and pressure. The AIR is the true
> Carnot working fluid with either a CI or SI engine. In an indicator
> diagram of the SI engine, one would be hard pressed to see the
> difference even if fuel were shut off during the induction stroke.
>
> The reason a Diesel is not a true (though close) Otto cycle is that
in
> the true Otto cycle the burning is instantaneous (or at least an
> infinitesmal number of degrees of crank rotation or percentage piston

> motion.

The Diesel is not an Otto cycle it is a completly differant cycle. The
Diesel is a constant pressure cycle where the presure is constant
through the expansion phase.

[Sport Pilot]

karel wrote:
> "Sport Pilot" > wrote in message
> oups.com...
> > Sooo. I oftern transpose letters, I don't proofread something as
> > triavil as usenet messages.
>
> If you consider your messages trivial, why post them?
> Anyway, I won't see them anymore. Ploink!

Only a fool assumes that someone who has trouble spelling or
pronuciation.

[Sport Pilot]

Don Stauffer wrote:
> Don Stauffer wrote:
> >>
> > A 4-stroke diesel is still an Otto engine. An Otto cycle engine is
one
> > with four strokes, intake, compression, power, and exhaust.
Doesn't
> > care whether SI or CI.
>
> Whoops
>
> Before everyone jumps on me, I left off an important qualification.
I
> was specifically talking about cars, airplanes and highway trucks.
> Large Diesels, (stationary, large ship, etc) do run a different
cycle-
> the true Diesel cycle.
>
> However, even the true Diesel cycle of larger engines is not the true

> cycle Diesel really wanted. He couldn't develop the true cycle he
> wanted (constant enthalpy), and a large Diesel comes somewhat close.
A
> high speed (vehicle) engine doesn't even come close with even today's

> technology. It is pretty close to an Otto cycle, though still not
> exactly. Otto cycle has infinitesmal fraction of cycle for ignition
and
> burn, while even a high speed Diesel (and even the SI engine) still
> ignites and burns over a finite angle of crank rotation. Still, the
> result, as I say is MUCH closer to Otto than the cycle Rudy had
> intended. Still makes a good engine, however :-)


You can only get so much speed when you inject the fuel through the
combustion or expansion cycle. High speed diesels get more speed by
injecting more of the fuel early. But an aircraft engine doesn't need
to turn more than 2500 RPM so we should be able to get the benifit of
the longer burn time.

[Richard Isakson]

"Sport Pilot" wrote ...
>
> Only a fool assumes that someone who has trouble spelling or
> pronuciation.
>

Isn't able to complete a sentence either?

Rich

[Sport Pilot]

Got cut off some how.

Actually I thought I had decided not to send it, and came back and some
how hit the enter key.

[Steve]

Sport Pilot wrote:
> karel wrote:
>
>>"Sport Pilot" > wrote in message
oups.com...
>>
>>>Sooo. I oftern transpose letters, I don't proofread something as
>>>triavil as usenet messages.
>>
>>If you consider your messages trivial, why post them?
>>Anyway, I won't see them anymore. Ploink!
>
>
> Only a fool assumes that someone who has trouble spelling or
> pronuciation.


......... what? I'm waiting for the rest. And its "pronuNciation."

Its one thing to have the occasional typo, but typing a constant run-on
of misspelled and non-punctuated text just screams "I'm a moron!" to the
world.

[Steve]

wrote:

> "Steve" > wrote in message
> ...
>
>
>>I pretty much agree, although today's high-speed diesels are doing a lot
>>better at approchin the constant-enthalpy cycle than they used to,
>>thanks to being able to divorce the injection profile from crankshaft
>>position via electronically-controlled injection systems.
>
>
> Now that you mentioned it, what sort of rpm ranges are the high speed
> diesels capable of?

Well, a "high speed" diesel in the usual sense is anything that turns
more than 1500-2000 RPM. So 18-wheeler diesels (Cummins N-14, DD Series
60, etc) are considered "high speed diesels" and locomotive engines are
'medium speed." Low-speed diesels are those direct-drive 3-story tall
ship engines that turn 120 RPM max and put out 25,000 horsepower.

But there are more and more small diesels that run just as fast as
gasoline engines. There's no fundamental limit thats any different than
a gasoline engine, really, but up until now there's not been a demand
for high-RPM diesels.

[Morgans]

"Steve" > wrote

> As already stated, 2-stroke diesels really don't have a power-to-weight
> advantage over 4-strokes. They still have to have a camshaft and
> exhaust valves (they aren't like weed whacker engines, you know), so
> they don't save that weight. Plus they have to have a blower for
> scavenge air. The only area where they save weight is in that the
> connecting rod and crank can be lighter, and that only helps offset the
> added weight of the blower.

How about the fact that they have power pulses in each revolution? They
could possibly have half the displacement, and still get the same power, (or
close to it) with less weight than the double displacement 4 cycle. Yes,
the blower weight is added, but it is nice to make good power, way up there.
--
Jim in NC

[Morgans]

"Sport Pilot" > wrote in message
oups.com...
> So what I often transpose letters. I don't spend time proofreading
> something as trivial as a usenet messsage.
>
Yur lak of ettension tu detale makes ti seam lik yu dounut giv a dam. Ti si
knot heard too tack a secant adn pruff reed a poust.
--
Jim in NC

[Richard Isakson]

"Sport Pilot" wrote ...
> Got cut off some how.
>
> Actually I thought I had decided not to send it, and came back and some
> how hit the enter key.
>

A long time ago I was working for small airline and I was asked to evaluate
any letters from the pilots that were sent to flight ops. I was acting as
filter for the Director of Flight Ops. Now, as a class, pilots aren't too
bright and none of them can spell but when I hit the fourth misspellled word
I'd throw the thing in the trash can. "This guy can't know what he's
talking about." It was done at a subconscious level. It takes me a while
to figure things out but I shared their contempt for spelling in my own
writing. It finally dawned on me that if I look down at bad speellers then
other people must look down my work. It's human nature and you can"t fight
it. If you want your work to be accepted then you have to project an image
of intellect.

Rich

[Frank van der Hulst]

Steve wrote:
> Sport Pilot wrote:
>>>> Sooo. I oftern transpose letters, I don't proofread something as
>>>> triavil as usenet messages.

> Its one thing to have the occasional typo, but typing a constant run-on
> of misspelled and non-punctuated text just screams "I'm a moron!" to the
> world.

Actually, what it screams is "I am dyslexic".

The ignorant often confuse dyslexia with (e.g.) being a moron.

However, failure to proofread, perhaps especially if dyslexic, does
indicate that he doesn't expect us to value what he's writing, which in
turn suggests that he doesn't think its worth much either. In a world
full of ignorance, a wise dyslexic would use a spelling and/or grammar
checker on anything he wanted taken seriously.

Frank

[Luke Scharf]

Steve wrote:
> But there are more and more small diesels that run just as fast as
> gasoline engines. There's no fundamental limit thats any different than
> a gasoline engine, really, but up until now there's not been a demand
> for high-RPM diesels.

When I was reading about the Volkswagen TDI engine, I vaguely remember
coming across someone who said that the redline of that engine was set
by the speed which which the burning fuel expanded.

Sounds rather fundamental to me - but, then again, I'm a computer guy.

-Luke

[LCT Paintball]

> writing. It finally dawned on me that if I look down at bad speellers
> then


Please tell me you did that on purpose.

[Richard Isakson]

"LCT Paintball" wrote ...
> > writing. It finally dawned on me that if I look down at bad speellers
> > then
>
>
> Please tell me you did that on purpose.
>
>

Usenet Rule #5: "All posts complaining about spelling must themselves
contain at least one misspeeling".

Rich

[LCT Paintball]

> Usenet Rule #5: "All posts complaining about spelling must themselves
> contain at least one misspeeling".
>
> Rich
>

Sorry, I missed that memo.
For the record, I disagree with you. I cannot spell, but I'm no idiot. Some
people are good at math, others are athletic, and others can spell. Just
because it's easy for you doesn't mean it is for others.

[[email protected]]

On Fri, 13 May 2005 08:52:00 -0500, "MJC" > wrote:

>
>"Andrew P." > wrote in message
ink.net...
>> Wandering aimlessly about the Web, I heard Sport Pilot say:
>> > You have most of it right. Some things you have wrong,
>> >
>> > 1. Desiel injection timing is differant than on an Otto engine. The
>> > fuel is injected during the intake cycle on the Otto engine and the
>> > fuel is injected during the ignition cycle on the Desiel. On the
>> > Desiel the fuel injection cycle starts just before TDC and ends well
>> > after TDC. The fuel ignites as soon as it hits the hot air.
>> >
>> etc., etc. --- SNIP ---
>>
>> It's Diesel, not "Desiel".
>>
>> --
>> Andrew P.
>
>Well if you're going to get picky, it's "Auto" engine, not "Otto" engine.
>
>MJC
>
No, it is OTTO, named after the guy who invented the "otto cycle"
engine - just like Diesel is named after the guy who invented the
compression ignition or "diesel cycle" engine.

[Rich S.]

"LCT Paintball" > wrote in message
news:M2dhe.77611$NU4.15647@attbi_s22...
>> Usenet Rule #5: "All posts complaining about spelling must themselves
>> contain at least one misspeeling".
>>
>> Rich
>>
>
> Sorry, I missed that memo.
> For the record, I disagree with you. I cannot spell, but I'm no idiot.
> Some people are good at math, others are athletic, and others can spell.
> Just because it's easy for you doesn't mean it is for others.

Easy is not a factor. All things worth doing require effort. What is
"cannot"?

Rich S.

[Morgans]

"LCT Paintball" > wrote

> For the record, I disagree with you. I cannot spell, but I'm no idiot.
Some
> people are good at math, others are athletic, and others can spell. Just
> because it's easy for you doesn't mean it is for others.
>
True, but _everyone_ can take the time to re-read their post, and everyone
can learn basic rules, like their-there, to-too-two. By not doing that,
people that can't spell _do_ look like morons.

They should run spell check if'in they know they have a speeling problem,
also.
--
Jim in NC

[LCT Paintball]

> Easy is not a factor. All things worth doing require effort. What is
> "cannot"?
>
> Rich S.

Very good argument.

[ower]

"MJC" > skrev i meddelandet
...
>
Snip
> > >
> > > 1. Desiel injection timing is differant than on an Otto engine. The
> > > fuel is injected during the intake cycle on the Otto engine and the
> > > fuel is injected during the ignition cycle on the Desiel. On the
> > > Desiel the fuel injection cycle starts just before TDC and ends well
> > > after TDC. The fuel ignites as soon as it hits the hot air.
> > >
> > etc., etc. --- SNIP ---
> >
> > It's Diesel, not "Desiel".
> >
> > --
> > Andrew P.
>
> Well if you're going to get picky, it's "Auto" engine, not "Otto" engine.
>
> MJC
>
It is NOT auto engine it IS Otto engine, dont belive?
Google for Otto engine and see for yourself.
And pardon me for bad spelling I am not fluent in
your language.

[ower]

"Morgans" > skrev i meddelandet
...
>
> True, but _everyone_ can take the time to re-read their post, and everyone
> can learn basic rules, like their-there, to-too-two. By not doing that,
> people that can't spell _do_ look like morons.
>
> They should run spell check if'in they know they have a speeling problem,
> also.
> --
> Jim in NC
>
So I am a moron if my spelling isnt correct? Bet I know more about your
language
(english) than you know of mine (swedish), and I will not call you any bad
names
if you are not correct when trying to use mine.

With bad or good spelling. Have a nice day Owe R

[Morgans]

"ower" > wrote

Bet I know more about your
> language
> (english) than you know of mine (swedish),

Well, I have to give you a break, considering you are a non English speaker.
I (and others) should have caught that fact.

Do as well as you can, and re-read your posts, and all is forgiven. <g>
--
Jim in NC

[Don Stauffer]

Steve wrote:
>
> I pretty much agree, although today's high-speed diesels are doing a lot
> better at approchin the constant-enthalpy cycle than they used to,
> thanks to being able to divorce the injection profile from crankshaft
> position via electronically-controlled injection systems.
>
>

Before I retired there was a group at work doing applications research
on micromachining. One of the things they were looking at was fuel
injector controls (one for each injector). They would have had a VERY
high frequency response. We knew others were working on this (Ohio
State was one, I believe). I have heard of nothing on this since I
retired in '00, and have lost contact with the group that was doing it.
Anyone aware of current work on this? At the time it was aimed at SI
engines, but I don't see anything that would prevent it being used on
Diesels.

[Don Stauffer]

Sport Pilot wrote:
>
> The Diesel is not an Otto cycle it is a completly differant cycle. The
> Diesel is a constant pressure cycle where the presure is constant
> through the expansion phase.
>

I wouldn't say the ENTIRE expansion phase. That would not be that great
for efficiency- sort of like a steam engine running with no cutoff. And
if one injects fuel into the cylinder at the instant just before BDC,
that fuel would be pretty much wasted. I was under the impression that
the cycle would look something like the steam (Rankine) cycle in that
the way Diesel envisoned it it would be either constant enthalpy or
constant pressure of part of the expansion phase, adiabatic during the
rest. The point where it changed would correspond to what would be the
throttle opening on a steam or SI engine. At full "throttle" the
changeover would be late in stroke, light load early in stroke.

[Don Stauffer]

Sport Pilot wrote:
>
> You can only get so much speed when you inject the fuel through the
> combustion or expansion cycle. High speed diesels get more speed by
> injecting more of the fuel early. But an aircraft engine doesn't need
> to turn more than 2500 RPM so we should be able to get the benifit of
> the longer burn time.
>

True, but even 2500 rpm is a high speed Diesel. When we speak of low
speed Diesels, those are like the big ship and stationary engines that
run maybe 800 rpm max.

[Rich S.]

"LCT Paintball" > wrote in message
news:BIehe.79335$WI3.31550@attbi_s71...
>> Easy is not a factor. All things worth doing require effort. What is
>> "cannot"?
>>
>> Rich S.
>
> Very good argument.


Thanks. Age is a mitigating factor, though. I will no longer play poker for
real money. :-=

Rich S.

[Sport Pilot]

LCT Paintball wrote:
> > Easy is not a factor. All things worth doing require effort. What
is
> > "cannot"?
> >
> > Rich S.
>
> Very good argument.


Only thing is that many things don't have to be perfect.

[Sport Pilot]

Morgans wrote:
> "LCT Paintball" > wrote
>
> > For the record, I disagree with you. I cannot spell, but I'm no
idiot.
> Some
> > people are good at math, others are athletic, and others can spell.
Just
> > because it's easy for you doesn't mean it is for others.
> >
> True, but _everyone_ can take the time to re-read their post, and
everyone
> can learn basic rules, like their-there, to-too-two. By not doing
that,
> people that can't spell _do_ look like morons.
>
> They should run spell check if'in they know they have a speeling
problem,
> also.
> --
> Jim in NC


HELLO! It's just the friggin usenet! Most of us don't even know who
we are talking too. Some of us have more important things to do, such
as correspondance on a 10 million dollor project. You bet that baby
gets proofread, spell checked, grammer checked, proofread, maybe ask a
co worker to proofread it, see what I missed, etc.

[Rich S.]

"Sport Pilot" > wrote in message
oups.com...
>
> HELLO! It's just the friggin usenet! Most of us don't even know who
> we are talking too. Some of us have more important things to do, such
> as correspondance on a 10 million dollor project. You bet that baby
> gets proofread, spell checked, grammer checked, proofread, maybe ask a
> co worker to proofread it, see what I missed, etc.

You want fry's with dat?

Rich S.

[Sport Pilot]

Don Stauffer wrote:
> Sport Pilot wrote:
> >
> > The Diesel is not an Otto cycle it is a completly differant cycle.
The
> > Diesel is a constant pressure cycle where the presure is constant
> > through the expansion phase.
> >
>
> I wouldn't say the ENTIRE expansion phase. That would not be that
great
> for efficiency- sort of like a steam engine running with no cutoff.
And
> if one injects fuel into the cylinder at the instant just before BDC,

> that fuel would be pretty much wasted. I was under the impression
that
> the cycle would look something like the steam (Rankine) cycle in that

> the way Diesel envisoned it it would be either constant enthalpy or
> constant pressure of part of the expansion phase, adiabatic during
the
> rest. The point where it changed would correspond to what would be
the
> throttle opening on a steam or SI engine. At full "throttle" the
> changeover would be late in stroke, light load early in stroke.

Where did I say the entire expansion phase? Where did I say there was
a perfect Diesel cycle?

[Sport Pilot]

Morgans wrote:
> "Sport Pilot" > wrote in message
> oups.com...
> > So what I often transpose letters. I don't spend time proofreading
> > something as trivial as a usenet messsage.
> >
> Yur lak of ettension tu detale makes ti seam lik yu dounut giv a dam.
Ti si
> knot heard too tack a secant adn pruff reed a poust.
> --
> Jim in NC

As long as I get 90% or so right, I really don't give a damn.

[Sport Pilot]

karel wrote:
> "ower" > wrote in message
> ...
> >
> > "Morgans" > skrev i meddelandet
> > ...
> >>
> >> True, but _everyone_ can take the time to re-read their post, and
> >> everyone
> >> can learn basic rules, like their-there, to-too-two. By not doing
that,
> >> people that can't spell _do_ look like morons.
> >>
> >> They should run spell check if'in they know they have a speeling
problem,
> >> also.
> >> --
> >> Jim in NC
> >>
> > So I am a moron if my spelling isnt correct?
>
> I am afraid you did not take the full meaning of the msg.
> It was not said that people who can't spell errorfree are morons.
> Really not!
> What was said is that people who have difficulties with spelling
> (one such difficulty may be dyslexia) will _look like_ morons
> if they don't take the trouble to correct for their weakness.
>
> There's no blame in committing errors, who errs never?
> But we should be humble about them
> and hence try to avoid them
> In this case, by proofreading our msgs
> and correcting the errors we detect.
>
> Karel (closer to SE than to US)


Sooo, why did you get so upset a few posts back there? Like my
misspelling of diesel was sooo important?

[Sport Pilot]

wrote:
> On Fri, 13 May 2005 08:52:00 -0500, "MJC" > wrote:
>
> >
> >"Andrew P." > wrote in message
> ink.net...
> >> Wandering aimlessly about the Web, I heard Sport Pilot say:
> >> > You have most of it right. Some things you have wrong,
> >> >
> >> > 1. Desiel injection timing is differant than on an Otto engine.
The
> >> > fuel is injected during the intake cycle on the Otto engine and
the
> >> > fuel is injected during the ignition cycle on the Desiel. On
the
> >> > Desiel the fuel injection cycle starts just before TDC and ends
well
> >> > after TDC. The fuel ignites as soon as it hits the hot air.
> >> >
> >> etc., etc. --- SNIP ---
> >>
> >> It's Diesel, not "Desiel".
> >>
> >> --
> >> Andrew P.
> >
> >Well if you're going to get picky, it's "Auto" engine, not "Otto"
engine.
> >
> >MJC
> >
> No, it is OTTO, named after the guy who invented the "otto cycle"
> engine - just like Diesel is named after the guy who invented the
> compression ignition or "diesel cycle" engine.

A compression ignition engine is not always a Diesel engine. Not sure
if Mr. Diesel invented comprssion ignition, but they used to be common
for model aircraft. Though called Diesel's modelers are often reminded
they are not really Diesel's.

[Morgans]

"Sport Pilot" > wrote

> Some of us have more important things to do, such
> as correspondance on a 10 million dollor project.

Your attitude makes me wonder why you are in "only usenet." Nice of you to
come and play with us mortals.

Good luck. You will need it, an it won't be from me. Plonk
--
Jim in NC

[Smitty]

In article . com>,
"Sport Pilot" > wrote:

> HELLO! It's just the friggin usenet! Most of us don't even know who
> we are talking too. Some of us have more important things to do, such
> as correspondance on a 10 million dollor project. You bet that baby
> gets proofread, spell checked, grammer checked, proofread, maybe ask a
> co worker to proofread it, see what I missed, etc.

Hello? You mean "to," (a preposition and therefore a word with which you
ought not end a sentence, anyway) "correspondence," "dollar," and
"grammar?" I'm not picking on you, particularly, but the pervasive
ignorance of spelling, grammar, punctuation, homonyms, sentence
construction, ad infinitum, makes me ****ing sick. And it isn't just
usenet, it's everywhere, even in your ten million dollar report, because
your computer can't fix everything and your coworkers are as apathetic
as you are. We're becoming a nation of ignorant idiots. I think that's a
bad thing, and a dangerous one. If we knew as little about airplanes as
we did the English language, and flew them as carelessly as we write,
we'd all be dead by now.

[ower]

"Morgans" > skrev i meddelandet
...
> Good luck. You will need it, an it won't be from me. Plonk
>
About spellig, an it won't. An? And?
Have a nice day Owe from SE

[wingsnaprop]

> Actually, it is Otto, as in 4-stroke spark ignition.

Dude, MJC was Joking

[wingsnaprop]

Yea me two! 90% spelling accuracy on Usenet is what should be
acepted without comment! My opinion.

[Don Stauffer]

Sport Pilot wrote:
>
>
> A compression ignition engine is not always a Diesel engine. Not sure
> if Mr. Diesel invented comprssion ignition, but they used to be common
> for model aircraft. Though called Diesel's modelers are often reminded
> they are not really Diesel's.
>

Good point. I think Rudy did indeed invent compression ignition. And
the old Ford Proco engine designs were virtually Diesel cycle engines
even though they had spark ignition. In fact, that idea seemed like a
really good one to me, and I would like to know why it never went
anywhere. Was the injection system just to complicated for production?

[Sport Pilot]

Smitty wrote:
> In article . com>,
> "Sport Pilot" > wrote:
>
> > HELLO! It's just the friggin usenet! Most of us don't even know
who
> > we are talking too. Some of us have more important things to do,
such
> > as correspondance on a 10 million dollor project. You bet that
baby
> > gets proofread, spell checked, grammer checked, proofread, maybe
ask a
> > co worker to proofread it, see what I missed, etc.
>
> Hello? You mean "to," (a preposition and therefore a word with which
you
> ought not end a sentence, anyway) "correspondence," "dollar," and
> "grammar?" I'm not picking on you, particularly, but the pervasive
> ignorance of spelling, grammar, punctuation, homonyms, sentence
> construction, ad infinitum, makes me ****ing sick. And it isn't just
> usenet, it's everywhere, even in your ten million dollar report,
because
> your computer can't fix everything and your coworkers are as
apathetic
> as you are. We're becoming a nation of ignorant idiots. I think
that's a
> bad thing, and a dangerous one. If we knew as little about airplanes
as
> we did the English language, and flew them as carelessly as we write,

> we'd all be dead by now.


Ass I said I really don't care. In fact your anger only make sme want
to make mroe miostakes. So i have not coreected any typos at all in
this one.

[Sport Pilot]

>There's no fundamental limit thats any different than
>a gasoline engine, really, but up until now there's not been a demand
>for high-RPM diesels.

Thought I had responded to this before, but cannot find it.

There IS a fundamental reason diesels do not turn as many revolutions
as a gas engine. Injecting the fuel throught most of the expansion
cycle prevents speed, but does give a constant push. You could shorten
the injection so that the end of the injection is closer to TDC, but
then it would be more of an otto cycle. If you put too much fuel at or
near TDC then you would have the same problem as an otto engine with
high compression and low octane fuel. Diesel fuel is not high octane.

[Thomas Tornblom]

Luke Scharf > writes:

> Steve wrote:
> > But there are more and more small diesels that run just as fast as
> > gasoline engines. There's no fundamental limit thats any different
> > than a gasoline engine, really, but up until now there's not been a
> > demand for high-RPM diesels.
>
>
> When I was reading about the Volkswagen TDI engine, I vaguely remember
> coming across someone who said that the redline of that engine was set
> by the speed which which the burning fuel expanded.

My '01 180 bhp Audi 2.5 tdi V6 has a redline of 4500 rpm.

>
>
> Sounds rather fundamental to me - but, then again, I'm a computer guy.
>
> -Luke

Thomas

[Thomas Tornblom]

Don Stauffer > writes:

> Sport Pilot wrote:
> > You can only get so much speed when you inject the fuel through the
>
> > combustion or expansion cycle. High speed diesels get more speed by
> > injecting more of the fuel early. But an aircraft engine doesn't need
> > to turn more than 2500 RPM so we should be able to get the benifit of
> > the longer burn time.
> >
>
>
> True, but even 2500 rpm is a high speed Diesel. When we speak of low
> speed Diesels, those are like the big ship and stationary engines that
> run maybe 800 rpm max.
>

I once had the opportunity to visit the engine room of one of the big
ferries cruising between Sweden and Finland. It had four engines and
two props.

The idle speed was 100 rpm and full speed was 150 rpm.

I could not hear any difference between 100 and 150 rpms. But then I
never knew what noise came from the propulsion engines. There were a
lot of other helper engines making a lot of noise.

The props were geared 2:1, so they did 75 rpms at full speed.

Thomas

[Luke Scharf]

Thomas Tornblom wrote:
> Luke Scharf > writes:
>
>
>>Steve wrote:
>>
>>>But there are more and more small diesels that run just as fast as
>>>gasoline engines. There's no fundamental limit thats any different
>>>than a gasoline engine, really, but up until now there's not been a
>>>demand for high-RPM diesels.
>>
>>
>>When I was reading about the Volkswagen TDI engine, I vaguely remember
>>coming across someone who said that the redline of that engine was set
>>by the speed which which the burning fuel expanded.
>
>
> My '01 180 bhp Audi 2.5 tdi V6 has a redline of 4500 rpm.

That's about where the one on the Jetta was -- right around 4500 rpm.
The displacement on the Jetta is only 1.6 liters, though... I wonder
what dimensions are similar to make the smaller engine redline at the
same speed?

When I got to the redline, the engine seemed to politely refuse to go
any faster. Not like the screaming tantrum I'm used to from my
run-of-the-mill gas engines as I open the throttle.

I dig diesels. :-)

-Luke

[Steve]

Morgans wrote:

> "Steve" > wrote
>
>
>>As already stated, 2-stroke diesels really don't have a power-to-weight
>>advantage over 4-strokes. They still have to have a camshaft and
>>exhaust valves (they aren't like weed whacker engines, you know), so
>>they don't save that weight. Plus they have to have a blower for
>>scavenge air. The only area where they save weight is in that the
>>connecting rod and crank can be lighter, and that only helps offset the
>>added weight of the blower.
>
>
> How about the fact that they have power pulses in each revolution? They
> could possibly have half the displacement, and still get the same power, (or
> close to it) with less weight than the double displacement 4 cycle. Yes,
> the blower weight is added, but it is nice to make good power, way up there.


The blower also takes away a significant chunk of crankshaft power. The
blower has to do the same net work as those "non power" strokes in a
4-cycle diesel because its doing the same job- expelling burnt mixture
and bringing in fresh air. You can't get something for nothing.

This is all old-hat. 2-stroke diesels have been in widespread use since
Winton developed the basic foundation for what became both the EMD and
Detroit Diesel 2-stroke engine architecture back in the 1920s. 2-strokes
became very simple to service and reliable, but they rarely won on
either fuel efficiency or total power output per unit weight. That's why
you find 2-strokes in locomotives and ships where weight doesn't matter
(or is a benefit), but they all but disappeared from on-road
applications by the end of the 1970s and DID completely disappear by the
turn of the century.

[Steve]

Luke Scharf wrote:

> Steve wrote:
>
>> But there are more and more small diesels that run just as fast as
>> gasoline engines. There's no fundamental limit thats any different
>> than a gasoline engine, really, but up until now there's not been a
>> demand for high-RPM diesels.
>
>
> When I was reading about the Volkswagen TDI engine, I vaguely remember
> coming across someone who said that the redline of that engine was set
> by the speed which which the burning fuel expanded.
>
> Sounds rather fundamental to me - but, then again, I'm a computer guy.
>
> -Luke

In almost ALL real-world engines, the actual limit is set by the point
at which some mechanical component would fail. The engine's torque *may*
drop off well before the mechanical failure point if it can't ingest
enough fuel or air at high speed. In the case of a diesel, you can
pretty much increase the burn rate to as high as the mechanical parts
can tolerate by increasing turbocharger boost (and injection rate to
match). Since detonation isn't possible (no fuel exists in the cylinder
until combustion is supposed to begin anyway) the only limits to boost
pressure are mechanical in nature. In practical terms, no one really
wants or needs a 9000 RPM diesel, though.

[Steve]

Don Stauffer wrote:

>
> I wouldn't say the ENTIRE expansion phase. That would not be that great
> for efficiency- sort of like a steam engine running with no cutoff. And
> if one injects fuel into the cylinder at the instant just before BDC,
> that fuel would be pretty much wasted. I was under the impression that
> the cycle would look something like the steam (Rankine) cycle in that
> the way Diesel envisoned it it would be either constant enthalpy or
> constant pressure of part of the expansion phase, adiabatic during the
> rest. The point where it changed would correspond to what would be the
> throttle opening on a steam or SI engine. At full "throttle" the
> changeover would be late in stroke, light load early in stroke.

True, although diesel engine manufacturers of late have discovered that
they can do things like reduce the injection flow rate instead of just
reducing injection duration. That has the nice side-effect of REALLY
quieting diesel "rattle" at light throttle openings, as most clearly
evidenced by the current Cummins diesel in the Dodge Ram. The flow
rate/duration combination can be played with to do really neat things to
the torque curve also. The stumbling block that prevented this for many,
many years was the camshaft-driven fuel injection pump, and its limited
ability to vary injection timing and volume. Once the move was made to
computer control and use of electronically controlled engine
oil-pressure activated unit injectors, a lot of possibilities opened up.

[Steve]

Sport Pilot wrote:

>
> As long as I get 90% or so right, I really don't give a damn.
>

Good luck on getting your next landing "90% right."

:P

[Sport Pilot]

Steve wrote:
> wingsnaprop wrote:
>
> > Guess why?
> > *Duh* Pollution laws, and no need for the power to weight
> > requirements of Aviation! Duh... whats that got to do with this
topic?
> > Other than to show that 2 stroke Compression ignition engines are a
> > proven concept?
> >
>
> As already stated, 2-stroke diesels really don't have a
power-to-weight
> advantage over 4-strokes. They still have to have a camshaft and
> exhaust valves (they aren't like weed whacker engines, you know), so
> they don't save that weight. Plus they have to have a blower for
> scavenge air. The only area where they save weight is in that the
> connecting rod and crank can be lighter, and that only helps offset
the
> added weight of the blower.


I said something similar, but I don't know that a desiel has to have
the valve, as the old locomotive two strokes. Could it not be ported,
as the two stroke spark engines? The fuel is already oily so if the
bearings are sealed ball bearings, you may not have to add oil to the
fuel.

Not saying this is preferable, just possible.

[Sport Pilot]

Steve wrote:
> Sport Pilot wrote:
>
> >
> > As long as I get 90% or so right, I really don't give a damn.
> >
>
> Good luck on getting your next landing "90% right."
>
> :P


I do, a good landing gear system is essential. Nobody makes a perfect
landing everytime.

[Sport Pilot]

Steve wrote:
> Morgans wrote:
>
> > "Steve" > wrote
> >
> >
> >>As already stated, 2-stroke diesels really don't have a
power-to-weight
> >>advantage over 4-strokes. They still have to have a camshaft and
> >>exhaust valves (they aren't like weed whacker engines, you know),
so
> >>they don't save that weight. Plus they have to have a blower for
> >>scavenge air. The only area where they save weight is in that the
> >>connecting rod and crank can be lighter, and that only helps offset
the
> >>added weight of the blower.
> >
> >
> > How about the fact that they have power pulses in each revolution?
They
> > could possibly have half the displacement, and still get the same
power, (or
> > close to it) with less weight than the double displacement 4 cycle.
Yes,
> > the blower weight is added, but it is nice to make good power, way
up there.
>
>
> The blower also takes away a significant chunk of crankshaft power.
The
> blower has to do the same net work as those "non power" strokes in a
> 4-cycle diesel because its doing the same job- expelling burnt
mixture
> and bringing in fresh air. You can't get something for nothing.
>
> This is all old-hat. 2-stroke diesels have been in widespread use
since
> Winton developed the basic foundation for what became both the EMD
and
> Detroit Diesel 2-stroke engine architecture back in the 1920s.
2-strokes
> became very simple to service and reliable, but they rarely won on
> either fuel efficiency or total power output per unit weight. That's
why
> you find 2-strokes in locomotives and ships where weight doesn't
matter
> (or is a benefit), but they all but disappeared from on-road
> applications by the end of the 1970s and DID completely disappear by
the
> turn of the century.

I would have agreed at the start of this thread, but the two stroke
desiel does not have to be the same as the old locomotive desiels. The
blower is not needed if the crankcase is used to pump fuel/air mixture.

[Sport Pilot]

Steve wrote:
> Luke Scharf wrote:
>
> > Steve wrote:
> >
> >> But there are more and more small diesels that run just as fast as

> >> gasoline engines. There's no fundamental limit thats any different

> >> than a gasoline engine, really, but up until now there's not been
a
> >> demand for high-RPM diesels.
> >
> >
> > When I was reading about the Volkswagen TDI engine, I vaguely
remember
> > coming across someone who said that the redline of that engine was
set
> > by the speed which which the burning fuel expanded.
> >
> > Sounds rather fundamental to me - but, then again, I'm a computer
guy.
> >
> > -Luke
>
> In almost ALL real-world engines, the actual limit is set by the
point
> at which some mechanical component would fail. The engine's torque
*may*
> drop off well before the mechanical failure point if it can't ingest
> enough fuel or air at high speed. In the case of a diesel, you can
> pretty much increase the burn rate to as high as the mechanical parts

> can tolerate by increasing turbocharger boost (and injection rate to
> match). Since detonation isn't possible (no fuel exists in the
cylinder
> until combustion is supposed to begin anyway) the only limits to
boost
> pressure are mechanical in nature. In practical terms, no one really
> wants or needs a 9000 RPM diesel, though.


Diesel fuel is not conducive to high speed running. Nor is a long
injection period through much of the expansion phase. Yes you can
boost the turbocharger and the other things, but an Otto cycle engine
will respond with even higher speeds. Parts failure from speed is not
a problem with diesel engines, the rotating parts have to be bigger
than an otto engine because of the higher compression, yet the otto
engine will turn higer RPM's with smaller parts.

[Sport Pilot]

Sorry about the two similar posts. I didn't think the first "took".

[Steve]

Sport Pilot wrote:

> Steve wrote:
>
>>wingsnaprop wrote:
>>
>>
>>>Guess why?
>>> *Duh* Pollution laws, and no need for the power to weight
>>>requirements of Aviation! Duh... whats that got to do with this
>
> topic?
>
>>>Other than to show that 2 stroke Compression ignition engines are a
>>>proven concept?
>>>
>>
>>As already stated, 2-stroke diesels really don't have a
>
> power-to-weight
>
>>advantage over 4-strokes. They still have to have a camshaft and
>>exhaust valves (they aren't like weed whacker engines, you know), so
>>they don't save that weight. Plus they have to have a blower for
>>scavenge air. The only area where they save weight is in that the
>>connecting rod and crank can be lighter, and that only helps offset
>
> the
>
>>added weight of the blower.
>
>
>
> I said something similar, but I don't know that a desiel has to have
> the valve, as the old locomotive two strokes. Could it not be ported,
> as the two stroke spark engines?

In order to scavenge the cylinders properly, the inlet ports need to be
at the bottom of the cylinder and exhaust valves have to be located at
the top. The only viable alternative is the opposed piston engine (ala
Fairbanks-Morse) in which one piston uncovers an inlet port array and
the other uncovers the exhaust ports. But then you have the weight of an
additional CRANKSHAFT, without any increase in output power!

> The fuel is already oily so if the
> bearings are sealed ball bearings, you may not have to add oil to the
> fuel.

I think you're confusing a weed-whacker/outboard motor type 2-stroke
with a 2-stroke diesel. A 2-stroke diesel has a closed crankcase just
like a 4-stroke.

[Steve]

Sport Pilot wrote:

> Steve wrote:
>
>>Morgans wrote:
>>
>>
>>>"Steve" > wrote
>>>
>>>
>>>
>>>>As already stated, 2-stroke diesels really don't have a
>
> power-to-weight
>
>>>>advantage over 4-strokes. They still have to have a camshaft and
>>>>exhaust valves (they aren't like weed whacker engines, you know),
>
> so
>
>>>>they don't save that weight. Plus they have to have a blower for
>>>>scavenge air. The only area where they save weight is in that the
>>>>connecting rod and crank can be lighter, and that only helps offset
>
> the
>
>>>>added weight of the blower.
>>>
>>>
>>>How about the fact that they have power pulses in each revolution?
>
> They
>
>>>could possibly have half the displacement, and still get the same
>
> power, (or
>
>>>close to it) with less weight than the double displacement 4 cycle.
>
> Yes,
>
>>>the blower weight is added, but it is nice to make good power, way
>
> up there.
>
>>
>>The blower also takes away a significant chunk of crankshaft power.
>
> The
>
>>blower has to do the same net work as those "non power" strokes in a
>>4-cycle diesel because its doing the same job- expelling burnt
>
> mixture
>
>>and bringing in fresh air. You can't get something for nothing.
>>
>>This is all old-hat. 2-stroke diesels have been in widespread use
>
> since
>
>>Winton developed the basic foundation for what became both the EMD
>
> and
>
>>Detroit Diesel 2-stroke engine architecture back in the 1920s.
>
> 2-strokes
>
>>became very simple to service and reliable, but they rarely won on
>>either fuel efficiency or total power output per unit weight. That's
>
> why
>
>>you find 2-strokes in locomotives and ships where weight doesn't
>
> matter
>
>>(or is a benefit), but they all but disappeared from on-road
>>applications by the end of the 1970s and DID completely disappear by
>
> the
>
>>turn of the century.
>
>
> I would have agreed at the start of this thread, but the two stroke
> desiel does not have to be the same as the old locomotive desiels. The
> blower is not needed if the crankcase is used to pump fuel/air mixture.
>

You're describing a weed-whacker engine, not a 2-stroke Diesel. Good for
cheap manufacture and relatively light total weight, but at the expense
of a very narrow power band, terrible efficiency, terrible emissions,
and except at the peak of the power band, terrible power/weight ratio in
spite of being lightweight.

[Steve]

Sport Pilot wrote:


> Diesel fuel is not conducive to high speed running. Nor is a long
> injection period through much of the expansion phase. Yes you can
> boost the turbocharger and the other things, but an Otto cycle engine
> will respond with even higher speeds. Parts failure from speed is not
> a problem with diesel engines, the rotating parts have to be bigger
> than an otto engine because of the higher compression, yet the otto
> engine will turn higer RPM's with smaller parts.
>


All of the above is true in the common practice of diesel design, but
none of it is necessarily true. There is nothing FUNDAMENTAL that limits
a diesel to low-RPM designs only. One can build a screaming high-RPM
diesel with light-weight rotating parts, but one would have to ask
"why?" Gasoline engines are made high-revving in order to increase power
output from a small package, but diesels can develop a lot more low-RPM
torque through high boost because they don't detonate when "lugged," so
there's no NEED to make them scream. If you need more power, don't spin
them faster, just boost them harder. High RPM is an aggravation, not an
advantage (no matter what Honda VTEC drivers think...).

[Sport Pilot]

Steve wrote:
> Sport Pilot wrote:
>
>
> > Diesel fuel is not conducive to high speed running. Nor is a long
> > injection period through much of the expansion phase. Yes you can
> > boost the turbocharger and the other things, but an Otto cycle
engine
> > will respond with even higher speeds. Parts failure from speed is
not
> > a problem with diesel engines, the rotating parts have to be bigger
> > than an otto engine because of the higher compression, yet the otto
> > engine will turn higer RPM's with smaller parts.
> >
>
>
> All of the above is true in the common practice of diesel design, but

> none of it is necessarily true. There is nothing FUNDAMENTAL that
limits
> a diesel to low-RPM designs only. One can build a screaming high-RPM
> diesel with light-weight rotating parts, but one would have to ask
> "why?" Gasoline engines are made high-revving in order to increase
power
> output from a small package, but diesels can develop a lot more
low-RPM
> torque through high boost because they don't detonate when "lugged,"
so
> there's no NEED to make them scream. If you need more power, don't
spin
> them faster, just boost them harder. High RPM is an aggravation, not
an
> advantage (no matter what Honda VTEC drivers think...).


Actually diesels don't really deliver that much torque at similar
speeds. Ok they do but only because the valving is timed for the
slower speeds. Many gasoline tractor engines will diliver similar
torque, but with a higher fuel consumption due to the lower compression
ratio. Diesel fuel burns slower and will knock when the injection
timing is shortened to allow higher speeds.

[Steve]

Sport Pilot wrote:

> Steve wrote:
>
>>Sport Pilot wrote:
>>
>>
>>
>>>Diesel fuel is not conducive to high speed running. Nor is a long
>>>injection period through much of the expansion phase. Yes you can
>>>boost the turbocharger and the other things, but an Otto cycle
>
> engine
>
>>>will respond with even higher speeds. Parts failure from speed is
>
> not
>
>>>a problem with diesel engines, the rotating parts have to be bigger
>>>than an otto engine because of the higher compression, yet the otto
>>>engine will turn higer RPM's with smaller parts.
>>>
>>
>>
>>All of the above is true in the common practice of diesel design, but
>
>
>>none of it is necessarily true. There is nothing FUNDAMENTAL that
>
> limits
>
>>a diesel to low-RPM designs only. One can build a screaming high-RPM
>>diesel with light-weight rotating parts, but one would have to ask
>>"why?" Gasoline engines are made high-revving in order to increase
>
> power
>
>>output from a small package, but diesels can develop a lot more
>
> low-RPM
>
>>torque through high boost because they don't detonate when "lugged,"
>
> so
>
>>there's no NEED to make them scream. If you need more power, don't
>
> spin
>
>>them faster, just boost them harder. High RPM is an aggravation, not
>
> an
>
>>advantage (no matter what Honda VTEC drivers think...).
>
>
>
> Actually diesels don't really deliver that much torque at similar
> speeds. Ok they do but only because the valving is timed for the
> slower speeds. Many gasoline tractor engines will diliver similar
> torque, but with a higher fuel consumption due to the lower compression
> ratio.

It depends on what you're comparing to. A lot of tractors use
normally-aspirated indirect-injection diesels, which are no comparison
to a turbocharged diesel. Or to a good normally-asipirated gasoline
engine, except in terms of longevity. Gasoline engines are hard to beat
for the *width* of their torque curve, but modern turbo-diesels do a
good job against them, and do so with better efficiency.

> Diesel fuel burns slower and will knock when the injection
> timing is shortened to allow higher speeds.
>

Higher speed requires more than just rapid injection, it also demands
higher boost pressure, which causes the fuel to burn faster without any
knock-like phenomenon. All serious diesels are turbocharged for that
reason (as well as others), and normally-aspirated diesels are limited
to very small power outputs and relatively low efficiency. You can only
get so much combustion chamber pressure through the compression ratio of
the engine- the rest has to come from forced induction. As someone
pointed out earlier, the VW TDI develops power up to 4500 RPM, which is
comparable to many gasoline engines, but it is able to do so only
because it is a turbo-diesel. As I said before, there's no reason that
building a 7000-RPM diesel isn't possible, but there's no REASON to
build one.

[Morgans]

"Steve" > wrote

In practical terms, no one really
> wants or needs a 9000 RPM diesel, though.

Oh, I don't know. NASCAR might be interested in going diesel ! <g>
--
Jim in NC

[Don Stauffer]

Steve wrote:
>
> In almost ALL real-world engines, the actual limit is set by the point
> at which some mechanical component would fail. The engine's torque *may*
> drop off well before the mechanical failure point if it can't ingest
> enough fuel or air at high speed. In the case of a diesel, you can
> pretty much increase the burn rate to as high as the mechanical parts
> can tolerate by increasing turbocharger boost (and injection rate to
> match). Since detonation isn't possible (no fuel exists in the cylinder
> until combustion is supposed to begin anyway) the only limits to boost
> pressure are mechanical in nature. In practical terms, no one really
> wants or needs a 9000 RPM diesel, though.

Actually, detonation can and does occur in Diesels. With today's Diesel
fuels and injection methods the fuel does not burn INSTANTLY upon
injection. The droplets are too large. The droplets tend to evaporate
from their surface area. It IS possible for unburned gases evaporated
from the fuel to exist in the chamber and detonate in local regions. The
effect is nowhere as severe as the detonation that occurs in spark
engines at times. Interesting traces made with high frequency pressure
sensors indicate these local "peaks" in combustion pressure when this
occurs. It is the cause of the "tinkling" sound that Diesels
occasionally make.

Detonation is not a full or nothing situation. Local regions can
undergo detonation even while the majority of the charge undergoes
normal wavefront burning, in either Diesel or SI.

[Don Stauffer]

Steve wrote:
> Sport Pilot wrote:
>
>
>> Diesel fuel is not conducive to high speed running. Nor is a long
>> injection period through much of the expansion phase. Yes you can
>> boost the turbocharger and the other things, but an Otto cycle engine
>> will respond with even higher speeds. Parts failure from speed is not
>> a problem with diesel engines, the rotating parts have to be bigger
>> than an otto engine because of the higher compression, yet the otto
>> engine will turn higer RPM's with smaller parts.
>>
>
>
> All of the above is true in the common practice of diesel design, but
> none of it is necessarily true. There is nothing FUNDAMENTAL that limits
> a diesel to low-RPM designs only. One can build a screaming high-RPM
> diesel with light-weight rotating parts, but one would have to ask
> "why?" Gasoline engines are made high-revving in order to increase power
> output from a small package, but diesels can develop a lot more low-RPM
> torque through high boost because they don't detonate when "lugged," so
> there's no NEED to make them scream. If you need more power, don't spin
> them faster, just boost them harder. High RPM is an aggravation, not an
> advantage (no matter what Honda VTEC drivers think...).
>
I would assume that use of hydrogen as a fuel would allow very high rpm
in a Diesel.

[Steve]

Don Stauffer wrote:

> Steve wrote:
>
>> Sport Pilot wrote:
>>
>>
>>> Diesel fuel is not conducive to high speed running. Nor is a long
>>> injection period through much of the expansion phase. Yes you can
>>> boost the turbocharger and the other things, but an Otto cycle engine
>>> will respond with even higher speeds. Parts failure from speed is not
>>> a problem with diesel engines, the rotating parts have to be bigger
>>> than an otto engine because of the higher compression, yet the otto
>>> engine will turn higer RPM's with smaller parts.
>>>
>>
>>
>> All of the above is true in the common practice of diesel design, but
>> none of it is necessarily true. There is nothing FUNDAMENTAL that
>> limits a diesel to low-RPM designs only. One can build a screaming
>> high-RPM diesel with light-weight rotating parts, but one would have
>> to ask "why?" Gasoline engines are made high-revving in order to
>> increase power output from a small package, but diesels can develop a
>> lot more low-RPM torque through high boost because they don't detonate
>> when "lugged," so there's no NEED to make them scream. If you need
>> more power, don't spin them faster, just boost them harder. High RPM
>> is an aggravation, not an advantage (no matter what Honda VTEC drivers
>> think...).
>>
> I would assume that use of hydrogen as a fuel would allow very high rpm
> in a Diesel.

But no one has come up with a completely satisfactory way to do direct
injection with a gaseous fuel, which is the same problem diesels that
run on natural gas face.

NG diesels are interesting beasts. They actually mix the gas with the
intake air and compress it like a spark-ignition engine would, setting
up the possibility of detonation, but since NG is has a very high
relative "octane" rating, it doesn't ignite until a *tiny* shot of
diesel is injected to initiate combustion. They do have to operate at
somewhat lower compression than a straight diesel, but its still in the
neighborhood of 14:1 or 15:1 which is much higher than you can achieve
with gasoline, at least on any fuel short of leaded aviation racing fuel
that is brewed up in ridiculously small (and expensive) quantities for
the Reno air racers.

[Steve]

The OTHER Kevin in San Diego wrote:
> On Mon, 16 May 2005 15:08:37 -0500, Steve > wrote:
>
>
>>High RPM is an aggravation, not an
>>advantage (no matter what Honda VTEC drivers think...).
>
>
> Shhhh.. Don't tell the guys at Pratt & Whitney that... :)

It depends... gas generator shafts need to spin fast, but the LP spool
on a PW4000 doesn't turn any faster than the engine in my car :D

[Stuart & Kathryn Fields]

We own a 2003 Jetta TDI and it poops out before it gets to 4500. However, it
goes uphill at 80mph gaining speed at around 2500RPM. BTW. Hp= Torque X
RPM. If your 100hp engine peaks at 2500 rpm and your 200horse engine peaks
at 7500 rpm, the 100hp engine has to develop 1.5 times more torque than your
200hp engine at the peak hp rpm.

--
Stuart Fields
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478
(760) 408-9747 general and layout cell
(760) 608-1299 technical and advertising cell

www.vkss.com
www.experimentalhelo.com


"Steve" > wrote in message
...
> Sport Pilot wrote:
>
> > Steve wrote:
> >
> >>Sport Pilot wrote:
> >>
> >>
> >>
> >>>Diesel fuel is not conducive to high speed running. Nor is a long
> >>>injection period through much of the expansion phase. Yes you can
> >>>boost the turbocharger and the other things, but an Otto cycle
> >
> > engine
> >
> >>>will respond with even higher speeds. Parts failure from speed is
> >
> > not
> >
> >>>a problem with diesel engines, the rotating parts have to be bigger
> >>>than an otto engine because of the higher compression, yet the otto
> >>>engine will turn higer RPM's with smaller parts.
> >>>
> >>
> >>
> >>All of the above is true in the common practice of diesel design, but
> >
> >
> >>none of it is necessarily true. There is nothing FUNDAMENTAL that
> >
> > limits
> >
> >>a diesel to low-RPM designs only. One can build a screaming high-RPM
> >>diesel with light-weight rotating parts, but one would have to ask
> >>"why?" Gasoline engines are made high-revving in order to increase
> >
> > power
> >
> >>output from a small package, but diesels can develop a lot more
> >
> > low-RPM
> >
> >>torque through high boost because they don't detonate when "lugged,"
> >
> > so
> >
> >>there's no NEED to make them scream. If you need more power, don't
> >
> > spin
> >
> >>them faster, just boost them harder. High RPM is an aggravation, not
> >
> > an
> >
> >>advantage (no matter what Honda VTEC drivers think...).
> >
> >
> >
> > Actually diesels don't really deliver that much torque at similar
> > speeds. Ok they do but only because the valving is timed for the
> > slower speeds. Many gasoline tractor engines will diliver similar
> > torque, but with a higher fuel consumption due to the lower compression
> > ratio.
>
> It depends on what you're comparing to. A lot of tractors use
> normally-aspirated indirect-injection diesels, which are no comparison
> to a turbocharged diesel. Or to a good normally-asipirated gasoline
> engine, except in terms of longevity. Gasoline engines are hard to beat
> for the *width* of their torque curve, but modern turbo-diesels do a
> good job against them, and do so with better efficiency.
>
> > Diesel fuel burns slower and will knock when the injection
> > timing is shortened to allow higher speeds.
> >
>
> Higher speed requires more than just rapid injection, it also demands
> higher boost pressure, which causes the fuel to burn faster without any
> knock-like phenomenon. All serious diesels are turbocharged for that
> reason (as well as others), and normally-aspirated diesels are limited
> to very small power outputs and relatively low efficiency. You can only
> get so much combustion chamber pressure through the compression ratio of
> the engine- the rest has to come from forced induction. As someone
> pointed out earlier, the VW TDI develops power up to 4500 RPM, which is
> comparable to many gasoline engines, but it is able to do so only
> because it is a turbo-diesel. As I said before, there's no reason that
> building a 7000-RPM diesel isn't possible, but there's no REASON to
> build one.

[Sport Pilot]

Stuart & Kathryn Fields wrote:
> We own a 2003 Jetta TDI and it poops out before it gets to 4500.
However, it
> goes uphill at 80mph gaining speed at around 2500RPM. BTW. Hp=
Torque X
> RPM. If your 100hp engine peaks at 2500 rpm and your 200horse engine
peaks
> at 7500 rpm, the 100hp engine has to develop 1.5 times more torque
than your
> 200hp engine at the peak hp rpm.
>
> --
> Stuart Fields
> Experimental Helo magazine
> P. O. Box 1585
> Inyokern, CA 93527
> (760) 377-4478
> (760) 408-9747 general and layout cell
> (760) 608-1299 technical and advertising cell
>
> www.vkss.com
> www.experimentalhelo.com
>
>
> "Steve" > wrote in message
> ...
> > Sport Pilot wrote:
> >
> > > Steve wrote:
> > >
> > >>Sport Pilot wrote:
> > >>
> > >>
> > >>
> > >>>Diesel fuel is not conducive to high speed running. Nor is a
long
> > >>>injection period through much of the expansion phase. Yes you
can
> > >>>boost the turbocharger and the other things, but an Otto cycle
> > >
> > > engine
> > >
> > >>>will respond with even higher speeds. Parts failure from speed
is
> > >
> > > not
> > >
> > >>>a problem with diesel engines, the rotating parts have to be
bigger
> > >>>than an otto engine because of the higher compression, yet the
otto
> > >>>engine will turn higer RPM's with smaller parts.
> > >>>
> > >>
> > >>
> > >>All of the above is true in the common practice of diesel design,
but
> > >
> > >
> > >>none of it is necessarily true. There is nothing FUNDAMENTAL that
> > >
> > > limits
> > >
> > >>a diesel to low-RPM designs only. One can build a screaming
high-RPM
> > >>diesel with light-weight rotating parts, but one would have to
ask
> > >>"why?" Gasoline engines are made high-revving in order to
increase
> > >
> > > power
> > >
> > >>output from a small package, but diesels can develop a lot more
> > >
> > > low-RPM
> > >
> > >>torque through high boost because they don't detonate when
"lugged,"
> > >
> > > so
> > >
> > >>there's no NEED to make them scream. If you need more power,
don't
> > >
> > > spin
> > >
> > >>them faster, just boost them harder. High RPM is an aggravation,
not
> > >
> > > an
> > >
> > >>advantage (no matter what Honda VTEC drivers think...).
> > >
> > >
> > >
> > > Actually diesels don't really deliver that much torque at similar
> > > speeds. Ok they do but only because the valving is timed for the
> > > slower speeds. Many gasoline tractor engines will diliver
similar
> > > torque, but with a higher fuel consumption due to the lower
compression
> > > ratio.
> >
> > It depends on what you're comparing to. A lot of tractors use
> > normally-aspirated indirect-injection diesels, which are no
comparison
> > to a turbocharged diesel. Or to a good normally-asipirated gasoline
> > engine, except in terms of longevity. Gasoline engines are hard to
beat
> > for the *width* of their torque curve, but modern turbo-diesels do
a
> > good job against them, and do so with better efficiency.
> >
> > > Diesel fuel burns slower and will knock when the injection
> > > timing is shortened to allow higher speeds.
> > >
> >
> > Higher speed requires more than just rapid injection, it also
demands
> > higher boost pressure, which causes the fuel to burn faster without
any
> > knock-like phenomenon. All serious diesels are turbocharged for
that
> > reason (as well as others), and normally-aspirated diesels are
limited
> > to very small power outputs and relatively low efficiency. You can
only
> > get so much combustion chamber pressure through the compression
ratio of
> > the engine- the rest has to come from forced induction. As someone
> > pointed out earlier, the VW TDI develops power up to 4500 RPM,
which is
> > comparable to many gasoline engines, but it is able to do so only
> > because it is a turbo-diesel. As I said before, there's no reason
that
> > building a 7000-RPM diesel isn't possible, but there's no REASON to
> > build one.

I think most of us know that torque is only a force and you need speed
(RPM) to develop power. More speed is more power. Or was there some
other point you are trying to make?

[Steve]

Sport Pilot wrote:

> I think most of us know that torque is only a force and you need speed
> (RPM) to develop power. More speed is more power. Or was there some
> other point you are trying to make?
>


II think the point is that there are TWO ways that do an equally good
job of increasing power. More TORQUE is more power too.

Since power=K*Torque*RPM, the result is that if you hold the speed
constant and double the torque, you get double the power. There are
diesel engines in this world that develop 20,000 horespower at only 150
RPM. Naturally, the torque value is astronomical. No, they don't fly.
;-) They swim.

[Sport Pilot]

Steve wrote:
> Sport Pilot wrote:
>
> > I think most of us know that torque is only a force and you need
speed
> > (RPM) to develop power. More speed is more power. Or was there
some
> > other point you are trying to make?
> >
>
>
> II think the point is that there are TWO ways that do an equally good

> job of increasing power. More TORQUE is more power too.
>
> Since power=K*Torque*RPM, the result is that if you hold the speed
> constant and double the torque, you get double the power. There are
> diesel engines in this world that develop 20,000 horespower at only
150
> RPM. Naturally, the torque value is astronomical. No, they don't fly.

> ;-) They swim.

Why the obvious apple and orange comparision? I can show you a model
diesel engine of less than 1/2 cubic engine that turns about 10,000
RPM? So what. A large engine is going to turn less RPM because of its
rotation mass. You need to compare engines of equal size. The model
diesel engines will not turn as fast as the gas or methanol/nitro
engines because the fuel (ether and kerosene) will not burn as fast.
But they will put out more torque than the other two types, though only
marginally more than gasoline. This is because the fuel burns slower,
not because of the cycle, because all, the spark ignition gas engine,
the glow plug methanol/nitro engine, and the compression ignition
engine, are actually otto cycle engines.

[Steve]

Sport Pilot wrote:

> Why the obvious apple and orange comparision?

To refute the statement that "more speed is more power."

> You need to compare engines of equal size.

OK, Lets do it!

Dodge 5.9 Liter v8 gasoline engine: 230 horsepower at ~5000 RPM

Compared to:

Dodge/Cummins 5.9 Liter turbo-diesel engine: 325 horsepower at 2900 RPM


More speed is NOT more power any more than more torque at the same speed
is more power.

[Steve]

Sport Pilot wrote:

The model
> diesel engines will not turn as fast as the gas or methanol/nitro
> engines because the fuel (ether and kerosene) will not burn as fast.


I say again: there is no magic rule that says "diesel burns slower" than
gasoline. Increasing the boost pressure can increase the burn rate AS
MUCH AS YOU WANT. Its just not done most of the time, because no one
WANTS a 7000 RPM engine when a 4000 RPM engine is available to do the
same job. People only build 7000 RPM engines when there's no other way
to get the power.

> This is because the fuel burns slower,
> not because of the cycle, because all, the spark ignition gas engine,
> the glow plug methanol/nitro engine, and the compression ignition
> engine, are actually otto cycle engines.

No, that's already been covered. Diesel (true diesel with either direct
or pre-chamber injection) is a subtly different cycle than the Otto
cycle. Its constant-pressure combustion instead of constant-volume
combustion.

[Thomas Tornblom]

Steve > writes:

> Sport Pilot wrote:
>
> > Why the obvious apple and orange comparision?
>
>
> To refute the statement that "more speed is more power."
>
> > You need to compare engines of equal size.
>
>
> OK, Lets do it!
>
> Dodge 5.9 Liter v8 gasoline engine: 230 horsepower at ~5000 RPM
>
> Compared to:
>
> Dodge/Cummins 5.9 Liter turbo-diesel engine: 325 horsepower at 2900 RPM
>
>
> More speed is NOT more power any more than more torque at the same
> speed is more power.

uh?

More torque at the same speed *is* more power.

power = torque * speed

Had the gas engine produced the same torque at 5000 rpms as the diesel
do at 2900, then it would have had about 560 hp at 5000.

Thomas

[Steve R.]

"Thomas Tornblom" -to-reply> wrote in message
...
> Steve > writes:
>
>> Sport Pilot wrote:
>>
>>
>> More speed is NOT more power any more than more torque at the same
>> speed is more power.
>
> uh?
>

Yeah, that was my reaction! (?) ;-)


> More torque at the same speed *is* more power.
>
> power = torque * speed
>
> Had the gas engine produced the same torque at 5000 rpms as the diesel
> do at 2900, then it would have had about 560 hp at 5000.
>
> Thomas

Actually, the equation to calculate power (or horsepower (HP) in this case)
is HP = Torque X rpm / 5252.

Torque being a measurable force that turns the crankshaft and ultimately the
wheels, main rotor, or propeller (I just noticed that this is going to two
aviation and one automotive newsgroups). Horsepower is defined as a
"measurement" of work performed. By the equation, at least as it applies to
internal combustion reciprocating engines, you can't have HP without torque!
So, if you can increase the torque value at a given rpm, you'll increase the
power output at that rpm. Likewise, if you can maintain a given torque
value at a higher rpm, you'll produce more power in that case too. It
doesn't matter what kind of engine you're talking about or the fuel burned.
Gasoline, diesel, methanol, it makes no difference. The equation still
applies.

FWIW!
Fly/Drive Safe,
Steve R.

[Sport Pilot]

Steve wrote:
> Sport Pilot wrote:
>
> > Why the obvious apple and orange comparision?
>
> To refute the statement that "more speed is more power."
>
> > You need to compare engines of equal size.
>
> OK, Lets do it!
>
> Dodge 5.9 Liter v8 gasoline engine: 230 horsepower at ~5000 RPM
>
> Compared to:
>
> Dodge/Cummins 5.9 Liter turbo-diesel engine: 325 horsepower at 2900 RPM
>
>
> More speed is NOT more power any more than more torque at the same speed
> is more power.

Steve,
As you said power is torque * RPM, so for the same torque more speed
is power. In fact with 0 RPM you have no power only a force. No I
have not argued that desiels cannot deliver power by increasing torque.
Only that their inherent design and fuel limits their maximum speed.
Your example is a poor one most diesels of equivelant size will deliver
more torque at less RPM and have less total horsepower. I don't know
where you found that pitiful Dodge 5.9 liter engine. I have a 4.7 V8
in my Grand Cherokee and it puts out 260+ HP. I know that the 5.7
Liter hemi V8 puts out about 320 or so HP and it is not turbocharged.
So that is a more equal comparison. Unlike the apple orange examples
you put up.

[Sport Pilot]

Steve wrote:
> Sport Pilot wrote:
>
> The model
> > diesel engines will not turn as fast as the gas or methanol/nitro
> > engines because the fuel (ether and kerosene) will not burn as fast.
>
>
> I say again: there is no magic rule that says "diesel burns slower" than
> gasoline. Increasing the boost pressure can increase the burn rate AS
> MUCH AS YOU WANT. Its just not done most of the time, because no one
> WANTS a 7000 RPM engine when a 4000 RPM engine is available to do the
> same job. People only build 7000 RPM engines when there's no other way
> to get the power.
>
> > This is because the fuel burns slower,
> > not because of the cycle, because all, the spark ignition gas engine,
> > the glow plug methanol/nitro engine, and the compression ignition
> > engine, are actually otto cycle engines.
>
> No, that's already been covered. Diesel (true diesel with either direct
> or pre-chamber injection) is a subtly different cycle than the Otto
> cycle. Its constant-pressure combustion instead of constant-volume
> combustion.

I was not quite correct if I said desiel fuel burns slower, it is
however made to ignite better with desiel engines so that the fuel
ignites spontanously when injected. The fuel burns slower because it
is injected over a period of time. However, I may have been correct
about the model fuel. There are diesel conversion heads for model glow
engines. This replaces the head and glow plug with a head with a
varible compression. You adjust the timing by adjusting the
compression. The fuel is a mix of kerosene, ether, amyl nitrate, and
oil. This fuel will ignite at a much lower temperature than true
desiel fuel. The ether and amyl nitrate are the componets which ignite
at a low temp. Though ether is extremely volatile it is not a very
high energy fuel and I think it burns slowly. These converted engines
will turn large propellers at slower speeds than the glow engines they
were converted from.

Another example of a high energy fuel that limits speed is
nitromethane. Because it is a monopropellent the racers can pretty
much inject as much as their ignition can ignite, except for
hydrolocking. That is if more fuel is injected than the combustion
chamber volume the engine will blow up. But nitro burns slowly so RPM
is more or less limited to just over 10,000 RPM loaded. The slow
burning is why you see huge flames coming out the exhaust.

[[email protected]]

On Tue, 24 May 2005 21:54:29 GMT, Thomas Tornblom
-to-reply> wrote:

>Steve > writes:
>
>> Sport Pilot wrote:
>>
>> > Why the obvious apple and orange comparision?
>>
>>
>> To refute the statement that "more speed is more power."
>>
>> > You need to compare engines of equal size.
>>
>>
>> OK, Lets do it!
>>
>> Dodge 5.9 Liter v8 gasoline engine: 230 horsepower at ~5000 RPM
>>
>> Compared to:
>>
>> Dodge/Cummins 5.9 Liter turbo-diesel engine: 325 horsepower at 2900 RPM
>>
>>
>> More speed is NOT more power any more than more torque at the same
>> speed is more power.
>

One BIG factor is being forgotten here. The diesel is turboed. This
makes it roughly equivalent to an 8 liter engine at about 6psi boost.
Any combustion engine produces power in proportion to the amount of
air consumed. On a diesel it does not necessarily "consume" all the
air that goes through it - but the maximum power output is definitely
limitted by how much air can be put through it. A turbo can eisily
double the amount of air an engine pumps through it at a given speed.

Running an engine at double the speed also increases the amount of air
going through the engine - not quite double due to reduced volumetric
efficiency at speed.

Double the CFM gives double the horsepower, before factoring in
frictional losses and / or pumping losses.

A naturally aspirated diesel engine generally produces less HP per
unit of displacement, but more torque at low RPMs due in part to less
pumping loss (no air throttle)
>uh?
>
>More torque at the same speed *is* more power.
>
>power = torque * speed
>
>Had the gas engine produced the same torque at 5000 rpms as the diesel
>do at 2900, then it would have had about 560 hp at 5000.
>
>Thomas

[Don Stauffer]

Steve wrote:
> Sport Pilot wrote:
>
> The model
>
>> diesel engines will not turn as fast as the gas or methanol/nitro
>> engines because the fuel (ether and kerosene) will not burn as fast.
>
>
>
> I say again: there is no magic rule that says "diesel burns slower" than
> gasoline. Increasing the boost pressure can increase the burn rate AS
> MUCH AS YOU WANT. Its just not done most of the time, because no one
> WANTS a 7000 RPM engine when a 4000 RPM engine is available to do the
> same job. People only build 7000 RPM engines when there's no other way
> to get the power.
>
Hydrogen, for example, is a very rapid burning fuel. Hydrogen can and
has been used in Diesels. I also suspect that natural gas, another
common diesel fuel, burns at a high rate. The slow burn rate with many
liquid diesel fuels is due to the time it takes the surface area of the
droplets to vaporize.

[Don Stauffer]

wrote:

>
> One BIG factor is being forgotten here. The diesel is turboed. This
> makes it roughly equivalent to an 8 liter engine at about 6psi boost.
> Any combustion engine produces power in proportion to the amount of
> air consumed. On a diesel it does not necessarily "consume" all the
> air that goes through it - but the maximum power output is definitely
> limitted by how much air can be put through it. A turbo can eisily
> double the amount of air an engine pumps through it at a given speed.
>
> Running an engine at double the speed also increases the amount of air
> going through the engine - not quite double due to reduced volumetric
> efficiency at speed.
>
> Double the CFM gives double the horsepower, before factoring in
> frictional losses and / or pumping losses.
>
> A naturally aspirated diesel engine generally produces less HP per
> unit of displacement, but more torque at low RPMs due in part to less
> pumping loss (no air throttle)
>
SOME diesels are turboed. Many are not. Some Diesels are normally
aspirated. Some are supercharged with geared chargers. Some are
turboed. It is by far an overgeneralization to claim that all Diesels
are supercharged, even more so to say they are all turbo-supercharged.

[Philippe]

Don Stauffer wrote:




> SOME diesels are turboed. Many are not. Some Diesels are normally
> aspirated. Some are supercharged with geared chargers. Some are
> turboed. It is by far an overgeneralization to claim that all Diesels
> are supercharged, even more so to say they are all turbo-supercharged.

You forgot supercharged plus turbocharged
http://www.wilksch.com/


--
Pub: http://www.slowfood.fr/france
Philippe Vessaire ҿӬ

[Steve]

Thomas Tornblom wrote:

> Steve > writes:
>
>
>>Sport Pilot wrote:
>>
>>
>>>Why the obvious apple and orange comparision?
>>
>>
>>To refute the statement that "more speed is more power."
>>
>>
>>> You need to compare engines of equal size.
>>
>>
>>OK, Lets do it!
>>
>>Dodge 5.9 Liter v8 gasoline engine: 230 horsepower at ~5000 RPM
>>
>>Compared to:
>>
>>Dodge/Cummins 5.9 Liter turbo-diesel engine: 325 horsepower at 2900 RPM
>>
>>
>>More speed is NOT more power any more than more torque at the same
>>speed is more power.
>
>
> uh?

huh. Read it again.

>
> More torque at the same speed *is* more power.

That's exactly what I've been saying. You can get more power by
increasing torque OR rpm or both.

[Steve]

Don Stauffer wrote:

> SOME diesels are turboed. Many are not. Some Diesels are normally
> aspirated. Some are supercharged with geared chargers. Some are
> turboed. It is by far an overgeneralization to claim that all Diesels
> are supercharged, even more so to say they are all turbo-supercharged.

I believe that if you look at modern diesels currently being produced
and sold, you'll find virtually NONE rated at more than 50-60 horsepower
that are not turbo-supercharged. And equally few that are strictly
mechanically blown (the Detroit Diesel 2-strokes are no longer in
production). The VAST majority are, indeed, turbo-supercharged.

[Steve]

Sport Pilot wrote:


> Steve,
> As you said power is torque * RPM, so for the same torque more speed
> is power.

Or for the same SPEED, more TORQUE is more power. That's the part of the
equation that you've never acknowledged.



> Your example is a poor one most diesels of equivelant size will deliver
> more torque at less RPM and have less total horsepower.

Not always true (obviously), and when looking at modern diesels its not
even GENRALLY true anymore. That's EXACTLY why I picked the example that
I did! If you don't like the Dodge comparison, go look at a
Ford/Navistar 6-liter diesel and compare it to the closest-sized Ford
(5.4L) gasoline engine tuned for a truck application. 10 years ago, the
diesel would have won on low RPM torque, but been lacking in peak HP.
That is no longer the case most of the time, because diesels are now
*always* turbocharged, and most of the time have modern electronic
injection control over both injection rate AND duration.

> I don't know
> where you found that pitiful Dodge 5.9 liter engine.

There's nothing pitiful about it at all, it was an EXCELLENT truck
engine used from 1972 until 2003. When built for power rather than
torque, it can easily put out well over 400 Hp without turning 7000 RPM,
but as delivered in factory trucks, it was tuned for a torque band
that's flat as Kansas over about a 3500 RPM span, and that results in a
rather modest 230 HP.

> I have a 4.7 V8
> in my Grand Cherokee and it puts out 260+ HP.

The 4.7 is the replacement for the 5.2, and while a fine engine in its
own right, its a little bit low in the torque department. It doesn't
move the fullsize Ram pickup or even the Durango with much authority-
the old lower-HP rated 5.9 actually "feels" a lot peppier in around-town
driving because it has more torque below 3000 RPM than the 4.7L does,
despite a lower peak HP rating. That's a symptom mostly of its small
size- when you excessively constrain the displacement of an engine, you
start HAVING to spin it faster and faster to get the same power and you
sacrifice torque at the lower RPM levels- Which is a key part of the
point I've been driving home. Modern gasoline-powered cars and trucks
tend to have very high peak horsepower ratings- and yet many of them
feel weak compared to older cars, simply because all that high-RPM
horsepower comes at the expense of useful low-RPM torque, and they need
5- and 6-speed transmissions just to match the performance of older
torquier engines.

Gas engines have been pushed smaller and lighter by fuel economy and
emissions considerations, resulting in peaky torque curves, poorer
low-RPM torque, and higher peak HP to compensate.

[Thomas Tornblom]

Steve > writes:

> Thomas Tornblom wrote:
>
> > Steve > writes:
> >>
> >>More speed is NOT more power any more than more torque at the same
> >>speed is more power.
> > uh?
>
>
> huh. Read it again.

Ok.

English is not my native language, and I read the sentence such that
the "NOT" in the first half also implied that there was an implicit
"NOT" in the second half, which made the statement wrong.

>
> > More torque at the same speed *is* more power.
>
>
> That's exactly what I've been saying. You can get more power by
> increasing torque OR rpm or both.
>

Then we agree :-)

Thomas

[Steve]

Thomas Tornblom wrote:

> Steve > writes:
>
>
>>Thomas Tornblom wrote:

>
>
> Ok.
>
> English is not my native language, and I read the sentence such that
> the "NOT" in the first half also implied that there was an implicit
> "NOT" in the second half, which made the statement wrong.


And I'll admit, it was a poorly written sentence. My bad.

[Morgans]

"Steve" > wrote

> I believe that if you look at modern diesels currently being produced
> and sold, you'll find virtually NONE rated at more than 50-60 horsepower
> that are not turbo-supercharged. And equally few that are strictly
> mechanically blown (the Detroit Diesel 2-strokes are no longer in
> production). The VAST majority are, indeed, turbo-supercharged.

Not true of some of our school busses that were produced in the past 5 or so
years. They make up for the lack of super or turbocharging with more cubic
inches.
--
Jim in NC

[[email protected]]

On Wed, 25 May 2005 09:37:53 -0500, Don Stauffer
> wrote:

wrote:
>
>>
>> One BIG factor is being forgotten here. The diesel is turboed. This
>> makes it roughly equivalent to an 8 liter engine at about 6psi boost.
>> Any combustion engine produces power in proportion to the amount of
>> air consumed. On a diesel it does not necessarily "consume" all the
>> air that goes through it - but the maximum power output is definitely
>> limitted by how much air can be put through it. A turbo can eisily
>> double the amount of air an engine pumps through it at a given speed.
>>
>> Running an engine at double the speed also increases the amount of air
>> going through the engine - not quite double due to reduced volumetric
>> efficiency at speed.
>>
>> Double the CFM gives double the horsepower, before factoring in
>> frictional losses and / or pumping losses.
>>
>> A naturally aspirated diesel engine generally produces less HP per
>> unit of displacement, but more torque at low RPMs due in part to less
>> pumping loss (no air throttle)
>>
>SOME diesels are turboed. Many are not. Some Diesels are normally
>aspirated. Some are supercharged with geared chargers. Some are
>turboed. It is by far an overgeneralization to claim that all Diesels
>are supercharged, even more so to say they are all turbo-supercharged.


The post being replied to was comparing a turbo cummins to a gas
engine.

Nobody ever said all diesels are turboed.

[Don Stauffer]

Philippe wrote:
> Don Stauffer wrote:
>
>
>
>
>
>>SOME diesels are turboed. Many are not. Some Diesels are normally
>>aspirated. Some are supercharged with geared chargers. Some are
>>turboed. It is by far an overgeneralization to claim that all Diesels
>>are supercharged, even more so to say they are all turbo-supercharged.
>
>
> You forgot supercharged plus turbocharged
> http://www.wilksch.com/
>
>
I know of some SI engines (aircraft engines) that have both geared and
turbochargers, but not any Diesels. Which Diesels are two-staged?

[Steve]

Morgans wrote:

> "Steve" > wrote
>
>
>>I believe that if you look at modern diesels currently being produced
>>and sold, you'll find virtually NONE rated at more than 50-60 horsepower
>>that are not turbo-supercharged. And equally few that are strictly
>>mechanically blown (the Detroit Diesel 2-strokes are no longer in
>>production). The VAST majority are, indeed, turbo-supercharged.
>
>
> Not true of some of our school busses that were produced in the past 5 or so
> years. They make up for the lack of super or turbocharging with more cubic
> inches.

I say AGAIN... what percentage of the market is that? Tiny. And they
only TRY to make up with more cubic inches- a DT466E would run rings
around them.

[Morgans]

"Steve" > wrote

> I say AGAIN... what percentage of the market is that? Tiny. And they
> only TRY to make up with more cubic inches- a DT466E would run rings
> around them.

I was not taking issue with the tiny percentage concept. I did take issue
with the following, and the NONE

>>I believe that if you look at modern diesels currently being produced
>>and sold, you'll find virtually NONE rated at more than 50-60 horsepower
>>that are not turbo-supercharged.

Not a big deal to me, one way or the other. I always found the non turbo
buses under powered, compared to their turbo brothers.
--
Jim in NC

[Sport Pilot]

mastic wrote:
> Bryan Martin > wrote:
>
> >Not so. In the Otto cycle, the fuel and air are introduced to the cylinder
> >during the intake stroke. In the Diesel cycle only the air is introduce to
> >the cylinder during the intake stroke, the fuel in injected at the end of
> >the compression stroke.
>
> Wrong. Mr Otto invented the four stroke cycle and it is named after
> him. The fuel or when it's introduced has nothing to do with it, Otto
> refers to the cycle.

SO? He didn't mention fuel in the part you snipped. Diesel is a
differant cycle named after Mr. Diesel.

[Don Stauffer]

mastic wrote:
>>1. Desiel injection timing is differant than on an Otto engine. The
>>fuel is injected during the intake cycle on the Otto engine and the
>>fuel is injected during the ignition cycle on the Desiel.
>
>
> An Otto engine is any four stroke engine, diesel, gasoline, LPG makes
> no difference.


And there is no "ignition" stroke. BTW, it is not ignition, or intake,
or combustion "cycle". There is only one cycle in either a four stroke
cycle or two stroke cycle engine. What is different is the number of
strokes in a cycle. Cycle means repeating operation. A two-stroke
cycle engine repeats its operation every two strokes, a four-stroke
repeats every four strokes.

I believe if we must shorten the terms then four-stroke and two-stroke
are better terms, because in both cases we are talking about what
happens in one cycle, not in two or four CYCLEs.

[Don Stauffer]

Sport Pilot wrote:
>
> mastic wrote:
>
>>Bryan Martin > wrote:
>>
>>
>>>Not so. In the Otto cycle, the fuel and air are introduced to the cylinder
>>>during the intake stroke. In the Diesel cycle only the air is introduce to
>>>the cylinder during the intake stroke, the fuel in injected at the end of
>>>the compression stroke.
>>
>>Wrong. Mr Otto invented the four stroke cycle and it is named after
>>him. The fuel or when it's introduced has nothing to do with it, Otto
>>refers to the cycle.
>
>
> SO? He didn't mention fuel in the part you snipped. Diesel is a
> differant cycle named after Mr. Diesel.
>

Actually, today's Diesels can operate over several cycle types. Modern
high speed Diesels as used in cars are closer to the Otto cycle than
they are to Rudolph's cycle. In his original engine the fuel was
supposed to be injected at a rate to create a constant combustion
temperature or a constant pressure. This really would take a feedback
of temperature or pressure during the combustion stroke, and was- and
is- extremely hard to do. The slower the speed of the engine, the
better current Diesels approach the intended Diesel cycle, as seen on an
indicator diagram. The indicator diagram on high rpm Diesel auto
engines look a lot like the diagram of an Otto cycle.

There are people developing Diesel systems using closed loop pressure
sensing to adjust fuel injection rate, but to my knowledge no Diesel car
or truck engine using this feature has ever made it to production.
Current production Diesels use open loop injection, so it is a hybrid
cycle, somewhere between true Otto and true theoretical Diesel.

[Sport Pilot]

mastic wrote:
> "MJC" > wrote:
>
> >
> >"Andrew P." > wrote in message
> ink.net...
> >> Wandering aimlessly about the Web, I heard Sport Pilot say:
> >> > You have most of it right. Some things you have wrong,
> >> >
> >> > 1. Desiel injection timing is differant than on an Otto engine. The
> >> > fuel is injected during the intake cycle on the Otto engine and the
> >> > fuel is injected during the ignition cycle on the Desiel. On the
> >> > Desiel the fuel injection cycle starts just before TDC and ends well
> >> > after TDC. The fuel ignites as soon as it hits the hot air.
> >> >
> >> etc., etc. --- SNIP ---
> >>
> >> It's Diesel, not "Desiel".
> >>
> >> --
> >> Andrew P.
> >
> >Well if you're going to get picky, it's "Auto" engine, not "Otto" engine.
> >
> >MJC
> >
> Picky, picky, picky. It's not an Otto engine as such. Otto is used to
> refer to the standard four stroke cycle because Otto was good enough
> to invent the four stroke cycle.
> So our friend was incorrect when he said:
>
> >1. Desiel injection timing is differant than on an Otto engine. The
> >fuel is injected during the intake cycle on the Otto engine and the
> >fuel is injected during the ignition cycle on the Desiel.
>
> An Otto engine is any four stroke engine, diesel, gasoline, LPG makes
> no difference.

Completely wrong, the Otto cycle has nothing to do with four stroke
engines. Don is right its not four cycle, I used it incorrectly. The
Otto and Diesel cycles are actually refering to the thermodynamics
chart of temperature pressure and volume, they invented their cycles on
paper and books, the engines we use are only close approximations. The
two stroke ignition engine uses the Otto cycle as it is has the four
phases of intake, compression, power, and exhaust, and the pressure is
not constant. The Diesel two stroke is a Diesel cycle because it also
includes the same phases and the fuel burns at a fairly constant
pressure.

[Sport Pilot]

Here is an animated link showing the differances of the Otto and Diesel
cycles.

http://www.ulb.ac.be/sma/testcenter/Test/solve/systems/closed/process/specific/closedcycle/closedcycle.html

Notice the near instant burning in the example gives very nearly a
constant volume, in actual practice some compression is going on at
this time.

Also during a Diesel cycle it is hard to maintain a constant pressure,
it would actually drop off, especially near the end of the down stroke.

[Don Stauffer]

Sport Pilot wrote:
>
> Completely wrong, the Otto cycle has nothing to do with four stroke
> engines. Don is right its not four cycle, I used it incorrectly. The
> Otto and Diesel cycles are actually refering to the thermodynamics
> chart of temperature pressure and volume, they invented their cycles on
> paper and books, the engines we use are only close approximations. The
> two stroke ignition engine uses the Otto cycle as it is has the four
> phases of intake, compression, power, and exhaust, and the pressure is
> not constant. The Diesel two stroke is a Diesel cycle because it also
> includes the same phases and the fuel burns at a fairly constant
> pressure.
>

I guess I'd quibble with the statement that the Otto cycle has nothing
to do with four-stroke engines- it was the first successful cycle to
incorporate four strokes. yes, there are other four stroke cycles, but
the Otto cycle is still by far the most common. There have been several
other four-strokes, several two-strokes, at least on six stroke- I
suspect several also.

New IC engine designs are among the most numerous US patents. Just
because something is patentable, of course, does not make it good or
successful, and most of these patents were for approaches that offered
insufficient advantages.

BTW, as I understand the new Miller cycle, I don't consider it a truly
new cycle- just a clever mod on the Otto. I don't consider the Otto
cycle to require valve openings at closings at the top or bottom dead
center, exactly.

[Sport Pilot]

Don Stauffer wrote:
> Sport Pilot wrote:
> >
> > Completely wrong, the Otto cycle has nothing to do with four stroke
> > engines. Don is right its not four cycle, I used it incorrectly. The
> > Otto and Diesel cycles are actually refering to the thermodynamics
> > chart of temperature pressure and volume, they invented their cycles on
> > paper and books, the engines we use are only close approximations. The
> > two stroke ignition engine uses the Otto cycle as it is has the four
> > phases of intake, compression, power, and exhaust, and the pressure is
> > not constant. The Diesel two stroke is a Diesel cycle because it also
> > includes the same phases and the fuel burns at a fairly constant
> > pressure.
> >
>
> I guess I'd quibble with the statement that the Otto cycle has nothing
> to do with four-stroke engines- it was the first successful cycle to
> incorporate four strokes. yes, there are other four stroke cycles, but
> the Otto cycle is still by far the most common. There have been several
> other four-strokes, several two-strokes, at least on six stroke- I
> suspect several also.
>
> New IC engine designs are among the most numerous US patents. Just
> because something is patentable, of course, does not make it good or
> successful, and most of these patents were for approaches that offered
> insufficient advantages.
>
> BTW, as I understand the new Miller cycle, I don't consider it a truly
> new cycle- just a clever mod on the Otto. I don't consider the Otto
> cycle to require valve openings at closings at the top or bottom dead
> center, exactly.

The confusion is that Otto invented the first four stroke engine and
called it the Otto cycle, not because of thermodynamics but because he
put it in a motorcycle. However the thermodynamic cycle can be
reproduced with a two stroke engine. Its just that the intake and
exhaust cycle's are much shorter.

[Don Stauffer]

Sport Pilot wrote:
>
> Don Stauffer wrote:
>
>>Sport Pilot wrote:
>>
>>>Completely wrong, the Otto cycle has nothing to do with four stroke
>>>engines. Don is right its not four cycle, I used it incorrectly. The
>>>Otto and Diesel cycles are actually refering to the thermodynamics
>>>chart of temperature pressure and volume, they invented their cycles on
>>>paper and books, the engines we use are only close approximations. The
>>>two stroke ignition engine uses the Otto cycle as it is has the four
>>>phases of intake, compression, power, and exhaust, and the pressure is
>>>not constant. The Diesel two stroke is a Diesel cycle because it also
>>>includes the same phases and the fuel burns at a fairly constant
>>>pressure.
>>>
>>
>>I guess I'd quibble with the statement that the Otto cycle has nothing
>>to do with four-stroke engines- it was the first successful cycle to
>>incorporate four strokes. yes, there are other four stroke cycles, but
>>the Otto cycle is still by far the most common. There have been several
>>other four-strokes, several two-strokes, at least on six stroke- I
>>suspect several also.
>>
>>New IC engine designs are among the most numerous US patents. Just
>>because something is patentable, of course, does not make it good or
>>successful, and most of these patents were for approaches that offered
>>insufficient advantages.
>>
>>BTW, as I understand the new Miller cycle, I don't consider it a truly
>>new cycle- just a clever mod on the Otto. I don't consider the Otto
>>cycle to require valve openings at closings at the top or bottom dead
>>center, exactly.
>
>
> The confusion is that Otto invented the first four stroke engine and
> called it the Otto cycle, not because of thermodynamics but because he
> put it in a motorcycle. However the thermodynamic cycle can be
> reproduced with a two stroke engine. Its just that the intake and
> exhaust cycle's are much shorter.
>

I am not sure what you mean by exhaust and intake "cycles". There is
one cycle- the actions that the engine goes through before everything
repeats. Do you mean the portions of the cycle during which the exhaust
and intake take place- they definitely take less crankcase revolution angle.

In the Otto cycle it is easy to break it down into four operations, each
lasting one stroke. A two-stroke is more complicated, because it still
has (existing, contemporary ones, do anyway) four seperate functions of
intake, compression, combustion and exhaust, but have to do it in two
strokes.

[Sport Pilot]

Don Stauffer wrote:
> Sport Pilot wrote:
> >
> > Don Stauffer wrote:
> >
> >>Sport Pilot wrote:
> >>
> >>>Completely wrong, the Otto cycle has nothing to do with four stroke
> >>>engines. Don is right its not four cycle, I used it incorrectly. The
> >>>Otto and Diesel cycles are actually refering to the thermodynamics
> >>>chart of temperature pressure and volume, they invented their cycles on
> >>>paper and books, the engines we use are only close approximations. The
> >>>two stroke ignition engine uses the Otto cycle as it is has the four
> >>>phases of intake, compression, power, and exhaust, and the pressure is
> >>>not constant. The Diesel two stroke is a Diesel cycle because it also
> >>>includes the same phases and the fuel burns at a fairly constant
> >>>pressure.
> >>>
> >>
> >>I guess I'd quibble with the statement that the Otto cycle has nothing
> >>to do with four-stroke engines- it was the first successful cycle to
> >>incorporate four strokes. yes, there are other four stroke cycles, but
> >>the Otto cycle is still by far the most common. There have been several
> >>other four-strokes, several two-strokes, at least on six stroke- I
> >>suspect several also.
> >>
> >>New IC engine designs are among the most numerous US patents. Just
> >>because something is patentable, of course, does not make it good or
> >>successful, and most of these patents were for approaches that offered
> >>insufficient advantages.
> >>
> >>BTW, as I understand the new Miller cycle, I don't consider it a truly
> >>new cycle- just a clever mod on the Otto. I don't consider the Otto
> >>cycle to require valve openings at closings at the top or bottom dead
> >>center, exactly.
> >
> >
> > The confusion is that Otto invented the first four stroke engine and
> > called it the Otto cycle, not because of thermodynamics but because he
> > put it in a motorcycle. However the thermodynamic cycle can be
> > reproduced with a two stroke engine. Its just that the intake and
> > exhaust cycle's are much shorter.
> >
>
> I am not sure what you mean by exhaust and intake "cycles". There is
> one cycle- the actions that the engine goes through before everything
> repeats. Do you mean the portions of the cycle during which the exhaust
> and intake take place- they definitely take less crankcase revolution angle.
>
> In the Otto cycle it is easy to break it down into four operations, each
> lasting one stroke. A two-stroke is more complicated, because it still
> has (existing, contemporary ones, do anyway) four seperate functions of
> intake, compression, combustion and exhaust, but have to do it in two
> strokes.

Sorry for the confusion, the two stroke doesn't take a stroke for those
functions so I used cycle, can't think of anything else to call it.

[Morgans]

"Don Stauffer" > wrote

> A two-stroke is more complicated, because it still
> has (existing, contemporary ones, do anyway) four seperate functions of
> intake, compression, combustion and exhaust, but have to do it in two
> strokes.

And some of the operations are happening simultaneously.

[Bill Daniels]

"Morgans" > wrote in message
...
>
> "Don Stauffer" > wrote
>
> > A two-stroke is more complicated, because it still
> > has (existing, contemporary ones, do anyway) four seperate functions of
> > intake, compression, combustion and exhaust, but have to do it in two
> > strokes.
>
> And some of the operations are happening simultaneously.

There is one very efficient 2-stroke variant that does have separate and
distinct intake, compression, combustion and exhaust functions - the
opposed-piston 2-stroke diesel with the pistons driven by cams, not
crankshafts.

As the pistons move apart (power), the exhaust port is uncovered first by
one piston (exhaust) and then the intake is opened by the other piston so
high pressure air from the supercharger can scavenge the last bits of
exhaust gas from the space between the pistons. After the cylinder is
scavenged, the first piston closes the exhaust port leaving the intake port
open so the supercharger can charge the cylinder with air (intake). Then
both pistons move together closing the intake port (compression). Fuel is
injected directly into the space between the pistons which forms a spherical
combustion chamber (ignition). The cams are designed to optimize the timing
and duration of the port openings as well as contour the compression and
power strokes.

This design makes extreme demands on metallurgy and lubricants so is just
now becoming practical.

Bill Daniels

[Sport Pilot]

Thinking a very large version of that was used before?

[Don Stauffer]

mastic wrote:
> "Sport Pilot" > wrote:
>
>
>>Here is an animated link showing the differances of the Otto and Diesel
>>cycles.
>>
>>http://www.ulb.ac.be/sma/testcenter/Test/solve/systems/closed/process/specific/closedcycle/closedcycle.html
>>
>>Notice the near instant burning in the example gives very nearly a
>>constant volume, in actual practice some compression is going on at
>>this time.
>>
>>Also during a Diesel cycle it is hard to maintain a constant pressure,
>>it would actually drop off, especially near the end of the down stroke.
>
>
> But both are still otto cycles.
> If you think the fuel burns instantly in a spark engine remove the
> exhaust manifold and run the engine, observe the flame exiting the
> exhaust port.

Indeed, if it does burn "instantly", that is detonation. However, it
burns more rapidly in a SI engine than in a true Diesel cycle Diesel. In
fact, it is astonishing to me how fast one can turn even relatively
large SI engines, such as Formula 1 car engines. Is there no limit :-)

[Don Stauffer]

mastic wrote:
>
> Otto cycle = four stroke, nothing to do with fuel injection, burn
> rates, phases of the moon or the flavor of ice cream.
> See
> http://en.wikipedia.org/wiki/Otto_cycle

I thought the Otto cycle was supposed to have the power stroke be
ideally completely adiabatic.

[~^Johnny^~]

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On Sun, 17 Jul 2005 11:48:43 -0500, Don Stauffer
> wrote:

> it is astonishing to me how fast one can turn even relatively
>large SI engines, such as Formula 1 car engines. Is there no limit
>:-)

http://www.petting-zoo.net/~deadbeef/archive/5304.html


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--
-john
wide-open at throttle dot info