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2-stroke diesel is the (near) future?



 
 
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  #1  
Old May 8th 05, 03:43 PM
Max Kallio
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Posts: n/a
Default 2-stroke diesel is the (near) future?

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.
  #2  
Old May 8th 05, 04:35 PM
Chas Hurst
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Posts: n/a
Default

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.



  #3  
Old May 13th 05, 01:26 AM
wingsnaprop
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Default

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?

  #4  
Old May 13th 05, 04:45 PM
Steve
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Default

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.
  #5  
Old May 13th 05, 11:39 PM
Morgans
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Default


"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

  #6  
Old May 16th 05, 05:35 PM
Steve
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Default

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.
  #7  
Old May 16th 05, 06:43 PM
Sport Pilot
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Posts: n/a
Default


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.

  #8  
Old May 16th 05, 07:04 PM
Sport Pilot
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Posts: n/a
Default

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

  #9  
Old May 16th 05, 09:03 PM
Steve
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Posts: n/a
Default

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.

  #10  
Old May 8th 05, 05:31 PM
Don Stauffer
external usenet poster
 
Posts: n/a
Default

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.

 




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