two stroke diesel

poadeleted21

poadeleted21

Touchdown! Greaser!
Joined
Aug 18, 2011
Messages
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I See some are being developed for automotive use. I know nothing about them. Are they viable for aircraft operations? I looked up the current set of aircraft diesels, they sem to be 4 stroke.
 
bartmc said:
I See some are being developed for automotive use. I know nothing about them. Are they viable for aircraft operations? I looked up the current set of aircraft diesels, they sem to be 4 stroke.
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We had a Minneapolis Moline propane 2 stroke tractor when I was a kid, the only thing it was good for was belt power. It simply wouldn't pull and in cold weather it was impossible to start.
 
Tom-D said:
We had a Minneapolis Moline propane 2 stroke tractor when I was a kid, the only thing it was good for was belt power. It simply wouldn't pull and in cold weather it was impossible to start.
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Sounds like a motorcycle I had back in the '60s. I hear they are a little better these days.
 
Detroit Diesel won their claim to fame with 2-stroke diesels. They simply had a perforated cylinder liner and the heads only had exhaust valves. A supercharger would push the clean air into the cylinder when the piston was below the perforations. They were inefficient, noisy, and not as good as the competition. You can hang a picture of one on the wall and it would leak oil on the floor. Even though I don't like them, I made a good living working on them for the people that did.
 
Seems to me the only current two stroke diesels are very large, such as locomotive and ship engines. I'm surprised to hear that they may make a comeback in automotive use.
 
FormerHangie said:
Seems to me the only current two stroke diesels are very large, such as locomotive and ship engines. I'm surprised to hear that they may make a comeback in automotive use.
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I've toyed with and been around quite a few EMD's. Fun stuff!
 
Snake said:
Detroit Diesel won their claim to fame with 2-stroke diesels. They simply had a perforated cylinder liner and the heads only had exhaust valves. A supercharger would push the clean air into the cylinder when the piston was below the perforations. They were inefficient, noisy, and not as good as the competition. You can hang a picture of one on the wall and it would leak oil on the floor. Even though I don't like them, I made a good living working on them for the people that did.
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That leakage is not a flaw. It is just marking its territory.
 
Snake said:
Detroit Diesel won their claim to fame with 2-stroke diesels. They simply had a perforated cylinder liner and the heads only had exhaust valves. A supercharger would push the clean air into the cylinder when the piston was below the perforations. They were inefficient, noisy, and not as good as the competition. You can hang a picture of one on the wall and it would leak oil on the floor. Even though I don't like them, I made a good living working on them for the people that did.
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Me too.....

To the OP... The DeltaHawk aircraft diesel is a 2 stroke design also...

http://www.deltahawkengines.com/
 
bartmc said:
I See some are being developed for automotive use. I know nothing about them. Are they viable for aircraft operations? I looked up the current set of aircraft diesels, they sem to be 4 stroke.
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4 strokes are more efficient unless you are talking extremely large low speed (<150rpm) engines. Due to the need for supercharging to operate, they are not particularly simpler or more reliable than 4 strokes. The engine ends up close to the same weight because a 2 stroke needs a fatter bottom end than a four stroke. The GM 2 stroke Diesels even still have a cam and valve train. The pre DDEC engines used the same camshaft to drive individual combined pump/injector unit.

Any weight you may save back through using a 2 stroke optimized for high pressure common rail will probably be lost to the extra fuel you have to carry for the same range.

There is no real advantage to running a 2 stroke. A couple decades ago in California if you had one of the GM 2 stroke "Jimmies" (53-71-92-149) there was a state administered private fund IIRC that would pay to put modern electronic control engines in your work boat, the only limitation was you could only upgrade horsepower 10% on their dime.
 
Here is a bit of funny history coming full circle. The Detroit Deisel 'Jimmie Diesel' patent designs which effect everything up to the 710 EMD designs became the intellectual property of General Motors from MTU as part of the Treaty of Versailles and war spoils from WWI and now MTU owns Detroit Diesel.:D
 
GeorgeC said:
Speaking of two stroke diesels... http://en.wikipedia.org/wiki/Wärtsilä-Sulzer_RTA96-C
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Well, those are some pretty impressive numbers.

Configuration Turbocharged two-stroke diesel straight engine, 6 to 14 cylinders
Bore 960 mm
Stroke 2,500 mm
Displacement 1,820 litres per cylinder
Engine speed 22–102 RPM
Mean effective pressure 1.96 MPa @ full load, 1.37 MPa @ maximum efficiency (85% load)
Mean piston speed 8.5 meters per second
Specific fuel consumption 171 g/(kW·h)
Power Up to 5,720 kW per cylinder, 34,320–80,080 kW (46,680–108,920 BHP) total
Torque Up to 7,603,850 newton metres (5,608,310 lbf·ft) @ 102 rpm
Power density 29.6 to 34.8 kW per tonne, 2300 tonnes for the 14 cylinder version
Mass of fuel injected per cylinder per cycle ~160 g (about 6.5 ounces) @ full load
Crankshaft weight 300 tons
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bartmc said:
Ought to be enough to get a 172 in the air :D
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Not unless you beefed up the firewall and nosegear a bit. :)

http://web.archive.org/web/20100716202400/http://people.bath.ac.uk/ccsshb/12cyl/index.html.o
rta96c_crank.jpg

rta96c_cyldeck.jpg

rta96c.jpg
 
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