Lighweight opposite 2-stroke engines

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Vigilant1

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Jbiplane, a two stroke that burns at the same hp as a 4 stroke the amount of fuel, is this possible today?
Valery will have more detailed information, but here's the fuel consumption/HP/torque graph for a large (100HP) Hirth water-cooled 2 stroke using fuel injection/electronic ignition:

3701-graph.jpg

At 80 HP, it is burning 4.8 gal/hour (18 liters/hour), which is about the same as an air-cooled 4-stroke engine. It's a bit hard for me to believe, honestly.
Price: The U.S. distributor sells this engine, with starter and PSRU gearbox, for about $14,000. Weight for engine, gearbox, exhaust, but without radiator: 127 lbs (58Kg)
 

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jbiplane

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Jbiplane, a two stroke that burns at the same hp as a 4 stroke the amount of fuel, is this possible today?
... It's a bit hard for me to believe, honestly.
Yes, dino already provide couple of samples. Direct high pressure injection on 2T give SPC equal to 4T engines.

But even simplest mono EFI on 2-strokes simplify user life and make fuel consumption acceptable and comparable to 4-strokes.
 

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They claim that with EFI and by running the engines at reduced power levels, they have fuel efficiency similar to 4-strokes.
Apples to apples and theory to real world.

Adding EFI to a 2 stroke can improve it's efficiency in the same way it does for a 4 stroke. It makes fuel metering more precise. The 4 stroke advantage is in cylinder clearing/scavenging. A 2 stroke is far more dependent on resonance to do this. In theory a 2 stroke operated at it's design point can do this as well as a 4 stroke. But that is just at the design point. Both 4 and 2 stroke engines can use variable bits of hardware to move this resonance point over a range of rpms. The 4 stroke is just naturally better because it uses a dedicated exhaust stroke and wastes a bunch of time.
 

Vigilant1

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Adding EFI to a 2 stroke can improve it's efficiency in the same way it does for a 4 stroke. It makes fuel metering more precise.
And at RPMs different from the resonance design point, direct injection EFI can improve 2-stroke specific fuel consumption by delaying introduction of the fuel until the exhaust port has closed. In this respect EFI is a more fundamental assistance to 2-strokes than 4-strokes (which have always had the exhaust "port" closed when the fuel arrives).
 

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In this respect EFI is a more fundamental assistance to 2-strokes .
And I'm kind of surprised that none of the automakers has followed this path - especially with hybrids where the 2 stroke can operate in a narrow rpm range. If they ever do that then we have a nice new source of auto engines adaptable to aircraft use.
 

Vigilant1

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And I'm kind of surprised that none of the automakers has followed this path - especially with hybrids where the 2 stroke can operate in a narrow rpm range. If they ever do that then we have a nice new source of auto engines adaptable to aircraft use.
Yes, a little efficient 20-30HP 2-stroke sustainer engine to recharge the batteries in a serial hybrid would be a handy thing for the E-AB crowd. Mazd was rumored to be working on a tiny Wankel for this purpose a few years ago.
Maybe the emissions regs are an issue. Even if the SFC matched a 4-stroke, the exhaust components/profile is likely going to be different (the 2 stroke is still going to have more combustion leftovers in the mix when it is burned, it's very unlikely the purge can be as complete as a 4-stroke). Even if the result from the 2-stroke was >better< for the environment, human health, polar bears, etc than the 4-stroke, the current regs were based on progressively whittling down the particular gases in a 4-stroke exhaust based on what was technically feasible. It would be strictly luck if >every< component in the 2-stroke exhaust met the requirements built for 4-stroke engines.
 

erkki67

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Ok, EFI is the magic word, but what about lubrication of the engine, has this to be done by prefixing the oil, or can the oil be injected into the engine directly, where it’s required?
 

jbiplane

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... has this to be done by prefixing the oil, or can the oil be injected into the engine directly, where it’s required?
Easiest way for existing engines when install EFI is premixing. Other variants on picture below, kawasaki variant. Works better than premixing and for EFI and for carb.
k1.jpg
 

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Ok, EFI is the magic word, but what about lubrication of the engine, has this to be done by prefixing the oil,
There are methods to avoid having to mix or inject oil but they aren't as simple as a the conventional 2 strokes in common use. The infamous Detroit diesel was an example, but it got legislated out of existence due to it being a very dirty engine. It's kind of ironic but that method coupled with modern direct injection has a pretty good shot at being, clean light and powerful. The market and legislators being what they are we may never know for sure.
 

blane.c

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I was thinking the primary advantage to using EFI is reducing pilot workload. If the pilot's responsibility is monitoring temps and pressures instead of adjusting for temps and pressures flight is safer because pilot spends more time flying, and the engine is more reliable because a computer can adjust for changes in a nano second. No pilot's reaction to engine needs is that fast. So flight is safer twofold, better vigilance and better engine reliability.
 

jbiplane

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That Kawasaki oil injection schematic is nice, to bad the oil isn't pressurized to the outboard bearing.
This schematic have couple of errors. Original Kawasaki have more details. I have somethere better picture.

Me personally modify this idea - I drilled by Super Drill EDM small hole in conrod along its length by to pass oil into upper bearing.
Drilling process in hardened steel look like this [video=youtube;vnmdrROssZM]https://www.youtube.com/watch?v=vnmdrROssZM[/video]
 
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proppastie

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At SKF we drilled 1/4 dia. in hardened bearing steel in about 10 sec. We called it ECM (electro chemical machining). The material was de-plated from around the electrode. This looks similar.
 

henryk

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Russian guy emigrated to USA made this amazing toy
[video=youtube;n4UxBQ-LLsI]https://www.youtube.com/watch?time_continue=90&v=n4UxBQ-LLsI[/video]
-can you translate="mozhik spit,a v polie pshenitza sama rastiot..." ?

=very cheap=5000 $ ???
 
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jbiplane

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-can you translate="mozhik spit,a v polie pshenitza sama rastiot..." ?

=very cheap=5000 $ ???
mozhik spit,a v polie pshenitza sama rastiot...
In cylilic sounds Мужик спит, а в поле пшеница сама растёт
Translation to English = The peasant sleeps, and in the field wheat itself grows

5000 USD is correct, but without protective gases can work with limited number of metal powders
 

henryk

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mozhik spit,a v polie pshenitza sama rastiot...
In cylilic sounds Мужик спит, а в поле пшеница сама растёт
Translation to English = The peasant sleeps, and in the field wheat itself grows

5000 USD is correct, but without protective gases can work with limited number of metal powders
-thankyou!

BTW=metal nanopowders are not cheap ?

=dr Sorokodums vortex technology can produce cheap nanopowders (f.e. alu...)
 
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