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Lotus Teases With a Fuel-Agnostic Two-Stroke Engine
JohnnyBGod writes "Lotus claim to have invented a new, more efficient engine design. The two-stroke, flex-fuel engine can achieve, according to the surprisingly technical press release, 'approximately 10% better [fuel consumption] than current spray-guided direct injection, spark ignition engines.' The engine has a sliding puck arrangement to control its compression ratio, and has direct injection and a wet sump, to eliminate fuel leakage to the exhaust and the need to mix oil with the fuel, two common problems with two-stroke engines. Lotus engineering have released a video explaining the engine's operation."
10%? So that's what? 22% instead of 20%? Whoope!
Ford built a Fiesta with a two-stroke engine that achieved 1.4l/100km (that’s 168 mpg!) in 1996! Not a drawing. Not a experimental model. No, a real driving prototype car. Looked just like a normal Fiesta.
I wonder why it took until now, for something that’s still worse to come out.
If I were the Ford engineer, I would be angry as hell.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
They can be run on multiple fuels (or indeed, mixtures thereof) and would be ideal for a series-hybrid vehicle, where the drivetrain could be eliminated (it was the weak point in the turbine cars.)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
You've missed the Flex-Fuel. It will run on any variation of ethanol/gas mixture, from E5 all the way up to E100. You decide how green you want to be and this engine will adapt to your choice of fuel.
You've missed the Flex-Fuel
There are lots of Flex-Fuel cars on the road these days. The big difference here is that it runs efficiently on multiple fuels.
Current flex fuel vehicles run on a standard ~9:1 compression ratio. This ratio burns regular 87 octane pump gas just fine. But E85 has an octane rating of approximately 105. This means it can run at much higher compression ratios (like 14:1). Higher compression ratios mean higher efficiency.
Because current Flex-Fuel vehicles burn E85 at 9:1 compression ratios, they experience a 30% reduction in efficiency on E85. This engine won't experience that. Not only can it run on multiple types of fuel, it can do so efficiently.
I'm interested in what kind of control logic they use to vary the compression ratio. How do they know the combustion properties of the fuel?
Disclaimer: I am a combustion engineer, and I have spent the past 3 years working on 2-stroke diesel engines.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
Not picking a fight here so please don't take it that way
Do you realize that using Electricity or Hydrogen is not quiet as green as everyone thinks is?
The combustion of H and O2 yields H2O but I have yet to see the spectrum of the exhaust gases of H - Atmosphere - Oil Vapor combustion.
I suspect it is something quite different then what the public has been sold since our atmosphere is 78% nitrogen, 21% oxygen, 0.93% argon, 0.038% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.
Until we find a way to isolate H from available sources with an efficiency factor an order of magnitude better then what we have now the cost will stay prohibitive.
Electric cars are great and battery technology is getting there but still quite a ways out for a pure electric ( as opposed to Hybrid ) vehicle that has the range and performance of the most efficient petroleum powered vehicle.
Electric cars are mostly a shift of the pollution problem from individual power generation ( the engine burning petroleum ) to the very very large and new power plants that would have to be built to charge those batteries.
I have never seen a study that shows how many Megawatts are produced by the average number of cars being driven at one time but I suspect it is rather high value. Just a completely off the cuff calculation here but, the San Francisco Bay Bridge has about 250,000 cars crossing it every day.So the average maximum power output of those cars is probably around 149 KW. Assume that each runs about 50% of rated power on average so... 74.5 KW * 250000 = 18.5 MW
So assume that an internal combustion engine is only about 30% efficient and an electric motor can approach about 90% efficiency in the 50 to 100hp power range. so 18 div 3 = 6 MW (give or take). So by that very rough calculation we need to add 6 MW of capacity just for the cars crossing the bay bridge in any 24 hour period.
That additional capacity has to come from someplace. We are pushing a very fine line on hydro power since we are trying to balance fish stocks and habitat -v- building bigger damns, I doubt it can come from there. So what does that leave? Geo-Thermal, Solar, Wind, Nuclear and of course fossil fuel. So the question is, which do we start building more of, and in who's backyard? These are hard problems with no easy answers. People still need to get from point A to points B,C,D etc.
Hey KID! Yeah you, get the fuck off my lawn!
Wouldn't a knock sensor be able to tell the PCM when to back off the compression ratio? The PCM could maintain short and long term trim tables of compression ratios mapped to throttle angle. Some engines already use these sensors for short and long term spark ignition timing advance tables. As for recognizing the fuel type, unless it can rely on a knock sensor, I can't see any way to detect what the fuel type is other than some easily detectable property(electrical resistance maybe? density?).
What I'm curious about is how fast can it change the compression ratio? Is it throttle by wire? If not and you mash on the gas from a dead stop, does it try to combust a few cycles at 50:1 compression? If so, the engine will not last long. It will break parts quicker than you can say "cast aluminum piston".
You can't legislate goodness. Let each to his own destiny, by will of his freely made choices.