Lotus Teases With a Fuel-Agnostic Two-Stroke Engine 269
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."
Internal combustion efficiency (Score:0, Interesting)
10%? So that's what? 22% instead of 20%? Whoope!
What took it all so long?? (Score:2, Interesting)
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.
I have in mind a superior fuel-agnostic engine (Score:4, Interesting)
They can be run on multiple fuels [wikipedia.org] (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 [wikipedia.org].)
Re:What took it all so long?? (Score:4, Interesting)
Euro & Japanese manufacturers are less influenced by the US fuel lobby. Explain why petrol costs way less in the US : (the answer is taxation in Europe). The taxation strategy indirectly subsidises (it's not quite a subsidy, of course, but to the end user making one fuel cheaper than the other is akin to subsidy even if the difference is the level of taxation)
Agree in part with behaviour patterns in Europe, but I've seen roads from Fort Worth & surroundings to Dallas clogged with large vehicles mostly used for a less than 20 mile daily commute...
Re:10% improvement isn't that much (Score:5, Interesting)
Re:What took it all so long?? (Score:3, Interesting)
People tend to buy for worst-case instead of average-case scenarios - just in case they ever take that holiday to Disneyland, they don't want to pack in to a compact. Europeans on the other hand take a train.
What on earth are you talking about? You can't just make retarded, unsupported statements like that! We Europeans are quite fond of our cars, and have no problem packing a family of four into a typical European/Asian family car for vacation. if you think you need to drive a Hummer or a 2-ton pickup truck to get where you're going, then perhaps you should learn to pack your stuff with some common sense (and perhaps put your all-American family on a diet).
Yes, that diet comment assumed a very clique image of Americans. I allowed myself this small freedom, as you seem to have no problem making stupid statements and assumptions about us.
Re:What took it all so long?? (Score:3, Interesting)
Re:What took it all so long?? (Score:3, Interesting)
Actually the ppm (parts per million) ratios are gone for on highway in the US, it is purely a grams per mile emissions standard for on highway cars in the US [dieselnet.com]. It is percent emissions only for off highway. However, that's for the manufactures to meet, your local emissions test is going to be a PPM rating that they look-up for compliance, so I understand the confusion.
Re:What took it all so long?? (Score:3, Interesting)
My '79 truck had one of those. Only thing it was good for was decreasing gas millage (caused by having to operate the pump? or by increasing the pressure engine that the engine had to push against when expelling exhaust?) My parents yanked that thing off pretty quickly at the recommendation of our mechanic. But, to this day I cannot register that truck in the city because I have removed an "emission decreasing device", even though the actual emission are well below the limits, and the damn pump actually increased actual emissions since it burns more gas with it on. I might not be so opposed to the idea of government regulation if the people doing so didn't constantly prove themselves to be idiots.
Re:10% improvement isn't that much (Score:3, Interesting)
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.
Re:10% improvement isn't that much (Score:3, Interesting)
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.
Re:What took it all so long?? (Score:3, Interesting)
A well done two stroke won't consume lubrication oil, that's the whole point of the wet sump in the Lotus engine. Further, it can provide nearly twice the power for it's weight since each cylinder fires twice as frequently. It also means a two cylinder engine can run as smoothly as a 4 cylinder 4 stroke engine.
As for engine power, Americans have adapted. Every time I see a commercial talking about a powerful V6, I recall that at one time V6 was the wimpy economy option and the V8 was the powerful option. At that time, 4 cylinder meant it was a street legal go-kart.
When I learned to drive, you had to use finesse with the accelerator to avoid smoking the tires on take-off. The speedometer might only have gone up to 80, but the car would do 150. Look at what's for sale today and you'll see that indeed, American consumers HAVE changed.
Re:10% improvement isn't that much (Score:3, Interesting)
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".
Re:What took it all so long?? (Score:1, Interesting)
Er, in theory, Wankel could be "more efficient (all rotating parts, no complete turns in direction." It's a seductive idea, and a lot of serious engineering work has been done without success.
Around 1965 Ford and Curtiss-Wright put years of sincere arguing to the test by investing in building similar test units of each of around 200hp. They tested these in cars and in lightplanes, which have different power-curve needs. No vested interest -- these guys really wanted to know if the Wankel was the future to build factories around. It didn't work out. At the end of the day the engines were coin-toss similar, plus the Wankel required more expensive machining.
And we haven't had any success since. Mazda, which competes in efficiency markets with pistons, only uses the Wankel in niche sexy sports cars because the Wankel is niche and sexy. I really like them, but they're not better, just different.
Very sorry I don't have a citation -- I read through the test results in my aircaft college library back in the 80s. It'd be /great/ if some current engineering student would unearth and upload these. And I'm kinda guessing no one has yet because only Wankel enthusiasts would track them down, and people tend to stop being Wankel enthusiasts after reading them.
Re:What took it all so long?? (Score:3, Interesting)
...I don't see me putting a diesel engine in my motorbike anytime soon...
Hayes Diversified has been developing a diesel enduro (http://www.hdtusa.com/vehicle-m1030-m2.php) for military applications, it seems like a pretty neat bike, if they start selling them to civilians, I'd really have to have a look at that.
Also, there are some Royal Enfield diesel bikes. They have the vintage British Twin styling that RE licensed so very, very long ago (I guess it's a timeless design, especially in India), and the charming purr of a diesel engine. I must say I'm tempted by those too, but they're a bit hard to come by in the States.