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Diesel-Like Engine Could Boost Fuel Economy By 50%
bonch writes "Autoparts manufacturer Delphi has developed a diesel-like ignition engine running on gasoline, providing a potential 50 percent efficiency improvement over existing gas-powered engines. Engineers have long sought to run diesel-like engines on gasoline for its higher efficiency and low emissions. Delphi's engine, using a technique called gasoline-direct-injection compression ignition, could rival the performance of hybrid automobiles at a cheaper cost."
FTFA: Diesel is dirty and requires expensive exhaust systems.
What keeps diesel engines from becoming a standard in the US? I know regulations nearly disappeared them from the market, but that was for environmental reasons, which are the very reasons why diesel cars are attractive. While in Europe it is not outside the norm, here it seems like you are committing a crime if you run a diesel engine.
Also - since diesel engines are so efficient and all - what stops them from making a hybrid car that benefits from the even greater efficiency of diesel? or this new type of diesel like gas engine for that matter?
Many reasons diesel hasn't been popular in the U.S. One reason is environmental concerns - at least in the north east U.S. and California, our emissions standards, particularly for particulates and sulfur compounds, are much stricter than Europe. A second reason is that people tend to buy cars based on horsepower, and diesels lag there. Third, lots of people have bad memories of noisy, smelly diesel engines from the 80's. Fourth, diesels cost more. All that said, they are making a comeback with the newer offerings from VW and BMW (and Mercedes?).
I believe the reason diesels haven't been seen in hybrids is a combination of several factors. One, they are heavier than gasoline engines which in a hybrid already facing weight issues due to batteries could be a problem. Second, they are more expensive than gasoline engines, and again hybrids already face a cost problem. Third, the efficiency gains using gasoline engines have been sufficient to set them significantly apart from most non-hybrid cars, so the additional mileage you might get from using a diesel instead isn't worth the additional cost and weight.
It is niether a bad idea nor magic. By pulsing injections they make the combustion behave closer to the Carnot cycle ideal, which is more efficient than the Otto cycle.
That aside, I have my doubts about the 50% improvement. And diesels are already closer to the Carnot cycle so you could say they are effectively running a diesel on gasoline.
One important benefit it could have over diesels though, is that diesel burns fairly slowly compared to gasoline - which is the reason why diesels rarely rev above 5000 or so. If they manage to get diesel-type efficiency but with faster-burning gasoline, it could result in an engine that feels and behaves like a gasoline engine but has the mileage of a diesel. That would be nice.
It's probably inevitable-- it's just a question of when. Battery cost per kWh has been decreasing at around 10% per year, and gasoline is getting consistently more expensive. It seems incredibly unlikely that both of these would stop moving toward the crossover point.
Gasoline engines have been keeping up with that 10% though. In 1998 the Ford Mustang GT with a 4.6L V8 had about 215hp. In 2011 the Mustang GT 5.0L V8 packed in 412hp. That's about 7% a year increase in power and a slight increase in mileage. It stands to reason if that extra efficiency was put towards more mpg instead of more power, that crossover point could be farther out than you think.
The good news is it's getting better on both fronts and fast!