There are plenty of advantages to diesel engines: High fuel efficiency, low CO2 emissions, and in modern turbocharged applications, plenty of easy-to-access torque and power.
However, they aren't without their faults--expense, particulate emissions and a lack of smoothness compared to the best gasoline engines and hybrids.
A mix of diesel and gasoline characteristics would be appreciated by many then, and that's just what Delphi is aiming for with its new engine.
Using gasoline direct injection--but compression ignition, like a diesel vehicle--Delphi says its new engine would allow gasoline vehicles to rival the efficiency of hybrids. It would also eliminate some of diesel's less favorable characteristics.
Technology Review (via Gizmag) reports that Delphi has solved some of the normal problems of getting gasoline to work well using compression--rather than spark--ignition. Delphi combines "a collection of engine-operating strategies that make use of advanced fuel injection and air intake and exhaust controls". Those strategies include injecting gasoline in timed bursts to reduce noise and maximize the speed at which fuel is burned.
Delphi's prototype uses a single cylinder layout, but when scaled up to more realistic sizes--that of a midsize car, for example--the economy improvements could be as much as 50 percent.
Naturally, any internal combustion engine technology could then be paired with hybrid tech for even greater improvements, though Mark Sellnau from Delphi questions whether it would be worth the extra cost.
We expect that even with greater fuel efficiency, the extra cost of hybrid technology would still be little barrier to those looking to really reduce their fuel consumption, just as they do today.
The technology may also prove appealing for future range-extended electric vehicles, where a fuel-sipping engine is clearly more in-tune with the low-emissions ethos.
You can read the full technical paper on Delphi's engine here (pdf file).