With both gasoline and diesel engines having their own particular advantages and disadvantages, automotive component manufacturer Delphi is looking for a best-of-both-worlds solution with a gasoline-powered engine that uses diesel engine-like technology for increased fuel efficiency. According to MIT’s Technology Review, such an engine has the potential to increase the fuel economy of gasoline-powered cars by 50 percent and give hybrid vehicles a run for their money in the fuel economy stakes.
Gasoline engines use spark for ignition while diesel engines rely on the heat of compressed air to ignite the fuel. There have been numerous attempts to develop gasoline-powered engines that use compression ignition, it has been difficult to provide the level of control needed under a variety of loads – idling, accelerating, cruising, etc.
Known as gasoline-direct-injection compression ignition, Delphi's approach reportedly overcomes this problem by "combining a collection of engine-operating strategies that make use of advanced fuel injection and air intake and exhaust controls." This includes injecting gasoline in timed bursts to reduce noise and maximize the speed at which fuel is burned.
Delphi has already built a single-piston test engine to demonstrate the technology and is now commencing testing of a multicylinder engine that would be closer to a production engine. Estimates resulting from simulations of how a midsize vehicle would perform with such an engine indicate that the new engines have the potential to improve the fuel economy of gasoline-powered cars by as much as 50 percent.
Mark Sellnau, the engineering manager of advanced powertrain technology at Delphi, told Technology Review that gasoline-direct-injection compression ignition engines could also be used in hybrid vehicles to further improve efficiency – although he’s unsure whether this would be worth the added cost.
A Technical Paper [PDF] on the Gasoline Direct-Injection Compression-Ignition technology was presented at the 2011 SAE® World Congress.