Gasoline-powered diesel-like engine could boost fuel economy by 50 percent
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.
Source: Technology Review, Delphi
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it;s not like they use ANY energy at all
so why couldn;t this more efficient engine just go ahead and use spark plugs, since it seems to be a major problem to eliminate them, what problem does eliminating them solve?
Next the 'hybrids' now available aren't. Only the Volt and Prius new plug in hybrids are true ones. The present 'Hybrids' just have electric boost.
What is really needed is the Toyota X-1 all composite Hybrid which will get over 100mpg. I'm building another 2 seat version that will get 200mpg in stronger than steel composites, EV drive, 80 mile range and rarely used unlimited range gas generator.
Sadly no one want to build these it seems and we need them as gas goes up with a bullet.
The efficient engines can run at lower, steady RPM's... And the concept is not new, it's been around about a hundred years. Just needs to be perfected, and with the advent of computer controllers, it should be a 100MPG car/engine concept.
In a spark ignited ignition a "slow" burning flame wall is ignited at the spark plug and works its way through the fuel creating pressure pushing the cylinder down.
In a compression ignited ignition all fuel immediately ignites in an explosion creating great instant force. This is what causes the loud pinging type sounds of older diesel engines.
It has the potential to increase performance if it can be controlled. Additionally it could prove to be useful in ultra lean burn technology which can greatly reduce the amount of fuel needed during a light cruise.
Looks to be possible that it will get greatly increased mileage. We can hope.