Diesel-gasoline hybrid engine in the works at Chrysler
The Chrysler minivan’s engine may look, or at least act, a lot different by 2013. Argonne National Laboratory is trying to combine the positive elements of the gasoline engine and the diesel engine for use in such vehicles as Chrysler’s popular Town and Country minivan. Steve Ciatti, a mechanical engineer at Argonne, is leading a team that is attempting to construct and test a hybrid engine that will employ the properties of the diesel engine, mainly the ability of the diesel engine to use compressed air without a spark to ignite the fuel into energy. Argonne isn’t alone in the effort to bridge the properties of the diesel and gasoline engines. The U.S. DOE is partaking in the effort, along with partners Chrysler, Delphi, FEV and the Ohio State University.
The DOE has spent almost $15.5 million on the project that first started in 2010, with the other partners putting up nearly the same amount. The end date for the project is scheduled for 2013 and to this point the work is only 17 percent complete, according to a presentation given by Chrysler during a DOE summit.
Argonne will continue work on the combustion properties of the engine, looking at fuel spraying imaging along with simulations of the engine. Delphi will work on the fuel control, FEV on the design of the engine, and OSU will work on controls for the thermal elements of the engine. “What we want to do is combine the efficiency of diesel with the cleanliness of gas,” Ciatti said on the work. “So we lose the throttle and spark plugs, because those create inefficiencies. We start with a diesel engine and inject gasoline, instead.”
As Ciatti said, the hybrid engine will work as a diesel would, compressing the air first before introducing the fuel, without using a spark plug for combustion. The compressed air is hot enough to create combustion a diesel engine, but the introduction of the fuel to the compressed air happens late in the engine’s cycle, effectively creating emissions. Because gasoline doesn’t ignite as quickly as diesel typically would when introduced to the compressed air, Ciatti said they can inject more fuel into the combustion chamber. This decreases the amount of emissions because a greater amount of fuel is mixed with the air, so more of the mix is turned into energy instead of NOx emissions.
To this point in the testing, results show the engine is 25 percent more efficient than a typical gasoline engine. The main deterrent of the hybrid is the loss of power when “the pedal is to the metal,” Ciatti said. But, for most drivers, those circumstances do not normally ever happen.
More than 80 people are working on the project, 16 of which are new positions created at Chrysler. The engine used for testing is a 4.0L V6 used in the 2009 Town and Country Minivan that typically gets 17 mpg in the city and 25 mpg during highway usage.