You probably drive a gasoline car. And surely you've heard of cars with diesel engines.

But how about a car with an engine that burns both fuels, at the same time?

That's what Chrysler is working on, it turns out, funded in part with research dollars from the U.S. Department of Energy. Author Mike Levine broke the story on KickingTires.

Goal: great gas mileage

The goal, as always these days, is to increase gas mileage in future vehicles to meet regulations after 2016 that could see average fuel economy goals as high as 62 miles per gallon.

Like every other carmaker, Chrysler is looking to use smaller, more efficient engines to develop equal performance to larger engines, but using less fuel.

Fiat MultiAir

Fiat MultiAir

According to a presentation Chrysler made at the DoE's merit review, the technology is being tested in a turbocharged 2.4-liter four-cylinder engine. That engine is fitted with the MultiAir electronically-actuated valve technology developed by Chrysler's new owner, Fiat.

The goal is inject the diesel fuel, which has more energy per volume than gasoline, at specific points during the combustion process.

That allows the engine to use a higher compression ratio for greater efficiency without creating "knock," or the chattering sound that indicates an engine is pre-igniting its fuel because the cylinder is too hot.

The higher ratio makes the engine more efficient under partial loads, where engines spend most of their time.

25 percent better than old V-6

The experimental engine is expected to return city and highway gas mileage 25 percent better than that of the older 4.0-liter V-6 engine fitted to Chrysler minivans until this year, with similar performance.

That means that in a Chrysler minivan, the engine might be rated at 21 mpg city, 31 mpg highway--versus the old V-6's 17 mpg city, 25 mpg highway.

2011 Chrysler Town & Country

2011 Chrysler Town & Country

With a pair of turbos, one low-pressure and one high-pressure, plus no fewer than three fuel injectors--two for gasoline, one for diesel--the proposed engine sounds complex, meaning it may be expensive to build.

We're also not convinced that it's going to be easy to explain to harassed minivan-driving parents that they will need to fill up twice: once at the gas pump, then again for the "other fuel tank" at the diesel pump.

Still, better gas mileage will largely be achieved with innovative technologies, so we're all for Chrysler's research efforts.

Ford did it with ethanol

They're similar to research at Ford that used ethanol injection in a smaller, boosted engine to achieve the same efficiency goals. The difference, of course, is that pure ethanol (E100) is available almost nowhere, but diesel fuel can be found in roughly half of the 150,000 filling stations in the U.S.

Total funding for the project is $30 million--roughly half from Chrysler and various technology partners, and half from the DoE.

The project started last May, and the design and simulation phases are ending this month, with the next steps to be designing and building one or more test engines. The complete effort is projected to run through April 2013.

For more details, see not only the Kicking Tires article below but also Chrysler's presentation to the DoE.

[Kicking TIres]


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