Reuters. Fiat, currently the number one automaker in Brazil, has announced that it will research developing a car that runs on four fuels: gasoline, diesel, ethanol and natural gas.

One of the fundamental differences between current diesel and gasoline engines is the method for injecting fuel into the cylinder and then combusting it. Gasoline engines pre-mix fuel and air, compress it and ignite it with a spark. Diesels inject a fuel spray directly into the cylinder where the heat of compression ignites the fuel. I’m just speculating on the above announcement, but to have one engine capable of burning both would seem to require either a very unwieldy kludge (e.g., supporting both direct- and spark-injection) or a transition to a different engine platform along the lines of an HCCI engine. (Earlier post.)

Researchers have been digging into HCCI and these fuel topics for several years. (There is also work being done, and some cars already produced, using a modified direct-injection system for gasoline.) Delivering a single-fuel HCCI platform will be challenging enough on the engine management side. Adding in the capability to switch fuels will require much additional software intelligence and control over the engine and emissions mechanisms. If successful, though, the result would be greater fuel-efficiency and emissions control.

Fiat already is in a partnership with GM in powertrains. (And it is GM which vies with Fiat to be Número Um in Brazil.) It will be interesting to see if they try to make this quad-fuel approach in Brazil, ahem, Real.