Diesel engines can greatly boost fuel economy, but they're dirty.
That's why DaimlerChrysler is partnering with a company called Syntroleum, to come up with a new type of fuel for diesels that burns very clean. The beauty of this fuel is that it's made from natural gas that is currently flared off in the oil refining process. Because it has no sulfur you can run it in a diesel engine and add a catalytic converter to the exhaust system and clean it up to where it's as clean as a current gasoline engine.