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Patent part of CNG Ram?

by David Zatz on

Chrysler is the only American automaker to make its own natural-gas (CNG) pickups, with GM and Ford both outsourcing CNG conversions. Part of their technology may be a technique for diagnosing fuel injector failures which works with both gasoline and natural gas, without adding much complexity or cost. Patent US008833148, filed by Michigan’s Robert G. Stack and Michael Cottrell, shows how the company achieved those ends.


While Chrysler has a history of making CNG-compatible vehicles in Canada, including large vans, Fiat is better known today for their flex-fuel vehicles, particularly in Brazil, where alcohol is added to the mix of common fuels.

The CNG-capable Ram 1500 automatically switches between gasoline, which it uses during warmup and when the other tank is empty, and CNG. This provides a combination of lower cost and convenience, and also increases the vehicle’s range, since CNG tanks take up much more space than gasoline tanks for a similar range. Thanks, Steven St. Laurent, Marine engineer.

David Zatz founded Allpar in 1998 (based on a site he had begun in 1993-94), after years of writing reviews for retail trades. He has been quoted by the New York Times, the Daily Telegraph, the Detroit News, and USA Today. Before making Allpar a full-time career, he was a consultant in organizational psychology. You can reach him by using our contact form (much preferred) or by calling (313) 766-2304

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