Cummins, the diesel engine maker , announced today that it would start conforming to 2014 fuel efficiency and greenhouse gases rules starting in January 2013. At that time, its engines, including the ISB 6.7 currently used in Ram trucks, will boost gas mileage by up to 2%.

Cummins high output diesel

Cummins' investments in natural gas engines have caused its stock to skyrocket in recent weeks; one line of engines will be launched through joint venture Cummins Westport in calendar year 2013. The engine is dubbed ISX12G, and will include a Jacobs engine brake ("Jake brake") -- an invention of Clessie Cummins . This new engine will be used by Peterbilt , which already uses Cummins Westport natural gas engines.

Cummins also announced that it would launch a new 15-liter engine based on its ISX15, which can use CNG, liquified natural gas, or bio-methane fuel, in 2015.