MINNEAPOLIS - Cummins is in the advanced stages of developing a new four-cylinder diesel engine potentially for the U.S. market, according to Motor Trend. The diesel engine maker was on hand at last week's U.S. Department of Energy Merit Review conference to provide a progress report on the engine it has been developing with the DOE using a Nissan Titan test truck.

In January 2010, the DOE provided Cummins with $15 million to help fund development of an efficient diesel for light-truck use. Cummins began work last September with a goal to produce a diesel engine that would nearly double the efficiency of a Nissan Titan equipped with the current gasoline 5.6L V8 engine while not exceeding strict Tier 2 Bin 2 emissions standards. According to PickupTrucks.com, Cummins hopes to achieve 28 mpg combined with the new engine. A two-wheel drive Titan is currently rated at 15 mpg combined city and highway.

According to a DOE report, Cummins has focused on various areas to achieve its fuel and emissions goals. One priority is the expansion of low-temperature combustion (LTC) which should result in very low emissions. For added durability, the prototype engine contains high-strength steel pistons, which are stronger than aluminum pistons commonly found in most gas or diesel engines. Nitrogen oxide emissions will be kept at bay by the use of exhaust fluid already used in current heavy-duty diesel trucks.

PickupTrucks.com reports that the prototype engine-likely based on the European market Cummins ISF2.8-produced 350 lb.-ft. of torque during a recent dyno test. Cummins has set the final target output at 220 hp and 380 lb-ft of torque. The Titan's V8 puts out a bit more (317 hp and 385 lb-ft of torque).