There has been a lot of talk of adding a small diesel to half-ton pickups in recent years, but little action. It appears Nissan may be on the path of action for the next-gen Titan.

Renowned diesel engine developer and producer Cummins, Nissan Motor Company and the Department of Energy have teamed up to create a working prototype half-ton pickup powered by a four-cylinder turbocharged diesel that may reshape the pickup market for North America.

The special project was recently announced at the Department of Energy's 2011 Merit Review, held in Washington, D.C.. As explained at the event, the DoE is providing $15 million of the $30 million being allocated to the project, which so far has produced promising results as outlined by PickupTrucks.

Officially, the project started last September, but it is possible Cummins had already put some time into their newest small diesel (or borrowed much of the design from its existing offerings from other market), as Nissan already has a fully functional prototype in testing, featuring the 2.8-liter inline-four engine.

The engine is producing torque in the realm of 350 lb-ft based on dyno testing, but horsepower figures were not yet released. PickupTrucks points out, however, that Cummins has both a 2.8-liter and a 3.8-liter turbo diesel in European markets, with the larger variant producing just 168 horsepower to go along with a more substantial 443 lb-ft of torque.

Should the horsepower rating coming in 20 percent lower than the comparable 3.8-liter unit already in service (350 torque represents a 20 percent drop from 443), horsepower could be in the neighborhood of 133. Even with a very healthy 350 lb-ft of torque, a horsepower rating of just 133 could prove to be insufficient for many Americans, even if the fuel economy is substantially higher.

How much higher, you ask? The DoE says it is aiming for a combined rating of 28 miles per gallon, which suggests highway fuel economy in the mid-30s - effectively doubling the dismal 17(2WD)/18(4WD) highway rating of the 5.6-liter gas-powered Titan currently for sale. Given the fact that the EPA is calling for a 30 mpg rating for light-duty trucks and SUVs by 2016, this engine may just fit the bill.

To achieve such a substantial gain in fuel economy, Cummins used a series of new technologies to boost efficiency. One such technology was the implementation of diesel exhaust fluid to help remove nitrous oxide from exhaust fumes. This technology is already being put to use in the latest offerings from Ford and GM, albeit in heavy-duty applications.

Cummins also outlined a NOx passive storage system which would store NOx produced during cold starts, later releasing it once the emissions system was up to running temperature.

It also just so happens that the next-generation Titan is due to arrive around 2016, which means Nissan and Cummins may be working on more than a government project, but a possible prototype for a future production vehicle. So far, neither party has confirmed production plans for the Cummins diesel in a future Titan truck.

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