Peake Fuel Solutions has a new product called "Diesel Natural Gas," or DNG, that allows truck owners to run a Cummins ISX 15 engine on a combination of natural gas (CNG or LNG) and diesel, or on 100% diesel, with conversion kits that the company says pay for themselves in about a year.

Peake's DNG technology allows a Class 8 Cummins ISX15L engine to run a dual-fuel mixture of diesel and CNG or LNG while still offering the option of running on 100% diesel when natural gas infrastructure is not available. This conversion kit is the only natural gas retrofit certified by the Environmental Protection Agency for a Tier 4 "new" engine, according to the company.

A DNG-equipped truck was on display at the recent American Trucking Associations Management Conference and Exhibition. Booth staff explained that the system is a dual-fuel conversion, meaning it runs on a combination of diesel and natural gas at the same time. This means it retains diesel compression ignition, rather than the less fuel efficient spark-ignited used in 100% natural gas engines.

The peak amount of natural gas substitution is 70%, but a more typical ratio would be 55% to 65%, depending on load and other factors, booth staffers explained.

The truck at the show displayed two different CNG tank configurations -- stacked 83-inch-long tanks in a cabinet on the back of the cab, as well as a 90-inch-long CNG saddle tank on the passenger side that will hold about 45 diesel-gallon-equivalents of natural gas.

Because the system is on a new engine, the company had to do much of the same work to have the engine EPA-certified as Cummins does, but there were certain flexibilities because they are a small-volume producer, according to company representatives at the ATA booth.