Photo courtesy of ROUSH CleanTech.

Photo courtesy of ROUSH CleanTech.

ROUSH CleanTech will begin offering a medium-duty engine powered by a propane autogas that's 75% cleaner than the current emissions standard and has been approved for use by regulators, according to the company.

The Livonia, Mich.-based vehicle modifier will also make the engine available for Blue Bird buses. The engines have been certified by the Environmental Protection Agency and California Air Resources Board and emit a nitrogen oxide (NOx) level of 0.05 grams per brake horsepower per hour.

"ROUSH CleanTech’s low NOx engine is a great step forward for the propane industry," said Tucker Perkins, president of the Propane Education & Research Council. "Propane autogas is well established as an economical, clean-burning and domestically produced alternative fuel ideal for fleets."

The vehicle is powered by the 6.8-liter V-10 3V engine used in Ford vehicles. The engine is converted to run on propane autogas.