Medium-Duty Propane Engine Closing in on “Near-Zero Emissions”

September 18, 2018

By: Todd Mouw, President

Last year, alternative-fuel vehicle technology company ROUSH CleanTech introduced a propane autogas engine that was 75-percent cleaner than the EPA’s emissions standard for nitrogen oxide. This low-NOx 0.05 g/bhp-hr propane engine comes standard on all of the company’s 6.8L V10 3V propane vehicles.

Yet, the race was far from finished. The company set the bar even higher to meet California Air Resources Board’s lowest optional NOx standard of 0.02 g/bhp-hr — and they’ve done it! The focus and investment has paid off as the 2018MY Ford 6.8L 3V V10 engine is 90-percent cleaner than the current EPA’s most stringent 0.2 g/bhp-hr heavy-duty engine standard.

Production featuring these new optional ultra-low NOx propane engines has already begun with several dozen 2018 Ford medium-duty trucks and Blue Bird Vision Type C school buses.

According to Wayne Nastri, executive officer for the South Coast Air Quality Management District, “the development and deployment of near-zero emission vehicle technologies are critical to meeting clean air standards.”

A recent study from the West Virginia University Center for Alternative Fuels, Engines and Emissions examined tailpipe emissions in school buses. The end results showed that NOx emissions emitted from propane autogas school buses were 96 percent less than comparable current diesel models. These results don’t even take into account the 0.05g or 0.02g NOx engines that are now available.

The innovation in propane technology provides solutions that lessen the impact to the environment while leveraging an abundant, domestically produced fuel energy source that provides a favorable total cost of ownership for customers. Propane autogas has fueled transportation for over a century. It’s the fuel source in more than 18,000 Blue Bird school buses and Ford commercial trucks and vans operating in communities across the United States and Canada.

To learn more about ROUSH CleanTech’s alternative fuel vehicle technology that powers school buses and Ford commercial vehicles, please visit