Cummins propane engine project reaches demonstration stage

June 12, 2020 By    

A propane engine project, years in the making and backed by an established U.S.-based manufacturer, is on track to give the LPG industry a premier alternative fueling option for on- and off-road market applications.

AmeriGas bobtail photo courtesy of Cummins Inc.

AmeriGas is demonstrating Cummins’ B6.7 propane engine in a 2018 Peterbilt 337 geared for propane delivery. Photo courtesy of Cummins Inc.

Cummins, a publicly traded company with global headquarters in Columbus, Indiana, has been exploring the latest opportunities that are possible with propane. With Cummins building on its research into LPG’s fueling properties, the project has progressed in the areas of engine prototype development and vehicle integration, and has reached a critical final stage: field demonstration.

What happens from here will determine the fate of a product that Propane Education & Research Council (PERC) President and CEO Tucker Perkins says will move engine technology to another level and result in sweeping changes for on- and off-road applications, power generation, irrigation and the like.

This “sea change of technology and innovation,” Perkins says, will provide to the industry a propane bobtail that it can trust and believe in for delivery operations. “To have a brand like Cummins is an important step forward. With the brand comes a lot of protection around reliability, service and support.

“Beyond that, it becomes almost mind-numbing,” Perkins adds. “All of a sudden you have robust irrigation engines for farmers to pump 24/7, a stationary power unit for people who need reliable power. We have technology that could power a locomotive, a barge, a piece of construction equipment. It’s limitless with where we go from there.”

A history with Cummins

Cummins’ previous experience with a dedicated propane engine started 25 years ago when it worked to develop the B5.9LPG.

Perkins calls it a workhorse engine that’s still used today but adds any comparison to the current engine project is like comparing “the wagon you rode in as a kid and a Corvette.”

Cummins’ B6.7 propane concept engine currently being demonstrated leverages the heritage of its B Series diesel engines, optimized to excel with LPG’s unique fueling properties.

“We really wanted to push the envelope, to see what’s possible if we really go after everything,” says Sam Geckler, product line architect at Cummins.

That involved Cummins taking a deep dive into the science of the combustion, emissions control and performance capability of propane as an engine fuel. Propane’s excellent fuel qualities for an internal combustion engine, its low-cost and abundant domestic supply, and its safety record, among other characteristics, “dovetail together to make it an interesting and useful fuel for the market,” Geckler says.

“There are a lot of solutions in the marketplace with regard to customer-specific needs for power solutions, and propane could be one that gains more prominence or importance,” he says. “We need to understand it.”

The industry renewed talks with Cummins nearly 10 years ago when PERC identified the potential for propane in the company’s high-output demonstration engine designed to run on ethanol, recalls Consulting Solutions’ Larry Osgood, vehicle and engine technology development coordinator for PERC.

“I spent three years working with Cummins to get them to acknowledge that propane had an opportunity,” Perkins adds. “We had an unofficial relationship for three years, and that relationship began in earnest about five years ago.”

PERC has thought so highly of the B6.7 engine that it has approved about $6 million to support Cummins’ efforts, making it one of the largest projects financially in council history, Perkins says. On the market development side, the PERC president and CEO adds, the product will be one of the most revolutionary for the industry.

“It’s a new way of introducing propane, mixing fuel and air, compressing it and igniting it,” Perkins says. “The combination of that becomes revolutionary because we use modern engineering and manufacturing to create a perfect scenario to burn propane.”

The Cummins propane engine, featuring new cylinder head and valve train designs and air handling system, allows for high output, high efficiency and low emissions. It produces 375 hp and 880 lb.-ft. of torque. The product offering is validated through a published SAE International paper that, Osgood says, shows “this is real engineering and real international engine technology-level stuff.”

“It’s a lot easier to do any one of those things. It’s extremely difficult to do all three,” he says of the engine’s output, efficiency and emissions benefits. “That’s the package of hardware, technology and electronics working together to do all three in one engine.”

Perkins adds, “The engine exceeds our wildest expectations – clean, powerful, strong, durable, robust. In the lab, it’s proven itself over and over to be better than we hoped, even though what we hoped was unlike anything we’ve ever seen.”

Demo vehicle

AmeriGas is putting those engine qualities to the test in a 2018 Peterbilt 337 geared for propane delivery. The demonstration will run through the year as Cummins looks to collect more valuable data about the engine.

“As much as the data, we want to get the customer experience feedback,” Geckler says. “Is it appropriate? Is it doing the kinds of things they would expect and need to satisfy their business needs?”

Geckler presented on the engine project early this year at the World LPG Association’s Innovation for Growth Summit in Washington, D.C. He shared his excitement about the results at the time and how Cummins was meeting many of its goals for the program, particularly on the power side.

“We feel good about the efficiency of this engine, the application and the rating that goes with it. It’s a big truck,” Geckler says of the demo. “We expect the customer will be quite pleased with the performance, and we hope to demonstrate good efficiency out of it.”

Geckler anticipates the project ending in the first quarter of 2021. What happens then has yet to be determined.

“One possibility is nothing happens, but there are other potential outcomes,” the result of Cummins’ rigorous product-planning exercises, that must be weighed by company leaders, Geckler says. That includes the possibility of evaluating additional market applications for the engine.

PERC, meanwhile, plans to move forward, working to push the engine technology into the market and build support within the propane industry and among high-profile fleets like UPS, FedEx and Frito-Lay.

“People are thinking through: What is my commitment to diesel, electricity, natural gas. There is a huge chess board, if you will, of options and investments and market demand from all of these competing fuels,” Perkins says. “This is where we have a strong belief that this engine is so much better, cleaner, cheaper to produce and buy and operate than almost any other technology. It will be successful.”


Cummins and PERC hosted a webinar about the engine project. Click here to access the webinar and view other presentation resources:

  • PowerPoint presentation download (includes contact information).
  • Q&A download.
  • Contact form to submit questions and comments for Cummins.

About the Author:

Brian Richesson is the editor in chief of LP Gas Magazine. Contact him at or 216-706-3748.

Comments are currently closed.