Photos: Roark Johnson
IC Bus and Power Solutions International have teamed up to bring the best propane engine to the school bus industry.
Inside of Power Solutions International (PSI), the brightly lit manufacturing facility in Wood Dale, Ill., the future of school bus engines is undergoing a revolution. Workers meticulously attach cylinder heads to the company’s signature alternative-fuel 8.8-liter engine. There’s a humming conveyor belt connecting the various build stations and plenty of automated machinery. But much of the work here is hands-on. “It gives us flexibility so we can create engines tailor-made for certain applications,” explains Jeff Ehlers, PSI’s vice president of on-highway engines. “We own the tooling, so we can do things other companies might not be able to do.”
It’s that ability to offer custom, purpose-built products that led Lisle-based IC Bus to partner with its suburban Chicago neighbor as the exclusive supplier of propane-fueled engines for its school buses, which the two companies expect to have on the road by the 2015 school year.
The seeds for collaboration were planted a few years ago when Troy Clarke, the CEO of IC Bus’ parent company, Navistar, personally drove a medium-duty test truck featuring the liquid-injected 8.8-liter. “He was amazed that we were able to create an alternative fuel engine that drives quietly, but with the power of a diesel engine,” says Eric Cohen, PSI’s chief operating officer.
It struck the leaders of both companies that the low-speed/high-torque profile would be ideal for the school bus market, offering all the fuel savings and environmental benefits of propane, without sacrificing performance. “We created an engine that has almost a flat torque curve. At very low RPMs, we’re able provide a lot of torque and a lot of power,” Cohen notes.
According to Don Wilkins, vice president of advanced product development for PSI and the main architect of the engine, one of the 8.8-liter’s major advantages for school bus fleets is its ability to handle a wide range of transmission options—an important consideration for districts with rugged and challenging terrain. “A lot of our competitors are producing [what are essentially] light-duty truck engines. There are compromises,” he says.
In contrast, the 8.8-liter from PSI works seamlessly alongside transmissions from heavy-duty suppliers such as Allison. “The acceleration is smooth, quiet, and delivers diesel-like performance,” Wilkins adds. “There’s no need to rev the engine out. It will simply climb the hill and be happy about it.”
Fueling the Future
When factored alongside propane’s inherent benefits, such as its ease-of-storage compared with other alternative fuels, the new 8.8-liter-powered IC Bus products have the potential to be game changers. “Propane is a great fuel because you can get a provider to drop a tank anywhere in America,” Cohen points out. “That means you can run longer routes without having to worry about finding a fuel station. Plus, we’ve seen municipalities cut their fuel costs in half. And at the same time there are less pollutants in the air.”
Thanks to the success of this cost-competitive and easy-to-integrate engine, the three-decade-old company has transformed itself from a regional diesel engine distributor into the world’s largest alternative-fuel engine maker. In 2003, PSI assembled a total of 5,000 engines; in 2015, PSI expects to build more than 100,000.
Both companies look forward to continued growth as they work in tandem to further the expansion of propane among school bus fleets. “It’s a perfect partnership,” says Cohen. “IC Bus has a wonderful product with a long history. We have a very unique engine that we’ve been able to tailor to their needs. Together, we’re providing something that doesn’t exist elsewhere in the industry.”
Horsepower: 270 hp at 2,600 RPM
Torque: 565 lb.-ft. at 1,500 RPM
Bore/Stroke: 4.35” x 4.50”
Compression Ratio: 10:1