COLUMBUS, Ind. – Cummins and Peterbilt have released test results showing their demonstration tractor-trailer achieved a 54 percent increase in fuel economy, compared to typical performance in similar situations. Under real-world driving conditions, the Peterbilt 587 powered by a Cummins ISX15 engine averaged 9.9 mpg during testing last fall on U.S. Route 287 between Fort Worth and Vernon, Texas.

This testing is part of an $80 million research project prompted by and partially funded by the U.S. Department of Energy. Cummins is a prime contractor, leading one of four teams under the DOE’s SuperTruck project. It’s one among several other public-private initiatives aimed at stimulating innovation in the trucking industry through the sponsoring government agencies, companies, national laboratories, and universities. Cummins, Peterbilt and their program partners will have invested $38.8 million in private funds over the four-year life of their SuperTruck program, which started in 2010, with matching grants from the DOE.

The “SuperTruck” developed by the two companies features a higher-efficiency engine and an aerodynamic tractor-trailer that significantly reduces drag. The truck also includes a system that converts exhaust heat into power delivered to the crankshaft, electronic controls that use route information to optimize fuel use, tires with lower rolling resistance, and lighter-weight material throughout.

During a dinner just prior to the Mid-America Trucking Show in Louisville, Cummins Turbo Technologies talked about a ‘Waste Heat Turbine Expander’ prototype, which captures what would otherwise be lost energy in the form of heat, from a number of sources onboard the vehicle — not just the exhaust — and turns it into 34 hp worth of useful mechanical power that’s capable of reducing vehicle fuel consumption by 5 percent. That technology, or something very much like it, is likely to be found on the SuperTruck, or soon will be.

The testing was conducted over 11 runs meeting SAE International test standards along a 312-mile route. The tractor-trailer had a combined gross weight of 65,000 lb.

Today’s long-haul trucks typically achieve between 5.5 and 6.5 mpg, says Cummins. The 54 percent increase in fuel economy would save about $25,000 annually based on today’s diesel fuel prices for a long-haul truck traveling 120,000 miles per year. It would also translate into a 35 percent reduction in annual greenhouse gases per truck.

In addition to the fuel-economy improvements, the truck also demonstrated a 61 percent improvement in freight efficiency during testing, compared to a baseline truck driving the same route. That’s based on payload weight and fuel efficiency expressed in ton-miles per gallon.

“Many of the technologies we are testing on the engine and truck will be integral parts of the trucks of tomorrow,” says David Koeberlein, principal investigator for the SuperTruck program at Cummins.

Cummins has been focused on the engine and its integration with the powertrain. They’ve been working with other companies and research institutions to develop changes in the combustion system as well as advances to reduce internal friction and so-called parasitic power losses from such things as lube and coolant pumps and air compressors.

In addition to the truck’s exterior, Peterbilt and its partners have been working on improvements in the drivetrain, the idle-management system, weight reduction, and vehicle climate control. An Eaton advanced transmission allows engine downspeeding for additional fuel economy benefits, for example.

Testing will continue in 2013 on a new Peterbilt 579. It will address use of the tractor-trailer over a 24-hour period, including times when drivers are at rest but still need power for such things as air conditioning and small appliances.