March 18, 2013 | 2 Comments
Cummins Inc. and Peterbilt Motors Company have released their test results showing their demonstration SuperTruck tractor-trailer achieved a 54% increase in fuel economy. Cummins, the prime contractor leading one of four vertical teams under the Department of Energy’s SuperTruck project shows nearly 10 mpg US (23.5 l/100 km) under real world driving conditions.
The SuperTruck project is one of several initiatives under the 21st Century Truck Partnership. The objectives include 50% thermal efficiency improvements in test cell, a 50% drive-cycle freight efficiency improvement, show a 68% freight efficiency improvement over a 24 hour drive and driver rest cycle. The big objective is demonstrating improvements for 55% engine efficiency. The effort isn’t quite there, but the results are astonishing for now.
The SuperTruck at a combined gross weight of 65,000 lbs averaged 9.9 mpg during testing last fall on U.S. Route 287 between Fort Worth and Vernon, Texas. The testing was conducted over 11 runs meeting Society of Automotive Engineers international test standards along a 312-mile route. Today’s typical long-haul trucks usually only achieve between 5.5 and 6.5 mpg. A 54% 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 and cut 35% off the annual greenhouse gas emissions per truck.
The SuperTruck also demonstrated a 61% improvement in freight efficiency during testing compared to a baseline truck driving the same route. In this measure the truck is measured similarly to rail that uses a ton per mile per gallon rating. For the truck freight efficiency is based on payload weight and fuel efficiency expressed in ton-miles per gallon.
The Cummins, Peterbilt and partners truck gains from a higher-efficiency engine and an aerodynamic tractor-trailer that significantly reduces drag. The truck’s engine includes a Rankine cycle waste heat recovery system; electronic controls that use route information to optimize fuel use; tires with lower rolling resistance; and lighter-weight material throughout.
For Cummins and its partner’s part it’s a focus on the engine and its integration with the powertrain. To raise the thermal efficiency of the engine, they worked with increasing the compression ratio, and optimizing piston bowl shape, injectors and calibration.
On the exhaust gas side improvements included a lower delta-P EGR loop and turbocharger match. Parasitic power reductions addressed cylinder kit friction and cooling pump power.
“Many of the technologies we are testing on the engine and truck will be integral parts of the trucks of tomorrow,” said David Koeberlein, principal investigator for the SuperTruck program at Cummins. “We are focused on developing innovations that meet and exceed the needs of our customers, while helping to create a cleaner, healthier and safer environment.”
Peterbilt and its partners also worked on the drivetrain with improvements to the idle management system, weight reduction and vehicle climate control.
Most noticeable is the slick aerodynamic look from Peterbilt and its partners. From a larger looking airdam up front, side skirts starting at the front wheels going all the way back, and a closed gap between the tractor unit, the cargo van appearance is greatly cleaned up. There is also a big hint of a rear air management zone.
“Aerodynamics has been a significant contributor to the efficiency gains,” said Scott Newhouse, Senior Assistant Chief Engineer of Product Development at Peterbilt. “We are very pleased with what our team has been able to accomplish using a comprehensive tractor-trailer approach.”
It’s not all government money making the project go. Cummins, Peterbilt and their program partners will have invested $38.8 million in private funds over the four-year life of their SuperTruck program, with critical support coming through awarded matching grants from the Department of Energy’s Vehicle Technologies Program.
The partnership isn’t over yet. 2013 will testing on a new Peterbilt 579 that Cummins and Peterbilt are confident will take what has been achieved so far to even higher levels. The testing will cover using the new tractor-trailer design over a 24-hour period including the time when drivers are at rest but still need power for such things as the air conditioning, heating and small appliances.
There are about 2 million registered tractor-trailers on U.S. roads today, according to The American Trucking Association. These levels of test result numbers when applied economy wide add up to some huge numbers.
Working with Cummins and Peterbilt are major companies including Modine, Delphi, Eaton, Dana and Bridgestone.
Now if the new trucks are affordable and the government players can provide incentives and avoid mandates while keeping the various state truck regulations such that the market would be national in scope, a lot of money could be saved and a boom in truck building might get underway.