Key learnings from Volvo’s SuperTruck efforts played a critical role in the design and engineering of Volvo Trucks North America’s recently introduced 2017 powertrain, delivering improved fuel efficiency and performance to customers. The development of several new features, such as the wave piston, turbo compounding and a common rail fuel injection system, was supported by the SuperTruck program, sponsored by the U.S. Department of Energy (DOE).
“The DOE’s support, together with the skill of our powertrain engineers working on the SuperTruck program, helped generate significant powertrain innovations,” says Gӧran Nyberg, President of Volvo Trucks North America. “We look forward to offering these innovative design features to our customers, who depend on Volvo Trucks to help them generate greater fuel efficiency benefits, as well as increased productivity.”
The U.S. DOE SuperTruck program is a cost-shared, public-private partnership that promotes research and development to improve the freight-hauling efficiency of heavy-duty Class 8 long-haul tractor-trailer trucks. The program aims to help accelerate the development of advanced efficiency technologies that are not currently available in the market.
Volvo’s new 2017 powertrain offerings, which include new, enhanced Volvo D11 and D13 engines, turbo compounding for the D13 engine and a one-box Exhaust Aftertreatment System (EATS), demonstrate Volvo’s commitment to integrated powertrain development and feature components derived directly from the SuperTruck program.
The SuperTruck program enabled extensive research of a typical combustion chamber and provided Volvo engineers the opportunity to test a new piston design. This new design added “wave” bumps on the side of the piston bowl, which allows the fuel to burn more cleanly.
The exact design of the piston was matured through tests and simulations, enabling exceptional gains in fuel efficiency, while significantly reducing soot generation. The patented wave piston, working in combination with Volvo’s other engine enhancements, delivers improved fuel efficiency of up to 2.2% for the D11 and 2.5% for the D13.
Despite today’s efficient combustion and use of turbocharging, energy is still available in the exhaust in the form of heat and pressure. A new turbo compounding system was designed to recover this normally wasted energy on the 2017 Volvo D13 with Turbo Compound, helping boost fuel efficiency by up to 6.5%.
The SuperTruck program enabled Volvo engineers to refine the mechanics and aerodynamics of the new geartrain and turbine, ensuring peak efficiency in the “sweet spot” for Volvo’s integrated powertrain solution, which includes the I-Shift automated manual transmission and downsped engines.
Common Rail Fuel Injection System
A proven common rail fuel injection system was adapted to Volvo’s 2017 D11 and D13 engines. It enables a higher injection pressure, which improves combustion, and allows for finer control of the injection event.
Through the SuperTruck program, the fuel injection system was optimized to match the new wave piston. Extensive engine testing and simulations led to an injector with enhanced flow rate, spray angle and pressure characteristics that allow the engine to operate more quietly and burn fuel more efficiently.