Freightliner Custom Chassis, CleanFuel USA, Powertrain Integration, General MotorsDevelopment, testing, and certification of an 8.0-liter engine for a range of medium- and heavy-duty applications.

8.0-Liter LPG Engine – Agricultural and Medium-Duty Truck and Bus (Docket 16723) — $2,000,000

Challenge The General Motors 8.1-liter engine — which is used in the Blue Bird Vision school bus chassis — has been phased out of production, creating a need for engines fueled by propane autogas in the medium- and heavy-duty vehicle market. Recognizing this opportunity, Freightliner Custom Chassis Corporation partnered with PERC to develop and certify an 8.0-liter engine fueled by propane autogas for use in medium-duty truck and school bus applications.

Partnership with PERCPERC is supporting Freightliner in the development, testing, and certification of an 8.0-liter engine for use in vehicles with 14,000-pound to 33,000-pound gross vehicle weight ratings, including school buses and bobtail trucks, and in agricultural and off-road applications. Freightliner will develop two school bus and bobtail chassis each, including the engine block, engine assembly, CleanFuel USA fuel system, and original equipment manufacturer control system. With the help of GM, Powertrain Integration, and CleanFuel USA, Freightliner will test the performance and durability of these systems and incorporate them into the 8.0-liter engine.

The 8.0-liter engine’s long block design incorporates improvements over the older GM 8.1-liter engine, including a stronger crankshaft, state-of-the-art tall-deck cylinder walls, new pistons with increased durability and decreased oil consumption, hardened valves, and optimized iron cylinder heads with improved cooling water flow and performance. To accompany these design improvements, Powertrain Integration is designing a new aluminum intake manifold that optimizes low-end torque, and CleanFuel USA is developing a new multivalve fuel tank assembly.

Result The 8.0-liter engine fueled by propane autogas is expected to be available for purchase in bobtails and Thomas Built school buses in early 2013. The engine will maintain the position of propane autogas in the school bus market, provide a propane autogas option in a bobtail market dominated by diesel, and expand propane’s use in off-road agricultural and industrial applications such as irrigation pumps and power generation.

  • Will meet GM durability, torque, and horsepower requirements.
  • Applications will be certified by the California Air Resources Board and the U.S. Environmental Protection Agency.
  • Vehicles will comply with Federal Motor Vehicle Safety Standards and with On-Board Diagnostic requirements through 2019.

For more informationVisit PERC's vehicles and equipment page