Cleanfuel Usa GM-LC8

The register lists here 3 versions with 318 to 346 hp rated output at 4,100 to 5,500 rpm, all with sequential injection and LPG or propane as fuel. Maximum torque ranges from 353 to 495 Nm at 3,100 to 4,200 rpm, model years from 2012 to 2017; the versions carry a USA certification.

Such LPG engines drive medium-duty commercial vehicles such as school buses and distribution vehicles, where autogas is an established alternative to diesel and petrol with lower local pollutant emissions.

Such LPG conversion engines built on large-displacement GM petrol blocks run, like their base engine, on the Otto cycle with spark ignition and a near-stoichiometric mixture; a conventional three-way catalytic converter is therefore sufficient for exhaust treatment, whereas a comparable diesel would need exhaust-gas recirculation, a particulate filter and an SCR system. Range stays tied to the available autogas infrastructure, so such vehicles mostly run on a depot basis, returning to their own filling station.

On a used purchase, the tightness of the gas system counts, along with the condition of the LPG tanks and lines, the spark plugs and injection valves, and the service history of the gas pressure regulator; service and spare parts for these converted engines are concentrated among specialist US workshops.