Medium-duty trucks such as this GMC Topkick can be ordered with the LPI fuel system. 
 -  Photo: GMC

Medium-duty trucks such as this GMC Topkick can be ordered with the LPI fuel system.

Photo: GMC

CleanFUEL USA has teamed with two other companies to develop and market propane-powered versions of trucks with General Motors (GM) 8.1L V-8 Vortec gasoline engine.

The Kodiak and GMC Topkick 3500-7500 series trucks use a liquid propane injection (LPI) fuel system developed by the Italian propane engineering company, ICOM, in conjunction with CleanFUEL USA. GM supplies engines compatible with gaseous fuels and vehicle bodies. The ICOM-developed system is installed, the vehicle control module (VCM) is reprogrammed, and the truck is shipped to the dealer for buyer pick up.

The LPI system used in the vehicles replaces the gasoline fuel tank, fuel pump, and fuel injector rails with a pressurized system that delivers propane to the engine ports as a liquid. The engine’s VCM is reprogrammed to run on liquid propane instead of gasoline to operate in the trucks. The LPI system controls fuel mixing and keeps the propane from vaporizing before injection.

Responding to Demand

In 2004, according to the CleanFUEL USA Web site, they responded to a demand by medium-duty truck and bus operators for a propane engine alternative. In conjunction with ICOM of Cisterna, Italy, the company developed an LPI system using its proprietary JTG-Common Rail technology for the GM 8100 Vortec engine. Based on European technology with more than 27,000 systems already in use, the LPI system delivers propane to the cylinders in liquid form, resulting in improved fuel economy and superior performance with lower emissions. The emissions meet estimated EPA requirements through the 2009 production year for both EPA 49 State and the California Air Resource Board (CARB) certification.

LPI is not just a liquefied petroleum gas (LPG) propane fuel system. It is an integrated system, designed specifically for the OEM engine. Using the GM P-59 engine computer with a dedicated calibration specifically for propane, the LPI system replaces the gasoline fuel tank, fuel pump, and injector rails with a propane fuel tank, pump, and injector rails. LPI is a direct replacement for the OEM gasoline injection system.

Cost Advantages

The LPI vehicles cost about $10,000 more than their gasoline counterparts but represent a $6,000 savings from a comparable diesel-powered truck. Taxable entities are eligible for a tax credit that equals 50% of the incremental cost of the vehicle, plus an additional 30% of the incremental cost for vehicles with near-zero emissions under the EPAct 2005’s Alternative Fuel Motor Credit. The LPI system on GM 3500-7500 series trucks is eligible for an 80% incremental cost credit. The propane used in the vehicles is also eligible for a 50-cent per gallon credit, regardless of tax status under the SAFETEA-LU Volumetric Excise Tax Exemption program.

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