Fuel and Fuel System Effects on Low Temperature Operation of Diesel Vehicles

Fuel and fuel system effects on low-temperature operation of 1980 and 1981 GM diesels were determined for fuels both with and without flow improver additives. Without flow improvers, the 1981 vehicle, containing a bypass in-tank fuel filter and an electric fuel line heater, could be operated at temperatures about 5°C lower than the 1980 vehicle, at which point the fuel reached its pour point and would not flow. With flow-improved fuels, the 1981 system could be operated at temperatures 10-15°C lower than those achieved in the 1980 vehicle. These data confirm the effectiveness of fuel system changes, and demonstrate the need to include effective flow improvers in diesel fuel to maximize the effectiveness.