Diesel engine performance as influenced by fuel temperature

The effects of diesel fuel temperature on the efficiency of a 4.4-L diesel engine were studied. Fuel temperatures of 41, 67, and 81 °C were used with engine loads of 0 to 100% of full load at three engine frequencies. Regression equations were developed that predicted fuel economy as a function of PTO power at three engine frequencies. An increase in engine fuel temperature did not improve fuel economy, but did result in reduced fuel mass flow through the injector pump and reduced maximum PTO power. Reducing engine frequency improved fuel economy and supported the ‘throttle back shift up’ technique for saving fuel.