Fuel temperature control in LPG fuelled SI engines

LPG is the most widely used fuel in spark ignition (SI) engines after gasoline. In SI engines, temperature of the fuel-air charge affects the engine performance and exhaust emission characteristics. At higher engine loads and speeds, LPG can be overheated. This will cause an increase in the charge temperature, and a decrease in engine performance. NO_x emissions will also increase as the charge temperature increases. By controlling the LPG temperature, some advantages can be gained. In this study, some preliminary results of a fuel temperature control system on engine performance and emission characteristics will be discussed. As the temperature of the engine cooling fluid changes, a valve controlled by LabVIEW adjusts the mass flow rate of the fluid to hold the LPG temperature in a band before injecting it to the engine intake manifold.