Measure of the volumetric efficiency and evaporator device performance for a LPG SI engine

The use of LPG as fuel for spark ignition engines originally designed to be petrol fuelled is common practice in many countries. Despite some theoretical and technical advantages related to LPG fuelling of internal combustion engines, the driving force for the ever-increasing adoption of LPG as fuel for passengers cars still remains its low price. However, money saving for the end-user is falling down year after year enforcing both technical developments and scientific research. Following some previous experimental studies about the real performance of dual-fuel engines during LPG operation, the present paper deals with the two main problems related to LPG port-fuel SI engines: the volumetric efficiency drop and the LPG evaporator device performance. A passengers car SI engine equipped with a “third generation” kit for the dual-fuel operation was tested at the dynamometer. Measures of engine performance, volumetric efficiency and change of LPG thermodynamic states in the evaporator were acquired both in steady state and transient operation of the engine. Experimental data are presented and discussed to evaluate the performance of the dual-fuel engine.