Study on a Gasoline/CNG Dual Fuel Engine

摘要

Aiming at solving the problems such as power loss and shortening in engine lifetime when fueled with CNG in a gasoline/CNG bi-fuel engine, a new gasoline/CNG dual fuel engine is introduced in this paper. A new special designed ECU that can integratedly control gasoline/CNG is developed, based on a bi-fuel engine which was modified from a prototype gasoline engine, and a dual fuel engine which can burn the gasoline/CNG mixture is put forward. The influence of various proportion of gasoline and CNG on engine power performance and emissions were investigated. The experimental results show that engine power, torque and exhaust CO, HC and NOx emission will decrease with the increase of CNG proportion in the gasoline/CNG dual fuel operating on the stoichiometric air/fuel ratio under the same engine speed and throttle opening. The maximum cylinder pressure, the maximum rate of pressure rise, the maximum rate of heat release, the initial combustion duration, the rapid combustion duration and the total combustion duration will increase with the increase in CNG/gasoline ratio under the same engine speed and load. The results suggest that optimized gasoline/CNG ratios should be adopted for different engine loads for achieving engine power performance and lower emissions.