Engine Performance and Emission Characteristics of DME Diesel Engine With Inline Injection Pump Developed for DME

The engine performance and exhaust characteristics of the DME-powered diesel engine with an injection system developed for DME were investigated. The injection pump is an inline type that can inject double amount of DME fuel compared to the base injection pump because the calorific value of DME is about half lower than that of diesel fuel. The effect of injection timing on engine performances such as thermal efficiency, engine torque, and exhaust characteristics were investigated.

Maximum torque and power with DME could be achieved the same or greater level compared to diesel fuel operation. Considering over all engine performances, the best dynamic injection timings without EGR were -3, -3, -6 and -9 deg. ATDC in 1120, 1680, 2240 and 2800 rpm engine speeds respectively in this experiment. Deciding the operating condition of this DME engine to be the same level as NOx emission with diesel fuel without EGR, the brake thermal efficiencies with DME were almost lower than diesel fuel at low and middle engine speed. However, in high engine speeds the brake thermal efficiencies were cross or at almost the same level as NOx emission level. In spite of lower injection pressure, there were negligible problems on the atomization of the DME spray for CO and soot emission.