Study on combustion control of a methanol SICI engine

Abstract

Spark induced compression ignition (SICI) combined mode combustion can effectively solve the problems existing in homogeneous charge compression ignition (HCCI) combustion, and expand its operation range. The SICI combined combustion of methanol is divided into two combustion stages and has the characteristics of spark ignition (SI) and compression ignition (CI) combustion modes at the same time. This paper studies the SICI combustion mode of methanol from two aspects: simulation and experiment. The simulation results show that with the increase of the wall temperature, it indirectly affected the SICI combined mode combustion by affecting the hot atmosphere in the cylinder, which shortened the whole combustion duration, the SI and CI duration, it had little effect on the combustion ratio of SI and CI. The bench test results show that the methanol engine can obtain stable SICI combined mode combustion mode under the conditions of appropriate intake temperature and suitable ignition timing. From the comparison of three combustion modes of methanol, the results show that the cyclic variability of SICI combustion is the smallest. With the increase of inlet air temperature and the delay of ignition, the BP of SICI combustion at methanol starting point moves backward, the CI combustion rate decreases, but the SI combustion duration changes slightly, and the compression ignition ratio decreases. In the SICI combustion mode of methanol engine, with the increase of intake temperature, NOx emission increases, HC and CO emission decreases. With the advance of ignition timing, CO emission decreases, HC and NOx emission increases.