The experiment was conducted on a diesel-methanol dual fuel engine retrofitted from a high-pressure common rail engine at various simulated altitudes in order to investigate the cyclic variation of combustion for diesel and methanol dual fuel (DMDF) engine. The influences of engine load, methanol mixing ratio and injection parameter on combustion stability were researched at 1 800 r/min. Incylinder pressure parameters such as the maximum pressure (pmax) and indicated mean effective pressure (IMEP) were used to quantify the cyclic variations. The results showed that DMDF combustion in plateau condition had a similar trend to that in plain condition. With the increase of altitude, the variation coefficient of in-cylinder maximum pressure (COVpmax) increased, while that of indicated mean effective pressure (COVIMEP) decreased. The distribution of in-cylinder maximum pressure tended to concentrate at a certain range of crank angle at high altitude. The increase of pilot injection quantity suppressed the cyclic variation in plateau condition. At all altitude conditions, injection timing had little influence on COVIMEP, but was sensitive to COVpmax. Compared with other injection parameters, injection pressure had little influence on cyclic variation.
FANG Sheng
,
ZHOU Defeng
,
WANG Bin
. Cyclic Variation of Dual Fuel Engine Fueled with Diesel and Methanol at Different Altitudes[J]. Vehicle Engine, 2021
, 0(4)
: 22
.
DOI: 10.3969/j.issn.1001-2222.2021.04.004
