Experimental Analysis of Combustion and Cycle-to-Cycle Variations in a Methanol-Diesel Dual-Fuel RCCI Engine
Abstract
This study experimentally investigates the combustion characteristics and cyclic variations of a methanol–diesel dual-fuel RCCI application in a four-cylinder, turbocharged diesel engine. The experiments were carried out at a constant engine speed of 1750 rpm, corresponding to the maximum torque condition, and at four different load levels (40, 60, 80, and 100 Nm). The findings indicate that the coefficients of variation increase with increasing engine load and methanol flow rate. In particular, values exceeding 10% for the coefficients of variation of the indicated mean effective pressure and maximum pressure suggest reduced combustion stability and a higher tendency for knocking. Therefore, optimization of the methanol ratio and operating conditions is necessary to ensure safe and stable engine operation. One of the key findings of the study is that the pressure rise rate increases with increasing engine load and methanol flow rate. Specifically, the value of 4.59 bar/°CA obtained with the highest methanol ratio (M21) at 100 Nm load approached the knock limit of 5 bar/°CA, which constrains the stable operating range of the engine.
Keywords
RCCI , Methanol , Combustion
Kaynakça
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