大功率甲醇发动机爆震的仿真分析与研究

Simulation analysis and research on knock of high-power methanol engine

为了研究大功率甲醇发动机的爆震特性,文章采用GT-power软件建立甲醇发动机的仿真模型,通过台架试验数据对仿真模型进行标定并调试爆震模型,对发动机在低、中、高转速全负荷工况下的性能和爆震特性进行仿真分析。结果表明:随着压缩比或点火提前角的增大,发动机产生爆震的趋势明显增大、爆震强度增大、爆震开始时刻提前,其中点火提前角增大引起的爆震使发动机整体性能提高;轻微爆震时,发动机整体性能提高;严重爆震时,峰值缸压急剧升高,发动机整体性能恶化;不同转速下,爆震对发动机性能的影响程度不同,其中,在中转速工况下,严重爆震对发动机动力性及燃油经济性的影响较小。

To investigate the knocking characteristics of high-power methanol engines,a simulation model of methanol engines was established using the GT-power software.The accuracy of the model is verified by comparison of test data and simulation data,and the knock model is calibrated.The performance and knocking characteristics of the engine were simulated and analyzed under the full load condition of low,medium and high speed.The results indicate that with the increase of compression ratio or the ignition advance angle,the tendency of engine knocking increases significantly,the timing of knocking advances,and the knock intensity increases.The knocking caused by the increase of the ignition advance angle improves the overall performance of the engine.When there is slight knocking,the overall performance of the engine is improved;however,severe knocking leads to a sharp increase in peak cylinder pressure and a deterioration in engine performance.Knocking affects engine performance differently at different speeds,with severe knocking having a relatively smaller impact on engine power and fuel economy at medium speeds.