船用微引燃双燃料发动机多缸平衡控制的试验

针对船用微引燃双燃料发动机多缸不平衡问题,开展了多缸平衡控制的仿真与试验,建立发动机仿真模型,用试验测量的进气歧管压力验证了模型精度,基于仿真模型定量分析了发动机各缸燃气量和过量空气系数的差异.采用燃气喷射量补偿的方法对各缸进行缸平衡控制的研究,分别以各缸爆发压力、平均指示有效压力(IMEP)和排气温度为控制变量修正各缸燃气喷射脉宽.研究表明:各缸燃气喷射量相对偏差最大可达2.76%;各平衡模式下其各缸对应的控制变量相对偏差均有效降低,其中爆发压力平衡时各缸爆压不均匀系数低于1.2%,IMEP平衡时IMEP不均匀系数低于0.8%,排气温度平衡时各缸排气温度差异控制在11℃之内;考虑发动机运行的稳定性和安全性因素,在中、低负荷时激活IMEP平衡模式以降低失火或弱燃的概率;在高负荷时激活爆压平衡模式以降低气缸压力异常升高的概率.

Experimental Research of Cylinder Balance Control for a Marine Micro-Pilot-Ignition Dual-Fuel Engine

An experimental research of cylinder balance control was carried out to address the multi-cylinder imbalance problem of a marine micro-pilot-ignition dual-fuel engine.The engine simulation model was established and verified by the measured intake manifold pressure,and the quantitative analysis of cylinder-to-cylinder variation of the natural gas(NG)quantity and the excess air ratio was conducted with the simulation model.The experimental study of cylinder balance control with the NG quantity compensation method was then carried out.The peak in-cylinder pressure pmax,IMEP and exhaust temperature of each cylinder were used as control variables to correct the NG injection pulse width of each cylinder respectively.Experimental study shows that the maximum difference of the NG injection quantity between cylinders is 2.76%.When each cylinder balance control mode is used,the relative deviation of the corresponding control variables is effectively reduced.In detail,the pmax unevenness coefficient is less than 1.2%in the pmax control mode,the IMEP unevenness coefficient is less than 0.8%in the IMEP control mode,and the difference of exhaust temperature between cylinders in exhaust temperature control mode is controlled within 11℃.Furthermore,the IMEP control mode is activated at low to medium loads to reduce the risk of misfire or weak combustion,and the pmax control mode is activated at high load to reduce the probability of abnormally high in-cylinder pressures.