通过对发动机泄气式辅助制动工作过程的分析,建立了发动机泄气式辅助制动计算模型,根据辅助制动相关参数(包括排气门开度、发动机转速和排气背压等),对发动机辅助制动进行了单因素和多因素条件下的仿真研究。结果表明:当发动机转速一定时,有一个与最大制动转矩对应的最佳排气门开度值,它随转速的升高而加大;缸内最大压力随着发动机转速的升高和排气门开度的减小而增高;制动转矩随着转速的上升和排气背压的增高而增大。
Through an analysis on the working process of bleeding-type engine-assisted braking, a calculation model for engine braking is set up, and based on related parameters of engine braking, including the opening of exhaust valve, engine speed and exhaust back pressure, numerical simulations are conducted on engine braking under both univariate and multivariate conditions. The results show that corresponding to maximum braking torque for a certain engine speed, there is a best opening of exhaust valve exhaust valve, which increases with the rise of en- gine speed. In-cylinder pressure peak rises with the increase of engine speed and the decrease of exhaust valve opening, and the braking torque increases with the rises of engine speed and exhaust back pressure.