Abstract：Based on the independently developed variable valve system of DK4A diesel engine, the effects of additional valve lift, duration of additional valve lift and intervals between additional valve lift peak and original valve lift peak on intake air state parameters were investigated by simulation and experiment. The results show that there is critical value of intervals between additional valve lift peak and original valve lift peak. If the interval is less than the critical value, the interval has no effect on in-cylinder air state parameters of engine. When the interval is larger than the critical value, the closing timing of intake valve is retarded with the increasing of interval, and the intake manifold air flow, the in-cylinder temperature and the in-cylinder pressure at the top dead center are decreased. Under the condition that the additional valve lift does not influence the closing timing, the change rate of in-cylinder air state parameters is increased with the increasing of additional valve lift. Under the condition that the additional valve lift has effect on the closing timing, the intake valve closing timing is retarded, and the intake air flow, the temperature and pressure at top dead center are decreased with the increasing of additional valve lift duration.
2017, Vol. 38 
