Study on the soft-landing of large inertia valve based on multi-objective optimization of annular gap

Abstract

Variable valve mechanism and its technology are widely used in vehicle diesel engines. As a critical component, the performance of reciprocating actuator is the guarantee for the realization of electro-hydraulic variable valve. In order to solve the problem of high setting speed in electro-hydraulic camless variable valve system, a variable valve actuator based on annular gap buffer is proposed and optimized to realize quick closing and soft landing. The experimental results show that the actuator can achieve the purpose of setting buffer, and the setting speed is 0.5 m/s with 15 ms of closing time. AMESim is used to build the system simulation model and calibrated by experiments. The simulated lift curve is close to the experimental curve, and its Pearson coefficient is 0.9995. The influence of structural parameters on the system driving ability and buffering effect is studied through the model. According to the simulation results, the annular gap eccentricity will affect the buffering effect. When the eccentricity increases from 0.005 to 0.035 mm, the landing velocity increases by 0.1 m/s and the valve closing time decreases by 0.9 ms. NSGA-II method is used to optimize the structural parameters of the annular gap, and an obvious Pareto front is obtained and the optimal solution is applied in next experiments. The landing speed is reduced from 0.5 to 0.25 m/s, and the landing time is still less than 15 ms. This paper provides a simple cushioning scheme for electro-hydraulic camless variable valve soft landing which is independent of proportional valve.