The Deblocking Function Optimal Design for a Continuous Variable Valve Lift System

Abstract

In order to optimize the deblocking characteristics for a hydraulic motor-driven CVVL system, we abstracted the working process of internal shaft actuator and investigated the parameters which could significantly affect system deblocking characteristics by simulation and test methods. The results show that: (1) Increasing the locking pin clearance can extend the time length of rotation movement under the same unlocking speed, which is able to improve system deblocking performance. (2) Replacing step unlocking signal by slope unlocking signal will restrain rotation and unlocking movement simultaneously, while rotation movement is affected more obviously due to the differences in oil chamber volume. (3) Stick issue has been solved after lower limit of locking pin clearance was adjusted to 0.5°, and the signal slope was well restricted. The optimal design method mentioned in this paper can be popularized in similar systems and brings more conveniences on the deblocking study and critical parameters definition.