Control method for transitions between open and closed loop operation in electronic VCT controls

摘要

In a Variable Cam Timing (VCT) control system, there are conditions when the system must operate in an open-loop mode, and other situations where closed-loop operation is desired. A number of operating states is provided for VCT control system to switch between the states. A control methodology for switching between these two modes of operation, with minimal disturbances, is described. Further, during switching from open loop to closed loop, a scheme that impedes the impact upon the VCT system is provided.