Variable valve operating system for internal combustion engine

摘要

A variable valve operating system for a two-bank engine includes a variable valve-lift and working-angle control mechanism changing at least one of a valve lift and a working angle of each of engine valves arranged in each of cylinder banks, and two variable valve timing control mechanisms provided for each of the banks for changing valve timings independently of each other. A control unit responds a failure in one of the variable valve timing control mechanisms for failsafe purposes. The control unit includes a failsafe section capable of executing a failsafe operating mode in which at least one of the valve lift and the working angle of each of engine valves is increasingly compensated for by the variable valve-lift and working-angle control mechanism, when the one variable valve timing control mechanism is failed.