Patent ID: 7204215

Claim:
A valve characteristic controller for an internal combustion engine, wherein the engine includes a variable valve actuation mechanism for varying a valve characteristic of an intake valve and a variable valve actuation mechanism for varying a valve characteristic of an exhaust valve, the controller comprising: a main control unit for calculating a target characteristic of a first valve, which is one of the intake valve and the exhaust valve, in accordance with an operation state of the engine, and controlling the variable valve actuation mechanism corresponding to the first valve so that the valve characteristic of the first valve is adjusted to the target characteristic of the first valve; and a sub-control unit for calculating a target characteristic of a second valve, which is the other one of the intake valve and the exhaust valve, based on a target valve overlap amount, which is calculated in accordance with the operation state of the engine, and an actual valve characteristic of the first valve, and controlling the variable valve actuation mechanism corresponding to the second valve so that the valve characteristic of the second valve is adjusted to the target characteristic of the second valve, wherein control with the main control unit is executed on the one of the two variable valve actuation mechanisms having a lower response speed, and control with the sub-control unit is executed on the other one of the two variable valve actuation mechanisms having a higher response speed.