Patent ID: 8037855

Claim:
A valve characteristic controller for an internal combustion engine which is applied to a valve characteristic varying apparatus including a hydraulic valve characteristic varying mechanism and an operation-fluid control means for adjusting a condition of an operation fluid supplied to the hydraulic valve characteristic varying mechanism in order to control a valve characteristic of an engine valve, the valve characteristic controller comprising: a means for obtaining a detection value detected by a detection means which detects the valve characteristic of the engine valve; and a learning means for learning a deviation amount of a response characteristic of the valve characteristic varying apparatus based on a temporal variation of the valve characteristic by using of the detection value detected by the detection means as an input, in a situation that a distance between an operational signal of the operation-fluid control means and a holding point where the valve characteristic is held is less than or equal to a specified value, wherein the specified value is defined in such a manner as to be a distant between a boundary of a holding unresponsive range and the holding point the holding unresponsive range being supposed to be a maximum range from the holding point to a point at which a variation speed of the valve characteristic relative to a variation in the operational signal is rapidly changed.