CONTROLLER

WIPO Patent Application WO/2006/030706

A1

A controller capable of avoiding an overload state of an actuator without using a sensor and so forth. An ECU (2) of the controller (1) calculates a lift control input U&lowbar Liftin into a variable valve lift mechanism (50) according to an algorithm of formulae ((2) to (5)) so that the valve lift Liftin follows up a target valve lift Liftin&lowbar cmd, integrates the product of the value Imot of the current flowing through the variable valve lift mechanism (50) and the sampling period Stime to calculate the integrated value SImot. If SImot≥SImot&lowbar J1, two parameters pole&lowbar f&lowbar lf, pole&lowbar lf are set to predetermined failure values pole&lowbar f&lowbar lf&lowbar J1, pole&lowbar lf&lowbar J1, respectively, at which the lift control input U&lowbar Liftin is smaller than that of when SImot