Variable valve mechanism control device and control method

A variable valve mechanism control device, comprising

• a variable valve mechanism for an internal combustion engine intake valve or exhaust valve, wherein a characteristic lift amount of the variable valve mechanism is continuously variable within a specified range;
• an actuator to drive the variable valve mechanism;
• a detecting means for obtaining a detection value indicative of the current characteristic lift amount being set by the variable valve mechanism;
• a target value calculation means which calculates a current target value for the characteristic lift amount based on current engine operating conditions;
• a first command value setting means for setting a first command value output for the characteristic lift amount, based on the current target value and the detection value;
• a second command value setting means for setting a second command value output for the characteristic lift amount;
• an error determination means for determining when an error occurs in the detecting means;
• and
• a command value switching means to couple the first command value output to the actuator during normal operation of the detecting means and to couple the second command value output to the actuator when an error occurs in the detecting means, wherein the second command value output from the second command value setting means is selected from within a sub-range of intermediate values in the specified range.

A variable valve mechanism control method for a variable valve mechanism for an internal combustion engine intake valve or exhaust valve having an actuator to drive the variable valve mechanism such that it has a valve lift characteristic value that is continuously changeable within a specified variable range, and a sensor for obtaining a detection value for the current valve lift characteristic, the method comprising

• calculating a target value within the specified variable range of valve lift characteristic values based on engine operating conditions;
• outputting a first command value to the actuator for the valve lift characteristic value based on the target value and the detection value during normal operation of the variable valve mechanism;
• and
• outputting a second command value to the actuator for the valve lift characteristic value when an error is identified in the sensor of the variable valve mechanism, wherein the second command value is selected from within a sub-range of valve lift characteristic values.

An internal combustion engine, comprising

• a variable valve mechanism for an intake valve or exhaust valve, wherein a characteristic lift amount of the variable valve mechanism is continuously variable within a specified range;
• an actuator to drive the variable valve mechanism through the specified range and set a current characteristic lift amount;
• a sensor to detect the current characteristic lift amount being set by the actuator in the variable valve mechanism;
• and
• a variable valve mechanism control coupled to the actuator and the sensor;
• wherein the variable valve mechanism control is adapted control the actuator to vary the characteristic lift amount within the specified range during normal operation and to vary the characteristic lift amount within a sub-range of the specified range when an error occurs in the sensor.