CONTROLLER FOR INTERNAL COMBUSTION ENGINE

Disclosed is a control device that is used for an internal combustion engine and capable of determining an actuator operation amount with enhanced accuracy by making the most of its computation capability. The control device includes a computation element that computes the actuator operation amount by using engine status amounts measured by sensors. The computation element uses a model during its computation process. The model includes a plurality of submodels arranged in a hierarchical sequence. When parameters are calculated by two consecutive submodels arranged in the hierarchical sequence, there is a means-end relation between a parameter calculated by a lower-level submodel and a parameter calculated by a higher-level submodel. The highest level submodel calculates a parameter that is a numerical value representing a request concerning the performance of the internal combustion engine, and is built so as to calculate the parameter by using the engine status amounts. Submodels other than the highest level submodel are built so that when an immediately higher-level submodel is used, a parameter calculated by the higher-level submodel is handled as a target value to calculate a parameter for achieving the target value from the engine status amounts, and that when the immediately higher-level submodel is not used, the parameter is calculated from the engine status amounts only. The computation element computes the actuator operation amount by using a parameter calculated by the lowest level submodel and changes the number of higher-level submodels to be used in combination with the lowest level submodel in accordance with the operation status of the internal combustion engine.