Abstract: A method of creating a simplified computer implementable engine model includes obtaining a complete computer implementable engine model and selecting, from the complete engine model, elements defining the simplified engine model. The method further includes obtaining from a library of rules at least one computer implementable model creation rule corresponding to the selected elements and using that at least one rule to create the simplified computer implementable engine model.

Abstract: A method of creating a simplified computer implement for engine model comprises obtaining a complete computer implement for engine model (110) and selecting, from the complete engine model (110), elements defining the simplified engine model (110). The method further comprises obtaining from a library of rules at least one computer implementable model creation rule corresponding to the selected elements and using that at one rule to create the simplified computer implementable engine model (110).

Abstract: A method and apparatus of identifying engine gas composition in an engine cylinder comprise obtaining a measure of cylinder pressure from a cylinder pressure sensor, deriving the polytropic index from said measure and obtaining a measure of the quantity of an engine gas component therefrom.

Abstract: A method and apparatus for obtaining a corrected engine operational parameter value, using cylinder pressure information. A real pressure sensor signal output from a sensor (41D) is compared for discrepancies with an estimated output from engine pressure model (42A), including an engine model and a sensor model. The engine pressure model is corrected dependent on the discrepancy and the model engine pressure is then taken as the output value.

Abstract: An engine management system for an internal combustion engine, which has at least one cylinder pressure sensor and at least one engine actuator, includes a data processor arranged to receive and process cylinder pressure data from the cylinder pressure sensor and the actuator controller arranged to control the actuator to optimize engine performance based on the processed data, in which the cylinder pressure data is obtained during a performance optimized engine cycle or cycles. The processor processes the data to construct a cylinder pressure variation function for the engine cycle or cycles and derive control data therefrom for the actuator controller.