Abstract
In this paper a small engine equipped with Continuous Variable Cam Phase (CVCP) has been considered. The CVCP is used in order to reduce the pumping work and consequently to improve the fuel consumption. The relationship between the valve timing position and engine variables (air mass flow, ignition timing and fuel amount) has been described. The possible errors on the calculation of valve timing position calculation have been analyzed. A tool (CEICA: CVCP Error Impact CAlculation), for quantification of the impact of an error of the valve timing position on the main engine performances (emissions, fuel consumption, engine protection) has been developed. Starting from weighting of the engine performances errors, the tool is able to iteratively arrange the calibration of CVCP management algorithms. The result of tool is a optimization of the CVCP target parameters in order to minimize the impact on the engine functions consistently with the assigned weights. The CEICA tool has been applied on the Control System for a Fiat Fire engine. The benefits of using this tool in the experimented cases have been presented and the future developments have been discussed.
Keywords: algorithm, automotive control, engine control, model based control, measured feedback, optimization, position errors