Development of a new automatic calibration method for control of variable valve timing

Abstract

The rising number of calibration variables and a decreasing time to market have led to the need for advanced methods of engine calibration. In this paper a new calibration method is developed for ignition timing. This calibration is based on an automated measurement and analysis method. This method enables the user to calibrate the optimal efficiency ignition angle (IA) and the torque control via the IA. The modern digital engine electronic control unit (ECU) is mainly based on look-up table methods. The combination of automatic knock detection analysis and automatic look-up table design reduces calibration time by the factor 3-4. The method was successfully applied to the low octane variation of the BMW AG 4-cylinder 2.0 l variable valve timing (VVT) spark ignition (SI) engine. The method is used in the SI combustion engine development section of the BMW AG for different types of engines. It has been shown that the application of the developed method dramatically reduces the calibration effort and time of VVT engines.