Fast Crank-Angle Based 0D Simulation of Combustion Engine Cold Tests including Manufacturing Faults and Production Spread

摘要

During series production of modern combustion engines a major challenge is to ensure the correct operation of every engine part. A common method is to test engines in end-of-line (EOL) cold test stations, where the engines are not fired but tugged by an electric motor. In this work we present a physically based 0D model for dynamic simulation of combustion engines under EOL test conditions. Our goals are the analysis of manufacturing faults regarding their detectability and the enhancement of test procedures under varying environmental conditions. Physical experiments are prohibitive in production environments, and the simulative approach reduces them to a minimum. This model is the first known to the authors exploring advanced engine test methods under production conditions. The model supports a wide range of manufacturing faults (with adjustable magnitude) as well as error-free production spread in engine components. Modeled effects include engine gas dynamics and mechanics, variable valve lift and -timing and the special cold test conditions. The challenge is to simulate a large number (i.e. >1000) EOL tests to cover a realistic production scenario. Compared to maximum-precision development tools, our 0D model has the advantage of high computational speed and the ease with which a wide range of faults can be introduced. As a use-case, a modern 2.0 liter four cylinder four stroke SI engine was modeled using only data readily available from the development process. Compared to real EOL measurements and a 1D model from engine development, the 0D simulation reproduced all relevant dynamics.