Integration and Validation of a Quasi-Dimensional Modelling Methodology and Application to Light-Duty and Heavy-Duty Methanol-Fueled Spark-Ignited Engines 2022-01-0385

To speed up the development of the next-generation combustion engines with renewable fuels, the importance of reliable and robust simulations cannot be overemphasized. Compared to gasoline, methanol is a promising fuel for spark-ignited engines due to its higher research octane number to resist auto-ignition, higher flame speed for faster combustion and higher heat of vaporization for intake charge cooling. These advantageous properties all contribute to higher thermal efficiency and lower knock tendency, and they need to be well-captured in the simulation environment in order to generate accurate predictions. In this paper, the sub-models which estimate the burning velocities and ignition delay of methanol are revisited. These building blocks are implemented and integrated in a quasi-dimensional simulation environment to predict the combustion behavior, which are subsequently validated against test data measured on both light-duty and heavy-duty engines. The light-duty application is represented by a spark advance sweep on a CFR engine with compression ratios ranging from 9 to 11 and lambda ranging from 0.7 to 1.3. The heavy-duty application is represented by a sweep of the indicated mean effective pressure on a Scania D12 engine from 13 to 26 bar with boost levels from 50 mbar to 1.5 bar and lambda from 1 to 1.8. The calibration results of the model for both applications are compared and discussed. The simulation results show that the current methodology works well with the light-duty application but extra work on the burning velocity sub-model is required to better capture the combustion behavior in heavy-duty applications.