Development of a Comprehensive Predictive QD Knock Simulation Model for Hydrogen, Methanol, and an Ammonia–Hydrogen Blend

This work presents a comprehensive predictive 0D simulation model for the knock behavior of hydrogen, methanol, and an ammonia-hydrogen blend. With the increasing focus on carbon neutrality, synthetic fuels are gaining attention as viable alternatives to fossil fuels. Their potential applications include land and marine transport, construction machinery, and automotive powertrains, sectors with high carbon dioxide emissions. As their development requires extensive experimental validation, simulations offer a cost- and time-efficient alternative. In particular, 0D simulations offer a good balance between predictive capability and computational effort, making them well suited for concept evaluations and parametric studies. In spark-ignition engines, knock is a major limitation to achieving high thermal efficiency, emphasizing the need for accurate and fuel-specific knock prediction methods. The objective of this work is to enable a predictive and versatile 0D knock modeling framework for the mentioned fuels, capable of outputting various knock-related characteristics. To achieve this, selected models were adapted from existing gasoline-based approaches, while others were developed entirely within this study. The extended models include the prediction of auto-ignition onset and a knock criterion for determining the center of combustion at a predefined knock boundary. This enables an optimized balance between engine protection and efficiency. Additionally, novel approaches for predicting knock frequency and knock intensity have been introduced. These allow for a more detailed assessment of the knock criticality of each operating point. Measurement data from single-cylinder engines were used to develop and validate the models. The resulting simulation framework enables fast, robust, and predictive knock modeling across a wide range of operating conditions and fuel types. It supports the efficient evaluation of combustion concepts using synthetic fuels and contributes to their future integration into carbon-neutral internal combustion engines.