Investigation of comprehensive performance and optimal control strategy of hydrogen-doping X-type rotary engine under part-load conditions

This paper aims to investigate the performance enhancement of a novel X-type rotary engine through hydrogen doping and proposes an optimal control strategy under part-load conditions. For this reason, an integrated model combining a dual zone model with recurrent neural network model for a hydrogen-doping X-type rotary engine is developed. Then, the effects of operating parameters on the comprehensive performance of engine are analyzed. Finally, an optimal multi-variable control strategy (OMCS) is introduced to achieve optimal performance under part-load conditions. The results show that the optimization of hydrogen is more pronounced at high rotational speeds, small ignition angles, or lean combustion conditions. Compared with single-variable control strategies, OMCS offers a broader regulation range and can maintain thermal efficiency above 0.27. At high loads, OMCS achieves high thermal efficiency by adjusting the equivalence ratio and ignition timing, albeit with a slight compromise on NO emission performance.