压缩比与点火正时对氢燃料椭圆转子发动机综合性能的影响

To address the problem of pror combustion performance caused by the narrow and long structure and eccentric motion of the rotary engine, a hydrogen-fueled elliptical rotary engine is proposed to explore the effect mechanisms of compression ratio and ignition timing on the dynamic and thermodynamic characteristics of the rotary engine, with the goal of improving overall engine performance and energy conversion efficiency. Therefore, a zero-dimensional model of the elliptical rotary engine is established based on the temporal method, treating the thermodynamic parameters and material components within the combustion chamber system as uniformly distributed. Sub-models for laminar flame combustion, air leakage, heat transfer, NO emission, and other factors are developed sequentially. Furthermore, the effects of compression ratios (7, 9, 11) and ignition timings (320°, 330°, 340°, 350°) on the heat release characteristics of the hydrogen-fueled elliptical rotary engine under lean burn conditions are investigated. The results showed that advanced ignition increased the duration of high pressure within the cylinder and raised working fluid leakage. However, at low compression ratios, overly delayed ignition caused the cylinder pressure to deviate significantly from the constant-volume combustion curve, reducing the heat-work conversion efficiency of the engine. Under a reference condition with a compression ratio of 9, as the ignition timing increased from 320° to 350°, the peak in-cylinder pressure dropped by 1. 30 MPa and was delayed by 13. 86°. When the compression ratio was increased to 11, the engine could achieve the highest indicated power and the lowest indicated fuel consumption, 12. 67 kW and 76. 03 g/(kW · h), respectively, with the later ignition timing of 340°. In this case, the thermal efficiency reached 0. 338, an improvement of 1. 65% over the reference condition (compression ratio: 9, ignition timing: 330°).