Abstract:  In order to reduce the development cost and shorten the development cycle, automotive natural gas engines were converted to small and medium power biogas power internal combustion engine, and this paper addresses the feasibility of this approach. Firstly, a one‑dimensional performance simulation model of the engine was established, and the model was calibrated and verified by using the bench test results of the automotive natural gas engine. The two compression ratio modification methods were compared by means of a calibrated model, and parameters such as the size of the compression ratio, the duration of intake opening, the phase of intake and exhaust opening, and the ignition advance angle were optimized. The results showed that the method of changing the compression ratio by using the variable combustion chamber volume had  better engine performance, and 14 compression ratio and smaller intake opening duration were desirable for converted biogas power internal combustion engine. Compared to the original engine, the optimized engine's power was increased by 3.01% and specific gas consumption was reduced by 2.8%, and the exhaust temperature was reduced, which  was more conducive to improving the service life of the exhaust pipe.

Key words: biogas power generation engine, compression ratio, ignition advance angle, gas distribution phase

摘要： 为降低开发成本和缩短开发周期，针对车用天然气发动机改制成中小功率的沼气发电内燃机进行可行性研究。首先建立发动机的一维性能仿真模型，并利用车用发动机的台架试验数据对模型进行标定，通过标定的模型对两种压缩比改制方法进行对比分析，并综合优化压缩比大小、进气开启持续期、进排气开启相位和点火提前角等参数。结果表明：采用变燃烧室容积改变压缩比的方法整机性能更优，改制后的沼气发电内燃机宜采用14压缩比，沼气发电内燃机宜采用较小的进气开启持续期；优化设计后较原机的功率增大3.01%，比气耗降低2.8%，排气温度有所降低，更有利于提高排气管的使用寿命。

关键词: 沼气发电内燃机, 压缩比, 点火提前角, 配气相位