Water direct injection into the cylinder is one of effective ways to suppress the combustion rate and knocking combustion in turbocharged SI engine. In this study, a detailed one-dimensional model coupled with the water direct injection was built by using the GT-Power according to the real tested hydrogen-enriched lean-burn natural gas (NG) SI engine, and validated against the experimental data. Then, a series of cases with various water injection quantity and injection timing were comprehensively investigated on the thermodynamics, combustion and emissions characteristics of the NGSI engine. The impact of the thermo-physical of the water were discussed in detailed by sweeping various water injection quantity and water injection timing. The results indicated that peak combustion pressure and peak heat release rate decreased with the increasing the water injection quantity. In addition, the 50% combustion location and peak combustion pressure location were retarded with the increasing the water injection quantity. As for the water injection timing, the peak combustion pressure and peak combustion temperature were slightly decreased with retarding the water injection timing. Apart from that, the indicated thermal efficiency decreased 4.03% and the equivalent fuel consumption increased 3.56% with injecting 60 mg water into the cylinder compared the case without water injection. Furthermore, the indicated thermal efficiency decreased 4.68% and the equivalent fuel consumption increased 4.66% by sweeping the water injection timing from the 150 CA to 50 CA before top dead center. However, the volumetric efficiency slightly ascended with increasing the water injection quantity and retarding the water injection timing. Finally, the NOx emissions declined with increasing the water injection quantity and retarding the water injection timing. However, CO emission and unburned HC emissions increased with increasing the water injection quantity and retarding the water injection timing. The main aim of this paper is expected to provide a comprehensively assessment of the thermo-physical of water on the thermodynamics, combustion, and emissions of the hydrogen enriched NGSI engine.

将水直接喷射到气缸中是抑制涡轮增压SI发动机燃烧率和爆燃的有效方法之一。在这项研究中，根据实际测试的富氢稀薄燃烧天然气（NG）SI发动机，使用GT-Power建立了详细的一维模型以及直接注水模型，并针对实验数据进行了验证。然后，针对NGSI发动机的热力学，燃烧和排放特性，综合研究了一系列不同注水量和注入时间的情况。通过扫描各种注水量和注水时间，详细讨论了水的热物理影响。结果表明，随着注水量的增加，峰值燃烧压力和峰值放热率降低。另外，随着注水量的增加，50％燃烧位置和峰值燃烧压力位置被延迟。至于注水正时，峰值燃烧压力和峰值燃烧温度随着注水正时的延迟而略微降低。除此之外，与未注水的情况相比，向气缸内注入60 mg水时，指示的热效率降低了4.03％，当量燃料消耗增加了3.56％。此外，通过将注水时间从上止点前的150 CA扫到50 CA，指示的热效率降低了4.68％，当量燃料消耗增加了4.66％。但是，随着注入水量的增加和注入时间的延迟，体积效率略有提高。最后，随着注水量的增加和注水时间的延迟，NOx排放量下降。但是，随着注水量的增加和注水时间的延迟，CO排放量和未燃HC排放量增加。预期本文的主要目的是对水的热物理性质进行全面评估，以评估富氢NGSI发动机的热力学，燃烧和排放。随着注水量的增加和注水时间的延迟，NOx排放量下降。但是，随着注水量的增加和注水时间的延迟，CO排放量和未燃HC排放量增加。预期本文的主要目的是对水的热物理性质进行全面评估，以评估富氢NGSI发动机的热力学，燃烧和排放。随着注水量的增加和注水时间的延迟，NOx排放量下降。但是，随着注水量的增加和注水时间的延迟，CO排放量和未燃HC排放量增加。预期本文的主要目的是对水的热物理性质进行全面评估，以评估富氢NGSI发动机的热力学，燃烧和排放。