湍流射流点火对天然气发动机燃烧特性影响的试验研究

湍流射流点火（Turbulent Jet Ignition，TJI）是一种有效的燃烧增强技术，可提供更高的点火能量，使发动机稳定着火，且可以提高燃烧压力和燃烧速率，缩短燃烧持续期，是实现发动机稀薄燃烧的有效手段。基于一台带有预燃室的点燃式单缸试验机，开展了TJI模式下天然气发动机性能的试验研究。首先，研究了不同过量空气系数下TJI对天然气发动机动力性能、排放性能及燃烧特性的影响，并与火花塞点火（Spark Ignition，SI）模式进行对比；其次，在稀燃条件下分别探究了进气增压和预燃室喷氢对天然气发动机动力性、经济性及燃烧过程的优化作用。结果表明：TJI的使用可有效拓展天然气发动机的稀燃极限，且燃烧滞燃期和燃烧持续期均更短，放热率更高；过量空气系数1.5为甲烷TJI最佳稀燃工况，此时燃油消耗率最低，且可实现氮氧化物近零排放；此外，采用进气增压的方式可以提高TJI发动机在高负荷下的经济性；TJI模式下，相较于预燃室喷甲烷，预燃室喷氢气可进一步缩短滞燃期和燃烧持续期，提高放热率，达到提升TJI性能的效果。

Experimental Investigation on the Effect of Turbulent Jet Ignition on the Combustion Characteristics of Natural Gas Engine

TJI (Turbulent Jet Ignition) is an effective combustion enhancement technology that can provide higher ignition energy, stabilize the engine on fire, increase combustion pressure and combustion rate, shorten combustion duration, and achieve engine lean Effective means of burning. Based on an ignited single-cylinder testing machine with a pre-combustion chamber, a test study on the perfor-mance of natural gas engines in TJI mode was carried out. Firstly, the effects of TJI on the power performance, emission performance and combustion characteristics of natural gas engines under different excess air coefficients are studied, and compared with the SI (Spark Ignition) mode; secondly, the intake air is explored under lean burn conditions. The optimization effect of supercharging and pre-chamber hydrogen injection on the power, economy and combustion process of natural gas engines. The results show that the use of TJI can effectively expand the lean burn limit of natural gas engines, and the combustion stagnation period and combustion dura-tion are shorter, and the heat release rate is higher; the excess air coefficient of 1.5 is the best lean burn condition for methane TJI. When the fuel consumption rate is the lowest at the time, and can achieve near-zero nitrogen oxide emissions; in addition, the use of air-intake boosting can improve the economy of the TJI engine under high load; in the TJI mode, compared with the pre-combustion chamber injecting methane, Injecting hydrogen into the pre-combustion chamber can further shorten the flame retardation period and combustion duration, increase the heat release rate, and achieve the effect of improving the performance of TJI.