天然气掺氢火花点火发动机性能与排放研究

在一台燃用CNG／H2混合燃料的火花点火发动机上，开发了一个电子控制单元（ECU）来控制发动机点火提前角和混合气浓度，并研究了不同掺氢比（氢气的体积分数分别为0%、10％、20％和26％）对发动机性能和排放的影响．研究结果表明：天然气掺氢后发动机功率和有效热效率有所降低；在相同过量空气系数下，随着掺氢比的增加，发动机的最佳点火提前角推迟，HC、CO2排放得到降低，NOx排放有所增加．掺氢后可以提高发动机的稀燃极限，在稀燃下可以得到较低的HC、CO、CO2和NOx排放。

Experimental Study on Performance and Emissions of a Spark Ignition Engine Fuelled with CNG-Hydrogen Mixtures

An experimental investigation was conducted on the influence of the different percent of hydrogen on the performance and emissions of a spark ignition engine fuelled with natural gas and hydrogen mixtures. Four different mixtures of hydrogen and natural gas were tested with hydrogen volumetric percent of 0%, 10%, 20% and 26%, respectively. An electronic control unit was developed to control the spark timing and mixture concentration. Compared with pure CNG operation, the engine fuelled with hydrogen and natural gas mixtures shows lower power output and effective thermal efficiency. With the same excess air ratio, the optimal spark timing retards and HC and CO2 emissions decrease while NOx emissions increases with the increase of hydrogen fraction. Adding hydrogen to natural gas can extend the lean burn limit of mixture. Moreover, low emissions of HC, CO, CO2 and NOx can be realized at lean mixture combustion for natural gas and hydrogen mixtures.