天然气加氢改性对柴油引燃气体发动机排放特性和经济性影响的研究

Study of the Effects of Adding Hydrogen to Diesel/CNG Dual Fuel Engine on the Emission and Fuel Consumption

在分析柴油/CNG双燃料发动机高THC排放来源的基础上,首次提出"柴油/CNG双燃料发动机加氢燃烧"的概念.利用氢燃烧速度快,燃烧界限宽,比热值小,淬熄长度长等特点,改善气体燃料的燃烧特性,达到降低THC排放的目的.试验中,在ZH1115单缸直喷柴油机的进气口加装电控喷气阀,实现了CNG和氢气的可控比例气口喷射,并且在这台发动机上进行了纯柴油、双燃料(柴油/CNG)和双燃料加氢的比较试验.研究了加氢对柴油/CNG双燃料发动机排放特性和经济性能的影响.研究表明,双燃料加氢后可以缩短滞燃期和燃烧持续期,明显改善柴油/CNG双燃料发动机的THC和CO排放,提高发动机的经济性.

A new concept—adding hydrogen to diesel/CNG(compression nature gas) dual fuel engine is proposed in this paper after analyzing the causes of high THC emission in the dual fuel combustion process. As hydrogen has a high combustion rate, wide combustion borderline, low specific heat and long extinguishable length,THC comes down when hydrogen is added in CNG. In the experiment, two electronic controlled gas injectors were added on the air intake port of ZH1115, a single cylinder direct injection diesel engine. Therefore, the proportion of the CNG and hydrogen were controllable when they were premixed. Three modes of experiments were employed. They were diesel mode, diesel/CNG mode, and the mode of adding hydrogen to diesel/CNG engine. The study was aimed to estimate the effect of adding hydrogen to the diesel/CNG engine on the emissions and fuel consumption. The result indicates that after adding hydrogen, the dual fuel engine′s THC and CO emissions decreased visibly, and the fuel consumption was lowered.