替代率对柴油引燃天然气发动机性能的影响

为研究替代率对柴油引燃压缩天然气(CNG)发动机性能的影响,将涡轮增压柴油机改装为柴油引燃天然气的双燃料发动机.在原柴油机柴油喷射系统中加装喷油泵齿条限位装置,并加装电控系统和天然气供给系统,控制柴油和CNG的喷射量.利用发动机台架试验,对比分析不同替代率对柴油引燃天然气双燃料发动机燃料经济性和排放特性的影响,研究了双燃料发动机在转速为1 400r/min、全负荷下的NOx、HC、CO与碳烟排放及有效燃料消耗率.结果表明:与原柴油机相比,双燃料发动机替代率为32.7%、38.9%、41.6%、47.2%、51.3%、55.8%、61.5%、65.8%、70.7%、75.8%和80.9%的有效燃油消耗率平均降低了5.4%;NOx排放平均升高了22.1%;HC排放平均升高了344倍;CO排放平均降低了20.1%;碳烟排放平均降低了47.9%.

Effects of replace ratio on engine fueled with natural gas with a pilot diesel fuel

In order to study the effects of replace ratio on performance of engine fueled with compressed natural gas(CNG) with a pilot diesel used to ignite the CNG-air charge,a turbocharged diesel engine had been converted into a dual-fuel engine to operate with natural gas together with a pilot injection of diesel fuel.The inhibiting device of the fuel injection pump rack in the diesel injection system,CNG supply system and electronic control system were installed on the diesel engine to control the injection quantity of diesel and CNG.The fuel economies and emissions of dual-fuel engine with different replace ratios were compared and analyzed by bench tests of a dual-fuel engine,the exhaust emissions of NOx,HC,CO,smoke and brake specific fuel consumption(BSFC) rate were investigated under full load at 1 400 r/min.The results showed that compared with diesel fuel,the dual-fuel engine with replace ratio of 32.7%,38.9%,41.6%,47.2%,51.3%,55.8%,61.5%,65.8%,70.7%,75.8% and 80.9% had a reduction of 5.4% on average,for effective fuel consumption rate,an increase of 22.1% for NOx emission,an increase of 344 times for HC emission,a reduction of 20.1% for CO emission and a reduction of 47.9 % for smoke emission.