低热值燃气-柴油双燃料发动机动力性能计算

Calculation on Power Performance of Low Calorific Value Combustible Gas-Diesel Dual-fuel Engine

推导了低热值燃气-柴油双燃料发动机动力性能计算公式,并对由单缸、四冲程、水冷、直喷式柴油机改装的生物制气-柴油双燃料发动机的动力性能进行了计算分析。结果表明:双燃料发动机能够达到原柴油机的动力水平;其动力性能随引燃油量的减小而降低;在新鲜空气充足的前提下,供给更多的燃气,双燃料发动机的动力性能增强;燃气替代率有一最大值,超过该值后,随替代率增大,动力性能急剧下降;燃气低热值越高,替代率便可越大。计算得出的生物制气-柴油双燃料发动机在标定点和最大转矩点的最大生物制气替代率和对应的燃气进气比,与试验结果相吻合。

The power performance of low calorific value combustible gas diesel dual-fuel engine is deducted.The power performance of biogas diesel dual-fuel engine that is modified from a single cylinder,four-stroke,water-cooled,direct injection diesel engine is calculated and analyzed.The results show that dual-fuel engine can gain the same power as diesel engine.The power performance decreases with the decrease of pilot fuel quantity,increases with the increase of combustible gas charge at the precondition of that fresh air is enough for fuel combustion.There is a maximum substitute ratio,exceeding the maximum substitute ratio the power performance decreases sharply with the increase substitute ratio.The higher the combustible gas＇s lower calorific value,the bigger the substitute ratio that the dual-fuel engine can get.The maximum biogas substitute ratio and its corresponding biogas charge ratio at rated and maximum torque condition of biogas diesel dual-fuel engine are calculated and the results fit well with the testing one.