缸内直喷LNG发动机燃烧过程测量分析

将1台直列4缸汽油机改装为缸内直喷LNG发动机,用自行开发的发动机工作过程测量分析系统测量其缸内压力.分析了标定转速和最大扭矩转速下最高燃烧压力、压力升高率、缸内温度的变化,并计算分析了其放热规律.结果表明:与汽油机相比,改装后的天然气发动机燃烧较慢,后燃现象较严重；最大扭矩点的最大压力及最大压力升高率大于标定点；转速...

Measurement and Analysis for Combustion Process of In-cylinder DI LNG Engine

An inline 4-cylinder gasoline engine was changed into an in-cylinder direct injection LNG engine.The cylinder pressures were measured and analyzed by the self-developed engine data acquisition system.The maximum combustion pressure,pressure rise rate and in-cylinder temperature of rated speed and maximum torque speed were analyzed and the heat release rate was also calculated.The results show that the combustion process of modified engine is slower and its post combustion phenomenon is more serious.In addition,the maximum pressure and maximum pressure rise rate of maximum torque condition are larger than that of rated condition.At the constant speed,the maximum combustion pressure increases,the corresponding phase of maximum pressure is ahead of TDC,the ignition timing advances,the in-cylinder temperature rises,the maximum heat release rate increases and the corresponding crank angle of maximum heat release rate is also relatively earlier with the increase of load.