生物制气-柴油发动机放热规律的影响因素

Influence of heat release rate of biogas diesel dual-fuel engine

采用气化炉热解气化各种农林废弃的生物质,产生可燃生物制气,作为以柴油引燃的双燃料发动机的主要燃料.双燃料发动机由一单缸、四冲程、水冷、直喷式柴油机改装而成,生物制气通过发动机进气管,在进气过程中被吸入气缸.实测生物制气-柴油双燃料发动机气缸压力,根据气缸压力计算放热规律并分析转速、负荷及供油提前角对它的影响.负荷增大时,双燃料发动机燃烧始点提前,最大燃烧放热率增高,最高燃烧温度升高,后燃加重;转速增大时,燃烧推迟;供油提前角增大时,最大放热率降低,对应相位提前,后燃减少.

Biogas is made from many kinds of agricultural and forestry residues by a gasifier. It is used as the main fuel of a biogas diesel dual-fuel engine ignited by diesel fuel. The dual-fuel engine is rebuilt from a single cylinder, four stroke, water cooled, and direct injection diesel engine. The biogas is induced to the cylinder through intake tube of the engine during intake process. The influence of heat release rate of the engine was analyzed based on the measured cylinder pressure. With the load increasing, the ignition time advances, the maximum heat release rate and maximum combustion temperature both increase, and the after combustion becomes longer. With the engine speeding up, the ignition time delays. With the fuel supply advance angle increasing, the maximum heat release rate decreases, its corresponding phase advances, and the after combustion is shorter.