To investigate the extreme condition of Low Temperature Combustion ( LTC ), referring to ab-sence of N2 in the exhaust gas, CO2 gas with variable injection mass, injection timing and injection pres-sure was injected into the intake pipe. The results showed that with increase of oxygen concentration, heat release rate decreased gradually at injection mass of 25 mg/cyc, and heat release rate showed an increas-ing trend and then decreasing trend at injection mass of 50 mg/cyc. At low intake oxygen concentration, a two-stage heat release is presented. When injection mass was 50 mg/cyc, the most effective method to de-crease smoke emission was to increase the injection pressure. To achieve low NOx and smoke emissions and high thermal efficiency, injection timing should be earlier than -20°CA ATDC.%为了研究低温燃烧机理的极端情况,即废气中不含比热容较小的N2,通过向进气管喷入CO2气体控制进气氧浓度、改变喷油量、喷油时刻、喷油压力等,研究了进气氧浓度对柴油机燃烧和排放特性的影响.结果表明,随进气氧浓度降低,在喷油量为25 mg/cyc时,放热速率逐渐降低,而在喷油量为50 mg/cyc时,放热速率先升高后降低;较低进气氧浓度时,燃烧呈明显的两阶段放热.喷油量为50 mg/cyc时,降低碳烟排放最有效的途径是提高喷油压力.综合性能和排放,喷油提前角应不小于20°CA,此时NOx和碳烟排放较低,且可保持较高的热效率.
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