论文部分内容阅读
作为同时降低小型直喷式柴油机NO_x和颗粒排放的方法,提出了低温、预混合燃烧的概念。按此概念,在进气流中吸入惰性燃气,以降低燃烧温度,通过大幅度推迟喷油定时来延长滞燃期,以达到预混合燃烧的目的。这种预混合过程避免了排气黑烟的增加(进气中氧气浓度下降时通常会产生黑烟)。大大提高进气涡流比,结合采用大口径、无挤流口的环形燃烧室可避免燃油耗和未燃总HC的增加。在单缸试验机上证明,在代表性运转工况下,可同时降低NO_x和烟度排放。
As a method of reducing NO_x and particulate emissions of a small direct injection diesel engine at the same time, a concept of low-temperature, premixed combustion is proposed. According to this concept, inert gas is introduced into the intake flow to reduce the combustion temperature, and the retarding period is extended by substantially delaying the injection timing to achieve the premixed combustion. This pre-mixing avoids the increase of exhaust fumes (usually black smoke as the oxygen concentration decreases in the intake air). Greatly improving the intake vortex ratio, combined with the use of a large diameter, no squirt ring annular combustion chamber to avoid fuel consumption and unburned total HC increase. In a single cylinder test machine to prove that in the representative operating conditions, both NOx and smoke emissions can be reduced.