柴油机双燃料复合燃烧的最佳运行范围研究

A Study on the Optimum Range of Dual-Fuel Combustion for Diesel Engines

通过在进气过程中加入容易汽化的燃料与空气形成一定浓度的预混合气进入燃烧室,利用压燃喷入的柴油形成着火源向整个燃烧室传播,以完成燃烧过程的部分预混双燃料燃烧模式可能是减少柴油机碳烟排放的有效措施。而在该燃烧方案中过低的预混燃料浓度可因火焰无法传播到整个燃烧室而增加HC排放,在保持柴油机压缩比的条件下,过高的预混合气浓度可能使燃烧最高温度上升而对NO_x排放不利,甚至在柴油喷入前压燃预混合气而发生爆震。燃烧模式的改变对CO排放水平的影响也可能不利;因此,确定双燃料的最佳运行范围是建立双燃料过程控制的基础,介绍了以液化气和柴油形成双燃料系统时的最佳运行范围的初步研究结果。

Through introducing certain concentration mixture of the gasifiable fuel and air into combustion chamber in the introduction stroke of a diesel engine, igniting the mixture by the injected diesel spray,and the flame then propagating to whole combustion chamber,organizing the partial premixed combustion may be the effective method to reduce the soot paniculate emission of a diesel engine. That the fuel concentration is lower then certain extent could cause that the flame can not propagate to whole combustion chamber resulting higher HC emission. That it is higher than certain extent may cause too higher temperature resulting higher NOX emission,ever more causing detonation. Maybe the influence of the combustion mode change on CO emission is not beneficial. To find the optimum range of LPG,adulterating rate in the LPG-Diesel dual-fuel engines is the base to build the dual fuel control system. This paper presents the preliminary work on this field.