低排放单缸风冷柴油机的优化设计与匹配

以非道路单缸风冷192 F柴油机为研究对象,匹配蓄压式喷油系统,以低排放为核心目标,计算并设计了高压油泵凸轮和电控喷油器喷嘴参数,优化了螺旋进气道,重新设计了燃烧室几何形状并优化了喷油油线在燃烧室的分布,使燃烧室、进气道与蓄压式喷油系统相匹配.在标定工况、最大转矩工况下进行了喷油参数对工作过程、排放和性能影响的研究,以标定最佳喷油参数,得到该样机的全工况喷油参数Map.该样机稳态8工况排放试验的CO、HC+NO_x和颗粒物(PM)排放结果分别为3.66、5.72和0.35 g/(kW·h),与非道路柴油机国Ⅲ排放限值相比,其劣化余量系数分别为1.50、1.31和1.71,在劣化周期内各排放均具有足够的劣化余量,该样机可满足现行非道路柴油机排放法规要求,具有满足未来更严格排放法规的潜力.

Optimal Design and Matching on a Low-Emission Single-Cylinder Air-Cooling Diesel Engine

To reduce exhaust emissions,an optimal design of a single cylinder air-cooling 192 F off-road diesel engine and a performance matching with an accumulator typed fuel injection system were studied.The cam profile of the high-pressure fuel pump and nozzle parameters of the electronically-controlled fuel injector were calculated and designed,the helical intake port was optimized,combustion chamber geometry was also redesigned.The fuel spray distribution was optimized in order that the combustion chamber and air intake system could match with the high pressure accumulator typed fuel injection system well.Experiment to study how injection parameters affect combustion process,performance and emissions were conducted under the rated and the maximum torque operating conditions.The map of fuel injection parameters across full operating points was obtained by best performance matching.Experiment results based on 8-mode steady state emission test cycle show that the brake specific emissions of CO,HC+NO_xand PM are 3.66,5.72 and 0.35 g/(kW·h)respectively,their deterioration coefficient are 1.50,1.31 and 1.71 respectively,it means that all emissions have an adequate deterioration margin within engine application life according to ChinaⅢoff-road diesel engine emission limits.The prototype diesel engine can meet the requirements of current off-road emission regulations and also has a great potential to meet much stricter emission regulations in the future.