【作者】 俞奎；

【导师】 王文格； 陆友林；

【作者基本信息】 湖南大学 ， 车辆工程， 2011， 硕士

【摘要】 随着能源危机的到来及公众环保意识的逐渐增强,柴油机越来越为人们所重视。为减少柴油机冷起动过程未完全燃烧物质的排放对环境造成的污染,从而满足日趋严格的排放法规要求;同时为有效缩短柴油机冷起动过程所需时间,减少对发动机的损伤,对于柴油机冷起动性能的改善是目前一大亟待解决的难题。本文便是以电控高压共轨柴油机冷起动性能作为研究课题。柴油机可靠起动必须具备三个基本条件:喷入气缸内的燃油与进入气缸内的空气形成一定浓度的可燃混合气;该可燃混合气要达到一定的温度;该温度的保持时间必须足够长。本文利用德国ETAS公司生产的INCA6.0标定系统,对配置某厂新开发的CPN2.2+电控高压喷油泵柴油机的重型卡车在黑河进行低温冷起动试验。研究了起动机、蓄电池、冷却液温度、机油品种等对电控高压共轨柴油机冷起动性能的影响,并且对起动机等硬件设备进行了优化匹配。试验了不同预喷提前角和喷油量、起动喷油量、进气加热时间以及轨压下的冷起动时间及HC和烟雾排放,对预喷提前角和喷油量、起动基本转矩脉谱以及进气预热脉谱等进行了优化,得出了使柴油机在低温下快速平稳起动的相关参数。试验结果表明:润滑油(机油)对于柴油机冷起动性能影响最大,温度越低,起动难度越大;蓄电池的容量在低温情况下使用效率较为重要,并且在低温下连续大电流放电的能力对起动影响较大;选用品质优良的燃油也至关重要,低温下保证燃油不结蜡从而堵塞燃油管路是保证发动机顺利起动的先决条件;存在一柴油机最佳的最低起动转速,从而兼顾最低起动消耗功率及起动平顺性;预喷射能使燃烧室内的温度升高,主喷经过短暂延迟即可着火,从而有效改善柴油机的冷起动能力;使用进气预热器对进入气缸的空气进行预热能有效的改善起动性能及起动阶段的HC排放;通过调整起动基础转矩及起动过渡转矩,可以更加顺利起动,同时可以降低燃油消耗及未充分燃烧物的排放。通过本文试验及相关参数的调整,解决了原先冷起动时间较长、HC排放超标以及黑烟严重的问题,提高了车辆起动的可靠性。更多还原

【Abstract】 With the advent of the energy crisis and environmental protection consciousness strengthened by the public,diesel engine is paid more and more attention by people.To reduce the incomplete combustion emission pollution to enviroment during cold start, and to meet increasingly stringent emission regulations,at the same time to decrease the diesel engine cold start cranking time,to improve the cold start reliability,and red- uce the damage for engine.The diesel engine cold start’s research and improvement is a such urgenr problem.The research of this paper is to study the cold start reliability of the Electronic-controlld high-pressure common rail engine.Starting diesel engine to be reliable must have the following three basic conditions: the fuel and the air into the combustion chamber must be mixed into certain proportion combustible gas;the mixed gas must reach certain temperature;the certain temperature can be hold long enough.This paper illustrates the low temperature cold start test for a vehicle which mounted a new developed diesel engine with CPN2.2+ electronic-controlled high-pressure pump in Heihe city HeiLongjiang province ,using INCA6.0 calibration system which made by ETAS Co., in Germany. Have done some research for the cold start influence elements of this electronic-controlled high-pressure common rail diesel engine, including batteries, starter, starting fuel quantity,coolant temperature and oil characteristic.Optimized the start system like starter and etc;tested the cranking time and the emission of HC and smoke in diferent pilot injection advanced angle and injection quantity, starting fuel injection quantity,pre-heating time and rail pressure.optimized the Maps of pilot injection advanced angle and injection quantity,cold-start basic-torque and pre-heating time also. Concluded related parameters of stable and quick start for diesel engine in low temperature.Related experiments show: Oil is the most influencing factor to the cold start performance, the higher temperature the more difficult to cold start;Battery capacity’s using efficiency is more important in low temperature,and in this condition big continuous Electronic’s discharge ability also affects cold start;choosing good fuel is also very important ,to ensure the fuel is not wax and so it can’t block pipe,this is the prerequisites for the enginestarting smoothly;There is a minnum and the best start speed,thus it can balance the minnum start power and the minnum speed;Pilot injection can rise combustion chamber temperature,main injection can fire after brief delay,so it can improve diesel engine cold start,Preheating intake air by preheater can improve effectivly starting performance and the HC emissions;Start can be more smooth ,fuel consumption and incomplete emission can be reduced by adjusting the start base torque and the start transition torque.Based on the cold-start test and the parameters adjusted,solved the problems of long cranking time,high HC emission and black smoking,improved the vehicle starting characteristics.更多还原