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基于一台2.0 L四缸涡轮增压汽油机,在设定的转速和负荷工况下,通过调节进气门提前角(VVTi,Variable Valve Timing-in)、排气门推迟角(VVTo,Variable Valve Timing-out)、废气再循环(EGR,Exhaust Gas Recirculation)率、点火提前角(SA,Spark advanced Angle)和空燃比(AFR,Air Fuel Ratio),进行涡轮增压发动机的性能开发,实现最佳的缸内燃烧和最低的燃油消耗与排放;同时,利用正交设计法分别对VVTi、VVTo以及EGR率排列组合进行优化设计,并进一步试验。结果表明:对于3因子4水平的系统试验,利用正交设计法可以减少50%~75%的试验次数。在发动机转速为2000 r/min,制动平均有效压力(BMEP,Brake Mean Effective Pressure)为500 k Pa,理论空燃比和最大制动转矩(MBT,Maximum Brake Torque)点火角工况下,与正交设计法中的试验组相比,当VVTi为40°CA,VVTo为30°CA,EGR率为8%时,发动机的燃油经济性最佳,此时的燃油消耗率为265.39 g/(k×Wh),但燃烧稳定性会受到一定影响,同时燃烧持续期会延长。此时,HC排放有所增加,CO和NO_x排放降低。
Based on a 2.0 L four-cylinder turbocharged gasoline engine, the VVTi (Variable Valve Timing-in), VVTo (Variable Valve Timing-in) Timing-out, EGR Exhaust Gas Recirculation, Spark Advanced Angle (SA), and Air Fuel Ratio (AFR), to develop the performance of a turbocharged engine to achieve the best Cylinder combustion and the lowest fuel consumption and emission. At the same time, orthogonal design method was used to optimize the design of VVTi, VVTo and EGR rate combinations, respectively, and further experiments were carried out. The results show that for the system test of 3 factors and 4 levels, the number of experiments can be reduced by 50% ~ 75% with the orthogonal design method. Under the conditions of engine speed of 2000 r / min, BMEP (Brake Mean Effective Pressure) of 500 k Pa, theoretical air-fuel ratio and maximum Brake Torque (MBT) When the VVTi is 40 ° CA, VVTo is 30 ° CA, and the EGR rate is 8%, the fuel economy of the engine is the best when the VVTi is 40 ° CA and the fuel consumption is 265.39 g / ( k × Wh), but the combustion stability will be affected to some extent, while the combustion duration will be extended. At this point, HC emissions have increased, CO and NO_x emissions decreased.