恒转速增转矩加载方式对柴油机性能的影响  

Effect of Loading Mode with Constant Speed and Increasing Torque on Diesel Engine Performance

作　　者：曹成欣 Cao Cheng-xin(Jiangsu Huaian Secondary Industrial School,Jiangsu Huai'an 223200)

机构地区：[1]江苏省淮安工业中等专业学校,江苏淮安223200

出　　处：《内燃机与配件》2024年第23期117-119,共3页Internal Combustion Engine & Parts

摘　　要：基于柴油机瞬态仿真平台,对柴油机恒转速增转矩瞬态加载特性进行了仿真分析及研究。结果表明:柴油机从50 N·m加载到外特性时,加载后同一时间下转速越高,增压器压比、进气压力及进气流量升高率越大,压比、进气压力及进气流量达到稳定值的时间缩短,进气响应特性提升。定转速加载后,柴油机空燃比限制在17.5,一定时间后逐渐升高,转速越低,相对限制时间越长,且空燃比不受限制后升高速率也相对较缓。柴油机扭矩瞬态从50 N·m加载到外特性扭矩,由于空燃比限制,不同转速下实际扭矩响应差异较大,在加载后1 s时,800 r/min,1100 r/min,1400 r/min,1600 r/min对应的扭矩升高率为:73.5,184.6,334.4,463.8;在加载后2 s时,1400 r/min及1600 r/min的扭矩即可达到外特性扭矩,800 r/min及1600 r/min需要在3 s后一段时间才能达到目标扭矩。柴油机瞬态加载过程中,由于进气滞后,燃烧速率降低,燃烧过程变差,瞬态有效燃油消耗率变差。从800 r/min到1600 r/min,柴油机加载后,其整体瞬时燃油消耗率呈现先降低后升高的趋势。瞬态加载过程中,NO_(x)与CO排放迅速升高,转速越高,NO_(x)与CO排放相对较低。瞬态NO_(x)排放与瞬态燃油消耗率呈现trade-off的关系。Based on the transient simulation platform of diesel engine,the transient loading characteristics of diesel engine at constant speed are simulated and studied.The results show that when the diesel engine is loaded from 50 N·m to the full load,after loading,the higher speed with the greater the rise rate of turbocharger pressure ratio and the intake air flow rate,the shorter the time for the pressure ratio and the intake air flow to reach the stable value,and the intake air response characteristics are improved.Under different speed,the air-fuel ratio of diesel engine is limited to 17.5 after a certain time,the lower the speed with the longer the relative limit time,and the increase rate is relatively slow.The load of diesel engine from 50 N·m to full load,due to the limitation of air-fuel ratio,the actual torque response is poor.After 1s of loading,the corresponding torque increase rates of 800 r/min,1100 r/min,1400 r/min and 1600 r/min are:73.5,184.6,334.4 and 463.8.At 2 s after loading,the torque of 1400 r/min and 1600 r/min can reach full load,while the target torque of 800 r/min and 1600 r/min can be reached after 3 s.In the loading process of the oil engine,combustion process is bad,and transient BSFC is bad.NO_(x)and CO emission is degradation,the NO_(x)and CO emission is bad for low speed.There is also a trade-off relationship between the transient NO_(x)emission and the transient fuel consumption rate.

关 键 词：增压柴油机 瞬态加载 瞬态特性 瞬态排放 

分 类 号：U464.172[机械工程—车辆工程]