DPF降怠速再生温度场分布测试及过滤效率分析

基于柴油机颗粒捕集器(DPF)降怠速(DTI)再生的特点,介绍了一种DPF极限碳载量、再生温度评估方法.在非道路瞬态循环(NRTC)工况进行DPF碳加载,通过缸内后喷控制再生温度,试验研究了碳载量为8 g/L、不同再生温度下降怠速再生时DPF的内部温度;在再生温度为600℃时测试了不同碳载量下降怠速再生期间DPF内部温度;通过AVL MSS-483烟度计在NRTC工况下分别测量发动机原排、再生前DPF后、再生后DPF后的颗粒物(PM)质量浓度,获得了降怠速再生后的PM质量浓度过滤效率.结果表明:碳载量为8 g/L时,随再生温度降低,DPF内部最高温度变高,降怠速再生导致载体损坏的风险变大;再生前DPF对PM的过滤效率高达99.95%,再生后降至97.10%.再生温度为600℃、碳载量为12 g/L时,DPF内最高温度超过1500℃,碳化硅载体损坏,DPF对PM的过滤效率降至87.30%,碳载量为8 g/L及10 g/L时,载体均未损坏.

Test of Temperature Field Distribution and Analysis of Filtration Efficiency During DPF Drop to Idle Regeneration

Based on drop to idle(DTI)regeneration characteristics of diesel particulate filter(DPF),an evaluation method for the amount of soot loading and the target regeneration temperature was introduced.DPF DTI regeneration testing was carried out in a diesel engine,in which DPF soot was loaded under non-road transient cycle(NRTC)operation and the regeneration temperature was controlled by in-cylinder post injections.The internal temperature of the DPF substrate during DTI regeneration process was measured at the soot loading amount of 8 g/L and different regeneration temperatures.At the target temperature of 600℃,the internal temperature of the DPF substrate during DTI regeneration was measured at different soot loading amounts.Under NRTC operating conditions,the engine row particulate matter(PM)and the PM concentrations in the upstream and downstream of the DPF were obtained by a AVL MSS-483 smoke meter.Furthermore,the PM filtration efficiency after DTI regeneration was also obtained.The results show that at the soot loading amount of 8 g/L,the maximum internal temperature of the DPF increases with the reduction of regeneration temperature,and the risk of DPF damage caused by DTI regeneration increases.The PM filtration efficiency of the DPF before regeneration is as high as 99.95%,but decreases to 97.10%after the DTI regeneration.When the target regeneration temperature is 600℃and the carbon load is 12 g/L,the peak temperature in the DPF exceeds 1500℃,leading to a damage of the silicon carbide carrier and a reduction of the PM filtration efficiency to 87.30%.In other soot loading amount cases,the DPF substrates are not damaged.