柴油机加装柴油机氧化催化器和催化型颗粒捕集器装置性能评定试验研究

Experimental Study on Performance Evaluation of a Diesel Engine Equipped with Diesel Oxidation Catalytic and Catalytic Diesel Particulate Filter System

为了研究加装柴油机氧化催化器(DOC)和催化型颗粒捕集器(CDPF)装置的柴油机性能,探讨DOC与CDPF的净化效率和再生特性随试验循环数的变化规律,搭建了柴油机高原试验台,并按13试验循环进行了性能评定试验。结果显示,在全负荷工况下,随着试验循环数的增加,发动机的进气量、转矩、功率和油耗均比未装DOC和CDPF的原机略有下降。同时,在排气后处理装置的后端,烟度和CO排放均趋向零,而NO2排放增加,NO排放减少。将第1试验循环与第13试验循环进行比较后可以发现,DOC和CDPF的前端温度均比后端低,而排气后处理装置经13试验循环后仍具有较高的净化效率。与原机相比,加装排气后处理装置的发动机,经性能评定试验后的外特性有所下降,但在排气后处理装置后端的烟度和CO排放趋近于零,而NO2/NO比例随发动机转速增加先升后降。此外,DOC和CDPF的后端温度低速时上升明显,后随转速升高而降低,直至趋于稳定,而CDPF的压差随转速增加先升后降。此时,捕集效率和再生效率仍保持较高水平。

In order to study the performance of a diesel engine equipped with diesel oxidation catalytic(DOC)and catalytic diesel particulate filter(CDPF)system,and to explore the change law of the purification efficiency and regeneration characteristics of DOC and CDPF system with the number of test cycles,a diesel plateau test bed was built,and the performance evaluation tests were conducted on 13 test cycles.Results show that at full load,with the increase of the number of test cycles,the engine's air intake,torque,power and fuel consumption are slightly lower than the original engine without DOC and CDPF system.At the same time,at the rear-end of the after-treatment system,both smoke and CO emissions tend to be zero,while NO2 emissions increase and NO emissions reduce.Comparing the first test cycle with the thirteenth test cycle,it can be found that the front-end temperatures of the DOC and the CDPF are lower than their rear-end temperatures,and the after-treatment system still maintains a higher purification efficiency after 13 test cycles.Compared with the original engine,the mapped performance(maximum torque curve)of the engine with after-treatment system has declined after the performance evaluation test,and the smoke and CO emissions at the rear-end of the after-treatment system still tend to be zero,while the NO2/NO ratio rises first and then falls with increased engine speed.Moreover,the rear-end temperatures of the DOC and the CDPF increase significantly at low speed,and then decrease with increased engine speed until stable,while the pressure difference between the front and rear ends of the CDPF rises first and then falls with increased engine speed.At this time,the capture and regeneration efficiencies remain at a higher level.