首页|柴油机SDPF催化剂涂覆策略对NOx排放特性和压降影响的仿真研究

柴油机SDPF催化剂涂覆策略对NOx排放特性和压降影响的仿真研究

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为了满足日益强化的排放法规指标要求,柴油发动机业界开发了选择性催化还原捕集技术(SDPF).SDPF将SCR催化剂涂覆在壁流式颗粒捕集器(DPF)载体上,通过催化还原过程,可以同时减少柴油机发动机排气中的氮氧化物(NOx)和颗粒物(PM),也解决了SCR原理中发动机排气门导致的温度过低排放控制困难的问题,可以显著改善冷启动下的NOx排放.本文建立了一个仿真模型,并基于发动机台架试验数据对模型进行了标定,研究了SDPF催化剂不同的涂覆策略——催化剂涂覆量和催化剂涂覆比例,对柴油机排放性能和压降特性的影响.仿真结果表明:SDPF的压降随着催化剂涂覆量和涂覆比例的增加而增加,但是过量的催化剂涂层导致的压降过高会使NOx转化效率下降;当催化剂涂覆量达到 70g/L时,NOx的转化效率最高;发动机处于低负荷工况时,当催化剂涂覆比例高于 60%左右时,NOx转化效率更高.
Modeling and Simulation of NOx Emission Characteristics and Pressure Drop of SDPF with Different Catalyst Coating Strategies
To meet the increasingly stringent emission regulations,an important aftertreatment technology(SDPF,the selective catalyt-ic reduction catalysts coated into a diesel particulate filter)was developed,which has the ability to reduce both NOx and particulate in the exhaust gas of diesel engines.Not only that,SDPF finds a solution to the problem of heat loss caused by SCR being far from the en-gine exhaust valve,and can significantly reduce NOx emissions during cold start conditions.In this study,a simulation model was es-tablished to explore the effect of different catalyst coating strategies(two variables are catalyst washcoat loadings and coverage rates)of SDPFs on the emission characteristics and performance of diesel engines.The simulation result showed that,pressure drop rises with increasing catalyst washcoat loading and coverage rate,and excessive catalyst coating led to a decrease in NOx conversion efficiency.The highest conversion efficiency for NOx is obtained when the catalyst washcoat loading reached 70g/L with an average conversion rate of 95.2%,and a coverage rate of catalyst washcoat above 60% could have better NOx reduction performance than full coating(at low engine load conditions).

diesel engineSDPFcatalyst washcoat loadingcatalyst washcoat coverage rateemissionpressure drop

谭丕强、杨晨晖、段立爽、王梓桐、楼狄明

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同济大学汽车学院,上海,201804

柴油发动机 选择性催化还原捕集技术 催化剂涂覆 排放 压降

国家自然科学基金项目

52076154

2024

内燃机
中国内燃机学会

内燃机

影响因子:0.234
ISSN:1000-6494
年,卷(期):2024.40(5)
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