DOC氧化柴油机排气微粒的性能研究
发布时间：2018-07-29 11:25
【摘要】：柴油机排放的微粒是构成雾霾的主要来源之一,我国参照和借鉴发达国家(尤其是欧洲国家)的治霾历程,颁布施行了相对严苛的汽车排放法规。为了达到排放法规标准,一系列的柴油机后处理技术应运而生,其中柴油机氧化催化器(DOC)主要作用是催化氧化排气中HC、CO以及氧化排气微粒中的SOF组分实现微粒的减排。DOC通常与其他后处理技术配合使用,达到最佳减排效果。本文基于发动机台架试验,研究了Pt基DOC对柴油机排放微粒烟度、粒径特性、氧化特性等方面的影响规律。在YN38CRD2型柴油机台架上,加装DOC装置,采用NI数据采集卡采集DOC前后温度和压力信号,用AVL415测量DOC前后微粒烟度。获得了柴油机试验工况排气温度变化规律,分析了DOC对排气烟度影响的规律。试验表明:随着扭矩增加,循环供油量增加,DOC入口温度升高;排气微粒经过DOC后,其烟度降低。用DMS500快速微粒光谱仪对DOC前后微粒粒径分布进行了测量。获得了DOC前后微粒粒径分布规律,以及DOC前后微粒总数量浓度变化规律。试验结果表明:DOC能降低核模态微粒数量浓度,排气温度越高,核模态微粒数量浓度峰值浓度和峰值粒径越低;DOC能降低积聚态微粒数量浓度,但随着扭矩的增加,DOC反而使积聚态微粒数量浓度增加。因排温关系(350℃是硫酸盐生成的临界温度),DOC对颗粒总数量浓度的影响随柴油机扭矩的增加呈现先降低后增加的趋势。用Netzsch公司生产的STA449F3同步热分析仪进行微粒热重分析。获得了DOC前后微粒在热重试验过程中的变化规律,得到DOC前后微粒的组分含量,分析了DOC对微粒SOF组分含量、微粒表观氧化活化能及微粒干碳烟组分起燃温度的影响规律。试验结果表明:因发动机各点燃烧标定不同,原排微粒SOF组分含量随转速变化无特定的趋势;因DOC能提高排气温度,微粒经过DOC后,其SOF组分含量降低;由于DOC的作用导致微粒的SOF组分含量降低,微粒表观氧化活化能增加,干碳烟组分起燃温度增加;同时由于SOF组分与干碳烟组分之间存在协同氧化作用,致使微粒的表观氧化活化能随SOF组分含量增加整体上呈下降趋势。
[Abstract]:Diesel particulate emission is one of the main sources of haze. Referring to the haze control process of developed countries (especially European countries), China has promulgated and implemented relatively strict automobile emission regulations. In order to meet the emission regulation standards, a series of post-treatment technologies for diesel engines emerged as the times require. The main role of diesel oxidation catalytic converters (DOC) is to catalyze the oxidation of HCG CO in exhaust gas and the components of SOF in oxidized exhaust particles to achieve the best emission reduction effect. Based on the engine bench test, the effects of Pt-base DOC on the smoke, particle size and oxidation characteristics of diesel engine emissions were studied in this paper. On the bench of YN38CRD2 diesel engine, the DOC device was installed, and the signal of temperature and pressure before and after DOC was collected by NI data acquisition card, and the smoke of particles before and after DOC was measured by AVL415. The variation law of exhaust temperature in diesel engine test condition is obtained, and the influence of DOC on exhaust smoke is analyzed. The experimental results show that with the increase of torque, the inlet temperature of DOC increases with the increase of fuel supply, and the smoke of exhaust particles decreases after passing through DOC. The particle size distribution before and after DOC was measured by DMS500 fast particle spectrometer. The distribution of particle size before and after DOC and the variation of total particle concentration before and after DOC were obtained. The experimental results show that: DOC can reduce the concentration of nuclear modal particles, and the higher the exhaust temperature, the lower the concentration of nuclear modal particles and the lower the particle size, the lower the concentration of accumulated particles. However, with the increase of torque, DOC can increase the concentration of accumulated particles. The effect of DOC on the total mass concentration of particles due to the exhaust temperature relationship (350 鈩，
本文编号：2152529
[Abstract]:Diesel particulate emission is one of the main sources of haze. Referring to the haze control process of developed countries (especially European countries), China has promulgated and implemented relatively strict automobile emission regulations. In order to meet the emission regulation standards, a series of post-treatment technologies for diesel engines emerged as the times require. The main role of diesel oxidation catalytic converters (DOC) is to catalyze the oxidation of HCG CO in exhaust gas and the components of SOF in oxidized exhaust particles to achieve the best emission reduction effect. Based on the engine bench test, the effects of Pt-base DOC on the smoke, particle size and oxidation characteristics of diesel engine emissions were studied in this paper. On the bench of YN38CRD2 diesel engine, the DOC device was installed, and the signal of temperature and pressure before and after DOC was collected by NI data acquisition card, and the smoke of particles before and after DOC was measured by AVL415. The variation law of exhaust temperature in diesel engine test condition is obtained, and the influence of DOC on exhaust smoke is analyzed. The experimental results show that with the increase of torque, the inlet temperature of DOC increases with the increase of fuel supply, and the smoke of exhaust particles decreases after passing through DOC. The particle size distribution before and after DOC was measured by DMS500 fast particle spectrometer. The distribution of particle size before and after DOC and the variation of total particle concentration before and after DOC were obtained. The experimental results show that: DOC can reduce the concentration of nuclear modal particles, and the higher the exhaust temperature, the lower the concentration of nuclear modal particles and the lower the particle size, the lower the concentration of accumulated particles. However, with the increase of torque, DOC can increase the concentration of accumulated particles. The effect of DOC on the total mass concentration of particles due to the exhaust temperature relationship (350 鈩，
本文编号：2152529
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