發(fā)布時(shí)間：2018-07-29 11:25

【摘要】：柴油機(jī)排放的微粒是構(gòu)成霧霾的主要來源之一,我國參照和借鑒發(fā)達(dá)國家(尤其是歐洲國家)的治霾歷程,頒布施行了相對(duì)嚴(yán)苛的汽車排放法規(guī)。為了達(dá)到排放法規(guī)標(biāo)準(zhǔn),一系列的柴油機(jī)后處理技術(shù)應(yīng)運(yùn)而生,其中柴油機(jī)氧化催化器(DOC)主要作用是催化氧化排氣中HC、CO以及氧化排氣微粒中的SOF組分實(shí)現(xiàn)微粒的減排。DOC通常與其他后處理技術(shù)配合使用,達(dá)到最佳減排效果。本文基于發(fā)動(dòng)機(jī)臺(tái)架試驗(yàn),研究了Pt基DOC對(duì)柴油機(jī)排放微粒煙度、粒徑特性、氧化特性等方面的影響規(guī)律。在YN38CRD2型柴油機(jī)臺(tái)架上,加裝DOC裝置,采用NI數(shù)據(jù)采集卡采集DOC前后溫度和壓力信號(hào),用AVL415測量DOC前后微粒煙度。獲得了柴油機(jī)試驗(yàn)工況排氣溫度變化規(guī)律,分析了DOC對(duì)排氣煙度影響的規(guī)律。試驗(yàn)表明:隨著扭矩增加,循環(huán)供油量增加,DOC入口溫度升高;排氣微粒經(jīng)過DOC后,其煙度降低。用DMS500快速微粒光譜儀對(duì)DOC前后微粒粒徑分布進(jìn)行了測量。獲得了DOC前后微粒粒徑分布規(guī)律,以及DOC前后微�？倲�(shù)量濃度變化規(guī)律。試驗(yàn)結(jié)果表明:DOC能降低核模態(tài)微粒數(shù)量濃度,排氣溫度越高,核模態(tài)微粒數(shù)量濃度峰值濃度和峰值粒徑越低;DOC能降低積聚態(tài)微粒數(shù)量濃度,但隨著扭矩的增加,DOC反而使積聚態(tài)微粒數(shù)量濃度增加。因排溫關(guān)系(350℃是硫酸鹽生成的臨界溫度),DOC對(duì)顆�？倲�(shù)量濃度的影響隨柴油機(jī)扭矩的增加呈現(xiàn)先降低后增加的趨勢。用Netzsch公司生產(chǎn)的STA449F3同步熱分析儀進(jìn)行微粒熱重分析。獲得了DOC前后微粒在熱重試驗(yàn)過程中的變化規(guī)律,得到DOC前后微粒的組分含量,分析了DOC對(duì)微粒SOF組分含量、微粒表觀氧化活化能及微粒干碳煙組分起燃溫度的影響規(guī)律。試驗(yàn)結(jié)果表明:因發(fā)動(dòng)機(jī)各點(diǎn)燃燒標(biāo)定不同,原排微粒SOF組分含量隨轉(zhuǎn)速變化無特定的趨勢;因DOC能提高排氣溫度,微粒經(jīng)過DOC后,其SOF組分含量降低;由于DOC的作用導(dǎo)致微粒的SOF組分含量降低,微粒表觀氧化活化能增加,干碳煙組分起燃溫度增加;同時(shí)由于SOF組分與干碳煙組分之間存在協(xié)同氧化作用,致使微粒的表觀氧化活化能隨SOF組分含量增加整體上呈下降趨勢。
[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，

本文編號(hào)：2152529