電熱式觸媒轉化器應用於機車引擎冷起動過程之污染排放特性研究

Pre-heated catalytic converter on the emissions of motorcycle engine during cold-start conditions

許天秋(Tien-Chiu Hsu)

指導教授 ： 洪榮芳

崑山科技大學/工程學院/機械工程研究所/碩士(2003年)

https://doi.org/10.6828/KSU.2003.00038

摘要

本文主要目的在於針對機車引擎冷車起動過程，探討預熱式觸媒對於污染排放的影響。探討的對象為引擎冷起動暫態過程的怠速運轉狀況，在此過程中，引擎及觸媒均未達工作溫度，故以預熱及預熱增濃方式提升進入觸媒的排氣及觸媒溫度，使觸媒提早反應，達到改善觸媒轉化效果的目的，並且以能量角度探討污染轉化效益。
在預熱部份，實驗參數包括加熱溫度、加熱位置及CO設定值等；在預熱增濃部份實驗參數包括加熱溫度、起動增濃時間，配合不同的排氣加熱溫度及CO設定值；量測項目包括觸媒進口排氣溫度、觸媒出口排氣溫度、污染排放及空燃比等。探討的排氣溫度範圍分為預熱及預熱增濃，預熱包括原始溫度（排氣未加熱）、加熱至100℃、140℃及180℃等；而預熱增濃部份包括原始溫度（排氣未加熱）、60℃、80℃、100℃及120℃，加熱器安裝部分則以六種不同的加熱位置組合；冷車起動觸媒之前的CO濃度分別設定為1.0%、1.3%、1.8%及2.3%等。
　　經由一系列的實驗測試獲得結果為，以較濃的CO設定濃度能使觸媒轉化器的溫度快速提高，並可於較短的時間達觸媒的反應溫度，且節省電瓶的能源。加熱位置集中於前段均比集中於中段加熱，其平均CO排放濃度較低，但以單位輸入能量之轉換效率比較時，集中於中段加熱則較為理想。冷車起動時進氣燃料額外增濃且配合電熱式觸媒的作用下，可有效降低使觸媒達反應溫度的設定加熱溫度。對於觸媒轉化效果及節省加熱能量有相當明顯的效果。

關鍵字

冷起動 ； 排放污染 ； 機車引擎 ； 電熱式觸媒轉化器

並列摘要

The investigation of the effect of a pre-heating catalyst on a four-stroke engine under cold start condition is the major purpose of this study. In the condition of cold start, engine and catalyst were both under the cold state. Pre-heating on the catalyst and additional enrichment of intake mixture can let the catalyst warm up fast. Pre-heating the catalyst to promote earlier reaction and to improve the conversion of catalyst was performed in the experiments. Further, the energy input on the conversion characteristics of catalyst was discussed simultaneously.
The investigated parameters were set exhaust heating temperature, heating position and CO setting level in the study of heating without additional enrichment. Nevertheless, in the study of additional enrichment of intake mixture, the experimented parameters were set exhaust heating temperature, additional enrichment time of cold start and CO setting level.
The measured items were the exhaust gas temperature of inlet and outlet of the catalyst, CO emission and air-fuel ratio. The set exhaust heating temperature included raw temperature, 100oC, 140oC and 180oC for the case of pure pre-heating. In the case of pre-heating with additional enrichment, the set exhaust heating temperature included raw temperature, 60oC, 80oC, 100oC and 120oC. The heaters were installed at four positions with six different combinations. The set CO level were 1.0%, 1.3%, 1.8% and 2.3%.
The experimental results revealed that the rich CO setting level could let the catalyst warm up quickly and to achieve light-off temperature earlier, so that it could attain the energy saving of battery. The best CO conversion efficiency was obtained by heating at the inlet of the catalyst. However, as the conversion efficiency per unit input energy was considered, the best energy using effect was achieved by heating in the mid-section of the catalyst and by lower heating power. That is, by using both of the additional enrichment of intake mixture and pre-heating of catalyst under cold start condition, the improvement of the conversion efficiency of catalyst and heating energy saving could be achieved at the same time.
Furthermore, the lower exhaust heating temperature for the reaction of catalyst could be obtained.

並列關鍵字

EHC ； cold-start ； motorcycle ； pre-heated catalytic convertor ； emossion

參考文獻

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