引擎於冷起動期間，排氣管中的觸媒均處於低溫狀態，致使觸媒無法反應，造成冷起動期間引擎嚴重的污染排放。故於冷起動期間預熱觸媒，使觸媒提前達反應溫度，為改善引擎冷起動污染的有效方法之一。本計畫以蓄熱式觸媒轉化器應用於四行程機車引擎，探討蓄熱材料長度、加熱位置、加熱溫度及加熱能量等，對於觸媒轉化器於冷車起動過程轉化效果的特性。由實驗結果得知，配合較短的蓄熱材料及較高的CO 設定值，於觸媒入口處加熱者，可獲得較佳的CO 轉化效率；較長的蓄熱材料及較低的CO 設定值，無論在何處加熱，均無法獲得較佳的轉化效果。另外，由機車引擎添加富氫氣體的研究可知，在怠速期間，富氫氣體的添加量必須配合進氣氧氣的供給，若富氫氣體添加太多，致使進氣中氧氣不足，則會導致污染排放的上升。在定速行車期間，隨著富氫氣體添加量的增加，可獲得較佳的省油效果，最佳的提升率約可達33%左右。Both of engine and catalyst are in the low temperature condition during cold start. Severeexhaust emissions are caused by poor conversion of unburnt gases during this stage. Pre-heatingthe catalyst is one of the promising ways to improve the exhaust emissions of the engine duringcold start. An electrically heated catalyst with heat storing material was adopted for reducing theemissions in this study. The length of heat storing material, heating position, heating temperatureand heating energy on the conversion characteristics were investigated. The results showed thatheating at the entrance of catalyst with the combination of shorter heat storing material and higherCO setting level, hence, better CO conversion was obtained. On the contrary, poor CO conversionwas obtained with the longer heat storing material and lower CO setting level. Besides, it could befound some results from the addition of hydrogen-rich gas fueled engine tests. In the idle operation,if the hydrogen-rich gas was over-supplied, the severe exhaust emissions were obtained due to richmixture preparation. In the cruising speed driving tests, better fuel economy could be obtained asmore hydrogen-rich gas was supplied. The best improvement of fuel economy was 33%,approximately.