在不改变发动机参数的情况下，在电喷汽油机上进行台架试验，对比分析了燃用含水乙醇汽油（E20W）和纯汽油（E0）的排气噪声、排气温度及排放特性。试验结果表明：相较于纯汽油，在低转速下燃用E20W产生的排气噪声要低于纯汽油，最大降低7.4% ；在中、高转速时，二者产生的排气噪声相差不大；另外，燃用E20W的排气温度要高于纯汽油，平均增加5.3%；汽油机燃用E20W可以大幅降低HC和CO排放，分别平均降低10.4%和33.6%，但NOx和CO2 排放升高。综合来看，含水乙醇汽油E20W可以直接应用于试验发动机，并能起到降低排气噪声和减排的作用。

The bench test was carried out on the EFI gasoline engine without changing the engine parameters and the exhaust noise, exhaust temperature and emission characteristics of ethanol gasoline (E20W) and pure gasoline (E0) were compared and analyzed. The test results show that the exhaust noise of E20W at low speed is lower than that of pure gasoline and the maximum reduction is 7.4% compared with pure gasoline. At medium and high speeds, the difference of exhaust noise between them cannot be identified. In addition, the exhaust temperature of E20W is higher than that of pure gasoline with an average increase of 5.3%.The gasoline engine fueled with E20W can significantly reduce HC and CO emissions with an average reduction of 10.4% and 33.6% respectively, but NO_x and CO₂ emissions increase. On the whole, the hydrous ethanol gasoline E20W can be applied to test engine directly and can reduce exhaust noise and emissions.