车用汽油机燃油空气加热器试验

Tests of Air Heater Heated by Fuel for Gasoline Engine of Vehicle

为减少车用汽油机低温冷起动排放并实现快速起动，采用低压喷射、高压点火的方案，研制了一种新型燃油空气加热器，并对其进行结构优化和性能试验研究。结果表明：喷油压力对排放影响很大；喷油压力为3．5×10^5～4×10^5Pa时，热风出口温度相差不大；喷油压力为4．5×10^5Pa时，燃烧40S后，热风出口温度上升较快，60S时能达到109℃；结构优化后，加热时间可控制在60S以内，但排气温度较高，燃烧室热负荷加大；采用该燃油空气加热器可实现快速有效的进气预热，为解决发动机低温冷起动排放高和起动困难等问题，提供了一个有效的措施。

A novel air heater heated by fuel for gasoline engine of vehicle which used low pressure injection and high voltage ignition was developed to make engine＇s cold-start quick and to reduce HC and CO emission. The tests on its performance were conducted after its structure was optimized. The results show that injection pressure plays an important role in emission. Within the range of 3.5 × 10^5 Pa to 4 × 10^5 Pa for the injection pressure, the outlet temperature difference of hot air is not significant. When the injection pressure is 4.5 × 10^5 Pa, the outlet temperature of hot air increases steeply after 40 s and reaches 109 ℃ after 60 s. Based on the optimized structure, the heating time can be decreased to less than 60 s, meanwhile, the exhaust temperature is fairly high and the heat load inside of chamber rises. The results of experiments demonstrate that this device can rapidly and effectively preheat intake air. An effective solving measure is provided for starting hardness and high emission of engine＇s cold-start.