沃尔沃轿车LH型电控燃油喷射系统采用热线式空气流量计,计量发动机吸入的空气量时能对影响空气密度的空气压力和温度进行自动补偿。空气流量计中有根导线(热线),工作时热线被加热到高出进气温度150℃,此温差必须保持恒定。当流经热线的空气量增加时,热线被冷却,为维持自身温度不变,就得提高加热电流。因此,可通过加热电流的变化反映流经热线的空气量大小。热线式空气流量计的结构原理如图1所示,它是 Volvo LH LH electric fuel injection system using hot-wire air flow meter, measuring the amount of air sucked by the engine can affect the air density of the air pressure and temperature automatically compensate. There is a root wire (hot wire) in the air flow meter. The hot wire is heated up to 150 ° C above the intake air temperature during operation. The temperature difference must be kept constant. When the amount of air flowing through the hotline increases, the hotline is cooled, and to maintain its own temperature, you have to increase the heating current. Therefore, the amount of air flowing through the hot line can be reflected by the change of the heating current. The structure of the hot air flow meter principle shown in Figure 1, it is