Weak current College】 【Buick air flow sensor working principle】.

<br> <br> Air flow sensor is a key part of the fuel injection system, it will have a direct impact on the vehicle's normal driving. <br> <br> Buick air flow sensor hot-wire flowmeter is, its role is .to measure the time, the air flow through the sensor, and the air flow of signals to ECU. ECU on the basis of the signal for monitoring engine performance, the calculation of the fuel supply. Air flow, indicates that the engine in the spin .-up; small air flow rate, engine speed or idling operation. <br> <br> Working principle: when entering the throttle body of air flows through the MAF sensor, took some heat, air flow, the larger the heat away. To .enable the induction of temperature at a constant temperature, they need extra current to heat the induction. MAF sensor by measuring the current voltage to determine the size of the air flow. <br> <br> Air flow sensor of the hotline is handled by .metal Platinum wire, into the throttle valves for the by-pass airway. This air flow sensor principle with whetstone bridge, over the air stream of power because of the airflow cooling hotline puckering resistance value changes, the bridge was out of balance, control circuit .automatically increase the voltage, the electric current flows through the hotline, the hotline resistance with temperature rise and rise bridge will regain balance. In the regulatory process, the air flow sensor to the engine control module (ECU) voltage signal with air traffic, the .air near the hot stream also has compensated resistance wire (cold) to avoid air temperature changes make the bridge out of balance. <br> <br> Air flow sensor hotline scale, to ECU voltage signal will not, at this point the dirt affecting .radiation so that the cooling effect is reduced. When the air flow increases, hotline, its temperature decrease slowly change resistance values are reduced, so the voltage and current flows through the hotline cannot be increased, thus corresponding to ECU signal voltage is low, the .resulting mixture is too lean. Although the hot air flow sensor is equipped with a fire that net circuits in each outage, ECU automatically to hotline at high temperature (1000 ¡æ) heating 1s to burn the hotline on the dirt and dust, but in .some areas, particularly in remote areas due to the use of fuel quality is too low, intake pipe produce tempered, causing excessive deposition of impurities and cemented in metal Platinum wire, so single heating hotline of purification plant was difficult to clear. Therefore, you .must remove the air flow sensor direct spraying to resume its normal function. <br> <br> Case study: a Buick, when the vehicle in 100km / h, the engine has a sense of vibration, and climbing. Clean air filter, replace .the fuel filter, remove the nozzle cleaning, are ineffective. Remove the air flow sensor cleaning hotline, troubleshooting. <br> <br> Finally introduce air flow sensor to the g / s for the measurement of air flow rate into the engine. Air .flow measurement values are reflected in engine load (throttle valve and air volume), and engine load, intake manifold absolute pressure sensor or vacuum sensor signal is similar to the relationship. Air flow (MAF) signal when the vehicle is in constant speed should remain .relatively stable, with the throttle valve of gradual change, and when a sudden acceleration of dramatic changes. Powertrain control modules (PCM) use air traffic control and fuel supply of the information. Sensor generates a test would not be measured frequency signal (32 ~ .150Hz). This change of signal and the air flow going into certain proportions. <br> <br>.