The Analysis Of Automobile Intelligent Air Flow Sensor

Engine electronic fuel injection system, as a crucial advancement in automobileelectronic technology development, is capable of closed-loop controlling the engine fuelinjection quantity timely and accurately, improving engine performances significantly. Inaccordance with the amount of air into the engine measured by air flow sensor, electriccontrol unit determines the essential injection quantity of a fuel supply system, thus preciselycontrolling the air-fuel ratio on purpose of improving the dynamic property, economicalefficiency as well as emission performances.Thermal air flow sensor is a type of a mass flow meter, which can measure the amount ofair inflow without temperature and pressure compensation, thus enjoying high measurementaccuracy. Besides, it also bears advantages of small size, lighter weight and quick response.For this reason, thermal air flow sensor enjoys widespread applications in engines. Theresearch contents of the design for analyzing intelligent air flow sensor can be listed asfollows:At first, the dissertation illustrates and compares different types of air flow sensor as wellas their working principles respectively, discussing advantages of thermal air flow sensor.Then, it focuses on the theoretical basis of thermal air flow sensor in perspective of Thomastheory and heat transfer analysis.In the design of intelligent air flow sensor, it selects single-chip microcomputer and otherelectrical components according to engine working environments and requirements; devisesamplifier and single-chip circuits based on principles of circuits and single-chip. It alsoconducts single-chip software programming aimed at achieving an intelligentized sensor anddevises the structure of the sensor in accordance with relevant packing and assemblyrequirements to satisfy specific usage requirements.Finally comes the establishment of test-bed for calibrating air flow sensor and testingtemperature compensation effect, and the measured data of intelligentized air flow sensor canbe compared with the measuring signal from standard sensor, through which the measurementdeviation of the sensor can be detected and analyzed. Equipped with the single-chip, the intelligentized air flow sensor is capable of correctingthe measurement signal uninterruptedly, thus it requires less from the measurement accuracyof the sensor unit probe, reducing production cost and improving measurement accuracysignificantly. It also enjoys features of automatic calibration and testing, self-compensating,fault prevention and automatic data collection and processing as well as carrying two-waycommunications with upper computer. According to the test results, the voltage signaloutputted by the intelligentized air flow sensor is in conformity to that of the standard air flowsensor, and the sensor has favorable temperature compensation, perfectly meeting therequirements of engine.