Location of the tape conductor in the air flow meter
- 1 - tape conductor
The engine management system is a combined ignition and fuel injection system.
The fuel pump, located in the fuel tank, delivers fuel to the fuel rail through the fuel filter. The fuel pressure in the system is controlled by the pressure regulator. The regulator allows excess fuel to return to the fuel tank when the pressure in the fuel system is exceeded. The fuel rail is a reservoir for four fuel injectors, which inject fuel into the intake ports of the engine cylinders. A sequential fuel injection system is used, in which the injectors inject fuel independently of each other. The control unit controls the fuel injector by changing the pulse width, that is, the length of time the injector is open, to provide a richer or leaner fuel mixture.
The air passes through the air filter, the air flow meter and the throttle valve to the intake ports of the cylinders. The air flow sensor is a ribbon conductor (1) under voltage. A constant ribbon temperature is maintained by an electric current, which varies depending on the mass of the passing air. The current that must be supplied to maintain a constant ribbon temperature is proportional to the mass of the air flow. Based on information from the air flow meter and other sensors, the control unit regulates the time and amount of fuel injection in accordance with the measured amount of air and the engine speed. The longer the injector is open, the more fuel is injected.
Additional sensors transmit information to the control unit about the coolant temperature, the temperature of the air entering the engine, and on models with a catalytic converter, about the oxygen content in the exhaust gases.
The activated carbon filter prevents harmful fuel vapors from penetrating from the fuel tank into the atmosphere. Fuel vapors accumulate in a container with activated carbon and are burned in the engine cylinders when the engine is running.
A memory device in the control unit recognizes the malfunction that has occurred and records it. If an important sensor fails, the control unit switches to an emergency program so that the engine continues to operate, albeit with less efficiency.
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