Unlike other systems, the Motronic system uses sequential fuel injection. This means that the opening of the injectors and the injection of fuel occurs in accordance with the operation of the cylinders.
The idle speed is controlled by the throttle stepper motor. The mass air flow sensor uses a special heating film. The advantage of using the film is that it does not need to be cleaned of contaminants by heating it, which is required when using a conventional filament.
The use of afterburning by supplying additional air to the exhaust valves reduces the amount of unburned particles in the exhaust gases. The exhaust gas recirculation system allows, depending on the operating mode of the engine, to supply a certain amount of exhaust gas to the intake manifold again. This reduces the content of exhaust gases.
The throttle body is part of the fuel injection control mechanism. The main task of the injection control mechanism is to maintain a stable idle speed of the engine under any operating conditions and engine loads, including when additional equipment is turned on, for example, an air conditioner. The damper potentiometer transmits information to the control unit about the angle of its opening. The control unit opens or closes the throttle by means of an executive motor, thus maintaining the nominal value of the idle speed.
The throttle position regulator consists of an actuator motor with a gear and a return spring. The throttle valve potentiometer is located on its axis and is a signal source for the engine control unit about the throttle valve opening angle. The second potentiometer is redundant and its signal is used by the engine control unit in case of failure of the main potentiometer.
The electronic fuel injection system has its advantages, which are as follows:
- A) accurate dosing of the amount of fuel in each engine operation mode, which ensures lower gasoline consumption while maintaining good dynamic performance;
- b) reduction of harmful exhaust gases as a result of precise fuel dosing and exhaust gas cleaning (OG) with the help of a catalyst;
- V) self-diagnosis of the control unit, which allows you to quickly find the fault. The injection system is equipped «memory», where errors are recorded during the operation of the car. If during operation failures occur in the ignition or injection system, they are recorded. If a malfunction occurs in the engine in a specialized workshop, you can get a printout of faults for a fee in order to independently eliminate one or another defect if necessary.
The microprocessor that controls the motor is a small, fast computer. It determines the optimum ignition timing, fuel injection timing and injected fuel volume. In this case, the actions of the microprocessor are coordinated with control units of other vehicle systems, for example, with a gearbox control unit or with an anti-theft system.
Precautionary measures
Attention! The fuel system is under pressure. Before disconnecting the fuel system hoses, wrap the junction of the hoses with a rag and only then carefully remove the hose, relieving pressure.
Fuel fumes are poisonous and highly flammable. Avoid skin contact with fuel. Wear protective goggles. Ensure adequate ventilation of the work area. Fire hazard! Equip your work area with a fire extinguisher.
To avoid personal injury or damage to the fuel injection system or the fuel system as a whole, the following safety precautions are recommended:
- Do not touch or remove the high voltage wires while the engine is running or the starter is engaged.
- Connect and disconnect wires of systems of injection and ignition only at the switched off ignition. The same applies to the instrument leads used to make measurements on these systems.
- Persons with a pacemaker must not be allowed to work on the electronic ignition system.
- Do not inject fuel when checking compression.
Attention! When working on the injection system, the general safety and cleanliness rules must be observed (see section «Fuel system»).
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