Pic. 2.319. Accelerator Pedal Components:
1 - support bracket; 2- plug; 3 - bolt 10 Nm; 4 - Accelerator pedal position sender G79 with accelerator position sender 2 G185.
The principle of operation of the electronic accelerator drive
The position of the accelerator pedal is transmitted to the engine control unit via two accelerator pedal position sensors (variable resistors; installed in one box), that are connected to the accelerator pedal.
Accelerator pedal position (depends on the actions of the driver) is the main input value for the engine control unit.
The throttle valve is driven by an electric motor (throttle servo) in the throttle control module, namely over the entire speed and load range.
The throttle valve is actuated by a servo drive according to signals from the engine control unit.
With the engine off and the ignition on, the engine control unit controls the throttle servo exactly according to the data from the accelerator pedal position sensor. This means that when the accelerator pedal is half depressed, the servo opens the throttle equally; in this case, the throttle valve will also be approximately half open.
Engine running (under load) The engine control unit can open and close the throttle independently of the accelerator pedal position sensor.
So, for example, the throttle valve may already be fully open, although the accelerator pedal is only half depressed. The advantage of this scheme is that throttling losses at the throttle valve are prevented.
In addition, under certain loads, there are noticeably better indicators regarding harmful emissions and fuel consumption.
Engine control unit, analyzing the amount of required torque for various components (e.g. air conditioning, automatic transmission, ABS/ESP...), calculates the optimal throttle opening angle for a given situation.
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