Throttle Valve Module (Electronic Accelerator Pedal)
A throttle valve module with electronic throttle valve servo motor and an integrated throttle valve potentiometer are used in the Z 22 SE engine. The cross–section of the throttle body is 58 mm. The idle speed is controlled in the Z 22 SE engine by the position of the throttle valve in the main current; the throttle valve is actuated by the throttle valve servo motor. The throttle body, throttle valve servo motor and throttle valve potentiometer are combined in one modular unit and can only be replaced as one unit.
The structure and function of the integrated throttle valve potentiometer are as follows:
Two throttle valve potentiometers are integrated in the throttle body and are located on one shaft together with the throttle valve. Voltage is supplied to both potentiometers via separate plus and minus connections. The potentiometers register the angular position of the throttle valve and transmit this information to the engine control unit. The engine control unit then calculates the required fuel quantity. The first potentiometer has a control range of 0.4 volts to 4.6 volts (positive curve). The second potentiometer has a negative curve (control range of 4.6 volts to 0.4 volts) for controlling the first potentiometer. As a result, both potentiometers can only supply the same output voltage at one operating point (throttle valve approx. three–quarters open) during fault–free operation. If both sensors fail, the appropriate engine emergency operation mode is activated - see "Emergency operation modes (electronic accelerator pedal)".
1.12.4.1 Throttle Valve Module (Electronic Accelerator Pedal)
Design and function of throttle valve with servo motor:
The throttle valve is driven by a direct–current motor via a two–speed gearbox. The direct–current motor receives a signal from the control unit which it then converts into a rotational movement of the throttle valve.
It is not necessary to delete or learn the zero setting of the throttle valve using TECH 2 after replacing the throttle valve module and/or engine control unit. When the ignition is switched on, the throttle valve closes fully and automatically adapts to the zero setting.
1.12.4.1 Throttle Valve Module (Electronic Accelerator Pedal)
- Gearbox
- Throttle valve
- Direct–current motor