GF30.35-W-4002MP | Determination of the gas pedal position, function | 5.3.03 |
ENGINE 541.9 in MODEL 930, 932, 933, 934, 950, 952, 953, 954
ENGINE 542.9 in MODEL 930, 932, 934, 950, 952, 954
W30.35-1078-75
1 Idling speed
2 Partial load
3 Full load
A PWM signal at Output 1
B PWM signal at Output 2
B1 Foot throttle actuator
A3 Vehicle engine control (FMR) control unit
T Time
U Voltage
1 Detection of the gas pedal position.
The position of the gas pedal is detected and determined over the electronic foot throttle actuator (B1):
there are two potentiometers in the foot throttle actuator (B1) which each are located downstream from an electronic component.
Both potentiometers operate in the opposite direction. This not only ensures a high degree of operating reliability but also means that breakdowns are reliably recognized.
The drop in voltage at each potentiometer will vary according to how far the gas pedal is pressed and the level of the voltage which is applied at the appropriately downstream electronic circuit.
The value of the voltage is also crucial for the level of the duty cycles of the respective PWM signals which are generated by each electronic circuit and sent to the drive control (FR) control module (A3).
PWM (pulse-width-modulated) simply means that the transmitted information is contained in the values for the width of the impulse. The impulse changes when the gas pedal is activated. The frequency remains constant, however.
2 Transmission of the gas pedal position.
Both PWM signals transmitted from the foot throttle actuator (B1) to the drive control (FR) control module (A3) are inversely opposed to each other.
This means that the PWM signal at Output 1 (A) in idling condition (1) has a low duty cycle of about 10 to 30% whichincreases to about 40 to 90% in the direction of full loading (3) while the PWM signal at Output 2 (B) in idling condition (1) has a high low duty cycle of about 40 to 90% whichreduces to about 10 to 30% in the direction of full loading (3).
3 Detection of the gas pedal position.
Detection and determination of the gas pedal position occurs exclusively over drive control (FR) control module (A3) which analyses the PWM signals from the electronic foot throttle actuator (B1) whose issued duty cycles represent the position of the gas pedal.
No switches are required for the idling and kickdown position. These gas pedal positions are established in the drive control (FR) during the teach-in phase.