Accelerator pedal module
The accelerator pedal module (FPM) picks up the pedal position. This leads to the transfer of the driver's choice to accelerate in the form of an electrical signal to the Digital Engine Electronics (DME).
Accelerator pedal position is monitored separately by 2 individual sensors. Two sensors are employed to provide redundancy, implement the monitoring function and facilitate recognition of malfunctions.
The accelerator pedal travel is detected by the sensors as an angle and output directly to the Digital Engine Electronics system (DME) as an analogue, linear signal. The total mechanically feasible operating travel of the accelerator pedal is 16° ± 0.5°. Each change to the accelerator pedal position is sent to the engine control system within a maximum of 50 milliseconds Digital Engine Electronics (DME). Sensor signals are transmitted in analogue form. The Digital Engine Electronics (DME) monitors the two input signals of the sensors and compares them for plausibility (e.g. synchronization, linearity).
| Index | Explanation |
|---|---|
| 1 | Accelerator pedal |
| 2 | WOT travel stop |
| 3 | six-pin plug connection |
The accelerator pedal is returned on closure of the throttle by means of spring elements.
The following characteristic curve represents the voltage curve depending on the pedal sensor position of an accelerator pedal module with kickdown switch.
| Index | Explanation |
|---|---|
| 1 | Sensor voltage (V) |
| 2 | Sensor 1 voltage at idle |
| 3 | Sensor 2 voltage at idle |
| 4 | Sensor 1 output signal curve |
| 5 | Sensor 2 output signal curve |
| 6 | Characteristic curve for rising pedal force |
| 7 | Characteristic curve for decreasing pedal force (releasing the pedal) |
| 8 | Increased pedal force for kickdown and decreased pedal force at end of kickdown |
| 9 | WOT position without kickdown |
| 10 | Kickdown OFF |
| 11 | Kickdown ON |
| 12 | Accelerator pedal value in degrees (°) |
| 13 | Pedal force in newtons (N) |
Start of kickdown phase: The detent position at which increased pedal force is required lies between a maximum of 13.8° and a minimum of 1.6° before the mechanical travel stop. On the characteristic curve for rising pedal force, the threshold value for kickdown ON must lie immediately after the maximum pedal force for kickdown.
End of kickdown phase: The final position for increased pedal force occurs 1.6° before the mechanical travel stop at the earliest and 13.8° before it is reached at the latest. On the characteristic curve for falling pedal force, the threshold value for kickdown OFF must lie immediately after the maximum pedal force.
Voltage values: The accelerator pedal values of the two sensors are percentages related to the power supply.
Sensor 1: At idle speed, the value is 15% of the power supply; at the end stop approx. 90%.
Sensor 2: At idle speed, the value is 7.5% of the power supply; at the end stop approx. 45%.