Electronic Engine Power Control

Electronic Engine Power Control

For "EPC", the throttle valve is not operated by a cable from the accelerator pedal. There is no mechanical connection between the accelerator pedal and the throttle valve.

The position of the accelerator pedal is communicated to Motronic Engine Control Module (ECM) (J623) via Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185) (variable resistances; stored in one housing) that are connected with the accelerator pedal.

The accelerator pedal position (driver's intention) is a main input unit for the Motronic Engine Control Module (ECM) (J623).

Operation of the throttle valve occurs via an electric motor (Throttle Drive (for Electronic Power Control (EPC)) (G186)) in the Throttle Valve Control Module (J338). This is true across the entire engine speed and engine load spectrum.

Throttle valve is operated by Throttle Drive (for Electronic Power Control (EPC)) (G186) according to specifications of Motronic Engine Control Module (ECM) (J623).

With engine off and ignition switched on, Motronic Engine Control Module (ECM) (J623) controls the Throttle Drive (for Electronic Power Control (EPC)) (G186) exactly according to specifications of Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185). This means, if the accelerator pedal is depressed half way, the Throttle Drive (for Electronic Power Control (EPC)) (G186) opens the throttle valve to the same degree; i.e. throttle valve is then opened approx. half way.

With engine running (under load), Motronic Engine Control Module (ECM) (J623) can open or close the throttle valve independently of Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185).

This means, for example, that the throttle valve could be fully opened even though the accelerator pedal has only been depressed half way. This has the advantage of preventing torque losses at the throttle valve.

In addition to this, it results in significantly better values relative to emissions and consumption under certain load conditions.

It would be incorrect to think that "EPC" consists of only one or two components. "EPC" is much more of a system containing all components that contribute to recognizing, controlling and monitoring the position of the throttle valve.