Electronic Power Control, Component Overview

Electronic Power Control, Component Overview

With EPC, the throttle valve is not actuated through a cable from the gas pedal. There is no mechanical connection between the gas pedal and the throttle valve.

The position of the accelerator pedal is transmitted to the Engine Control Module (ECM) via two accelerator pedal position sensors (adjustable resistances, accommodated in one housing), that are connected to the accelerator pedal.

The position of the accelerator pedal (driver controlled) is a main input for the Engine Control Module (ECM).

Operation of the throttle valve occurs via an electric motor (throttle valve actuator) in the throttle valve control module. This is true across the entire engine speed and engine load spectrum.

The throttle valve is operated by the throttle valve actuator according to the instructions of the Engine Control Module (ECM).

With the engine at standstill and the ignition switched on, the Engine Control Module (ECM) activates the throttle valve actuator precisely according to the specifications of the Throttle Position (TP) Sensor. This means, if the accelerator pedal is depressed half way, the throttle drive opens the throttle valve to the same degree; i.e. throttle valve is then opened approx. halfway.

With engine running (under load) the Engine Control Module (ECM) can open and close the throttle valve independently of the accelerator pedal position sensor.

That way e.g. the throttle valve can already be completely opened, although the accelerator pedal is only depressed half-way. An advantage of this is that throttle losses at the throttle valve are avoided.

Aside from that, it results in clearly better pollutant output and consumption values 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, e.g. sensor for accelerator pedal position, throttle valve control module, EPC warning lamp, Engine Control Module (ECM).