Electronic Power Control System Function

Electronic Power Control System Function

For Electronic Power Control System (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 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 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 drive according to the instructions of the ECM.

With the engine is at a stand still and the ignition switched on, the ECM activates the throttle valve actuator precisely according to the specifications of the Throttle Position (TP) sensor. This means, if the accelerator pedal is pressed half way, the throttle drive opens the throttle valve to the same degree; for example, throttle valve is then opened approximately half way.

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

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

After evaluating the torque requirements of the various components such as the Air Conditioning (A/C) system, automatic transmission, Anti-lock Brake System (ABS)/Electronic Stabilization Program (ESP), etc., the ECM calculates the optimal throttle valve opening angle for the current situation.

Aside from that, it results in clearly better pollutant output and consumption values under certain load conditions.

EPC is a system containing all components that contribute to determining, controlling and monitoring the throttle valve position, for example, TP sensor, throttle valve control module, EPC warning light, ECM.