| With the EPC system the throttle valve is not operated by a cable. There is no mechanical connection between accelerator and throttle valve. |
| The accelerator position is transmitted to the engine control unit by means of two accelerator position senders (variable resistances; positioned in a housing), connected to the accelerator. |
| The position of the accelerator (decided by the driver) is one of the main input parameters to the engine control unit. |
| The throttle valve is operated over the complete revolution and load range by an electric motor (throttle valve positioner) in the throttle valve control unit. |
| The throttle valve is operated by the throttle positioner according to the data provided by the engine control unit. |
| With the engine off and the ignition connected, the engine control unit operates the throttle positioner according to the data provided by the accelerator position sender. This means that if the accelerator is pressed half way, the throttle positioner opens the throttle valve proportionately; the throttle valve is then half open. |
| When the engine is running (and under load), the engine control unit can open and close the throttle valve independently of the accelerator position senders. |
| This means that the throttle valve can already be completely open even though the accelerator pedal is only depressed half way. This avoids choking losses caused by the throttle valve. |
| After evaluating the torque requirements of various components (e.g. air conditioning, automatic gearbox, ABS/ESP and so on), the engine control unit calculates the optimal throttle valve opening angle for the respective situation. |
| This also gives vastly improved consumption and exhaust emission levels at certain load conditions. |
| It is incorrect to believe that the “E-Gas” is comprised of one or two components only. The EPC is a system, which is comprised of all components which have an influence, control or monitor the position of the throttle valve, e.g. the accelerator pedal position sender, the throttle valve control unit, the EPC warning lamp, the engine control unit |
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