| In the EPC, the throttle is not operated by a control cable from the accelerator. There is no mechanical link between the accelerator and the 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 is operated over the complete revolution and load range by an electric motor (throttle positioner) in the throttle control part. |
| The throttle valve positioner actuates the throttle valve according to the commands it receives from 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. For example, when the accelerator is pressed down half way, the throttle valve positioner opens the throttle valve by an equivalent amount, i.e. about half way. |
| 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. |
| For example, the throttle valve might already be fully open even though the accelerator is only pressed down half way. The advantage of this is that losses through bottlenecks caused by the throttle are avoided. |
| After evaluating the torque requirements of various components (e.g. air conditioning (heating), automatic gearbox, ABS/ESP ), 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, e.g. the accelerator pedal position sender, the throttle valve control unit, the EPC warning lamp, the engine control unit... |
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