| In the EPC, the throttle is not operated by a control cable from the accelerator. There is no mechanical connection between accelerator and throttle. |
| 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 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. |
| In this way, the throttle valve can, for example, be fully open, although the accelerator is only half pressed. The advantage of this is that losses through bottlenecks caused by the throttle valve are avoided. |
| Also, at certain load values, much better contaminent emission and consumption values are thus produced |
| The engine control unit can generate the necessary engine torque using an optimum combination of throttle valve aperture section and the boost pressure control. |
| It is incorrect to believe that the EPC 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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