| 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 position of the accelerator is transmitted to the engine control unit by two accelerator position senders (variable resistors together in a housing) which are connected to the accelerator pedal |
| The position of the accelerator (driver's requirement) is the main input value for the engine control unit |
| The throttle is operated over the complete revolution and load range by an electric motor (throttle position device) in the throttle control part. |
| The throttle valve position device 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. 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 (under load) the engine control unit can open or close the throttle valve independently of the accelerator pedal position sender. |
| This means that the throttle valve can already be completely open even though the accelerator pedal is only pressed 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, 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 E-Gas is a system that contains all components that are used to determine the position of the throttle valve, to regulate it and to monitor it. These are, e.g. the sender for the accelerator, the throttle valve control unit, the EPC warning lamp and the engine control unit. |
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