| Function of the electronic throttle system |
| In the electronic throttle system, the throttle valve is not operated by a cable connected to the accelerator pedal. There is no mechanical connection between the accelerator pedal and the throttle valve. |
| The position of the accelerator pedal is communicated to the engine control unit by two accelerator position senders (variable resistances located in a single housing) connected to the accelerator pedal. |
| The position of the accelerator pedal (decided by the driver) is one of the main input parameters to the engine control unit. |
| The throttle valve is actuated, over the full range of engine speed and power, by an electric motor (throttle valve actuator) in the throttle valve control unit. |
| The throttle valve actuator moves the throttle valve as instructed by the engine control unit. |
| After selecting display group 062, whether in mode 04 basic setting or 08 reading measured value block, the engine control unit controls the throttle valve positioner accurately using the information received from the accelerator position sender. This also applies for display group 060 in reading measured value block mode and in basic setting after adaption of the throttle valve control unit. |
| 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. |
| As an example, the throttle valve can be fully open even though the accelerator pedal is only pressed half way down. This has the advantage of preventing throttle losses at the throttle valve. |
| Under certain engine load conditions, markedly improved emission and consumption figures are also attained. |
| It is incorrect to believe that the “electronic throttle” is only comprised of one or two components. The electronic throttle is much rather a system which includes all the components which contribute to determining, controlling and monitoring the throttle valve position, e.g. the accelerator position sender, the throttle valve control unit, the EPC warning lamp, the engine control unit...) |
|
|
|
