Electronic Throttle Control (Drive By Wire or Fly By Wire)
The throttle cable has almost become redundant ontoday’s motor vehicle. The drive-by-wire system is by no means a new concept as it was introduced by BMW on their 7 series range back in 1988. The system BMW use is referred to as EML (German term forelectronic throttle control). The system has now found its way onto other vehicles with humbler routes and can be found on base models. Historically a mechanical linkage between the accelerator pedal andthe throttle butterfly has always existed, be it via a cable or via rods and linkages. These have now been replaced by sophisticated electronic control modules, sensors and actuators. This system isalso referred to ‘Fly-by-Wire’.
There are several reasons why electronic throttle actuation is preferable to a conventional throttle cable:
* The vehicle’s on board electronic systems are able tocontrol all of the engine’s operation with the exception of the amount of incoming air.
* The use of throttle actuation ensures that the engine only receives the correct amount of throttleopening for any give situation
* The optimisation of the air supply will also ensure that harmful exhaust emissions are kept to an absolute minimum and drivability is maintained, regardless of thecircumstances. Coupling the electronic throttle actuation to the adaptive cruise control, traction control, idle speed control and vehicle stability control systems also means finer control can beachieved.
The use of such a system has advantages over the conventional cable version by:
* Eliminating the mechanical element of a throttle cable and substituting it with fast responding electronics,reduces the number of moving parts (and associated wear) and therefore requires minimum adjustment and maintenance.
* Greater accuracy of data improves the driveability of the vehicle, which in...