Electronic Throttle Control

Basic Description

In traditional vehicle designs, stepping on the accelerator pedal moves a cable that is mechanically connected to a butterfly valve in the engine's throttle. The position of this valve directly controls the amount of air supplied to the cylinders and consequently determines the engine speed. In the growing number of vehicles that have electronic throttle controls, stepping on the accelerator pedal adjusts two potentiometers that send a signal to the engine control module (ECM). The ECM uses this information to send a control signal to an electric motor mounted to the throttle body that adjusts the position of the butterfly valve accordingly.

A major advantage of an electronic throttle is that it can be easily linked to other systems such as engine control, traction control, electronic stability control and cruise control. These other systems are able to take control of the throttle when necessary to help improve vehicle safety, convenience and fuel economy. Like all of the electronic systems controlling safety critical functions in a vehicle, electronic throttle controls are designed with certain fail-safe features and self-diagnostic capabilities.

A simple demonstration how electronic throttle controls work can be found here.

Sensors

Pedal position sensors, throttle valve position sensors

Actuators

Motor on throttle body

Data Communications

Typically a CAN bus connection between the ECM and other systems capable of controlling the throttle.

Manufacturers

Bosch, Continental, Delphi, Denso, Hitachi, Magnetti Marelli, MCS

For More Information

[1] Electronic throttle control, Wikipedia

[2] Electronic Throttle Control System, Denso Automotive OEM Products website.

[3] Electronic Throttle Control (Drive By Wire or Fly By Wire), Pico Technology website.

[4] Subaru Electronic Throttle Control (ETC), YouTube, July 2008.

[5] What is Electronic throttle Control?, Christine & Scott Gable, About.com.

[6] Electronic Throttle Control Advances, Michael Knowling, Autospeed.com, 2001.