What Is Throttle By Wire?
Drive by wire is a technology that replaces traditional physical connections with a wire carrying an electronic signal. For example, on gasoline engines the throttle cable normally runs from the gas pedal to the butterfly in the throttle body that limits the amount of air going into the engine. As the gas pedal is pressed further down the butterfly opens wider, allowing more air into the engine. On fuel injected vehicles sensors detect the additional air and increased throttle position and instruct the fuel injectors to supply more fuel so that the engine starts to make more power.
With throttle by wire a sensor is attached to the gas pedal and detects how far it has been pressed. This information is then sent down an a wire to the car's computer. The computer analyzes the information and commands a motor to open the butterfly in the throttle body. Since the computer is in control of the throttle opening things like idle speed control, cruise control, and traction control can easily be integrated. Because automatic transmissions are also usually controlled by the computer it can adjust the throttle during gear changes. It also allows the addition of eco or sport buttons to change the way the throttle reacts when pressed, increasing fuel economy or throttle response.