How electronic throttles work?
The pedal is connected to what essentially are potentiometers. They generate a certain amount of voltage which the ECU reads and equates to throttle angle openings. They first of all measure how far your foot travels when you push the pedal to a certain point as well as how fast you pushed the pedal to reach that point and creates a throttle calculation for your ECU. The ECU then sends a signal to the butterfly position sensor which controls the opening rate of your butterfly on the throttle body, and opens it up by the amount programmed into the ECU for a given voltage generated at the pedal. There is also a feedback sensor on the throttle body which informs the ECU that the throttle butterfly is doing what it is supposed to ( i.e. opening the throttle up to the angle dictated by the ECU ).
Now, like with most electronic control systems, there is redundancy built into drive by wire systems. Instead of just one demand sensor at the pedal, there are two. Same goes with the feedback sensor at the throttle body. This is to avoid loss of control should one fail. The complex nature of this system with its variety of potentiometers, computers, sensors and management systems is what results in a noticeable delay when you first hit the pedal, known as throttle lag or dead zone. No matter how hard or fast you stomp on your accelerator there is no overcoming this delay, it is an inherent electrical delay that physical input can not conquer.
The fact of drive by wire systems
The voltage signals generated by the redundant sensors are not identical. The ECU always monitors both signals to constantly check if everything is working normally. Should one signal be outside of expected sensor readings or fail outright, the ECU will throw a code and go into fail-safe mode. This means power is reduced to avoid having the car speed out of control, exceed the ECU’s expected parameters, and the orange light comes on and your engine loses power.
Why use drive by wire systems?
Well a few reasons, first of all the electronic throttle system is a lot lighter, reducing weight in modern cars, also they are far easier to service and tune, simply hook up a computer and let it do the work for you. It is also worth mentioning the impact of emissions control in regard to switch to electronic throttle systems, using electronics allows for much more precise control of the throttle opening compared to a cable that stretches over time. It also allows the throttle response to be programmed in by the manufacturers. Yup, that’s right. The throttle response on drive by wire control systems can be programmed. This is where the Potent booster throttle controller