Drive-by-wire systems explained.

Author: Dan   Date Posted:5 October 2018 

Drive-by-wire systems explained. main image Drive-by-wire systems explained. image

What exactly is a Drive-by-wire throttle system (also known as fly-by-wire) and why does it create lag?

Well first we have to take you back, to the good old days of throttle cables and carburettors. In the old days, the gas pedal was directly connected to the engine's throttle plate by a cable, and any lack of response from the engine could be attributed to a couple of things. Either the cable has stretched enough to create slack and, consequently, a delay in pedal response, or the engine was out of tune which meant it was not making as much power as it should've been. Easy fix, by a new throttle cable for $20 and get your carby tuned. Nowadays though it's not that simple.

Let's look at how electronic throttles work.

Instead of a cable, the pedal is now 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. 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 cannot conquer.

An interesting fact about drive by wire systems: the voltage signals generated by the redundant sensors aren't 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 engine loses power.

Why the change from a physical cable to invisible electrons telling your engine what you want to do? 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 switching 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 Windbooster Throttle Controller comes in.

The WINDBOOSTER throttle controller modifies the voltage signal from the drive-by-wire pedal assembly to allow you to tune the response from your accelerator pedal and greatly reduce the dead zone from when you initially depress the pedal commonly referred to as throttle lag. The WINDBOOSTER is providing new points of reference for the vehicle's throttle mapping. It is still working within the standard parameters; however, it introduces a far sharper throttle curve. It is also bringing the throttle in earlier in the pedal stroke, introducing petrol and air into your engine earlier in the throttle stroke thus improving throttle response and acceleration.

The real benefit of the Windbooster though is its ability to give you complete control over the throttle response of your engine, if your engine is too responsive you can dampen its response to a level that suits your driving style. You can also change the Windboosters settings and modes on the fly so if you are driving along the freeway and need to overtake someone, crank the Windbooster up a few levels to deliver better throttle response, or if you are towing a trailer/ caravan you can bump up the throttle settings to account for the extra added weight. Don't just take our word for it though, every Windbooster comes with a 30-day money back guarantee so you can try the Windbooster and see its effectiveness for yourself.


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