What IS drive by wire? How does it work exactly?

 

How exactly?
Maybe you shouldn't have asked
Here ya go.......

Torque Based Electronic Throttle Control (ETC)
Overview
Torque Based Electronic Throttle Control (ETC) is a strategy that delivers a transmission output shaft torque (via throttle angle) based on driver demand (pedal position). It utilizes the Visteon Gen II electronic throttle body (replaces throttle cable).

Torque based ETC strategy was developed mainly to improve fuel economy. This is possible by not coupling the throttle angle to pedal position, which enables various fuel economy schemes and technologies.

Background "Why Torque Based ETC"
Torque based ETC enables aggressive automatic transmission shift schedules (earlier upshifts and later downshifts). This is possible by adjusting the throttle angle to achieve the same wheel torque during shifts. In other words the engine shifts can result is an engine lugging condition (low RPM and low manifold vacuum) while still delivering the same torque requested by the driver. It should be noted that the ETC system includes a wrench light on the instrument cluster that illuminates when a fault is detected. Faults are also accompanied by DTCS and the "Check Engine Soon" light.

It also enables many fuel economy/emission improvement technologies such as:

VCT (deliver same torque during transitions)
Continuously varying Transmission (CVT)
Hybrid Electric Vehicle (HEV)
Torque based ECT also results is a less intrusive vehicle and engine speed limiting, along with smoother traction control.

Other generic benefits of ETC are:

Eliminate cruise control actuators
Eliminate ISC Bypass actuator
Better airflow range
Packaging (no cable)
Electronic Throttle Body
The Gen II electronic throttle body (Figure 133) has the following characteristics

The DC motor is driven by the PCM (requires two wires). The gear ratio from the motor to the throttle plate shaft is 17:1.
There are two designs; parallel and in-series. The parallel design has the motor under the bore parallel to the plate shaft. The motor housing is integrated into the main housing (in general this is more difficult to package). The in-series design has a separate motor housing that protrudes out and offers more packaging flexibility.
Two springs are used: one is used to close the throttle (main spring) and the other is in a plunger assembly that results in a default angle with no power applied. This is for limp home reasons (forse of plunger spring is 2X main spring). Default angle is usually set to result in a top vehicle speed of 30 MPH (typically 7 to 8 degrees from hard-stop angle).
The closed throttle plate hard stop is used to avoid the throttle from binding is the bore (~0.75 degree). This hard stop is non-adjustable and is set to result in less airflow than the minimum engine airflow required at idle.
Unlike cable type throttle bodies, the intent for the ETB is not to have a hole in the plate or use plate sealant. The hole in the plate is not required with ETB because the required idle airflow is provided by the plate angle, which also is the reason there is no IAC.
The system has two throttle position sensors. Redundant throttle position signals are required for monitor reasons. TP1 has a negative slope (increasing angle, decreasing voltage) and TP2 has a positive slope (increasing angle, increasing voltage). During normal operation the negative sloped TP sensor (TP1) is used by the control strategy as the indication of throttle position. The TP assembly requires four wires.
5 V Reference Voltage
Signal Return (ground)
TP1 voltage with negative voltage slope (5-0)
TP2 voltage with positive voltage slope (0-5)
Accelerator Pedal Position Sensors (APPS)
The ETC strategy uses pedal position sensors as an input to determin the driver demand.

There are three pedal position sensors required for safety monitor reasons. APP1 has a negative slope (increasing angle, decreasing voltage) and APP2 & APP3 both have a positive slope (increasing angle, increasing voltage). During normal operation APP1 is used as the indication of pedal position by the strategy.
There are two VREF wires, two signal return wires and three signal wires (total of seven wires and pins) between the PCM and APPS assembly.
2- (5 V Reference Voltage)
2- (Signal Return "ground")
APP1 voltage with negative voltage slope (5-0)
APP2 voltage with positive voltage slope (0-5)
APP3 voltage with positive voltage slope (0-5)
The pedal position signal is converted to pedal travel degress (rotary angle) by the PCM. The software then converts these degrees to counts, which is the input to the torque based strategy.
The three pedal position signals ensure a correct input to the PCM, if any one signal has a fault. The PCM knows if a signal is wrong by caculating where it should be, inferred by the other signals. A safe value will be substituted for a faulty signal if two out of the three signals are bad.

 

I hope the computer allows me to do doughnuts in the snow and power slides around corners There is no way I would want to purchase a truck that doesn't allow me to control what it does with the steering wheel, shifter and gas/brake pedal.

I was all for the fuel injection and the computer-controlled transmissions, but the first thing that I did to my current '95 truck was disconnect the anti-lock brakes.... I went into a slide one winter and almost killed myself because they didn't act as they were supposed to, haven't had a problem like that in the past 6 years.

I'm all for one of these trucks - I just hope Ford doesn't make these trucks so computer-controlled that those of us who like to have control of our have to fight with the stupid chip all the time.

Just my 2cents
--Ryan

 

Well, the drive-by-wire sounds like it offers many advantages that could really turn out to be useful. But it also sounds like a diagnostic nightmare should there be problems with it. I guess we'll see how it goes over with the new F-150. I hear that it's been used in other vehicles already, so maybe it will be fairly safe.

 

Interesting to read these posts from the informed and the general public. I have worked in the Automotive industry for 14 years now in both the Anti-loc brake world and the Electronic Throttle Control. ETCs offer great packaging advantages over cables, such as use with adjustable pedals, incorporated with memory seats, in total make a great safety package with air bags. These pedals as stated have been in Semi trucks for years and are now in all chevy, ford, dodge, nissan and toyota trucks and cars. Surprisingly look under the dash and hood of your truck not as much room as you think.

Regarding the ABS unit, 99.5% of the time, issues with the ABS is the DRIVER. I understand the whole idea behind control as a driver, but I would be willing to bet the issue ryan95f150 had with the out of control F150 was between the steering wheel and the seat and I would not recommend to disconnect any ABS units even the rear wheel only units. As a reference ABS valves control in 10 milli-second pulses. I will put my money on a tuned unit before any human driver, any day.

And not to get any one paranoid but "brake and steer-by-wire" is just around the corner, 2 - 3 years max.

Also The effect of a bad "xx-by-wire" anything in a plane is completely different effect in a car. For instance on the accel, fails on a car still limps home at 10-20mph, in a plane....big boom, hence the mechanical backup.

 

that was a great explanation by racerguy on this throttle-by-wire. it's super complex and when these babies are out of warranty its going to be super expensive. lets be realistic about this. i'm with wxboy-this is going to always be a diagnostic nightmare (along with all these other sensor, limphome/towable problems caused by computers). this securilock system is expensive and real pain just to get a spare key made. i dont care about how this throttle-by-wire system is going to help a little here and there, i prefer something thats depenable and able to get you off that railroad track when you stomp on the gas. they talk about all the advantages of these throttle sensors helping with gas mileage-it doesn't seem to be doing much when 15mpg is about average. i wouldn't do it again for this reason alone.