Driving by wire
“By-wire” technology, as it applies to automotive engineering, is a concept in which a vehicle’s traditional mechanical functions are electronically linked and controlled by use of sensors, computers and other components. The principle has quietly been making its way into our cars and trucks for around two decades, but it’s steadily gaining momentum.
Originally categorized generically as “drive-by-wire,” such vehicle functions are now commonly termed “x-by-wire.” That’s because the only drive-by-wire feature initially found on motor vehicles was “throttle-by-wire,” whereas now we have “brake-by-wire,” “steer-by-wire” and a proposed host of others.
Fifty years ago, accelerator pedal input from the driver was transferred to the fuel delivery system (usually a carburetor) via mechanical throttle linkage consisting of a Rube Goldberg-esque conglomeration of steel brackets, rods and pivots — a complex bell crank system that changed motion using angles and levers. Later, a simplified cable system was adopted.
But a new method of linking the driver to the fuel delivery process was possible when electronic fuel injection became common in the 1990s. As with other x-by-wire systems, the driver interface for operating the system is a familiar device: in this case, the “gas” pedal. Instead of being physically connected to fuel delivery, though, the connection is made electronically through electrical sensors and wiring, then capable of activating a response from the fuel injection system.
In the case of throttle-by-wire, the pivoting pedal sends an electronic message to a computer (or multiple computers) as to its position, and the engine management systems respond accordingly.
Since its inception, detractors have complained that by-wire technology reduces driver “feel.” I believe, however, that most drivers would have difficulty noting the difference between the old and new technology, especially in its current advanced state. Nevertheless, many unintended acceleration lawsuits focus on proving questionable reliability of throttle-by-wire setups.
X-by-wire systems will continue to proliferate since automakers contend that throttle-by-wire, brake-by-wire and steer-by-wire systems will make cars easier to manufacture, safer and lighter. That last point will, of course, enhance fuel efficiency. With strict new economy standards in place, it’s inevitable that the weight savings gained through the use of x-by-wire systems will make them alluring.
For example, an all-electric brake-by-wire setup eliminates the hydraulic fluid, cast iron reservoirs and vacuum pump/booster. A steer-by-wire system also eliminates fluids and the accompanying heavy pump. Besides adding weight, those pumps drain power.
Another factor causing manufacturers to expand x-by-wire technology is the desire to develop autonomous (self-driving) vehicles, something that is not possible without x-by-wire components.
If only as a necessity for autonomous operation, x-by-wire features will flourish. But their added benefits of weight savings, manufacturing ease, improved economy, lower maintenance and accuracy of operation will assure their continued development. The job of automakers will be to convince consumers of x-by-wire safety and reliability.
Since these systems are emerging and relatively unknown, some consumers are concerned over potential electronic malfunctions in sensors and computers which could lead to vehicle accidents and passenger injury. Similar systems are commonplace in the airline industry and have established a respectable reliability record.
The safety of x-by-wire systems is inarguably excellent when everything is working properly. Each system is guided by programming of computer software, where built-in operations and decision making can far exceed human recognition and reaction.
Though reliable, any sensor or computer component can become faulty — that’s why many still fear that correct driver input could result in incorrect acceleration, braking or steering when computers are in control. Again, that’s why manufacturers have a task in creating consumer confidence.
Airline reliability is one direction to point to, along with the past success of throttle-by-wire. Additionally, software engineers are continually improving their auto-related programs, while creating better redundancy and backup.
It genuinely appears that as time passes, although our vehicles will still have pedals and steering wheels, we will be yielding some of the control and “feel” of our automobiles to computerized systems designed by engineers and programmers. All things considered, let’s hope that’s a change for the better!
Readers may contact Bill Love via e-mail at precisiondriving@spokesman.com.
