Greg Rogers

I just read a article in Motor Trend. It was a comparison of a bunch of "super cars", one being the 2020 mid engine Corvette. It said that the braking system on the new Vette was "brake by wire", there is no physical connection between the pedal itself and the brake system !! Huh? In the event a total vehicle electrical loss or short what would happen? What if this happened at 80 MPH? Now if your throttle by wire completely malfunctioned you probably would coast to a stop. But what would happen on a total malfunction of brake by wire??
Sure sounds like a awesome car though!

oldcutlass

Aircraft have been using brake and fly by wire systems for about 45 years now.

OLDSter Ralph

Aircraft have had redundant systems. Most have duplicate systems in case one system fails. Some airlines in the past had triple redundancy. I am sure Corvette will consider backup systems. Many "over the road trucks" have a rheostat connected to the "Go pedal" and wires running to an ECU.

Indy_68_S

Most consumer cars & light trucks do too. I can't think of one off-hand that isn't now. Throttle cables started fading away 20 years ago. My 2001 VW was throttle-by-wire (Mk IV platform debut 1999).

Braking & steering will all be "by wire" in future vehicles. It's much cheaper to manufacture and reliability has improved to where it's acceptable. One big reason for not having more vehicles with steer-by-wire now is the challenge of (re)creating meaningful / accurate feedback to the driver.

joe_padavano

Mercedes first offered a brake-by-wire system, called Sensotronic, in the 2001 model year. It had a completely independent backup hydraulic brake system as a safety measure. After several recalls, the system was dropped by 2005. I don't know anything about the Corvette brake system, but hybrids and electric cars have similar systems now. Most commercial aircraft you may fly on also have similar braking systems. As discussed above, you build in system safety by incorporating independent redundant systems that do not have common cause failure modes. Your hydraulic brakes are dual fault tolerant - you can tolerate two failures before a catastrophic event. The dual circuit M/C can still provide some braking with a leak in one side, and the mechanical e-brake is the system of last resort. Two fault tolerance is the common standard for human-rated aerospace systems.

don71

I was shocked when I heard about electric steering a few years back when applied to automobiles. Little did I know the throttle of the truck I was driving at the time,had no cable.

That was 15 years ago.

rustyroger

Kind kind of scary at first glance, however a redundant mechanical backup system would surely be required by law in any sophisticated country. My Peugeot dd has electric steering and fly by wire throttle. After 15 years and over 250k miles behind it neither system has given a hint of trouble.
My wife's Citroen dd has hydraulic brakes but an electronically controlled e brake. She likes it because it comes on automatically when she turns of the engine, and releases itself smoothly when she presses the gas pedal in drive or reverse. She can override it if she wishes simply by lightly pressing a lever, a boon for anyone with arthritic fingers.
The only downside is when I want to deliberately leave it off (for routine maintenance for example) it's a bit of a fiddly job.

Roger.

joe_padavano

Electric power steering is just like hydraulic power steering - the assist function is in parallel with the steering shaft. If you lose the power assist, there is still a mechanical connection between the steering wheel and the front wheels. Brake by wire and throttle by wire typically are series systems, meaning that if they fail, the system doesn't work. Again, this is all about performing a thorough failure modes and effects analysis and implementing redundancy where necessary.

Koda

Hydraulic brakes aren't the holy grail anyway. I think semis have air brakes that brake when pressure is dumped or lost. You could make wired brakes fail ON, but I am not sure you'd want that, either.

Yellowstatue

Maxi brakes are piggy-backed onto the regular air chamber. Air pressure holds the maxi off ( separate circuit shut off/on ) a massive spring pushes the brake on, 'park'.

oldolds88

my trailer is brake by wire, and it has the emergency battery and pull cord in case it comes unhooked.