I’m not aware of a vehicle sold in the US today that doesn’t use throttle by wire technology. What is it? The videos below will explain that in as much detail as you could possibly want. To briefly describe it, throttle by wire uses sensors and motors to open and close the fuel injection’s throttle body. Previously, on both carbureted and fuel injected motors, this was done via a cable linkage between the accelerator and the carburetor or throttle body. Why go to throttle by wire? Theoretically at least, it’s more reliable, more precise and allows greater monitoring capabilities of emission control systems and engine performance.
Where did throttle by wire originate? In aircraft, where it was originally called “fly by wire”. As any DC3 pilot will tell you, muscling a big plane with cable activated ailerons, elevators and rudder takes some strength and endurance. As planes got bigger, heavier and faster, it became necessary to develop flight controls that used servo motors to do the hard work.
So if they’re used in aircraft, where safety is paramount, they should be bulletproof in other applications, right? The car manufacturers, Toyota especially, would like you to believe that. I have a friend who’s a flight control engineer on military aircraft, and he’s less than convinced. In his words:
“ To be honest, I’ve always thought it to be the height of arrogance by the car companies when they claim that (failure) COULDN’T be electronic. I work with aircraft flight controls. We use quad redundant electronic systems (when you take into account internal modeling, it is more like 8x redundancy) and monitor hundreds of parameters in clock cycles measuring in ms. We STILL get cases where we have failures that cause strangeneess in the air and our fleet is measured at around 1500 aircraft.
Take a car, with far less rigorous maintenance, working on a dual redundant system and tens, if not hundreds, of thousands of copies and I’d be shocked if there weren’t annunciated electrical failures.”
In any case, here are the videos, courtesy of Toyota. While produced by Toyota, they’re still relevant to other manufacturers, who use the same technology, albeit with slightly different hardware and software. Hat tip to Brad for the heads up on the videos.
Electronic Throttle Control Overview
Electronic Throttle Control System Animation
Electronic Throttle Control System Animation: Diagnosis
Electronic Throttle Control System Animation: What If?
Still have questions? Still want answers from Toyota? The following webinar, source of the above videos, was held on February 22. It goes into a bit more detail about Toyota’s testing process to counter RF and EM interference, and includes a Q&A session with the press. It’s about an hour in length, so make sure your coffee cup is full before you hit play.
Toyota Throttle Control System Webinar