"The Prius is controlled by computers because it is drive by wire and when the ECU locks up, it ignores your inputs from the starter button, brake, gear selector and gas pedal." People like to post this as the explanation of what causes unintended acceleration that cannot be controlled or stopped. So, what is wrong with those statements?
What people, where'd the quote come from? It's wrong b/c there are a dozen or so ECUs and nothing prevents input from any of those things except turning the car off.
That is not an exact quote. It was a mix of statements from several quotes in online forums and consolidated into one sentence.
prius is more like a mac, they do not "lock up" p/c's sometimes do because ms is archaic and overburdened and susceptible to viruses.
Prius is not like a mac and even less like a windows. And most of the things still have mechanical fail safe mechanisms in place. Only gas is actually fully drive by wire. Everything else, including breaks is only partially drive by wire and works also during catastrophic system failure. Steering column steers and brakes brake even when system is down.
The day Microsoft controls my car, I stop driving. My Prius rarely crashes, my PC always does, guess which one Microsoft installed their 'Operating System' in ? Then ask how many times my PC was running great until Microsoft 'Updated' it, or "fixed" something on it. And, GOD FORBID, you ever UpGrade it to the New, Better Microsoft Operating System. Most PC's never recover from That mistake.
'The ECU' is wildly incorrect, the Prius has multiple ECUs, on LAN called CANbus, if any of the ECUs quit communicating, the Prius Instrument panel lights up big time. It would not surprise me if the four items you mention talk to four (or more) independent ECUs. I googled Prius ECU and found: skid control ECU Hybrid ECU brake ECU the Motor ECU, Battery ECU Inverter ECU Body ECU, Engine ECU, Air Conditioner ECU, Display ECU key transponder ECU EPS ECU USB ECU on the first three pages.
Hmmm... hypothetically let's think about what would happen if whatever ECU responsible for controlling the gas engine locked up. It would stall out and stop running! The computer controls firing of the engine. If the computer stops running, the engine doesn't get fired.
Yeah, it's like having multiple separate computers running at the same time, the chance of having all of them crash is minimal. It doesn't look like a blue window of death to you?
When your computer locks up, you press and hold the power button for 3 or more seconds. That aways shuts it off, as it does in the Prius.
The embedded micro controllers that are used in the automotive, aviation, and a million other industries are application specific devices. They are designed and programed with firmware/software written only for their intended use. The units that controls the A/C, brakes, windshield wipers etc. will not send email, play solitaire, or download porn. The bios/firmware that initially starts your personal computer works every time or it doesn't start the computer at all. What causes PC's to crash is all the uncontrolled incompatible software and hardware that is added to it. Closed systems like you find in cars, planes etc do not have these add-ons to cause problems. I am not aware of a single proven case of sudden or unintended acceleration having taken place in any vehicle do to mechanical or electrical reasons. Ever! Show me engineering proof not just he said she said accusations and theatrics.
Every time I see a Ford commercial featuring the Microsoft Syncâ„¢ Audio system, I think to myself "I'll never buy a Ford again". You have to use your iPhone to do that. :madgrin:
Hey Apple Fanboys, there are lots of websites where you can go and post stuff that makes you feel good about your choice of phone and/or computer. This website is about the Prius. Please keep that in mind.
Most devices like a Prius use embedded microcontrollers that are built from the ground up to be reliable. They have dual clocks that are always monitoring each other. They have watchdog timers that have to get updated by code that is executing or they go into a safe fail mode. The compilers scrub the code for any possible situations that can go wrong. A PC is a device has to to be compatible with old applications and hardware from 20 years ago. This creates a lot of issues that Microsoft cannot control. A Windows box does not crash any more or less than a Mac. If you own a Mac or a Windows box and it is crashing as much as people are posting in this thread then you have other issues. I own a lot of PC’s, they do not crash. Here is an old pic of my office http://mbu.com/black/ and a very old pic of the server room in the basement http://mbu.com/234.jpg
From what I read Toyota only pulled 2 from Sykes car. At least that is what he was paid for from the NHTSA.
Just to elaborate a bit on this concept: The Accel Pedal communicates directly with the HV ECU. The HV ECU then communicates with the Engine Control ECU. The Engine Control ECU sends the signal to the throttle motor to open the throttle. The Engine Control ECU also does ignition and fuel injector timing. The Brake Pedal Stroke Sensor communicates directly with the Skid Control ECU. The Skid Control ECU sends a signal to the ABS/BA/TRAC/VSC actuator which applies/releases solenoids to apply/release the brakes. The Skid Control ECU also receives other data from the Battery ECU and HV ECU to decide how much regen vs friction braking. The Power Control Switch (button on the dash) communicates directly with the Power Control ECU. The Power Control ECU opens/closes the IG1 relay to disable/enable the ignition via the Engine Control ECU. The Power Control ECU also communicates with the HV ECU. HV ECU enables/disables the hybrid system by closing/opening the System Main Relays. The Shift Lever communicates directly with the HV ECU. So the HV ECU is an important piece of the puzzle, but it would have to fail in a way where it became unresponsive but didn't set any codes plus did not cause any of the other ECUs to set codes based on incorrect data from the HV ECU plus didn't cause any communication errors which would set codes in the Gateway ECU that controls the 3 communication buses (CAN, Bean and AVC-Lan). Its probably a non-zero possibility, but I'm thinking there is a higher likelihood of a meteor hitting my car.
