Unintended Acceleration analysis

Discussion in 'Gen 3 Prius Main Forum' started by jayman, Mar 3, 2011.

  1. rebenson

    rebenson Member

    Apr 12, 2008
    Suburb of Chicago
    2010 Prius
    I just read an article in latest 2010 Car and Driver magazine. I couldn't find it on line, but article basically said that the facts were very clear that this has been fixed and was caused by the imroperly installed floor mats as well as ... apparently operator error. They said the latter was proven by the new "black box" technology in the new cars.
  2. qbee42

    qbee42 My other car is a boat

    Mar 2, 2006
    Northern Michigan
    2006 Prius
    My first table saw had a single on/off toggle switch mounted directly on the drive motor. In an emergency, to shut it off, you had to lean over the table, across the whirling blade, and flick the switch in the proper direction. Clearly the new buttons are better.

  3. jayman

    jayman Senior Member

    Oct 21, 2004
    Winnipeg Manitoba
    2004 Prius
    So has the Corolla, the Camry, the Tundra, and the FJ Cruiser. So has the Chevy Impala, Corvette, and HHR. The Dodge Charger and Chrysler 300 (The new models have push button ignition). Etc

    Every motorcar on the road has the potential to kill, sometimes without an obvious reason. I frequently have to rent Chevy Impala's, and they are a favorite of government fleets too so I get to drive them a lot

    Here is one key difference between a 2011 Chevy Impala and a regular car from Toyota, especially the Prius: the gas pedal and brake pedal are spaced further apart

    Haven't compared to other domestics because I have not had a drive in them. But in a domestic car - made in Oshawa Ontario - and seemingly intended for fleet use with different drivers expected on a daily basis, they are pretty basic machines

    What else? The 2010 Impala, and especially the 2011 Impala, the gas pedal is STIFF. The return spring is strong. Ok on the highway, I engage cruise. City driving, after half an hour it feels as if my right foot is going to fall off

    But like almost 100% of new vehicles on the road, the Impala has no direct connection between gas pedal and throttle body. The PCM takes signals from the pedal, and commands a stepper motor to open the throttle body an appropriate amount

    I'm old enough to remember carb's with return springs. Was not unheard of for a return spring to fail, and the throttle lever to go to wide open

    On a smallblock with a four barrel carb, that suddenly turns into a very exciting ride.

    Every manufacturer went to electric throttle control for a very simple reason, they are much more reliable.

    More are going to push button start. I don't buy the arguement they are dangerous

    The Prius doesn't use engine vacuum for power brakes. Neither does the FJ Cruiser, both use electric power assist

    I bet you refuse to fly then

    Most of my career has been with RTOS used in military and civillian aircraft, primarily Green Hills. Long before fly-by-wire civillian airliners, such as the Airbus series and the Boeing 777, widebody aircraft development began to abandon direct control of flight surfaces

    A simple fact is that to rig push-pull tubes and cables, over a very large aircraft, dramatically REDUCES reliability. The first phase of such development replaced push-pull and cables with hydraulic servo assist

    There have been famous crashes related to what happens if you design-in a single point of failure. The most famous example was United AIrlines 323, a DC-10 that crashed at Sioux City, Iowa

    The DC-10 had the fan hub fracture on the center tail-mounted turbofan. Shrapnel escaped the turbofan and hit all three hydraulic lines. As there was no direct connection to the rudder or other flight control surfaces, the aircraft became uncontrollable. The flight crew used asymetric engine thrust on the wing engines to turn the aircraft

    Another example is the 747 that crashed in Japan after the rear bulkhead failed and the tail blew off. All three hydraulic systems were damaged and lost all fluid.

    The early build 737 had issues with the servo used to control the rudder. Under some situations, the servo would jam and command full control surface deflection. Two 737 crashed as a result

    The point being is this: would direct cable control have saved the day? Given the failure modes involved, probably not.

    The DC-9 and MD-80 have direct control. An Alaska Airlines MD-80 crashed into the ocean off San Diego after poor maintenance procedures caused the elevator trim jackscrew to strip. The entire elevator assembly was allowed to swing up which caused catastrophic failure and subsequent crash

    Contrast the new Airbus to the 777: in the Airbus, a joystick is used to control the aircraft when it is manually controlled. The 777 uses a conventional looking yoke, but it is hooked up to transducers, not servos.

    Pilots had a steep learning curve. Ergonomics are mostly to blame for that, in particular a very small display on the glareshield that indicates autoflight status. In one mode it will indicate FPA flight path angle. In another mode, decent in thousands of feet per second, or f/s

    All that indicates the separate modes are a very tiny "FPA" or "F/S" and a missing decimal point in the display. That ergonomic boo-boo resulted in an Air Inter jet CFIT crash in France

    Sounds good. Let us know how that works out for you

    Like a carb return spring

    I agree. But one thing to keep in mind that makes the United States unique from all other countries, especially the reports of UA

    The litigation environment

    Oh that is so true


    A lot of it also depends on the litigation allowed in your country. When Sikes story hit the news, suddenly EVERYBODY obsessed over UA. I even had an Aunt call me and warn me not to ever buy a Toyota again, as apparently her Dodge Durango was MUCH safer

    Can't you see the beauty of that simple design? If you are already despondent, just let yourself drop on the whirling blade of doom

    And despite all those bright red kill switches, people are still chopping off their fingers and worse
    1 person likes this.
  4. robbyr2

    robbyr2 New Member

    Jun 28, 2008
    Commerce City, CO
    2010 Prius
    Be happy its still a button. It won't be long before all those buttons will be replace with a touch screen, right?
    Just a side note: I'm no fan of touch screens but apparently I'm in a very tiny minority.
  5. wick1ert

    wick1ert Senior Member

    Dec 3, 2009
    2010 Prius
    Touch screens are great for certain applications, but I hope they NEVER make it to the power/ignition/etc button for vehicles. In fact, I even hate typing on the virtual keyboard on my phone with one.
  6. bisco

    bisco cookie crumbler

    May 11, 2005
    2012 Prius Plug-in
    Plug-in Base
    i can't stand them, especially when there's plenty of room for knobs and buttons and it's just a 'tech' thing. i feel like it takes my eyes off the road too much.
  7. Skoorbmax

    Skoorbmax Senior Member

    Mar 19, 2010
    Western NY
    2010 Prius
    I don't like touch screens but haven't used many. Tactile response is something I appreciate.
  8. cit1991

    cit1991 New Member

    Apr 5, 2010
    Tulsa, OK
    2010 Prius
    In the mid80's, Audi 5000's had keys, and nothing was drive by wire.