Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

AutoBrake Connection

  1. Sep 13, 2014 #1
    When is the motion sensor being connected to the brake line of the automobile?
     
  2. jcsd
  3. Sep 13, 2014 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    What motion sensor? I'm afraid being terse and cryptic is not helping.
     
  4. Sep 13, 2014 #3
    I assume he means city safety braking systems provides braking assistance or even brakes for you. Typically a laser at the front.

    It has some sort of accumulator and actuator on the hydraulic circuit.
     
  5. Sep 13, 2014 #4
    Would you or wouldn't you recommend mandating that on all vehicles like the third brake light has been?
     
  6. Sep 14, 2014 #5

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    NO !!!!

    I wont tolerate a machine that presumes to think for me.

    I'm fed up with being forced to buy and maintain junk i neither need nor want.
     
  7. Sep 14, 2014 #6
    Can't stop the march of technology.

    The rule of thumb is if you want to know what safety technology will be on your car in 10 years, look at the Mercedes S class today.

    Assisted braking and collision detection is a perfectly logical evolution of safety systems. In many instances of emergency braking people don't apply enough force, or simply forget to steer out of the way.

    In 10 years we'll all be saying how marvellous the new safety systems are. The same way that airbags, ABS and stability control are seen as essential safety aids today.
     
  8. Sep 14, 2014 #7

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    Exactly why i keep my 1968 Ford.
     
  9. Sep 14, 2014 #8
    Luddite ;)

    Late 60s. Isn't that after the introduction of the collapsible steering column? You must be some sort of safety hippy. Real men don't mind speared through the chest when they crash.
     
  10. Sep 14, 2014 #9

    jack action

    User Avatar
    Science Advisor
    Gold Member

    Exactly why I keep my 1969 Chevrolet.

    Fatalist ;)
     
  11. Sep 14, 2014 #10

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    If you're a poor driver you might get some good from ABS.
    Or it might kill you.
    Statisticaly it's of no benefit.




    NHTSA :
    http://www.nhtsa.gov/cars/rules/regrev/evaluate/808206.html

     
  12. Sep 15, 2014 #11

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    Dandy ;)
     
  13. Sep 15, 2014 #12
    Last edited: Sep 15, 2014
  14. Sep 15, 2014 #13

    jack action

    User Avatar
    Science Advisor
    Gold Member

  15. Sep 15, 2014 #14
    I think that it is of less benefit than it could be. It is statistically of no benefit because many people do not realized that with ABS they can still steer clear of a collision with the brakes fully engaged. A lot of people became wary of ABS in the early years and rightfully so. The 1990's vehicles seemed to be a trial and error period.

    http://www-nrd.nhtsa.dot.gov/Pubs/811182.pdf

    I have a 1972 International Harvester 1/2 ton truck. It has no power steering, no power brakes and no A/C. Ironically International had ABS as an option even way back then. I thought it was an expensive toy and opted out.

    ABS on the rear wheels of trucks is essential for safety. A truck with no load in the bed is especially prone to skidding.
     
  16. Sep 15, 2014 #15
    Most crashes occur in urban areas (particularly at junctions), and motorways have Armco barriers so going off road isn't as much of an issue. It's the reason the EU have made ABS mandatory on all cars.

    The main problem with ABS is that people panic and forget to steer. I've seen it of several occasions, a clear escape path to the side, someone under ABS just plows straight into the back of the car infront.

    Modern 4 channel systems are so good now that they are very close to threshold braking. You can feel the car squirming as it pluses the wheels in succession.
     
  17. Sep 15, 2014 #16
    Wouldn't it prevent accidents in situations where the driver fell asleep at the wheel?
     
  18. Sep 15, 2014 #17

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    How much automation is too much? Aviation industry is struggling with that now.


    I expect the brakes to do what i command them. If i want all four wheels locked i expect the brake calipers to obey my right foot.

    I would welcome a switch that allows me to engage an electronic gizmo that'll apply brake to whichever drive wheel loses traction. Have more than once contemplated two separate parking brake handles..

    "Newer" and "Better" are not synonyms.
    That Mercedes Benz marketing men can create in some people a desire for fancy doodads does not create in me an obligation to spend three years' salary for one. Let alone maintain that silly stuff.
    I drive two-thousand dollar cars because they last me half as long as forty thousand dollar cars.
    I took my '92 Oldsmobile out on the ice last winter to familiarize myself with how its ABS behaves. I wasn't impressed, it pushes the front from side to side as if attempting to steer . When the ABS dies of old age i will remove it.

    I used to repair computers as part of my job; see my signature. I simply will not own an automobile with a computer in control of throttle butterfly plate , brakes or power steering.

    However - being a controls guy I doappreciate the benefit of closed loop fuel mixture control, so long as it fails to a "Limp Home" mode and provides a diagnostic message.

    old jim
     
  19. Sep 15, 2014 #18

    cjl

    User Avatar

    Judging modern ABS behavior on the basis of a '92 Oldsmobile is not really giving it a fair chance - the modern systems behave dramatically different, and I would never want to drive on a slick surface without modern ABS. Can it be done? Sure, but the additional control under braking is really nice to have when descending a long icy hill at 30 or 40 miles per hour. I also like ABS in my fun car, since I appreciate the protection against flat spotting the tires when I take it to the track. The automated braking on the other hand is too much, in my opinion.
     
  20. Sep 15, 2014 #19
    I like the idea of preprimed brakes that allow maximum deceleration even if you only use minimal pedal effort.

    Fully auto braking is slightly more dubious, especially with pedestrian recognition. How long til the kids figure out you can jump into the road and then jump back and cause the car to emergency brake... fun times.
     
  21. Sep 15, 2014 #20
    But Jim the electronic stability control systems have multiple sensors that can decide what you want.:devil:

    http://en.wikipedia.org/wiki/Electronic_stability_control

    I have to admit that I was impressed when I took a new Infinity out for a test drive. I did a quick double lane change while going through a curve and it was flawless.

    A lot of accidents happen when people lose control or run off of the road in a curve and ESC really helps with that. On the other hand will drivers come to rely on the systems when they do dumb things like making a double lane change in a curve? What happens if there is a flaw in just one sensor?

    I am old school myself and I just don't trust that many sensors on a vehicle.
     
  22. Sep 16, 2014 #21

    cjl

    User Avatar

    Generally, the vehicle can detect the anomalous sensor data, and respond in one of several ways. If the sensor is redundant, it can ignore the sensor. If the sensor is not redundant, the vehicle can continue to operate in a degraded mode where at worst, it simply behaves as it would have with no electronic stability control.
     
  23. Sep 16, 2014 #22

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    I guess you do have a point, it's an older car now.
    Funny how as we get old time compresses - i've had that Oldsmobile for fourteen years now and it's still my new "Sunday-Go-To-Meeting" car.
    Last of the rear drive nineteen foot-long stationwagons with that Pullman car ride. Only thing i'd trade it for would be a Model A Ford with hydraulic brake upgrade, to the end of achieving ultimate simplicity.
    "No check engine light, no metric bolts, No Problem! "

    old jim
     
  24. Sep 16, 2014 #23
    I enjoy old cars, they so have a soul and personality, and mood swings. But they simply can't compare to modern machinery for getting a task done. For all the talk of simplicity, new cars are simply more robust.

    Modern unreliability means you arrive at your destination annoyed because there is a yellow light on your dashboard.

    Old school unreliability means you don't arrive at all.

    Cars are cars, modern equipment is fundamentally no different to old stuff if you follow simple rules of keeping the engine watered, oiled and clean and electrics free from moisture.
     
  25. Sep 16, 2014 #24
    I had an old 1936 ford with mechanical brakes when I was in high school. Come to think of it they were anti lock brakes, and also anti stop, at times. Keeping the cables lubed and everything adjusted was essential.

    Even the hydraulic brakes had to be adjusted. We went a long time with no major change In brakes until the self adjusting brakes came along in the 1960's.

    I wonder what lies in the future. The New Honda Accord hybrids use a fly by wire electric servos to apply the brakes.

    http://www.autoguide.com/manufacturer/honda/2014-honda-accord-hybrid-review-3522.html
     
  26. Sep 16, 2014 #25

    jack action

    User Avatar
    Science Advisor
    Gold Member

    There must be fairies and unicorns in the world you live in. :rolleyes: You should read the news about GM, Toyota, Honda, Hyundai and Volkswagen, to name a few.

    A well maintained car from the 50's is just as reliable as one from today (Everybody relied on their cars to go to work back then and the ones who arrived weren't consider the «lucky ones»). But routine maintenance had to be done more often and if it wasn't done, the car was unreliable, just like today's car. The difference between old and modern cars is that the simplicity of old cars made them cheaper to buy, but demand more maintenance and they were not as idiot-proof as modern cars (for example, a carburetor is easy to flood if you keep pushing the gas pedal with the ignition off). The problem with the complexity of modern cars is that once their maintenance-free period is over, they're only good for the scrap yard as they become too expensive to repair.

    I prefer to see this as different philosophies rather than one better the other. IMHO, the only true improvements that have been done in cars are in the materials (tires, lubricants, etc.). So I agree with you, cars are cars.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...