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Testing pre-collision system?

Discussion in 'Gen 4 Prius Technical Discussion' started by Kablooie, Sep 17, 2016.

  1. JayLn

    JayLn Active Member

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    Oh I thought we are talking about Prius, hehe I dont want to google volvo, here in bay area everybody say if you talk about any volvo, for sure you are one retired dude haha
     
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  2. alanclarkeau

    alanclarkeau Senior Member

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    Not these days, VOLVO has lifted their game and changed their image dramatically over their hey days of the '70s/'80s. I've owned 3 in the past - will look at the new V40 IF they bring the Hybrid version here.
     
  3. baoweezy

    baoweezy New Member

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    Actually the car automatically stop even if parking. I was skeptical when I read from another user but I tried it and it works. I just let off brake and the car will creep forward and then throw up the brake warning and automatically stop like 2-3 inches from the wall. It has been pretty consistent. Of course if you have to get closer then you will need another method like the tennis ball.
     
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  4. Tideland Prius

    Tideland Prius Moderator of the North
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    That's only if you have ICS. ICS isn't available in Australia where Alan is.
     
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  5. GreenJuice

    GreenJuice Active Member

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    Another YT video example. Can't read Japanese, but it looks like the test was at 60kph...
     
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  6. alanclarkeau

    alanclarkeau Senior Member

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    True - we only get RADAR Cruise which I don't think will do that, plus AEB which isn't designed to do it either.

    I'd need a new garage back wall if I tried it. And an insurance claim form - and probably an enforced medical check.
     
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  7. Tyfly

    Tyfly Member

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    I had to stop from 70 to 20 MPH. The collision warning activated and as I was skidding to a stop, the PCS braked even harder. I have no doubt it saved me that day. This technology really does work.

    A Tahoe 3 cars behind me wasn't as lucky and collided with another vehicle. I've attached a picture of the wrecked Tahoe. IMG_1263.jpg

    I don't know how to add a video to this discussion. It's from my dashcam and it shows the PCS warning and braking action.
     
    #47 Tyfly, May 6, 2017
    Last edited: May 6, 2017
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  8. Tideland Prius

    Tideland Prius Moderator of the North
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    You can add it here to your own album. There should be an "Add media" near the top left.

    Media | PriusChat
     
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  9. wrprice

    wrprice Active Member

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    Since ICS has come up, has anyone had a "test" of ICS preventing side or rear contact? I've had it brake automatically for front sensors, and I'd probably be willing to test rearward, but the side zones is what I'm most curious about.

    For instance, I need to make a left turn across two lanes of a busy street in order to get to the parking garage at work from my normal route. Sometimes there's a gap in traffic before the light ahead changes and I can cut and make the turn right after the oncoming car in the nearest lane passes. On occasion the ICS beeps a warning and highlights the left rear sensor area for just a second (plus or minus) before it realizes the area is actually clear.

    I've never had it auto-brake in those scenarios, where there was little actual danger. Nor in others where I'm really close to a bollard after a tight turn, to the point where I had serious concern about making contact. I don't want to put too much confidence in the system, because it's still my job to avoid obstacles, but it'd be nice to have confirmation without learning the hard way. I've only seen videos focused on frontal avoidance.
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
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    ICS keeps in its memory objects for up to 2 minutes (according to the manual or tech notes.. can't remember where I read it).

    In theory, it's supposed to combine the memory plus steering angle, calculate the trajectory and potentially warn you if you're going to scrape a bollard or concrete column because you're turning too sharply.
     
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  11. RCO

    RCO Senior Member

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    Well, I think that's better than my driving....
     
  12. Tyfly

    Tyfly Member

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    Ok, I will try that. Thanks!
     
  13. wrprice

    wrprice Active Member

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    I understand that, and it does a good job of it as far as warning goes. But ICS also functions to automatically apply the brakes to prevent collisions at low speed (as opposed to PCS which operates at cruising speeds), or is that technically a different system acronym?

    My question is whether the auto-brake function of ICS is triggered by the side sensors, or if those only give warning but no prevention?
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    That's correct. ICS will provide low speed collision avoidance.

    Triggered by the side sensors? Indirectly. Again, it's a memory thing so while the car may not "see" the column/pillar that you're about the scrape with your door (because there are no sensors mounted on the door) , it will calculate that it you may hit it.

    Now whether it stops automatically or just warn you, I'm not sure. I think it does stop but I can't confirm because I don't have a Gen 4 with ICS.
     
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  15. Offline

    Offline Active Member

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    Maybe I missed it but I didn't see any mention of automatic seat belt tightening when PCS intervenes. And some seem to be confusing automatic braking under DRCC, emergency braking under PCS, and the Brake Assist feature.

    I don't remember PCS on our Prius ever entervening but when a previously stopped vehicle pulled in front of our Sienna two summers ago when I was going about 60 mph, my seat belt tightened with incredible force. PCS nailed the brakes with full force while my foot was still on the accelerator pedal. It was like a boat anchor had been thrown out. I swerved and avoided impact by inches. After the danger had passed the seat belt tension returned to normal with a loud "zing" sound. It was physically painful and my chest hurt the rest of the day from the seat belt.

    PCS has been invoked two or three other times when oncoming vehicles turned left quickly across my lane. Each time the seat belt tightened at the same time the brake was automatically applied but both were released in a split second after the turning vehicle got out of my path.
     
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  16. Tideland Prius

    Tideland Prius Moderator of the North
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    Yes, there are 3 components to PCS:

    1. PCS Seatbelts
    2. PCS Brake Assist
    3. PCS Braking

    1. Tightens the front seatbelts in anticipation of a collision or braking (keeps you in place, rather than having you lean forward before the emergency locking retractors [ELRs] tighten)

    2. Provides additional braking force if it determines a collision is possible and you're not pressing the brake hard enough

    3. This is the automatic braking and will come on if it determines a collision is highly likely and you haven't taken action.
     
    #56 Tideland Prius, May 11, 2017
    Last edited: May 12, 2017
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  17. Offline

    Offline Active Member

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    One of my points and perhaps the main one is that, although DRCC braking uses some of the same components as PCS braking, it is not the same thing. DRCC braking is usually gradual and gentle without seat belt tightening. PCS braking is usually severe and accompanied by tightening front seat belts.

    Like others participating in this thread, when I got my first vehicle with PCS, I tried to force it to activate by playing "chicken" with other vehicles and fixed objects. I could never make it happen as apparently PCS is smarter than I am.
     
  18. wrprice

    wrprice Active Member

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    Seatbelt pre-tensioners are pyrotechnic, aren't they, so they'd need to be serviced after use, right? I knew PCS could tension the seatbelts, but is this a separate, earlier-stage component? Is it resettable/reusable?
     
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    Yes, they use pyrotechnics. I think I'm referring to emergency locking retractors (ELRs). I'll fix my post.

    PCS seatbelt is reusable. You usually don't notice it until afterwards (at least I don't). I hear the electric motor unwind and release the seatbelt, only then do I notice that PCS seatbelts were activated. Again, the nice thing is that you don't lean forward because the seatbelt has already retracted, keeping you in the proper driving position to deal with the situation.
     
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  20. alanclarkeau

    alanclarkeau Senior Member

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    This article describes the difference fairly well. (if it doesn't open at it automatically, select the section "Pretensioners and webclamps")

    Seat belt - Wikipedia
     
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