Wow.. Hybrid brakes work great!

Discussion in 'The Daily Grind' started by Dan, Apr 4, 2008.

  1. Dan

    Dan KiloTanked in post 153451

    Since I started on my Hypermiling life, I haven't really used the brakes to any great measure. As I move month to month, I use them less and less. Suffice to say, I don't really recall any time that I was "surprised" enough to have to slam on the brakes..... Until today!

    So for those non-Prius guys, my I have 3 brakes. One is the 'D' gear, another is the 'B' gear and the third is that fat pedal on the floor. Now the only time I use that fat pedal is when my speed is reduced to below 5 mph. In the 5 mph to 20 mph window I use 'B' gear and in the 20 mph or above window I use the 'D' gear. So suffice to say, I've never really used the floor brakes to any great degree at all. Well there I was on my glide when people started to zipper in to the left lane. Since there were lots of trucks and SUVs with lift kits, I couldn't see over traffic to determine what was obstructing my right lane, so I followed the hordes.

    Now of course, I made sure I waited till the racers were passed and I had a good 20 yard buffer before I zippered to the left. Well of course, some racers came to the right and filled the vacuum I had left. So what are they gonna do when they see their lane is blocked? You guessed it... jump in my buffer! Well this is standard low level jerk behavior and I'm fairly used to it, no big deal. Well today it was.

    Turns out 2 of the jerks decided to fill two buffers at the same time. My buffer, and the much smaller buffer of the car in front of me. Well the first one in was the one who ate my buffer. Seeing this I started a slow deceleration. Problem was that this reduced my buffer from 20 yards to about 5 yards, and since he was braking, I was actually closing on him. It looked like our velocities would match in about 5 seconds, so I tried to ride it out with a gentile 'D' brake. Well about the time my buffer is down to about 3 yards, Jerk number 2 comes FLYING up on the right and jumps in two cars up. Well this caused a serious ripple braking event in the chain, that (as always) got stronger as it went further back.

    So now the jerk about 6 feet in front of me lights his brakes and I hear the none to good screech of brakes locking. Well I hit the big pedal on the floor as fast and as hard as I could, and waited as the inevitable slowing of time sunk in for the half second ride of terror. Now just before this had happened, I had committed to a gradual deceleration so I was doing 'D' braking since my speed was at 30 mph. Also whenever I'm in a 'D' or 'B' braking event, my foot usually hovers about a half inch over the brake pedal just in case gear braking is not enough. By the time the second jerk cut into the zipper, I'd slowed but was still ticking along at 25 mph.

    Hybrid braking pays off. So as best I can tell, I went from 25 mph to 0 mph in what looked like less than 10 feet. May have been more since I started with about 6 feet and the guy in front of me was in a free skid. Since I got my adrenalin up the half second stretched out to about 3 mentally. I didn't even get a single chirp from my tires till I was all but kissing this guys bumper. So I think from 25 mph to 5 mph the MGs were working overtime. Now from what I remember from Hobbit's presentation, in this event, everything jumps in. Regen braking, rear drum braking and front disk braking. Throw into the mix an ABS system that seems as clever as HAL, you your left with one d4mn grateful hypermiller. In my 20+ years of driving I've never experienced such a competent braking system!

    Way to go Toyota and you have my respect on an even greater level than you ever had before. Not because I didn't ding my Prius or rear end that Jerk, but because both of my cars are hybrids, and it's effectively the only type of vehicle my kids get transported in. I for one feel a lot better for any time I put them in their car seats now.

    Last edited: Apr 4, 2008
  2. hobbit

    hobbit He who posts articles

    If you slammed the pedal that fast, you were likely 100% on
    physical binders. When it comes time to save your butt, regen
    doesn't matter, and that's the premise under which the prius
    braking system is designed...
  3. some_other_dave

    some_other_dave Well-Known Member

    Glad to hear it!!

    You know what really saved you, though? Slowing down before braking, and seeing what was happening before it had already happened.

    Brakes are good--having more time to use them is better. And you are the one who did that, by looking ahead and slowing down before you "needed" to! :)

  4. brick

    brick Answers to "that guy."

    I do have my own appreciation for that automatic panic braking feature that applies full pressure faster than your foot can hit the floor. Haven't used it but once or twice in 25000+ miles but it sure was handy.
  5. fitmpg

    fitmpg Well-Known Member

    Yes. Anticipation was the initial key to salvaging your vehicle from someone elses folly. I like to think I am actually a much better driver FOR hypermiling. Great that I can get great FE gains and all the while I'm driving safer than most. Great "one-two punch" if you ask me. Keep up the good work and keep those children safe!
  6. rweatherford

    rweatherford Times my Mileage by Six

    Has anyone actually owned a car that didn't have enough brake power to lock the wheels up?
  7. ILAveo

    ILAveo Well-Known Member

    Yes. It needed a new master cylinder.

    Probably his ABS (or the Prius equivalent) did a really good job since he didn't get chirping until he got slowed down.
  8. seftonm

    seftonm Veteran Staff Member

    Braking from low speeds is largely dependent on available traction and less on the brake system. Your extra tire pressure may have been the biggest difference in helping you to stop shorter.
  9. Dan

    Dan KiloTanked in post 153451

    Ha... I'm truly warped. Here I thought 20 mph was fast!

  10. seftonm

    seftonm Veteran Staff Member

    LOL, maybe I should have been clearer considering the group we have here: low speeds, when compared to speeds the car was designed to be able to handle safely.
  11. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___Thank goodness that close call passed without incident but more importantly, that may have been the first time your Prius’ brakes were ever used :rolleyes: :D

    ___Good Luck


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