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Trying for personal best - need advice on bridges

Discussion in 'Gen 2 Prius Fuel Economy' started by Bill A, Aug 22, 2012.

  1. Bill A

    Bill A New Member

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    I was able to get behind a semi going 62 MPH on the highway yesterday on my way back from a trip, and averaged 57.1 to start off a new tank. So, I figured it would be a good opportunity to shoot for a personal best on a whole tank. I'm trying to eliminate small trips by taking my bike some, but I've got a 50 mile trip to make 4 times at the end of the week. There are two large bridges, and I can't quite figure out what to do on the down side. Will putting it in neutral damage the vehicle? How can I get the best results?
    Thanks!
     
  2. gmcneil05

    gmcneil05 Member

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    As long as you put it in N above 41 mph the motor will idle so the electric motors don't over rev.
     
  3. Agent J

    Agent J Hypoliterian

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    After you've bled off speed approaching the crest, start to feather the throttle to get into warp stealth or super highway mode for a moment to keep the momentum going over the crest. Since it's a big bridge, you can either do what gmcneil05 suggested, or what i usually do:
    1. if HV battery charge is >60%: use B mode going down to keep a healthy charge (60-65%).
    2. if HV battery charge is <55%: regen using normal brakes (more amps for charging) and vary speed or increase momentum for the next uphill.

    so it all depends on how long the descent goes for and also the speed limit for the bridge. It also pays to keep and eye on the HV battery charge and get the chance to manage it downhill to keep the batteries happy. I tackle two big hills and two big bridges everyday and use this technique which works for me.

    **edit: i just remembered, #1 would apply to long, fairly steep hills where B mode would just manage to hold the speed and not slow down rapidly. I'm guessing your bridge is not that steep so i'd be more inclined to use #2.
     
    Bill A likes this.
  4. F8L

    F8L Protecting Habitat & AG Lands

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    My usual techniques are as follows and depends on traffic behind me.

    1. No traffic - maintain iMPG and keep throttle position steady. I allow my speed to drop and as I crest the hill I allow my speed to go back up to my desired cruising speed. If the bridge is large and I have reached my desired speed but there is still decline left then I will go into warp stealth and glide until I sense my speed is about to drop below my desired speed. At that point I reapply throttle to maintain speed.

    2. With traffic - I maintain my desired speed all the way up to the crest at which point I go into warp stealth and glide down the other side for as long as I can while maintaining a minimum of my desired speed but I will allow myself to go as fast as the hill will take me. I try to never let my speed drop below my desired minimum but often times I crest the hill at 1-2mph lower on accident.

    The first option is the most efficient. The second option is efficient but keeps you from holding up traffic or ticking off other drivers.
     
    Bill A likes this.
  5. Bill A

    Bill A New Member

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    Awesome. Thanks for the tips.