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Using "B"

Discussion in 'Gen 2 Prius Main Forum' started by ajrowell, Feb 23, 2006.

  1. richard schumacher

    richard schumacher shortbus driver

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    Agreed, but the context was a question about staying in "B" during "daily driving", which surely was meant to include other driving conditions and not only downgrades. Staying in "B" all the time recovers less energy, and therefore burns more gas; burning more gas means poorer economy and more engine emissions. (Does CAN-view actually show that there is less hydraulic brake application in "B"?)
     
  2. Frank Hudon

    Frank Hudon Senior Member

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    agreed for daily normal driving D is the gear. CAN-view doesn't show hydraulic brake pressure to my knowledge at least I didn't try that yet, but is shows Amps regened in D or B going to the battery.
    Hydraulic brake pressure is the the same once the stroke simulator piston is bottomed. That is the difference between the Classic and the new generation Prius, and the pedal travel isn't very much till the piston is bottomed.
     
  3. jeromep

    jeromep Member

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    To the OP: think of B as a low gear in a conventional automatic. Seems to me that you have been using it apropriately, especially down hills. In normal city driving there is little good conventional use for B mode, aside from engine braking assistance should you absolutly need it.

    Using the ICE as a compression brake is not damaging at all. Consider that oil and coolant are pumped through the engine whenever it is spinning and that no fuel or spark is introduced so no heat from combustion is created. The ICE becomes nothing more than a sophisticated air compressor. Air compressors last a very long time when properly lubricated and cooled, as a point for comparision.
     
  4. Frank Hudon

    Frank Hudon Senior Member

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    Tony CAN-view shows the amount of stroke simulator compression as a percentage 0-100% which is the area of "regen" before friction braking occures.
     
  5. KMO

    KMO Senior Member

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    Just a thought - won't all that pumped air cool your catalyst quite quickly? Will it inject fuel occasionally on a long downhill run in B to keep it warm? Or just reheat it at the bottom? (And could that be anything to do with the engine cycling which has been traditionally attributed to "battery draining"?)
     
  6. Frank Hudon

    Frank Hudon Senior Member

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    Tony the CAN-view shows total brake request as I just found out driving it this after noon.
     
  7. Frank Hudon

    Frank Hudon Senior Member

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    most time on a long down hill the battery gets to full before the cats' get cooled to the point of injecting fuel. I'm sure that Toyota has set it so if it needs fuel just a little is injected and being to lean to burn completely gets sent to the cats and they react with it and warm back up.
    Also when you compress air it gets warm to hot depending on how much you compress it. Vis a vis diesels compress the air with a high compression ratio to get it very hot and then inject the fuel in and the air is hot enough to ignite the fuel.