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pulsing and gliding wear on engine

Discussion in 'Prime Fuel Economy & EV Range' started by idahohacker, Oct 6, 2019.

  1. idahohacker

    idahohacker Junior Member

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    I heard about pulsing and gliding where you accelerate and then EV down to a lower speed and rinse and repeat. Also city driving does less damage to engine than highway driving due to varying speeds. Will doing this do more damage to the engine than cruising with the engine on. Also engine does more damage when colder and turning it off will reduce temperature.
     
  2. bisco

    bisco cookie crumbler

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    it doesn't stay off that long.pulse and glide won't turn the engine on and off more, in fact, it might be less.

    either way, prius is designed to do it millions of times over its lifetime.

    what are you driving?
     
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  3. mr88cet

    mr88cet Senior Member

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    I would not expect “pulse and glide” to cause any appreciable amount of wear on the engine, but either way, the “glide“ portion of “pulse and glide“ is not “EV“ operation as such.

    Glide is everything off — engine off, and the MGs functioning neither as motors nor as generators.

    So, if it were a boring ol’ manual-transmission car, it would be as if you use the engine to drive the car up to speed, then shut off the engine and put it into neutral or throw in the clutch. (Don’t try that on such a car please, but that’s the effect you’re trying to achieve.)

    On the Prius, the way to achieve that effect is to accelerate with the engine, then move your foot on the gas pedal to press it just hard enough to prevent it from regenerating.
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    You ask about pulse and glide (varying engine speed as a economy plan) as bad yet mention that city driving (varying engine speed to keep up with traffic) as a good thing. I doubt either has any effect, as the Prius varies engine speed every second all the time even at constant speed on a level road. (My commute gains 90 feet in 154 miles)

    What does help engine life are:
    The prius has an Offset bore, the piston pushes straight down in the power stroke. Desaxe - Wikipedia
    Motor/Generator 1 brings the engine fully up to speed before it tries to start, the engine is already lubricated before it makes power.
    The Hybrid Synchrony Drive limits low and high speed RPMs (Burst power is often electrical power)

    Toyota designed the Prius engine to turn on and off routinely. Prius have been doing so since 1997. (2001 in the US) It is almost certain we would hear about it if there was a design defect. (notice how often we hear about head gaskets in Gen 3s; we don't keep secrets from each other)

    It is true that the engine will turn off less often in cold weather; this is one of many reasons Winter MPG is not as good as Summer. One side effect of this, you may notice your HV Battery stays charged more in Winter; the engine was running anyway, so it made power. With each new generation, the engine runs fewer auxiliary accessories, so needs to stay on to power them less often. Starting with Gen 3, the Prius has no belts at all. You still want a warm engine for the heater. (The Prime uses a heat pump instead) The engine oil pump and ATF pump are still mechanical, not electric.

    I hope you check into the 4 generations of Prius and notice when A/C quit being a belt, when Power Steering quit being a belt, etc. This is a constantly refined drive line.
     
    #4 JimboPalmer, Oct 6, 2019
    Last edited: Oct 6, 2019
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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    I think most of my pulse-and-glide is what I'd call micro-pulse-and-glide, keeping the pulses and glides really short and subtle, so I don't bug people. Also: opportunity-pulse-and-glide, which is basically giving it a kick, then costing up to an obstruction, say a red light or whatever.

    I can't see anyway either of those would be hard on an engine, more the opposite: every glide, throttle shut, means high vacuum in the intake manifold, which pulls oil higher up the cylinder walls, gives the the engine a breather, and so on. Kinda the opposite of a relentless hill climb.
     
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  6. idahohacker

    idahohacker Junior Member

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    I currently drive a 2011 Sienna but plan to buy a Prius Prime. My bad about city driving being better than highway driving. I meant the opposite im going to change that. I was wondering about the wear on the generator?
    EDIT: looks like I can't change that.
     
  7. meeder

    meeder Active Member

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    MG1 and MG2 will most probably outlast the rest of the car. I wouldn't worry about the wear of those components.
     
  8. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    If you change your ATF WS at 30,000 miles, 100,000 miles and then every 100,000 miles; you care doing all you can for M/G1 and M/G2.
     
  9. idahohacker

    idahohacker Junior Member

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    I have heard of people needing to change them
     
  10. bisco

    bisco cookie crumbler

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    very few though
     
  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Gen 1 had issues with the windings of M/G2. Gen 2 was better, but had some bearing issues. Gens 3 and 4 seem considerably improved. None since Gen 1 have an error rate that Consumer Reports has been able to measure.
     
  12. idahohacker

    idahohacker Junior Member

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    Right but they haven't been out that long so they may be problems farther down the line.
     
  13. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Gen 3 is a decade old, it was out in June 2009. There are a number of known Gen 3 issues, just not with the transaxle. Each Generation attempts to address know issues, and since they tend to last 6 years, a lot is known by the time the next Gen appears.

    Prius are attractive as taxis, so be the time you finish the next design, you have a large body of cars with 1/4 million miles on them.

    If you are interested in the evolution of the transaxle, I can recommend the Weber Auto series on you tube, Professor John Kelly goes in depth on each variation.

    Evolution of the Toyota Prius Transaxle - YouTube
     
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