Hard to achieve pure glide in new Gen 4

Discussion in 'Gen 4 Prius Fuel Economy' started by TKW_NOLA, Jun 26, 2021.

  1. TKW_NOLA

    TKW_NOLA New Member

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    Just traded in my 2009 Gen 2 for a new 2021 Gen 4 XLE. I used to be able to easily achieve pure glide in Gen 2, but can only do it for moments or not at all in Gen 4.

    Is that the way it supposed to work now? No complaints here - getting > 60 mpg on my first tank.

    Energy monitor just bounces back and forth from battery --> EM --> wheels mode to wheels --> EM --> battery. Once in a while I can get "no energy flow," but only briefly. It was very easy in my 2009 to get into this pure glide until car slowed down so much that I needed to pulse power.

    Is a) something wrong, b) I'm not doing it right, or c) that's the way the new system works?
     
  2. The Professor

    The Professor Senior Member

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    That's the way it works now.

    If you want to have no conversion losses, you can take your foot off the pedals and tap the lever over to Neutral. If done correctly it'll respond with a beep and a message asking the lines of "Rapid shift to Neutral accepted".

    It's honestly more hassle than it's worth though. While a pure glide or being in Neutral will remove any conversion losses, the gains when the at those closely matched road speed + pedal position are very minimal, negligible even. Bear in mind that in this mode you have effectively switched off regen until you put it back into Drive with the same method.

    In general, even though we don't want to admit it, the Gen4 computers are nearly always better than us humans at figuring out what to do. This is in no small part to the fact it has access to information we don't, such as battery temperature, voltage, engine temperature, etc, which we don't. When these variables are factored in to the equation, letting the car figure out what to do usually gives the best long term gains. Most seasoned Gen4 drivers here end up saying "just drive it". Everything else only serves as distraction, which of course is dangerous.

    There are exceptions of course. The car can't know what terrain lies ahead, so a human may want to prioritise EV use to use up that stored energy if they know there is a long stretch of downhill approaching, but that's about it.
     
  3. bisco

    bisco cookie crumbler

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    that started with gen3. toyota found out about glide from priuschatters, and programmed it into gen3 for better mpg's for unaware drivers.
    best bet is to try to keep it just above glide, it uses a tiny amount of electricity, whereas just bekow will slow you down with regen, and give back almost none.
     
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  4. fuzzy1

    fuzzy1 Senior Member

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    It seems that Gen2's displays had an understanding of 'close enough', and rounded the display to zero, no flow.

    But Gen3 didn't have that concept, thus demanding something much closer to zero before it would display as zero energy flow. And at numerous speeds, it seemed that a true zero was arithmetically impossible. That is why many of us abandoned that display and preferred the HSI display instead, with a bar graph showing just how close we were to zero energy flow. Gen2 didn't have this display.

    I haven't driven a Gen4, so can't compare.
     
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  5. Tideland Prius

    Tideland Prius Moderator of the North
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    While it is more soft to glide, I don’t think it’s that much more inefficient to lightly be in EV mode. The only issue is that Toyota gives no indication of energy use, just an on/off light for the arrows in the Energy Monitor screen (Ford had a scale in their Fusion Hybrid). The substitute screen is HSI. There, you can better figure out glide and not worry if the car is using a tiny bit of energy from the battery.

    For me, HSI has replaced the Energy Monitor I used to use in the Gen 2.
     
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  6. Valiant V

    Valiant V Member

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    Though I can't compare what a Gen 2 is like, our 2017 Gen 4 is pretty easy to keep it where you want it watching the hybrid monitor.

    You can pretty much also tell just by how the car "coasts". I noticed right away that foot totally off the "gas", the Prius slows down a lot more than my old beater truck and van. On a very gentle hill in the city, I'd have to tap the brakes a few times to stay under the 30mph limit. In the Prius, feet on the floor will slow you down much quicker than I expected.

    'Course, I appear to be the only guy in town who obeys that 30mph speed limit. (Even the school bus blows it away.)

    We live in an area with a lot of gentle hills, so there's ample opportunity to pick up quite a bit of "free" speed on the downside keeping the "eco guide" bar right at the neutral mark - no power, no regen. I can get 62-63 mpg on the 8 mile trip from home to work with no problem - even if I'm running the A/C pretty good because it's 90F+.
     
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