Dramatic throttle response change between EV and Hybrid modes

Discussion in 'Prime Main Forum (2017-Current)' started by GT4Prius, Apr 24, 2019.

  1. GT4Prius

    GT4Prius Active Member

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    Mostly we use our UK Prius Plugin 2017 in EV mode, with the Drive Mode (Throttle response) setting on ECO.

    But when we need to run the car in Hybrid mode, the throttle response dulls dramatically, and we have to switch the Drive Mode to "Normal" to get a similar throttle response ( i.e. to what we get when in EV with ECO Drive mode).

    Obviously, the Drive Modes (Throttle response) affect the throttle response in both EV and Hybrid mode, and I can't see any logic or value in having different response profiles for each Drive mode, between EV and Hybrid mode.

    Is this a fault on our car, or is it a rather odd design decision?



    (Responses from UK / European owners are of particular interest, as I have a UK vehicle [@RCO?]).
     
    #1 GT4Prius, Apr 24, 2019
    Last edited: Apr 24, 2019
  2. mr88cet

    mr88cet Senior Member

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    Yeah, our US Prius “Prime” works the same. It feels pretty sluggish upon switching over to HV from EV, at least in the Eco setting.

    Not surprisingly, it also shows considerably more delay when you “step on it” at-speed, in HV, than in EV mode.

    I personally haven’t compared the power curves in other than Eco mode. However, when I test-drove one, the salesman had me try out HV Power mode, and it struck me as reasonably peppy.

    I presume this is ultimately because they engineered the power curves semi-quasi-independently, without putting much effort/emphasis to making corresponding EV/HV power curves match.
     
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  3. jerrymildred

    jerrymildred Senior Member

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    Same here. It's weird to feel the lurch if you start from a stop in HV and hit the EV button while keeping the same throttle position. o_O

    I'm trying to train myself to drive in EV Eco and HV Normal. Since over 90% of my miles so far have been EV, it's taking me a while to catch on. :D

    My deduction from watching the Weber State videos is that when they put the sprague clutch in the Prime to allow MG1 to help drive the car it actually added more power than necessary to match the Hybrid mode power.
     
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  4. bresna

    bresna Active Member

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    I find that it feels even weirder when I switch to EV on the highway on my ride home as I bleed off the rest of my EV range. I get a noticeable surge when I switch.
     
    #4 bresna, Apr 24, 2019
    Last edited: Apr 24, 2019
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  5. mr88cet

    mr88cet Senior Member

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    FWIW, I personally am not all that disappointed that the power curves mismatch a bit. However, I do have a little — not much but a little — concern for it being a minor safety issue: Getting used to EV-mode response and the getting that lag in the comparatively rare cases when I drive it in HV mode: That can be risky in the case of changing lanes to pass somebody, only to discover a not-previously-visible speeder rapidly pulling up behind you.
     
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  6. Salamander_King

    Salamander_King Senior Member

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    Yap, same here as others said. I got so use to driving in ECO mode on Gen3, for me PRIME on EV and ECO mode is almost too responsive. lol My usual average speed is 30mph and I rarely get on highway that requires faster than 60mph.
     
  7. NSXT

    NSXT Active Member

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    I have stayed in Normal mode since the lag issue from EV to HV under ECO. Did not see much of MPG loss neither.

    If I drive local+short distance, ECO makes sense. Once driving in a mix of local/highway, I think Normal or Power mode makes more sense for me at the least. I might not be fuel efficient but when I drive in ECO, I hate seeing people tailing me and cutting me all the time :confused:
     
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  8. jb in NE

    jb in NE Senior Member

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    I see exactly the same in the US version. I run Eco in EV mode, normal in HV mode to get similar throttle response.

    Consider it a "feature."
     
  9. mr88cet

    mr88cet Senior Member

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    Yeah, I haven’t noticed much range difference either across the various EV economy/power modes, although I’ve mostly driven ECO anyway. I personally find it to be more a question of pedal feel/response between ECO and normal. There is, however, also the difference that ECO drive mode, by default, also automatically turns on the ECO-climate mode.
     
  10. jb in NE

    jb in NE Senior Member

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    It appears to me that in Eco mode and EV, there is more regenerative braking with zero throttle than when in Normal mode.
     
  11. Trollbait

    Trollbait It's a D&D thing

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    The power and torque curves between motors and engines are inherently different. The max torque at zero rpm of the motor makes the car feel peppier, while the engine needs to rev up to get that output. More engine output could be converted to motor in hybrid mode by diverting more output through the series path, but that has an efficiency price. Plus, it can never match the zero rpm torque of of both motors together.

    The accelerator mapping of the drive modes could be programmed to automatically change between the hybrid and EV modes to reduce the change the driver perceives.
     
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  12. jerrymildred

    jerrymildred Senior Member

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    As @mr88cet said earlier, it's not a problem for me. Just an interesting quirk.
     
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  13. NSXT

    NSXT Active Member

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    True. Once I have mine with Normal Mode, I had to manually change the climate to ECO mode only once. It remembers that option since.
     
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  14. m8547

    m8547 Senior Member

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    I tested this yesterday, and I didn't see any difference. It does seem to depend on speed a little. I was coasting down a hill on the highway at 70mph while switching between drive modes if it matters.
     
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  15. mr88cet

    mr88cet Senior Member

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    That’s curious: I thought I observed slightly more regen in Normal mode; not a huge difference though. I’ll have to compare again...
     
  16. jerrymildred

    jerrymildred Senior Member

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    I would not expect any difference in regen between Eco, Normal, and Pwr modes. All that would really be doing is changing the force required on the brake pedal for equivalent deceleration. And for coasting, the amount of simulated engine braking should be consistent in any throttle mapping mode as long as it's in Drive. Remember, that the three modes (Eco, Normal, & Pwr) just remap the throttle for different amounts of throttle travel required to get the same acceleration.
     
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  17. E-GINO

    E-GINO Active Member

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  18. breakfast

    breakfast Active Member

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    The Prime drives very consistently (in terms of throttle response) and very efficiently in "Normal" mode for gas and electric - I just leave it that way regardless of whether I am in HV, EV, EV Auto (aka EV City), etc.
     
  19. mr88cet

    mr88cet Senior Member

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    I diddled a bit with Eco, Normal, and Power modes (in EV), taking my wife out to see her 中医 (Chinese-medicine doctor).

    Yeah, I don’t see much difference in regen rates, if any.

    What I was probably noticing earlier was that I, being more used to Eco, was still slightly accelerating in Normal mode when I let my foot off the gas. So even though they decelerated about the same, the “jerk” — the change in acceleration — was higher in Normal mode.
     
    #19 mr88cet, Apr 25, 2019
    Last edited: Apr 25, 2019
  20. m8547

    m8547 Senior Member

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    They also change how quickly the cruise control accelerates, so they might change other things too.
     
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