Different response feel!!

Discussion in 'Prime Main Forum (2017-Current)' started by Sgt Bill, Sep 19, 2021.

  1. Sgt Bill

    Sgt Bill New Member

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    Hi My wife and I have recently purchased our second Prius a 2021 Prime Limited,(our other was a 2015 Prius 4 with tech package).Anyway our new PP feels or has a different response after the ev is depleted and the we drive the vehicle in HV mode from the start.It seems that the car has more power if after the EV mode is depleted and we stop turn off the car then later get back in the car and drive inHV mode the car performs better and has more power.Is that just me or am I doing something wrong.(traded our 15 after 60,ooo miles and have not had a hybrid for a couple of years.We returned after 2 years in a 2019 CHR we missed the Prius.Any comments!!
     
  2. vvillovv

    vvillovv Senior Member

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    If you start out in HV mode with a full charge, than after a few miles your switch to EV mode, sometimes it feels like there is more power in EV mode. With the Prime, it often hard to tell what's actually happening by gut feelings.
     
  3. bisco

    bisco cookie crumbler

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    completely different vehicle, normal
     
  4. jerrymildred

    jerrymildred Senior Member

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    I feels to me like the accelerator is mapped differently between HV & EV. If I'm driving at, say 40 mph, in HV and switch to EV, the car will accelerate without me moving the pedal. It's a push you can feel. I sometimes wonder if they copied the calculations for EV mode from the regular Prius and forgot that the Prime uses both MG1 and MG2 and therefore has more power in EV than the regular Prius in EV. But, in fact, the Prime in HV has the power of the motor/s and the ICE while only having the motors in EV. Therefore, more power in HV but not as aggressive with throttle mapping. Plus, since the electric motors offer instant torque, it's quicker off the line in EV.

    Prime 0-60 :15 sec in EV mode | PriusChat
     
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  5. Sgt Bill

    Sgt Bill New Member

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    The difference is not going from hv to ev it is the opposite.when ev depletes and the system switches to hv and there is completely different response than when driving from start in hv .The car s response in straight hv has one response and when it switches from ev to hv it has another,much more responsive in straight hv mode?
     
  6. bisco

    bisco cookie crumbler

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    r u in eco mode?
     
  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Yes there is a difference and that’s the benefit of EV’s instant torque. It’s there in HV but it’s usually fleeting as the battery just fills in the torque before the engine revs up.

    The car is slower 0-60 in EV mode than in HV (about 12-13 seconds vs 11 ish seconds). It’s tuned to be peppy in the 0-30mph range where most of the city driving is done.
     
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  8. Trollbait

    Trollbait It's a D&D thing

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    Electric motors have a lot of low end torque. For most, their peak torque is at 0 rpm. You feel this in EVs and full hybrids with strong acceleration from a stop. As @Tideland Prius mentioned, the feeling is fleeting in the hybrid as the energy to get the full output from the traction motor is coming from the engine and battery. Since it is a small battery, full motor output only lasts for a short burst. Bigger battery in the EV means the motor can maintain full output. For most people, EV mode will feel faster at typical street speeds, because of that.

    With 0 rpm being peak means that the motor's torque output drops as the rpm's increase. M/G1 can help out the traction motor in the Prime, but only so much. Accelerating at higher speeds means the motor(s) will lose their pep. In a hybrid, the engine's higher torque output at higher rpms surpasses what the motor alone loses in EV mode. This is seen in the higher 0 to 60 mph times for HV mode.

    Other factors are at play. The accelerator map is different between HV and EV mode. I believe Toyota tried to keep the feel close between the two, but they are essentially two different drive trains. Differences between the two will be felt.

    But I think the factor in effect for what you are seeing is the battery's state of charge. You are comparing EV with depleted battery to HV. The battery's charge at that point is just a little higher than the maximum available in HV mode. It can't supply 100% of the energy needed to get full performance out of the motor. It could be seen as an engine with normal fuel supply to one running on fumes.
     
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  9. vvillovv

    vvillovv Senior Member

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    The behavior of the Prime switching to HV mode after the EV range is depleted (can sometimes also) be different at slower speed when climbing a steep enough hill. ( Can be, not always Will be) It's a Prime, I'm still not used to all the different things it throws at me every once in a while.
     
  10. jerrymildred

    jerrymildred Senior Member

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    Considering how differently the two modes (EV/HV) are powered, it's surprising to me that there isn't more of a difference in how they feel.
     
  11. Tideland Prius

    Tideland Prius Moderator of the North
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    Also, in EV mode, MG1 acts as a motor too so there’s two motors powering the Prime forward. In HV mode, only MG2 powers the car forward like a regular Prius. MG1 deals with regen, and engine rpm balancing/offset
     
  12. Sgt Bill

    Sgt Bill New Member

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    Thanks for all the info.I guess we will get use to in a while. We are taking a couple hundred mile trip in couple of days and should get familiar with some more of its little quirks .Thanks again for the info.
     
  13. FuelMiser

    FuelMiser Senior Member

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    None of these comments, while completely correct, are addressing the OPs observation that the car "feels" different in HV mode under the following two scenarios: 1) the car switches to HV after running in EV when the EV portion of the battery is depleted and 2) the car is started--brought to READY from OFF--in HV mode without ever being in EV, i.e., no EV is available when starting the car because the battery is already in the HV portion. Should be an easy experiment to replicate: drive until your EV is depleted and observe the performance when the car automatically goes into HV. Then stop the car, turn it OFF and restart to READY and drive in HV mode. The OP is saying the performance in HV in these two different scenarios "feels" different. Let's get some additional observations under these conditions. There's been plenty of comments in this Forum that a Prime in HV mode just doesn't feel the same as the "regular" Prius Hybrid, which is always in HV of course.
     
  14. jerrymildred

    jerrymildred Senior Member

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    We have a 2017 Prime and a 2017 Prius trim 2. I can't feel any difference between the Prime in HV and the Prius other than, with the Prius having a NiMH battery, it's a little less eager than the Prime to shut off the ICE on its own and the Prime gets a couple more miles to the gallon.

    I recommend relaxing and enjoying the amazing economy and comfort (especially compared to previous generations) and just driving it.
     
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  15. Sgt Bill

    Sgt Bill New Member

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    I have driven it for longer time now and have observed that the difference to me any way , is basically what one of the earlier threads have said.When the prime ev depleats and the car shifts to hv mode the battery is low and only runs on the ice until the battery regens then the feel is similar to the hv mode.It appears that it was just me not used to the ev mode.Car runs great just took trip for 350 miles and got 60 plus mpg.PP still at 200 mpg overall with 6500 miles.Love the car !!!
     
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  16. Old Bear

    Old Bear Senior Member

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    A few of observations:

    1. When the Prime has depleted its EV range and switches to HV while driving, one can feel the slightly additional vibration of the ICE. It's subtle, but definitely perceivable. I have pointed this out to passengers just as the transition is about to happen and they always agree that they can feel the change but that they would not have noticed it if I had not told them it was happening.

    2. The Prime has a "drive by wire" system where the position of the accelerator is controlling the electric motor or the ICE by way of the car's computer system. The computer interprets the physical position of the pedal differently depending upon whether the Prime is in Normal mode, ECO mode, or PWR mode. And, depending upon whether the computer is controlling the flow of electricity to the motor or gasoline to the ICE, the response curves will feel different.

    3. If you are running your Prime in HV mode, when you turn it off, it automatically will reset to EV mode and, if there is charge left in the battery, you will have to manually switch it back to HV mode. (I first observed this behavior when I was intentionally running in HV mode on the highway so that I would have battery charge available at my destination. I stopped briefly at a rest area and when I restarted the Prime, it was several miles before I realized I was back in EV mode, which was not what I wanted.)

    4. Because of the "drive by wire" system, it can be hard to discern the additional torque and slightly smoother acceleration of EV mode. But it is definitely there and if, like me, you drive 95% of the time in EV, you will notice the slightly different response when in HV mode.

    5. Electric motors don't behave much differently whether they're at ambient temperature or when they're running at their normal operating temperature. The Prime's ICE has a very quick warm-up period and the excellent manufacturing tolerances and the behavior of the synthetic motor oil are such that there is very little performance change as the engine warms up. However, that is not to say that there is no performance change between the ICE at a cold start and the ICE after a period of driving at highway speeds.

    6. And, finally, there is the placebo effect where you can honestly believe that you're feeling a difference just because you're aware of some operating parameter change and hence expect the car to feel different.

    After four years of driving my Prime, I am no longer worrying about the subtleties and am just enjoying the car. It does what it's supposed to do and is comfortable, reliable and still fun to drive.
     
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  17. jerrymildred

    jerrymildred Senior Member

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    That's it right there. Even though I'm wanting to jump to full EV as soon as I can get one, this is still a GREAT car and I like driving it.
     
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