Why I feel lose traction when switch from EV to HV?

Discussion in 'Prime Main Forum (2017-Current)' started by CoolMoon, Jul 1, 2017.

  1. CoolMoon

    CoolMoon New Member

    Joined:
    Oct 15, 2016
    13
    7
    0
    Location:
    USA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Every time my car runs out of juice and forced to switch from EV mode to HV mode, I feel less power if I keep the gas pedal in the same position. In other words, I have to depress the gas pedal harder/more to keep my car in current speed, otherwise it will slow down a little bit. Anyone feels the same or just me? Isn't the car gaining more traction from the engine after the ICE kicks in?
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,345
    11,867
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    When driving the 1G Volt, I felt it was quicker in CD mode than in CS mode (mountain mode).

    Also, you might want to perhaps pick a difference choice of word? When I read the title, I thought the tires slipped (lost traction) when changing from EV to HV mode (as if you hit a patch of ice). What you're really saying is that it feels less powerful in HV mode than in EV mode based on the same accelerator pedal position, right?
     
    Trollbait and alexcue like this.
  3. Pdog808

    Pdog808 Active Member

    Joined:
    Mar 30, 2017
    346
    232
    0
    Location:
    Los Angeles
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    I swapped from Eco mode to Normal mode to get a feel that is closer to an ICE vehicle. The different modes (Eco/Normal/Power) only affect the scaling of the pedal depression and don't actually impart additional mileage. Eco mode is good for someone that is a bit more "lead footed" and will scale down the effects of that type of driving (thus resulting in higher mileage).

    I prefer Normal mode, especially when going long distances as Eco mode requires you to depress the pedal quite a bit further to achieve the same speeds as in Normal. I end up using smaller pedal depressions to simulate Eco mode if that makes sense.
     
    Prodigyplace likes this.
  4. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,920
    3,547
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    The pedal mapping is very different in Hv compared to Ev and, yes, you need much more pedal deflection for the same power in Hv. This is a strange choice by the designers.
     
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    85,511
    37,698
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i prefer to make the decision to switch from ev to hv, rather than have it happen when i'm not aware. one for the reason stated, and two, to do a better warm up while i'm still in ev.
     
  6. john1701a

    john1701a Prius Guru

    Joined:
    Jan 6, 2004
    11,746
    4,484
    57
    Location:
    Minnesota
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Better warm-up refers to what?

    Toyota's choice to emphasize the switch was intentional, making the driver well aware of the transition so the subtleties of operation to follow won't be overlooked.

    For example, the MPG remains unchanged. You can drive for 50 miles before MPG drops below the maxed out "199.9" value. I did that last week to find out how far I could go on just a single charge before efficiency in HV would actually go unnoticed. 50.6 was the distance traveled, just on my ordinary commute, followed by a run to the coffeeshop. Had I plugged in between, the MPG would have stayed at 199.9 for all my driving that day.

    Another thing to keep in mind is that warm-up is more aggressive in Prime than it was in PHV. If I drive my entire commute on just a single charge, the engine will fire up around 33 miles. Shortly after warm-up completes, I notice EV capacity available. This newer system takes advantage of stoplight & acceleration activity. How many owners would notice that, especially if the transition from EV to HV wasn't emphasized?
     
  7. excitingguy58

    excitingguy58 New Member

    Joined:
    May 30, 2017
    4
    8
    0
    Location:
    US
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I noticed loss of power also. It drives good in the electric mode but when switches you do not have much power and really have to step on the gas pedal like everyone says.

    Posted via the PriusChat mobile app.
     
  8. fotomoto

    fotomoto Senior Member

    Joined:
    Apr 22, 2009
    4,750
    3,088
    0
    Location:
    So. Texas
    Vehicle:
    Other Hybrid
    Interesting. First I've heard that. Citation?
     
    Trollbait likes this.
  9. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    14,642
    6,473
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    Perhaps to give the user that EV performance they want, while attempting to give them better ICE fuel economy.
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
    Staff Member

    Joined:
    Oct 2, 2004
    40,345
    11,867
    41
    Location:
    Canada
    Vehicle:
    2018 Prius Prime
    Model:
    Technology
    First I've heard of it.
     
    Prius from Dad likes this.
  11. joachimz

    joachimz Senior Member

    Joined:
    Jan 21, 2012
    445
    599
    17
    Location:
    SoCal
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I always use ECO drive mode and too have noticed that when switching from EV to HV I am slightly losing speed speed and need to push harder on the pedal ... interesting read about torque in the manual below.

    Question for the more tech savvy: aren't both electrical motors utilized in EV mode? and only 1 in HV mode? Could that explain why i feel a loss of "power" when switching?

    ECO drive mode2.jpg
     
  12. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,920
    3,547
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    No.

    Both are used in Hv mode too, just differently. The maximum total drive train output in Hv mode is higher than it is in Ev mode.
     
  13. stevepea

    stevepea Senior Member

    Joined:
    Apr 16, 2017
    510
    554
    0
    Location:
    California
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Though the ECO vs NORMAL vs POWER switch works for BOTH EV and HV modes, I think you feel the ECO vs NORMAL difference more in HV than you do it EV. So if you have it set to ECO (as I do), when the EV juice runs out and the car goes into HV mode, as soon as you take your foot off the accelerator for the first time, the "HV ECO" mode kicks in, and you'll have to physically push the pedal in more (the old "mind trick" to help you want to not be as aggressive and thus save gas). I don't know how the difference between EV and HV compare in NORMAL because I always drive in ECO, but yes, you're not imagining it. If it bothers you, then you can always switch to NORMAL once you're in HV, but I've simply gotten used to it...
     
  14. Sam Spade

    Sam Spade Senior Member

    Joined:
    Dec 3, 2016
    2,036
    996
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    Power and "traction" are two entirely different things.
    When the battery gets low enough then ONLY the ICE provides the power or the electric motors proved much less........so yes for a while there IS less power. But that has nothing to do with traction.
     
    stevepea likes this.
  15. Nancy S

    Nancy S Member

    Joined:
    Dec 6, 2015
    50
    57
    0
    Location:
    Chandler, AZ
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Nope it's not just you. I know when the juice is gone too. My husband drives us to work on all electric. I'm the one driving who drives home when the electric runs out. It's about at the same place in our commute ever day. It's a define feeling of loss of power. Putting the pedal down ( but not to the metal!) keeps me going at the same pace.
     
  16. White 17

    White 17 Junior Member

    Joined:
    Dec 11, 2016
    59
    17
    0
    Location:
    Nor Cal
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I'm just guessing here but I suppose if it was the opposite someone somewhere would claim the car surged ahead (!!!) when the uncommanded transition occurred. So an engineer was tasked with making sure it wouldn't happen then subtracted a little more just to be sure.
     
    Trollbait and bisco like this.
  17. PT Guy

    PT Guy Active Member

    Joined:
    Nov 23, 2016
    668
    457
    0
    Location:
    Washington, the state
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    ...if there is battery power available.

    One more time...traction is the tires' grip on the pavement. The power put out by the drivetrain is something completely different.

    We always switch to PWR mode in freeway traffic. More scoot when an opening appears....
     
  18. E-GINO

    E-GINO Active Member

    Joined:
    Dec 27, 2009
    146
    153
    2
    Location:
    Rome, Italy
    Vehicle:
    2017 Prius Prime
    Model:
    N/A
    While in EV mode both MG1 and MG2 are used to drive the wheels, in HV mode one of the two motors has to generate electricity thus is unable to drive the wheels. Furthermore, during the ICE warm up (S0 phase) the HSD tends to minimize the ICE power output in order to speed up the warm up process and prolong the engine longevity - cold engines do not like high loads and RPM.
     
    stevepea and bisco like this.
  19. Lee Jay

    Lee Jay Senior Member

    Joined:
    Jun 25, 2009
    4,920
    3,547
    0
    Location:
    Westminster, Colorado
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Full throttle is the same regardless of drive mode.
     
  20. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    14,642
    6,473
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    Both motors can be used for propulsion in EV mode. Besides for maximum output, if and when M/G1 spins up to help isn't public knowledge at this point.

    In HV mode, you have the ICE to provide propulsion with M/G2(the main traction motor) instead of M/G1. M/G1 is being used though, to generate electricity for M/G2, and to work with the ICE to make the gear ratio changes of the transaxle.

    The loss of power sounds to be from a slightly different mapping for the accelerator, but it could be because the ICE has a different torque curve than the electric motors.
     
Loading...