1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Starting HV mode at 60 MPH

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by bill188, Jan 22, 2018.

  1. bill188

    bill188 Junior Member

    Joined:
    Dec 15, 2017
    41
    21
    0
    Location:
    Aurora, Colorado. USA
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    I'm Prius Prime 4598. I was BODGM but lost my password and have started a new log in. I live in Denver and I usually start my day in EV mode with the heat on. I go about 5 miles and scoot on the highway and while on on the highway, going 60 mph, I go to HV mode. Sometimes the heater goes cold for a few minutes before the motor heats up. My issue is, am I causing damage to the engine if I suddenly start the engine at 60 mph?


    Posted via the PriusChat mobile app.
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    can't be sure, but i wouldn't do it. i'm sure toyota takes precautions, but i would warm it up before entering the highway. they don't exactly have a pristine record of protecting their engines.
     
    bill188 likes this.
  3. Kramah313

    Kramah313 Active Member

    Joined:
    Oct 3, 2015
    408
    321
    0
    Location:
    Dallas, TX
    Vehicle:
    2012 Prius
    Model:
    Four
    I don't have a prime, so I can't be sure, but I'm guessing that the car runs off the traction battery while the engine warms up. It most likely keeps a reserve for this reason. If true, it wouldn't hurt it to start it at any speed that the EV motors and battery can handle without the engine.
     
  4. bill188

    bill188 Junior Member

    Joined:
    Dec 15, 2017
    41
    21
    0
    Location:
    Aurora, Colorado. USA
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    When I hit the HV button , my Prime does register 100 mpg for a while, so that might be the case. Does the heater change its function away from the heat pump and uses the engine to heat the car after I hit the HV button?

    Posted via the PriusChat mobile app.
     
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    once the engine is producing enough heat, most likely.
     
    Kramah313 likes this.
  6. Kramah313

    Kramah313 Active Member

    Joined:
    Oct 3, 2015
    408
    321
    0
    Location:
    Dallas, TX
    Vehicle:
    2012 Prius
    Model:
    Four
    I would suspect that the warming up engine charges the battery while idling to warm up with the battery driving. It probably doesn't switch over to engine provided heat though right away because the engine temp isn't high enough to provide it.
     
  7. john1701a

    john1701a Prius Guru

    Joined:
    Jan 6, 2004
    12,747
    5,243
    57
    Location:
    Minnesota
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    We've seen how PHV (2012-2015) protects the engine, allowing highway-speed start-ups while reducing the burden by heavily favoring electricity until warm-up is complete. We have seen similar behavior with Prime now too. There is nothing else to doubt anymore. We are sure.
     
    bill188 likes this.
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    when i turn on the heat, in ev mode, the engine comes on. when i step on the accelerator, the engine revs. does this behavior persist in prime?
     
  9. bill188

    bill188 Junior Member

    Joined:
    Dec 15, 2017
    41
    21
    0
    Location:
    Aurora, Colorado. USA
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced
    In the Prime, when the car is in EV mode and you turn the heat on, the engine does not come on. If the traction battery is down to Zero, then the engine will come on.

    Posted via the PriusChat mobile app.
     
    bisco likes this.
  10. Pdog808

    Pdog808 Active Member

    Joined:
    Mar 30, 2017
    411
    271
    0
    Location:
    Los Angeles
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    I do this all the time.

    From a cold start, my Prime is in EV on surface streets and until I get up to speed on the freeway (i.e. 65+ MPH). Then I switch the car into HV mode and the ICE runs thru it's startup routine. While the ICE is going through warm up (about 3-5 minutes, not sure), the car is running off of the traction battery and the ICE is providing very little energy (if any) to the motors. This keeps the ICE from being stressed from a sudden cold start. Keep an eye on the energy diagram on the 11.6" screen and you'll see the engine icon go yellow when it has finished it's warm up period.

    You can see the traction battery level drop down while the engine is in warm up mode - you'll get the lost charge back eventually after the engine warms up and "tops you off" so to speak.

    Also - keep in mind that since the engine has 0-20W oil, it can warm up and lubricate quickly. That's what it was designed for.

    All of the above is based on EV Auto being off.
     
    #10 Pdog808, Jan 23, 2018
    Last edited: Jan 23, 2018
    bill188 likes this.
  11. bill188

    bill188 Junior Member

    Joined:
    Dec 15, 2017
    41
    21
    0
    Location:
    Aurora, Colorado. USA
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Advanced