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S4 (Stage 4) Temperature

Discussion in 'Gen 2 Prius Technical Discussion' started by tom1l21, Oct 26, 2009.

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  1. tom1l21

    tom1l21 Member

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    What is the temperature the engine must be to get into stage 4 and to allow for gliding with no engine revolutions? I have heard temps for S4 to be 157F, but at that temp on my ScanGauge, the engine will still run when trying to glide. I even used the xgauge engine temp for this. What is the target temp and how do you display it on the SG? Thanks!
     
    #1 tom1l21, Oct 26, 2009
  2. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    Its actually about 70C or around 157-159F. I always shoot for 159F minimum.
     
    #2 TheForce, Oct 26, 2009
  3. Matt Herring

    Matt Herring New Member

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    I also use the 159 degree mark as my hurdle for EV but recently with the lower temps I have noticed I am needing around 162 degrees on my SGII to capture EV.

    That being said, when I get into EV in the 160 degree range there is some cooling that occurs at current ambient temps while in EV so I have to get back up to temp afterwords to use it again.

    On my commute to work there is a long downhill that I usually get into EV at the crest (about 3/4 mile from my house) and I'll usually do an EV neutral coast to the bottom and beyond. After that coast I'm at about 155 degrees so a small amount of ICE is necessary to get back up to temp over the next couple small hills before getting back into EV on the next long flat/slightly downhill stretch.
     
    #3 Matt Herring, Oct 26, 2009
  4. efusco

    efusco Moderator Emeritus
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    According to CAN-View, 157F is my consistent threshold. Remember that you must do the idle check to enter S4 (full stop, with engine running, for about 7 seconds and until the ICE shuts down).
     
    #4 efusco, Oct 26, 2009
  5. tom1l21

    tom1l21 Member

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    I'm not quite sure I understand this explanation.

    If I read an engine temp of 150F on my SG (engine temp xgauge) and decide to accelerate from say from 10mph to 35mph and in doing so, I reach 165F on my ScanGauge, will I be able to take my foot off the accelerator and then feather back on the accelerator to glide? I'm not quite sure what you mean by full stop for 7 seconds. I hope you didn't think I meant going into EV mode (I don't have that installed) which I would imagine you would have to come to a stop to engage it.
     
    #5 tom1l21, Oct 26, 2009
  6. efusco

    efusco Moderator Emeritus
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    Yes, at 165F (or 157), when you hit any speed b/w 42mph and 35mph you can feather off into a glide...but you are NOT in S4 at that point...I think that's S3b or something.

    If, after getting up to 157F you come to a full stop, with the ICE running, the wait for the idle check/ICE shut down, you are THEN in S4 and will be able to feather into a glide from ANY speed below 42mph (Gen II), not just b/w 42 and 35mph.
     
    #6 efusco, Oct 26, 2009
  7. tom1l21

    tom1l21 Member

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    Ahh thanks for clearing that up. In stage S3b, I take it the engine is just spinning while you try to glide?
     
    #7 tom1l21, Oct 26, 2009
  8. Matt Herring

    Matt Herring New Member

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    I do the stop for several seconds process once in awhile when I accidentally trip ICE in EV. On my commute home I have 1/4 mile of driving to get through my living community and if I trip the ICE I just pull over...wait for ICE to shut off...then continue my EV driving to the parking location.

    I don't trip the ICE often during this 1/4 mile stretch...maybe 1 out of every 20 times...but if you're limping home on EV with 3 bars and apply too much pressure to the GO pedal it's easy to trip the ICE vs. 4-6 bar operation. The several second stop process to shut down ICE is a handy little trick to conserve mpg.
     
    #8 Matt Herring, Oct 26, 2009
  9. tom1l21

    tom1l21 Member

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    My engine temp was at 172F when I came upon a red light. After waiting for 20 seconds, I accelerated off and tried gliding which didn't work. I then came to another red light at 180F 15s down the road and again waited for 30s. After accelerating, I was able to glide. How come I wasn't able to at the first red light?
     
    #9 tom1l21, Oct 26, 2009
  10. efusco

    efusco Moderator Emeritus
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    b/w 35-42 you can have a true ICE-off glide. If you try to enter a glide at less than 35mph in S3b the ICE will continue to run.
     
    #10 efusco, Oct 26, 2009
  11. efusco

    efusco Moderator Emeritus
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    Was the ICE running when you waited the first time? Probably not. If you come to a stop and are not sure if the ICE is running, just gun the accellerator (with your foot firmly on the brake) to get it running, then wait until you feel it idle off.
     
    #11 efusco, Oct 26, 2009
  12. hobbit

    hobbit Senior Member

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    Those little cooldowns are a good reason to install an ECT fakeout.
    Even a little boost can get you back over a 70C reading as you
    take off again and can get right back into the glides.
    .
    _H*
     
    #12 hobbit, Oct 26, 2009
  13. ken1784

    ken1784 SuperMID designer

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    Adding to Dr. Evan's comment...

    Shift to P, then gun the accelerator.
    Or,
    Power off, then restart Prius after five seconds or more.

    Ken@Japan
     
    #13 ken1784, Oct 27, 2009
  14. tom1l21

    tom1l21 Member

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    No, the ICE was not running while I waited at the first light. It ran as I approached the light, and once I stopped, it shut off. Since it was in the 170's, I thought when it shut off it would constitute as one of those "idle checks" you were talking about previously. I guess it shut down the ICE but it didn't do the "idle check."? Wonder why. Sorry if I am not understanding this.

    BTW, I can tell when the ICE is running either by the sound of it or the RPM's on my scangauge.
     
    #14 tom1l21, Oct 27, 2009
  15. Bob64

    Bob64 Sapphire of the Blue Sky

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    How fast were you going as you approached the first light? Over 35mph?

    Heres what I think may have happened:

    You were traveling between 35-40mph. You started to deaccelerate. Because you were in stage 3, the engine shutoff as you approached the stoplight (conditions for engine stop: between 35-40mph, coolant temp above 70c, stage3 or above). As you accelerated to the second stoplight, you did not reach 35mph, so the engine was running as you stopped at the second stoplight. Because the engine was idling for over 7 seconds at 2nd stoplight, you entered stage 4, and the engine stopped. After the second stoplight, you are able to glide at any speed under 41mph.
     
    #15 Bob64, Nov 2, 2009
  16. tom1l21

    tom1l21 Member

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    I believe so, the speed limit there is 40mph.

    That seems right, I didn't reach 35 going to the 2nd light. Good insight, I think I might have it figured out now. Thanks!

    EDIT: One other question. What would cause the engine to run if the temperature is ~180 and the battery is at 6 bars when trying to glide. No heat or air conditioner on. This seems to happen sometimes out of the blue, my guess is that it is the battery, even at 6 bars, will still charge if it drops below a certain SOC?
     
    #16 tom1l21, Nov 4, 2009
  17. TheForce

    TheForce Stop War! Lets Rave! Make Love!

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    If you just reach around 176F-180F the engine must run to curculate the coolent or something. I cant really remember right now. It takes about 30 or so to do this then you can get back into a glide.
     
    #17 TheForce, Nov 4, 2009
  18. Bob64

    Bob64 Sapphire of the Blue Sky

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    I've noticed this behavior before and I believe someone mentioned that it was storing hot coolant in the thermos when that happens. Tends to happen early on in the commute, after which the computers is like: oh, the thermos stored as much heat as it can, lets not bother with this anymore.
     
    #18 Bob64, Nov 8, 2009
  19. tom1l21

    tom1l21 Member

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    Thanks for clearing up the previous point. Makes sense.

    Sometimes I can stop at a light for several seconds at 150 F and when I accelerate off, I can then glide even under 159F. Is this stage 3b or something? It never did the idle check until I came to another stop after that was at 170F. I could definitely feel the idle check shudder there.
     
    #19 tom1l21, Nov 8, 2009
  20. ken1784

    ken1784 SuperMID designer

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    Under 159F, you were in stage-2.

    Ken@Japan
     
    #20 ken1784, Nov 8, 2009
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