Answers to those "unexplained" ICE operations in EV mode

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by usbseawolf2000, Jan 24, 2013.

  1. usbseawolf2000

    usbseawolf2000 HSD PhD

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    First, what we knew from the owner manual (page 40-41) also see the PiP FAQ. The gas engine may operate:
    1. When the heater etc. is in use. (defogger included)
    2. When the temperature of the hybrid system is high. The vehicle has been left in the sun, driven on a hill, driven at high speeds, etc.
    3. When the temperature of the hybrid system is low. The vehicle has been left in temperatures lower than about 32°F (0°C) for a long period of time etc.
    4. When power is needed temporarily, for example when accelerating suddenly.
    5. When vehicle speed is more than approximately 62 mph (100 km/h).
    6. When the accelerator pedal is depressed firmly or the vehicle is on a hill etc.
    7. When the outside temperature is low (less than 14°F [-10°C])
    8. After driving for approximately 124 miles (200 km) with the gasoline engine off, the gasoline engine may start for a short amount of time in order to protect the system
    9. If you regen charge a full battery pack. If you live on top of a hill and drive down after a full charge, the gas engine can come on to "bleed" the extra electricity, operating like a Jake brake.
    With more information from a Ford plugin engineer, I can use that information and address the bolded items. Ford plugin have the same battery cells as PiP, from the same supplier. We will assume the thresholds are similar.

    The gas engine may operate because the battery is at reduced power in EV mode.

    #2 - What's the high temperature of the hybrid system? 113 deg F (45 deg C). We can monitor it using TB1, TB2 and TB3 using Torque app with custom PIDs for PiP. If one of those temp is higher than 113 deg F, we cannot expect a full battery power in EV mode. This means the gas engine may start before the EV bar reaching the PWR region (all the way to the right).

    #3 - What's the low temperature of the hybrid system? 32 deg F (0 deg C). We can use the same TB1, TB2 and TB3 to monitor. If one of the battery temp is below freezing point, the gas engine may start since the battery is not allowed to provide "normal" power.

    #7 - For the outside temperature, I think we can use the temp shown on the dash. We can also use Ambient Temp Sensor in torque.

    The battery power allowed to discharge also depends on the battery state of charge. Here is a graph showing discharging from EV mode (fully charged) to hybrid mode (minimum). You can use Discharge Control PID to monitor the maximum allowed battery power.

    What's great about Torque app is, we can set up alarms with threshold specified in each individual PID. This can be used as a warning to indicate EV mode battery power is reduced.
     
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  2. bisco

    bisco cookie crumbler

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    i'm finding that #7 is not a given.
     
  3. usbseawolf2000

    usbseawolf2000 HSD PhD

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    What do you mean it is not a given?
     
  4. bisco

    bisco cookie crumbler

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    well, so far, i have driven in as low as 9 degree weather, and the ice has not come on.
     
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  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    How much battery power did you use?

    Engine won't come on automatically but the battery power would be limited. If you don't exceed the threshold, ICE won't trigger.
     
  6. bisco

    bisco cookie crumbler

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    i use all the battery power. yes it has been diminishing since temps dropped below 70. i can only go 11 or 12 miles in ev at 10 degrees, what threshold are you speaking of? doesn't #7 say the threshold is 14 degrees?
     
  7. vincent1449p

    vincent1449p Active Member

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    There is an Ambient Temp Sensor which is much closer to the temp shown on the dash.
    Column 1
    0 [TH]Name[/TH][TH]ShortName[/TH][TH]ModeAndPID[/TH][TH]Equation[/TH][TH]Min Value[/TH][TH]Max Value[/TH][TH]Units[/TH][TH]Header[/TH]
    1 [TR][TD]Ambient Temp Sensor[/TD][TD1]Ambient[/TD1][TD1]2122[/TD1][TD1]A * 160.65 / 255 - 9.94[/TD1][TD1]-9.94[/TD1][TD1]150.71[/TD1][TD1]F[/TD1][TD1]7C4[/TD1][/TR]
    Vincent
     
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  8. El Dobro

    El Dobro A Member

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    #7 happened for me yesterday morning. I used the car in EV only Monday evening. I charged up the car, but did not use it at all Tuesday. Wednesday morning, I hit the power button and the ICE fired right up. It was 12F. The ICE didn't fire up this morning, until I hit the Parkway.
     
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  9. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I was asking about the EV power bar. At 14 degree, it is likely that ICE will come on before you reach the PWR region.

    What I was saying is, the colder it gets, the less power (not range) the battery can provide and feel sluggish in EV mode.

    Perhaps you did not need that much power in your commute so ICE didn't trigger at 9 deg F.

    Yes, it does. Thanks, we can use it as one of the "alarm".

    I think it was a combination of #3 and #7. The battery temp would have been closed to 12 deg F.
     
  10. bisco

    bisco cookie crumbler

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    gotcha. i'm sure it was all over the place, from light accelleration to medium/high, but never more than 1/2 way between the ev car icon and the power bar. that aside, the manual makes it sound like the ice may start below 14 degrees. i guess 'may' is the operative word.
     
  11. priuskitty

    priuskitty PIP FAN

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    fyi: I check my coolant temperature on my ScanGuageII because it's changes very little with fluctuating outside temperatures when I have 15 degrees Fwt, ICE doesn't come on,14 degrees, ICE comes on as soon as I hit "Ready"
     
  12. bisco

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    you're saying it's 14 coolant and not ambient?
     
  13. priuskitty

    priuskitty PIP FAN

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    Correct

    SCH-R530M ? 2
     
  14. ukr2

    ukr2 Senior Member

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    I also thinks it's the Coolant Temp limit, not the OA Temp limit. I read it referred to as a Cold Soak.
     
  15. RBooker

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    This week daytime temperatures have been in the 5 to 15 degree range. At home I park in an uninsulated garage and an underground garage at work. This week when I head off to work PIP's temp gauge was ~25F the ICE starts within 1 or 2minutes of departure. Thursday leaving work PIP's temp gauge ~37F, outside temp was 10 F I completed trip in EV.
    FYI: since most trips are <6 miles I do not use the heater in PIP or previous vehicle.

    This seems consistent with coolant/battery as opposed to ambient temp.
    Overall, I am very impressed with the PIP's 'cold tolerance'. Despite the low temperatures according to the on board computer I am still averaging ~125 mpg. However, I do notice the maximum power output in EV is reduced in low temps. As a result I have made some adjustments to my driving style. However, I think it is the covered garage at work that has made the biggest difference. I have a feeling the garage will also boost my EV range on hot summer days. The PIP will be sheltered from the heat of the sun which means less battery stress and no AC.

    I assume that they batteries warmup as they charge and discharge. Any data on the time required for the batteries to reach the specified temp range after start up at different temps with & without running the heater? What is the battery temperature during and after charging?
    In the summer when ambient temps are 90+ F is it better to use the AC in an effort to keep the battery temperature in the optimal range? I am assuming the efficiency of the battery declines before it reaches the 114 F mentioned above. Does anyone have images of the Toyota's battery output curves?
     
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  16. bisco

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    i thought it said cold soak was under 32 degrees?
     
  17. bisco

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    makes sense. since my garage is in the low 30's when it's ten outside. and i have my grille blocked, and i'm only out for a few hours, the coolant probably doesn't drop below 14.
     
  18. lensovet

    lensovet former BP Brigade 207

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    given that the batteries are cooled by fans which draw air from the passenger cabin, it would most certainly be in your interest to run A/C in the summer. keep in mind that the A/C is electrically driven and therefore doesn't need the ICE to be on to operate.
     
  19. bisco

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    i wonder if it is too hot if the a/c is forced on like the ice when it is too cold.