Poll: Unexpected ICE Turn-ons with full battery?

Discussion in 'Clarity' started by M.M., May 12, 2018.

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Does your Clarity's gas engine ever come on when the battery is full and you don't expect it?

  1. Battery is full & long downhill & it's hot outside

    11 vote(s)
    16.9%
  2. Battery is full & long downhill & it's cold outside

    8 vote(s)
    12.3%
  3. Battery is full & little or no downhill & it's hot outside

    21 vote(s)
    32.3%
  4. Battery is full & little or no downhill & it's cold outside

    7 vote(s)
    10.8%
  5. Battery is full & car is in park & it's hot outside

    3 vote(s)
    4.6%
  6. Battery is full & car is in park & it's cold outside

    1 vote(s)
    1.5%
  7. ICE has never started unexpectedly that I've noticed.

    31 vote(s)
    47.7%
Multiple votes are allowed.
  1. DVoran

    DVoran Member

    I was just going to start a thread on this very issue. This has happened to me 3 times in the 3 months I've owned the Clarity (now with nearly 3,000 miles). This morning was interesting as the motor was on as soon as I changed from reverse to drive. The battery was full and EV range 56 (one of the higher EV ranges I've noted). Outside temperature was 70F. No matter what I did for the 1st 10 miles of the commute the ICE was engaged. Then it just reverted to normal EV mode after about 11 miles while on the highway at around 65 mph in relatively heavy traffic.
    This behavior was similar to the other two times. Haven't had time to research it but somewhere I read these PHEV engines need to run periodically. I can usually cover my 40 mile round trip commute in EV mode only unless the temperature has been very cold.
    What's interesting is that when I turned on the Vehicle Energy visual there were many times the engine kicked off but the main speedometer gauge still was white as if it was in the ICE modes. This raises the possibility that it is a software issue rather than an actual malfunctioning of the car.
     
    Last edited: May 15, 2018
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  3. KentuckyKen

    KentuckyKen Well-Known Member

    DVoran, until M.M. parses all this out, I’d say that what you described is normal and is the same thing I am experienceing. For me, the white also does not turn back to blue but ICE shuts off and EV lights up with car driving like it’s in normal EV mode. Blue returns upon restart at destination later.

    I just noticed that the manual states that after a System Check the power meter will return to blue. So is this a indication that it’s not a SC and could be the assumed fully charged battery not allowed to accept any regen thing?
    Or as M.M mentioned, could just be another software bug.
     
  4. DVoran

    DVoran Member

    After reading all the replies and looking through the manual I am leaning towards this being normal behavior of the engine that needs to be run periodically, not unlike the Volt and some other PHEVs.
     
  5. dstrauss

    dstrauss Well-Known Member

    None of the choices match my experience (just this morning) - full charge, flat terrain, and 68 degrees (very moderate for West Texas this morning). i think it was routine "it hasn't run in many weeks so let's make sure the engine is still lubed."
     
  6. KentuckyKen

    KentuckyKen Well-Known Member

    Dstrauss, was your trip long enough to have the ICE turn off and if so did the power band turn back to blue without turning off car? And was the regen (pedal or paddle) very limited compared to normal when the ICE came on?
    Just trying to puzzle this out.
     
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  8. M.M.

    M.M. Active Member

    To me this sounds exactly like the sort of motor exercise routine I'd expect--about once a month, runs for about 10 minutes, starts as soon as you start driving the car.

    The Volt does the exact same thing, with the difference being it very clearly tells you what it's doing (and even gives you a % countdown) so you don't get confused. It even lets you put it off in case you know you'll only be driving for a mile or two. Much better design, honestly.

    Question: Are all your miles EV, or have you run the ICE apart from those three times over the past 3 months? Wondering, if this is engine maintenance, whether it counts normal runs like the Volt or if it does it regardless.

    That said, the behavior you're describing (which apart from the lack of user notification seems quite normal) does not appear to match what some others are seeing, so it does seem likely there is more than one thing at play here.

    For example, while I haven't had the ICE start in that sort of apparent system exercise, nor while driving, I have three times had the car start the ICE and run it for about 5 minutes after sitting in park for 5 minutes, even though the battery was around half full, and it hasn't done it other times I've been looking at the sunset or messing with the setup screens.
     
  9. dstrauss

    dstrauss Well-Known Member

    No - trip was only 2 miles before I parked at a store and when came back it was fully blue with no ICE interference. Guess I'm just not a very good test subject.
     
  10. HariN

    HariN New Member

    One more data point
    This is first time it happened to me.
    Mileage 3000miles
    Battery charged full-61mile
    Temperature 60F
    Happened with in mile of drive from home
    Sports mode with full regen
    Noticed engine sound loud at stop sign
    The indicator show ICE powering wheels even when not accelerating
    I turned off power and restarted with Econ mode
    Initially battery powered but soon ICE turned on and powering wheels, it did for 8 miles trip, I dropped my kid at school. Then turned of power and started again, now it starts behaving normal. It look like it’s running ~ ICE for 10 mile for maintenance reason. Generally I rarely use ICE, unless the EV range falls below 10mile.
    I have used ICE for 5-6 mile on highway last week.



    Sent from my iPhone using Inside EVs
     
  11. Kestrel

    Kestrel Member

    Here's what happened this morning. Left my garage with a full charge (45.3 mi EV range shown) and outside temp 58F. Got through both stop signs and started down the big hill. Gauge turned to white, EV light went off, ICE came on. Continued down the big hill, went up a bigger hill to the freeway, and started driving on the freeway. ICE stayed on through about 4.5 freeway miles, then suddenly turned off. Gauge went back to blue and EV light came on. All bars on the EV gauge were still showing full. It stayed in EV for the rest of my commute (20 miles total).
     
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  13. KentuckyKen

    KentuckyKen Well-Known Member

    Thanks, Kestrel. I’m trying to find the common denominator in all this. It’s not crystal clear yet, but every little bit of helps.
    That sounds like the full charge hits a downhill, regen not allowed, and ICE called for braking/battery protection somehow. Then runs until engine warmed up even though ICE no longer needed. The interesting part is that it went back to EV and blue gauge which is what you would hope it would do. Others have reported that theirs would not. Mine was like yours except I didn’t get the blue back, but did get EV back.
     
    Last edited: May 18, 2018
    Kestrel likes this.
  14. M.M.

    M.M. Active Member

    I think one mistake might be looking for a common denominator--I suspect there's more than one thing happening.

    For example, what Kestrel describes (thank you for the report!) sure sounds like the car is using the ICE for braking on a full battery. That it didn't turn off for a while makes sense; the manual specifies that once the ICE starts (for whatever reason) it won't shut off until it has warmed up, which I'd noticed when it kicks in for aggressive acceleration and takes maybe 10 minutes.

    What dstrauss describes, in contrast, seems to make perfectly good sense as an exercise routine.

    And neither of those fits your hard-braking-starts-ICE experience, which seems more like a controls bug. Your experience, likewise, doesn't fit my own experience with the ICE starting after about 5-10 minutes sitting in park.

    So it's quite likely there is some combination here of "exercise routine without sufficient driver notification", "ICE is being used for braking on a full battery", and one or more unexpected or outright buggy bits of logic related either one of those or entirely different situations.

    Incidentally, I had the ICE start up while sitting quietly in park for a while again, and was paying closer attention this time. After some driving I had previously sat in park for probably 5-10 minutes without any ICE action, then drove another ~10 EV miles and stopped again for another 10 minutes or so. After about 5 minutes the ICE started, ran for probably 5 minutes or so, then turned off, but the power gauge was still showing entirely white. When I started driving shortly after the ICE did not start up while I drove around the parking lot. I accelerated onto the highway and still could not hear the ICE at all, although it's possible it started running at low enough speed I couldn't hear it over the wheel noise at some point, then within a minute of getting on the highway the gauge returned to blue. The temperature was mild so the climate control wasn't doing much through any of this, so none of it really makes much sense as far as control logic.
     
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  15. KentuckyKen

    KentuckyKen Well-Known Member

    M.M., my bad; I should have said common denominators since there are obviously several scenarios where ICE is being called for. I was just hoping your poll and software/engineering knowledge could help sort out all these experiences into some kind of logical groupings.
    If we assume we all have the same software (all same or all bugged the same) then in the absence of sensor tolerances/malfunctions shouldn’t we expect our experiences to group into some kinds of patterns? And then from these hopefully deduce what the algorithm is for ICE operations outside of HV mode? I’m counting on you, because this is really bugging me!

    Like you and I having the blue P/C gauge not come back and Kestrel did. Or your parking lot experience. Or some getting the “angry bees” and some not. Grrrr, I thought computers were supposed to be consistent!
     
  16. M.M.

    M.M. Active Member

    Got it, I probably should have been able to figure it out from context.

    So I’ve spent some time experimenting and have managed to reliably replicate one of the regen-braking ICE startup scenarios, although the exact conditions are surprisingly specific.

    From my house, there is about a 4-block stretch of gradual downhill slope with two flat areas, then a couple of stop signs within 30 feet of each other (it’s an odd intersection), and another block or so of steep downhill with a stop sign at the bottom. So basically flat block, gradual downhill block, flat block, slightly steeper downhill block, stop sign, steep downhill block, stop sign.

    If I drive normally through there on a full battery, nothing happens. I’ve done it dozens of times without an ICE start. If I drive very carefully with efficiency in mind, still nothing happens. If I slam on the brakes at or between any of the stop signs in there, nothing happens (I was trying to replicate your hard-stop ICE start possibility). But if I’m sort of hypermiling and put the car in neutral for the first flat stretch, then in gear and regen, then in neutral again, then regen again, the ICE will start. I haven’t done enough experiments to say definitively, but it looks like one shift into neutral isn’t sufficient--it seems to take two. It isn’t just a matter of the amount of regen going into the battery, otherwise it would start on the steep downhill nearly every time, since there’s definitely more energy available on that slope than is being consumed moving away from the stop sign.

    I’m just guessing randomly at this point, but something about maybe the gear change causing the regen subroutine to put a spike of energy into the battery, which triggers some sort of over voltage protection, could be a culprit. That would actually align with why a hard brake might also cause it to happen, although I couldn’t replicate that myself.

    One possible factor that I haven’t tested definitively is that when plugged in my car sometimes shows 99% on the app when full, and sometimes shows 100%. Which seems completely random and I had chalked it up to variables in the calculation, but it’s possible that the car is making decisions based on this slight difference in calculation, which could cause it to be more sensitive to regen braking at 100% than at 99% (although it’s weird that they didn’t leave more buffer than that before it starts getting worried about overcharge; I think the volt has maybe 1kWh of overage before it goes into its hill-braking-full-battery routine).

    Other things I noticed:

    Once started, the ICE will run for about 5 minutes (either until it’s warmed up, as expected, or possibly there’s an ICE braking timeout). I also confirmed the bug that in this particular state the car doesn’t turn off the white dashed line on the energy gauge even when it’s back in EV mode. I drove around for a while to make sure, the display is definitely stuck in the wrong state.

    When the ICE is running like this, if you put it in 4 regen chevrons the indicator will flash and it will go down to 3 chevrons. This seems to confirm that it’s in a reduced-regen mode; perhaps (again, pure speculation) three chevrons worth is as much as it’s capable of dumping with the ICE. This happened even after climbing a couple steep hills, so is tied to the mode, not battery state of charge.

    In this mode, you can hear the load on the ICE change between when you’re coasting or braking and when your foot is on the accelerator, although in either mode the RPM never goes above idle. I would guess this is because when you’re coasting, it's disconnecting the ICE’s generator entirely, so it isn’t trying to charge an already-charged battery, but once you put a load on the bus it reconnects it so that the idle energy goes to the wheels. That’s roughly what it sounds like although it’s possible I’m interpreting sounds incorrectly.

    Also of interest in this mode, at exactly 14mph the car turns something either on or off related to regeneration. If I start regenerating at, say, 18mph (3 chevrons, the max in this state), just before the speedometer shows 13mph there is an audible click from the engine compartment and a slight but noticeable reduction in the regenerative braking force. I have no idea what this is; it sounds a bit like a relay clicking (maybe the ICE’s generator being mechanically disconnected at speeds where friction braking should be taking over?), but could be other things.

    Oddly on that 14mph click, there is no hysteresis built into whatever is controlling it; if you’re on just the right downhill slope that the car will be hovering around 14.0mph depending on whether whatever the click is controlling is increasing regen or not, it will click on and off quite quickly.

    Also, it’s hard to tell for certain, but it appears that reduced regenerative braking is visible on the energy indicator. While braking at some stop signs near my house, the amount the line will go below 0 seems to change depending on how full the battery is. Maybe somebody else who has more consistent hills near home can eyeball this and chime in.

    Other unrelated thoughts:

    It was noted elsewhere here that the mechanical transmission for highway driving is not a CVT, it’s a fixed-ratio gearbox. That being so, it seems quite unlikely that the car is capable of using the mechanical transmission for engine braking since the gearbox is designed for efficient, relatively-low-RPM operation at highway speeds. That would narrow the ICE regen down to the seemingly-nuts version of putting a load on the ICE by dumping power into the generator.

    Summarizing, we appear to have one state of engine exercise that happens without any user indication after around a month without running the ICE (which is expected although should have had a user indication), a second ICE run state that can kick in shortly after starting driving on a gradual downhill on a full battery, but only in certain situations (probably related to a full-battery-long-hill-ICE braking state, but being started erratically by a bug), and some additional state related to sitting in park for several minutes.
    They are, but with a complex state machine that has a lot of variables and unpredictable analog inputs it can be hard to suss out what exact condition or set of conditions caused something to happen.
     
    Last edited: May 20, 2018
  17. KentuckyKen

    KentuckyKen Well-Known Member

    Wow M.M, even the old East German Olympic judges would have to give that observation/explanation a 9.9! That all makes a lot of sense.

    I’ll throw out the following for your always logical analysis:
    -Could some of the people indicating that their ICE has never come on unexpectedly have just missed it coming on? I know for a fact that it can be very quiet and System Checks muSt be occurring for them at some frequency.
    -Could some of the unexpected ICE w angry bees be due to entering HV Charge by mistake? As in holding down button too long and in rush to get it to stop not noticing the charge indication below the HV symbol on the battery gauge. It is off to the left side and not entirely obvious.
    These two would help explain the seemingly different experiences by taking into account the human factor.

    -Here is an excerpt from the manual that lets us rule out some conditions for unexpected ICE and note the last part where it talks about the blue line coming back after a System Check. So if blue doesn’t return then does that mean it wasn’t a System Check? Or may be the bug you hypothesized? I’m pretty sure the blue has come back for me except for one time I had to restart car to get it back. Could that be System Check vs battery full/no regen ICE activation? More data will tell I guess.

    “Auto Engine Stop/Start
    The car will select the appropriate source of power depending on the drive mode you select.As a result, the engine will automatically start or stop as needed to either charge the battery or provide supplemental power.Under certain circumstances, the engine may turn on or, if it is already on, it may not turn off.
    ●You are going uphill or accelerating aggressively.
    ●The climate control system is in heavy use.
    ●The Ambient temperature is too hot or too cold.
    ●The High Voltage Battery state of charge is very low.
    ●The vehicle is running a system check.
    System Check
    When the engine initially starts (between the time the POWER button is turned on and turned off), the vehicle conducts a system check.
    ●While the check is being conducted, the engine may periodically turn on and off. This, however, is normal.
    ●The curved blue line in the POWER/CHARGE Gauge will not appear during the system check (EV indicator may still turn on).
    ●Once the engine starts, it will continue to run until the system reaches operating temperature.The curved blue line in the POWER/CHARGE Gauge will reappear once the system check is complete. “

    -Here’s an interesting comment from the manual on when regen may be limited. It mentions what we already see with a full battery (plus battery temp) but adds “hybrid system protection”. Wonder what that means?
    P391
    “In the following situations, the stage may not change and the stage number will blink even if you pull back the selector. The deceleration stage may decrease or cancel automatically:
    •The high voltage battery is fully charged or its temperature is too cold or too hot.
    •The speed of the vehicle is beyond the deceleration range with SPORT mode off.
    •Hybrid system protection is needed.
    •The paddle selector is operated while your vehicle is stopped automatically by ACC with LSF.
    If either paddle selector is operated, ACC with LSF will cancel automatically.”

    Isn’t reverse engineering fun!
     
    Last edited: May 20, 2018
  18. KentuckyKen

    KentuckyKen Well-Known Member

    M.M., one more data point:
    Rich Shaffer in thread New car, whiring sound when accelerating from low speed reported he got a msg that said Engine started for oil circulation. This was at 2,500m, 5 months, and 3.5 gal used. So the question is, was that a separate event from the System Check? Not mentioned in the manual that I can find.
     
  19. M.M.

    M.M. Active Member

    That is of course a possibility. The ICE is quiet enough at idle that even I likely wouldn't notice driving at higher speeds unless I noticed that the power gauge had turned white or was intentionally listening for it.

    It's pretty easy to accidentally do this (since the button seems to require a "slightly long" press to kick in to HV mode, I had to mess with it a bit myself), but I'm going with possible but unlikely. As part of my goofing around experimenting today, I had the battery completely empty and was near the bottom of a very steep hill, so I put it into HV Charge and drove a mile or two up it, halfway in Eco and the rest in Sport. The engine was never particularly loud at any point; it would run slightly faster at low energy use times, but otherwise wasn't noisy at all. I suspect it eventually would have increased RPM when the battery buffer ran out, but HV Charge certainly did not agressively ramp up ICE compared to regular HV mode.

    You might have already mentioned this, but just a confirmation that the "stuck white after regen braking ICE start" is a bug, after a few minutes (when the engine had already shut off on its own), I turned HV mode on then immediately back off, and the energy gauge turned blue again. I wasn't even in HV mode long enough for the ICE to start. That obviously resets whatever is stuck and gets it back into the mode it's supposed to be in.
     
  20. KentuckyKen

    KentuckyKen Well-Known Member

    Thanks M.M., that’s one more piece of the puzzle.

    Interesting... 0 charge, HV Charge Mode and steep uphill. Until now I would have bet the ranch that those 3 together would guarantee the angry bees show up. So I wonder, are the angry bees more car specific or condition specific? Which leads me to ask:

    Has your Clarity ever had the angry bees/high revs at any time?

    And if you can, when convenient, could you do the same test but in plain HV Mode?
     
  21. M.M.

    M.M. Active Member

    I've never personally heard high revs on the ICE, but I also have barely used it--maybe 50 miles total, nearly all on relatively flat highway--so that's a weak data point.

    The hill is right next to home, so the next time the battery is empty when I get home (which admittedly might be a while unless I'm intentionally emptying it for a test) I'll try driving up in plain HV mode. If I have more time I might also go farther up (it's a 7-mile, 2000' windy climb to the top) to see what happens when the battery is more stressed.
     
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  22. bobcubsfan

    bobcubsfan Active Member

    ICE is not quiet. It is very noticeable. Came on again this morning. Twice. At stop signs. Battery fully charged. Sport Mode, reg paddles at max.
     
  23. HariN

    HariN New Member

    It’s happening past several days in the morning at least in first 10 miles. It’s happened in Econ and sports mode, power band turns white all the way, engine sounds very noticeable. It goes away after 10 miles or so,, has anyone contacted Honda. I haven’t noticed until recently this behavior


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