The elusive gear icon

Discussion in 'Clarity' started by MNSteve, Dec 18, 2018.

  1. MNSteve

    MNSteve Well-Known Member

    Thank you for posting that actual data. It makes me feel that perhaps I'm not nuts. I just don't understand it. I can drive the same road at the same speed with the same conditions with wildly different behavior of the gear icon. Obviously there is an input parameter we cannot see, unless the Honda engineers decided to introduce a random number generator just to thwart those of us trying to reverse-engineer their work.
    insightman likes this.
  2. MPower

    MPower Well-Known Member

    It's run by leprechauns.
    Thomas Mitchell likes this.
  3. MNSteve

    MNSteve Well-Known Member

    MPower likes this.
  4. Clarity_Newbie

    Clarity_Newbie Active Member

    @Ray B @MNSteve The engine clutch engagement is predictable for the Clarity I drive. I have not noticed any lapses in engagement when within speed parameters. The data posted previously is holding true relative to RPMs and clutch engagement...(ie) 1600+- 5% @45 mph to engage AND stay engaged is spot on for the Clarity I drive. Other ratios holding true as well...realizing more data is needed of course.

    @Ray B Your comment on the SoC gauge corresponds to my findings as of the SoC gauge is tied loosely to ~%5 per bar...the correlation is much tighter 75% and downward.
    Last edited: Feb 11, 2019
  5. SkipperT

    SkipperT Member

    C_N - quick question, did you have the updates applied to your car? I've read some conflicting info from people regarding their car operating differently relative to when the Gear Icon appears indicating clutch engagement to the wheels from the engine.
  6. Clarity_Newbie

    Clarity_Newbie Active Member


    I had the updates applied in late October. I never really had an issue before the updates...or one that I was aware of anyway. Since the updates, engine clutch engagement has functioned very well...determined through OBDll data and visual observation.

    For the Clarity I drive at least, engine clutch engagement is predictable even to the point of RPM's at initial engagement for a given speed.
  7. ClarityBill

    ClarityBill Active Member

    I am guessing the SOC is critical to gear mode operation. I am having much more gear mode with SOC around 25% of miles on GOM. It seems the generator is able to charge and discharge battery to keep ICE in gear mode with lower SOC.

    HV Charge only goes to 57%, and this seems to be an upper range for effective gear mode. MNSteve mentioned trip out and back had 29 miles and 20 miles, and called that no difference on SOC: That is 20% (of 47 mile range) difference, and I think he was on each side of the 'cutoff'. The cutoff is not an absolute line, but lower seems better.

    I drive the same highway every week, and I was frustrated with the noise of the engine over 3K rpm. Running SOC at a lower level has made me very happy.

    I had posted some OBD data on the 'Angry Bees' thread. I was just trying to pull out appropriate graphs, but I gotta get back to work.
    Last edited: Feb 12, 2019
  8. MPower

    MPower Well-Known Member

    Not my experience. On my 1500 mile trip, I was running the car with +-75% SOC, at 67/68 mph on relatively flat terrain and the tiny gear icon showed up continuously except when I needed more power for passing or hills.
  9. ClarityBill

    ClarityBill Active Member

  10. ClarityBill

    ClarityBill Active Member

    What is your operational plan? Do you switch to HV mode when you start your drive, or do you wait a little while?
  11. Clarity_Newbie

    Clarity_Newbie Active Member


    I agree 100% with @MPower assessment. On the two Clarity's I have access to...engine clutch engagement works very well independent of SoC. As alluded to in other posts...engine clutch engagement is designed to maintain speed with very little tolerance for increased throttle.

    Using several OBDll devices, I am breaking down engine clutch engagement to the RPM level based on 5 mph increments...45 to 65 mph. There is a direct correlation to RPM's vs initial clutch engagement...and a corresponding display of de-linking along with a request for more power. Example of this is preliminary data can be found in post number 64 in this thread.

    You mentioned high revs...this very well may be one reason the engine clutch engagement is more sporadic than you would like. If the OBDll data is correct which indicates a strong correlation to RPMs and initial clutch engagement...there in lies one possible answer.

    It has been suggested by others that perhaps the engine gear icon is slow to appear/disappear/sensor relay issues etc. I have not observed this with data but perhaps others can enlighten you.

    And you said it all in your response..."I drive the same highway every week, and I was frustrated with the noise of the engine over 3K rpm. Running SOC at a lower level has made me very happy". consumer who purchases a 30-35k car should be worried about getting in a Clarity and having to ensure the "SoC is this number" or "remembering to put it in HV mode when 10 miles is left in EV mode" to avoid angry bees or having to listen to "high revs" and turn radio up to drown it out. Ridiculous for Honda to expect this of folks.

    These "git-r-done" every day solutions are understandable to tolerate the ride. I get that. At the end of the day though...these "solutions" do nothing more than mask a problem which Honda should own up to...period.

    The link below will take you to a post I shared a month ago about preliminary RPM data. I would love to know others experience with RPM ranges. IS the Clarity I drive "normal" or "Abby Normal"??? Dunno but would love to.

    If you have RPM data to share...I'd love to see it. More data is definitely needed since every owner should know what constitutes "high revs" if nothing else.

    Good luck!
    Last edited: Feb 12, 2019
  12. ClarityBill

    ClarityBill Active Member

    I completely agree that clutch engagement only happens when RPM's are 36.5 times the speed, without regard to SOC.

    My goal is to keep ICE rpm's in range for a wider variety of driving conditions.

    I believe the drive system has a greater flexibility of power output with the SOC below 50%. It appears the ICE is able to stay at gear mode rpm's while the battery input/output flexes to match varying drive conditions (uphill, downhill, wind, etc.) Obviously, the drive system has no regen flexibility when the battery is 100%, and no boost flexibility when the battery is 0%.

    I think it would be useful to know what MPower's (and others) operating method is, and the satisfaction level with the operation. Do you switch to HV mode as soon as you get in the car, when you remember, or when you get to the highway? It is the beta testers that develop the options the manufacturers add to systems. If there is a 'best' operating policy, Honda may add a 'Highway mode' that matches that policy. They already have a mode that gets SOC to 57%.

    My opinion on rpm's: Highway driving with rpm's around 4K, the cabin noise was loud (approaching 80 dBa): I considered that unacceptable. The gear mode at 73 mph was about 2650 rpm: and that seems 'nice'.
  13. MPower

    MPower Well-Known Member

    What i did on my 1500 mile (total 3000 mile trip VT to KS and back), was to drive out to the highway, a couple of miles on EV and then change to HV and let the car do whatever it wanted. The battery charge stayed almost full, but depleted somewhat going over the mountains. The first day was the most challenging terrain, but I was able to charge that night at my cousin's. It was in the 30s, raining/snowing, and I had the heater and lights on.

    As I got closer to my cousin's, I put It in EV so that it the battery would be nearly depleted by the time i arrived.

    For the next two days, I ran in HV all the time (that I could remember to turn it on which was almost always) because I was not going to be able to charge again. It maintained the charge above 50% most of the way to my daughter's. At no time, did I hear any excessive ICE noise. (Bear in mind that my previous ride was a 2012 Prius Plugin that roared any time you accelerated uphill.)

    I don't have any gizmos to measure the revs, and was not able to watch for the little gear icon most of the time because I needed Google maps up for directions, but when Google told me to drive straight for 157 miles, I was able to turn on the info screen and watch for the gear icon. I-70 there was straight as a die and flat as a pancake. (The car kept saying "STEERING REQUIRED" when no steering was required.) I was cruising along in ACC set at about 67-68 mph and the car was running the whole show and I saw a lot of the gear icon. Only passing or accelerating up hill caused it to go away.

    Sorry I don't have hard data for you. I can tell you pretty much how much gas I used and how many miles I went and how many battery fill ups I had but none of my data correlates very well. Since I didn't fill up when I left home.
  14. Clarity_Newbie

    Clarity_Newbie Active Member


    Very good. Sounds like you've got a handle on the Clarity you drive.

    For reference, my operating method is basically drive the car. For a typical month the Clarity I drive runs 70%-30% split EV to ICE. I rarely use ECON or Sport mode. I engage HV in the garage only if I intend to run the heat. I engage HV prior to entering the interstate if I am going to be on it more than, say, 5 miles. I do make it a habit to run 2-3 days a month strictly in HV mode to exercise the ICE as I believe it needs to run more than a few minutes a month.

    I ask for RPM data simply for comparison sake...I have no idea if the Clarity I drive*** is at the top of the bell shaped curve or significantly to the right or left. More data needed. The Clarity I drive does not exhibit any of the symptoms you describe. If you looked at my RPM data, ~97% of the time RPM's for the Clarity I drive are below 2600. I have never heard what I consider to be egregious high revs. The one and only time it has breached 3600 was for 42 seconds at the top of a 5 mile, 6% incline while maintaining 55 mph...with RPM/revs much like any other 4 cyl car I have driven up that mountain. Once I crested the mountain...revs returned to "normal"...whatever that is.

    One question...if you agree ~1600 RPM the engine clutch engages at 45 mph..what happens if a car such as yours is in "high rev" mode? The data indicates that would keep the clutch from engaging even if at 45 least until revs calm down. Does the clutch indeed engage when revs calm down? I am asking this because I don't know.

    I am currently collecting data via the OBDll device for the entire month of February. I will share data in early March. I put the preliminary data I collected out for everyone to see and digest in % format. I will do the same for the February data. I'd love to see the data point chart(s) you referenced since quality data from as many Clarity's as possible is needed to form a truly representative curve.

    My goal remains to figure out what are the "norms" for the Clarity RPMs and, more importantly, try to figure out correlations for those with power loss.

    Continued good luck.

    ***I have access to a second Clarity a friend drives and the data from her car using the same OBDll exhibits very similar trends.
  15. ClarityBill

    ClarityBill Active Member

    I am posting two PDF's drive data graphs that I posted at another thread on this site.

    'Bee Control' is the day I 'confirmed' that SOC made a difference on the ICE rpm. I wore earplugs for the first half of the Interstate driving: RPM's were often over 4K, and spent much of the time over 3K. Then I went into EV mode and got the SOC down. Continuing on the same Interstate, the ICE went into gear drive for much of the trip, and only exceeded 4K for a brief time (an extended incline).

    'Bee Control 2' is driving the first half of that Interstate drive with a lower SOC, and much higher percentage of gear mode. I drove the same section of Interstate as the loud drive in the Bee Control graph. I started in EV mode, until the SOC was down, then continued on the same section that was very loud with a higher SOC, but it was gear mode and quiet this time.

    Graph notes: RPM is ICE rpm divided by 100 to keep the scale the same. Temp is the ambient temperature F. Battery is the traction battery SOC. Speed is mph. The x-axis is time in minutes.

    I am using a Blue Driver OBDII system. Really wish it would work through CarPlay, it would make a great display!

    Attached Files:

  16. ClarityBill

    ClarityBill Active Member

    The car is in gear mode on the flat sections on the rpm graph. They are about 36.5 times the speed.
  17. Clarity_Newbie

    Clarity_Newbie Active Member


    Thanks for providing the graphs and notes.
  18. David Towle

    David Towle Active Member

    Many thanks for this data, concurs with my observations. To me it is near-proof that the car's charging software is not well thought out. I can come up with no possible reason why it would strive to charge the battery more when the battery is at a higher state of charge. It doesn't make the car unusable or anything, just requires more manual intervention to bring the charge down before invoking HV mode.
  19. ClarityBill

    ClarityBill Active Member

    There is another file that may have an impact. This was also published in another thread, but it seems appropriate for this discussion. This was reported to be similar to our battery...

    The graph on the right shows the low temperature (-10C +14F) operation of the battery. It shows significantly less regen capability above 47% SOC, and significantly less assist capability below 47% SOC. This would tend to be the sweet spot in battery power operation. This would mean you want to be running HV with 47% SOC at 14F. The sweet spot may be lower at lower temperatures.

    The graph on the left shows operation at more pleasant temperature (25C 77F). The gear mode may be more available as the temperatures warm up.

    I'm not sure what temperatures or Interstates are like in Japan, but their engineers might appreciate our recommendations.

    It would be nice to have a highway button that would run EV until the SOC has dropped to the temperature appropriate number and then switch to HV. It would also be nice to be able to program in a total trip distance, so the system would switch back to EV when remaining distance is EV range. Without these buttons, it looks like we can do it manually.
    Li-ion EV perf4.png
  20. insightman

    insightman Well-Known Member

    I don't experience any relationship between SoC and Engine Drive mode. I can get the gear icon to come on at any SoC other than no SoC.

    Here's a new extreme, unfounded, tongue-in-cheek conspiracy theory: Every Clarity PHEV customer is a beta-tester and each car was produced with its own, unique software build. Honda is wirelessly gathering data from our cars (we know this to be true). This data helps to determine which software build works best. Because my Clarity hasn't exhibited any problems other than the HV-range overstatement, I feel I was lucky to get one of the good software builds. The question is: Will Honda ever figure out which software build is the best and make it available to all Clarity PHEV customers?

    Disclaimer: I made up this wild theory based on no facts whatsoever in an effort to explain the amazingly wide diversity of experiences reported on this forum. Despite the miracle of mass-production, no two cars are alike--even before cars had software. I worked on the line at "Ford's" 50 years ago and saw what can happen to individual cars in the manufacturing process to make them different.
    David Towle likes this.

Share This Page