The elusive gear icon

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

  1. MNSteve

    MNSteve Well-Known Member

    I love it!
  2. Clarity_Newbie

    Clarity_Newbie Active Member

    Therein lies the problem...Clarity performance issues are seemingly all over the map. As mentioned above, the Clarity I drive shows absolutely no correlation to SoC/ambient temps etc for engine clutch engagement nor RPMs. I can just about make the clutch engagement/disengagement occur at will...its that predictable.

    This presents one of the challenges to the collective efforts underway to try and corral all these widely ranging variables into some sort of logical sense.

    The one that causes me the most concern is the loss of power. The unknown is how many Clarity's may eventually exhibit such behavior. There is always hope Honda worldwide is working on a software update to fix any/all power train issues...but till then...efforts continue to isolate power loss cause via data.

    As to your conspiracy theories...its often been said beta production run x gets OS vA, production run y gets OS vB, production run z gets OS vC...tongue in cheek of course...or is it? lol
  3. ClarityBill

    ClarityBill Active Member


    What do you do to get the clutch to engage (at will)?

    Does it engage when the RPM's are not close to 36.5 x speed?

    I would like to try the same procedure on my Clarity.
  4. Richard_arch74

    Richard_arch74 Active Member

    I don't think your WACT is off base. Several of us have posted that we feel that we are beta testing these cars.
    How do you explain the lack of advertising the Clarity? I have seen exactly one commercial on TV (and that had the car in the back ground). How many have we seen on the civic? Plenty. IMO they are testing it and accumulating beta test information before they sell too many units. They feel that, due to risk management, they need to get real world data before they completely plunge in.

    Sent from my SM-G955U using Inside EVs mobile app
  5. David Towle

    David Towle Active Member

    The company I worked for (ABB) sold about 50 gas turbine powerplants of an all new design in the late 1990's before they had the first one operational, each at a cost of say about a half billion. They were sold with performance guarantees that it turned out the plants could not meet as-built. As a result there were total losses between ABB and successor company Alstom of about $5 billion, which would have bankrupted both companies if not for a French government bailout and lots of financial shenanigans.

    So maybe Honda is wise with the Clarity. I have also thought they intentionally did not make it an SUV to reduce sales potential.
  6. Clarity_Newbie

    Clarity_Newbie Active Member


    Data I have posted and mentioned in several posts draws a strong correlation to RPM and initial engine clutch engagement while in HV mode.

    For the Clarity I drive...for example...when entering a 4-lane highway with a posted speed limit of 45mph...after acceleration to 45 I decrease throttle to "maintain speed"...the engine clutch engages ~1600 clock work. It will stay engaged as long as I don't request more power/RPMs...of say +- 5% of ~1600. If I accelerate/decelerate significantly the clutch disengages...predictably.

    Preliminary data suggests I can do the same at 50-55-60-65 mph albeit at higher RPM's. Much more data to be collected though. We have collected data from two other Clarity's and both exhibit the same traits as the one I drive.

    You mentioned the Clarity you drive does the high rev thing*** on its question to you remains the same:

    "...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 at 45 mph when revs calm down? I am asking this because I don't know."

    For perspective, I do live in the mountains. My typical driving experience is flat to up/down to steep. I learned in two days of ownership I will lose 2 miles EV range going ~1/2 mile to my house. And I routinely experience the ICE running when departing in the am if at full EV range. Kool...all part of the experience.

    I usually end a post like this with one caveat...Is the Clarity I drive "normal or abby normal". Dunno. The folks who say the Clarity functions based on SoC, ambient temps etc may be 100% correct and their car is "normal" making mine an outlier. Dunno. Trying to get data from several Clarity's with high rev/questionable clutch engagement/power loss issues for comparison.

    ***the Clarity I drive does not exhibit excessive high revs described by you and others...hence no experience/data to draw any assumptions from. More data needed. Knock on wood...
  7. David Towle

    David Towle Active Member

    So you don't do anything special. Some of the time mine will do that on partial charge, but not on full charge. When mine is engaged, and I'm going up a long hill, it always disengages after a little under a mile of uphill, I assume to start recharging the battery. Since you live in hills does yours disengage like that also?
  8. Clarity_Newbie

    Clarity_Newbie Active Member

    David Towle

    Nothing special. All my data logging is done routine, day to day, whatever I'm doing driving.

    Yes...significant inclines will cause the engine clutch to disengage. My data indicates, and as others have said, this is normal since the purpose of the engine clutch mode is to assist with "maintaining speed" nothing more. The engine clutch will also disengage when on the down hill side especially when ACC mode is on since engine braking slows RPM's to "maintain speed".

    I keep thinking perhaps I'll pull out the GIS tools and cipher on percent slope on the main roads where I know from experience the engine clutch disengages very predictably on the uphill climb. If I was forced to make a SWAG...less than 2% slope engine clutch stays engaged...3% plus disengagement likely. Again...just a SWAG.

    There are plenty of steep back roads that the engine clutch never comes on regardless of much power needed to climb the mountain never mind maintain it. lol

    FYI...So far, SoC has not seemed to play into the engine clutch engagement/disengagement. When I conducted one of the EV 0/SoC 10% tests...I took pictures of the dash, energy display and the ScanGauge ll at 45/55/60 mph...all pics for the specified mph were taken within 15 seconds of one another. If you go to the link below...the pics for 56 mph and 45 mph clearly show the gear icon engaged at 0 EV (aka) 10% SoC.

    When I took the pics, I had no idea if the gear icon was on or off...too busy driving and taking a quick picture when it was safe. I only noticed the parameters after grouping pics and then posting for all to see. Some folks say they don't get the gear icon at SoC 10%/EV 0...don't know what to say...proof is in the pics.

    If you look at the pics...perhaps you (or anyone else for that matter) can let me know how the Clarity drives under similar SoC 10%/EV 0 conditions. Curious minds want to know.

    Good luck.
  9. ClarityBill

    ClarityBill Active Member


    Sounds like your Clarity acts like mine - Looks like we have a failure to communicate.

    My gear shows up when I am drawing about 5/16 power on the dash. If the battery can make up the difference (+ or -), the gear mode will stay on while I deviate from 5/16 power: The flexibility to stay in gear mode depends on SOC. Yes, gear mode is possible at any SOC, but more frequent / flexible at 47% with varying drive conditions.

    Looks like your 0 EV pictures were at low drive load, so the ICE was able to push the car and charge the battery.

    My 'high-rev' is when the generator is charging the battery and pushing the car harder.

    My Clarity will go back into gear mode when the 'revs calm down'. It seems like the SOC has to get back to target range (close to HV starting point), and the ICE does not have to charge the battery. The OBDII graphs I posted both showed high RPM's followed by gear mode (flat RPM's).

    I drove 'my section of Interstate' again today, and the gear stayed on most of the time.
  10. insightman

    insightman Well-Known Member

    Of course, the revs have no choice but to calm down when the Clarity PHEV is in Engine Drive mode because that's the only time when the revs are locked by the clutch and the single-speed gearbox to the car's road speed.
  11. Clarity_Newbie

    Clarity_Newbie Active Member


    Very good. Sounds like you have a great handle on your DD.

    I took a minute to prepare a graph from a log file which was generated during one of the HV mode only tests I have conducted. My only selection criteria was a file with at least 2500 data points or greater...this was the third file I opened. No cherry picking of data...random choice.

    One answer you provided is your Clarity will not engage during high rev events...which we totally suspected...until revs calm down to the allow for clutch engagement. This inherently means clutch engagement may be more sporadic for the Clarity you drive versus a Clarity which does not exhibit a case of the "high revs". Just saying

    My thought is suggests a correlation between ~1600 RPMs @ 45 mph the engine clutch will engage routinely. If you are going 45 mph but engine is in high rev mode...say 2500 rpms...then clutch will not engage until revs calm down and approaches ~1600.

    Graph info:
    Data points = 3100 @ ~.5 second polling which equals a 25 minute drive. The SoC was ~85% for that day.

    In context of this thread...what stands out to me is the normalcy of the high end of the rpms. As I have stated, the Clarity I drive rarely revs...this .csv data demonstrates RPM consistency on the high end. Its easy to spot the clutch engagement especially at ~60 mph. 1 inch of bottom axis = 5 minutes of time btw, which covers the 25 min drive time.

    One stretch of clutch engagement was ~7 minutes. Perfect straight line data should not be expected...I figure a 5% +- on either side of the engagement RPM due to road variances, throttle pressure etc.

    Again my thoughts are simple...because the Clarity I drive exhibits uniform RPMs on the high side (aka no excessive revs) 97% of the time, I get very predictable engine clutch engagement.

    This is all about trying to found out what is "normal" for this car. The goal remains to figure some commonality for revs and especially for those with power loss.

    I appreciate good banter and all points of view.

    Thanks for your input.

    Attached Files:

  12. ClarityBill

    ClarityBill Active Member


    The end of your drive at 30 - 40 mph would be 'high-rev' in my definition. The RPM's (2K+) are equivalent to synchronous speed at 60 mph, so it is more than 30% over gear drive speed. This is what happens when the battery needs heavy charge during driving. I regularly drive over 70 mph, so 30% over gear speed is loud...

    Your drive at 60 mph had the engine shut off a couple times so the battery was maintaining target charge easily. This was probably not a significant incline. Another way to achieve that is to switch out of HV mode (this resets target charge).

    When you say "the Clarity I drive exhibits uniform RPMs on the high side (aka no excessive revs)"
    Are you saying that your RPM's do not exceed 2500 when you are driving 60 mph going up an extended hill? The graph does show a couple times that look over 3K. There is a reason to be that high, does that mean they are not considered excessive? If you had accelerated over 70 mph these may have gone over 4K, and you would get to be in the "high-rev" world.

    My clarity rarely goes over 3K rpm at less than 60 mph, the battery would have to reach an extreme condition. I guess we could say that shows 'uniform RPM's on the high side'. 3K at 60 mph, and 2K at a stop light are noticeable engine noise, and are conditions I consider high-revs.

    I'm not sure the RPM patterns are so different for our Clarity's, but the difference is our driving conditions. Our drive speeds are obviously different. What is your ambient temperature?

    One condition that I found to give high-revs. Drive EV with a cold ICE. Just before starting a highway on-ramp, shift to HV (sets target charge). The goal is for the battery to be losing charge during the engine warmup time, and results in a large difference between the SOC and the target charge. The engine warmup stays at 1500 rpm, when the warmup time is over, the engine will high-rev. Preferably want to be going over 60 mph at the end of the warmup time. The RPM's come back after charge is restored, and it may even go to gear mode. (This is a procedure I now avoid).
  13. Thomas Mitchell

    Thomas Mitchell Active Member

    Not being flip here, but what does the gear indicator signify and why do folks care so much about it showing or not?

    Sent from my iPhone using Tapatalk
  14. David Towle

    David Towle Active Member

    It signifies the car is in direct drive mode (like a normal car in top gear) rather than using the engine as a generator to power the batteries and the electric motor. It SHOULD be a more efficient mode than the generator mode yielding a few more mpg although that is probably impossible to directly prove. The conditions under which the car decides to switch into this mode seem to vary by many factors yet to be fully understood here.
    Thomas Mitchell likes this.
  15. ClarityBill

    ClarityBill Active Member

    There is also a scenario that is described as "Angry Bees" - generally considered a high-rpm condition. "Gear Mode" would be an opposite of that, and possibly a solution to Angry Bees.

    My driving experienced high rpm's for extended periods of time, and therefore would not go into 'gear mode'. RPM's over 4,000 are very loud in the cabin (80 decibels). Figuring out how to get my Clarity to drop into gear mode would solve an annoyance for me, and possibly others.

    My impression is my set of driving circumstances would have caused the same response in any Clarity. I have a section of Interstate that I decided to wear earplugs, but I have now driven the same section of road "in gear mode" with much lower noise level.

    The important aspects of my loud driving experience would be HV mode, 73 mph (cruise control), 75% SOC, -5F ambient temperature, significant inclines and declines - resulted in rpm's ranging 3500 - 4300. My solution to the issue has been to drive with lower SOC (25%). Ambient temperatures have also warmed up. I really don't want to slow down, or avoid this road: But lower SOC and warmer temperatures have dramatically changed the driving experience every time I take this Interstate. (Gear mode at 73 mph is about 2650 rpm). I make the round trip on this 50-mile section of Interstate at least once a week.
  16. Clarity_Newbie

    Clarity_Newbie Active Member


    Thanks for the input.

    There are different views on how to look at data as that is part of the game. Interpretation is subjective like "angry bees" or what constitutes "high revs".

    If I read your charts correctly, the time is in seconds...if so...the data encompasses 3 minutes. That's all fine and well but hardly enough to draw solid conclusions. The way I see your data...the Clarity you drive is at 3500 to 4500 rpms 1/3 of the time.

    What I have done is attached graph depicting 11.5 hours of RPM data collected during the HV mode only test over a 7 day period. My interpretation of the graph is I stay below 2600 RPMs 97% of the time. The spikes are explained by road conditions. Explanation on graph. Straight raw data.

    As I have stated before...I am in the process of collecting data for the entire month of February and will post results in March.

    As far as I know...a typical 4 cyl car will idle at 800-1000 rpms and routinely go to ~2500 during sustained driving. So it is reasonable to expect the 4 cyl in the Clarity to act the same when ICE is running...sans the EV mode

    I am hoping to find two folks who experience high revs who are willing to provide OBDll data using my device so we (yes we) who own a Clarity will have some sense of what constitutes "high revs". The data should provide a basis for folks to either be comfortable with the revs if within "normal"...or perhaps those unlucky enough to experience routine high revs to seek assistance form Honda USA to explain why their Clarity has RPMs so high its egregious.

    I firmly believe data will also help to isolate the power loss issue...which to me is important. I have always try to lift the whole boat..not just my canoe.

    There is always hope Honda will appear with a software update to solve all the perceived issues and send those with "angry bees" into the land of unicorns and rainbows.

    Thanks again.

    Attached Files:

  17. ClarityBill

    ClarityBill Active Member


    My charts are in minutes, so the 3 minutes you referred to would actually be 3 hours... I tend to examine rpm's with the backdrop of speed, SOC, and ambient temperature.

    I am no longer at 3500-4500 rpm for 1/3 of the time. I have modified my SOC management, and rarely go over 4000, even over 70 mph. I was hoping to pass on this experience, and get reactions.

    I'm not sure how "below 2600 RPMs 97% of the time" is being used by you. It appears you are below 70 mph for 97% of the time, so your rpms will be dramatically lower than mine. What percentage of the time are you over 60 mph?

    I would be curious to know the percentage of time your rpm's are over synchronous speed. by 10%, by 30%, by 50%.

    Looks like your experience on 5 mile grade is what I would expect from my 'high-rev' Clarity, except that I do significant grades 5-10 times a week, at 70+ mph.
  18. ab13

    ab13 Active Member

  19. ClarityBill

    ClarityBill Active Member

    A little off topic, but this seems to be the group examining operation of the drive train:

    If I were a Honda engineer assigned to fix the power loss problem...

    I would dream of having some data for the 60 seconds before and during the power loss:

    Pedal position (Cruise control on or off)
    EV or HV mode
    "Target SOC" if HV mode
    Amperage and voltage to the traction motors
    RPM and torque of the ICE
    Clutch engagement

    Is there a way for an owner to have his Clarity recording this information, in case the power loss occurs? (Obviously Honda could do this, but I am not seeing much progress on this issue...)

    My OBDII only offers Pedal position, SOC, RPM, and Torque. Do other systems offer more information, or other information useful to power loss problem?
    insightman likes this.
  20. leop

    leop Member

    You also want throttle opening (usually angle), spark advance, and intake manifold pressure. I think these are all available from the OBDII dongle with the Torque Plus app.

    Part of the ICE/EV algorithm may include keeping the ICE working in the most efficient mode. For example, rather than just opening the throttle plate to get a bit more torque (perhaps needing to reduce the spark advance to prevent knock) while directly engaged, it may be more efficient to disconnect the ICE and run it at a more efficient higher rpm. Also, the VTEC ICE can switch between two (or more?) valve timing modes (Atkinson and power). The whole system may be optimized for the Fed's fuel economy test rather than real on the road driving. The Clarity's system is complicated and difficult to reverse engineer.

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