Clarity Issues

The last two bars are reserved for hybrid mode.

My Cmax has a much better gauge to watch how this works. I also use a scan gauge II on the cmax that displays usage in percentages and the ev portion is 100-22% and hybrid mode from 22-15%. The Clarity basic display just shows this as 2 bars. I took mine on a 1,000 mile highway trip with about 95% of it in HV mode and never saw the two bars change (even climbing one short but steep hill with three 25mph switchbacks).

I'm beginning to think the biggest issue with the Clarity is its lack of information/feedback that it gives the driver + 1st time PHEV owners. That and a volume knob!

 

fotomoto

Exactly. Agree 100%. My data shows the same trends.

The unknown to me is...those who experience "excessive high revving" when in low SoC...does the Clarity on-board computer function correctly or does the SoC go past the point of "drive assist" and goes into full-on recharge mode?

I ran one test drive in HV charge mode out of curiosity. My data showed a ~30% increase in RPM's at 50 MPH over normal. Not enough data to draw conclusions but it does make sense.

Dunno. Its a classic conundrum

 

Is the Honda hybrid system the only one that has no ability for the ICE to power the car directly below circa 35 MPH? That constraint would go along way to explaining angry bees at lower speeds. At highway speeds it's a but of a mystery unless the Clarity has a significantly lower power to weight ratio than other hybrids.

 

I don't have any data-collection devices, just my empirical observations.

In your linked post you say you "noticed the Clarity seems to throw as much energy back into the traction battery to maintain SoC at ~10% as it possibly can" and I agree with that. Would you agree that if the battery gauge is down to 2 bars and Clarity is throwing some of the power generated by the ICE and the starter motor/generator back into the traction battery, then at that moment the traction battery is not sending any power to the starter motor/generator? If true, the ICE the only source of propulsion in this limited case.

You theorize the last 2 bars on the battery charge gauge represent power reserved for Hybrid drive operation after the power allowed for EV Drive operation is exhausted. I can't come up with a better explanation than that but it doesn't answer all my questions. Will the Clarity dip into this 2-bar reserve if you need to pass while driving up a steep incline? If it is dipping into this 2-bar reserve, why not show that by displaying just 1 bar until the Clarity steals back enough ICE power to restore the 2-bar reserve?

My big beef is that the never-changing 2 bars don't provide any useful information other than to let you know that the Clarity's engineers are taking care of your big, expensive battery. I'd be happy to assume there's power left for Hybrid drive operation when all the EV drive bars are gone. A bar-graph display is supposed to enable the driver to assess the information it portrays with a quick glance. Instead, I have to count the visible bars, subtract 2, and divide the difference into 18 (20 - the 2 unchanging bars) to determine the percentage of EV Drive power remaining. (OK, I don't really do all that.) The battery charge gauge should echo the operation of the gas gauge.

 

One thing I've realized with the Clarity ICE operation is that the rev level setting is very short term based, when it doesn't have to be. There's lots of battery capacity to tide you over. Instead of having revs screaming while you climb a hill, and nothing going down a hill, why not set up the software so revs start at a reasonable base point, if in the gear engage range then use the correct gear speed. When you go down a hill have the gear disengage while the engine maintains the same speed supplying power to the battery. Steady operation should be the most efficient way to go.If its not keeping up with the power needed it could speed up on the downhills, and conversely if its making too much it could slow down a bit. These incidents where it revs for 10 seconds then slows down just make no sense, as does going into EV mode for a few seconds.

 

These threads about the meaning of the 2 bottom bars on the SoC gauge got me thinking. I realized that my 2012 Prius Plugin had exactly the same arrangement except that it was expressed differently in the graphics.

The all EV capability was shown by a picture of a green cylinder. Slowly (or speedily because the battery was so much smaller) the green level in the cylinder got lower and lower. When the car was no longer able to run on battery alone, it would change to HV operation. The graphic cylinder change to a pale pinkish color (equivalent of the Clarity 2 bars), the difference was that the level of pink in the cylinder would ebb and flow with the amount of regeneration. It gave just a little more graphic info than the Clarity when the SoC was no longer able to support running as EV.

Boy was that car loud — bees smees, I had a couple of hives. I never worried about it. I thought that was just the way dinky cars were. It's all I ever knew.

 

Below is a link to a folder which houses a 3 min 17 sec video of Scan Gauge ll recording SoC and RPM's immediately after the Clarity I drive went to two bars, EV miles = 0 and transitioned to HV mode automatically.

The folder also houses a screenshot of the hondalink app at the end of the drive.

Terrain flat'ish to gently rolling. Speed starts out at 55 mph then to 65 quickly and remains at 65 for the most of the video. Running ~2200 RPMs at 65 which is normal for the Clarity I drive.

The SoC was ~11.0% when EV=0 appears on HU screen.

The SoC gets to a low point of ~6.25%.

At the 1:51 minute mark you will notice RPMs jump from ~2200 to ~2800 (~30% jump) which is where I theorize the Clarity goes into HV charge mode. If you watch the SoC there is a continual back n forth while the trend line inches upward (ie trying hard to maintain 10% SoC) while alternating with trying to use electrons to help propulsion (as displayed on the HU energy flow screen...back n forth green to blue).

The ~30% jump in RPMs at 1:51 corresponds with the ~30% jump in RPMs I noticed when I ran the HV charge mode rpm test last week. More data needed but is trending that way.

If the RPM's increase ~30% due to charge mode activating...that could explain some folks reporting "sudden high revving" when operating under low SoC conditions. If so, I believe the Clarity is operating as designed and there is no need for alarm.

I theorize if the SoC drops close to 5%...one bar will disappear. If this is the case...it stands to reason the second bar will disappear ~0. So again...the two bars serve a purpose...if one or both disappear...that's a warning sign...that would tell the driver your out of "emergency electrons".

At this point would super high revving occur? Probably. Dunno. Loss of power? Dunno

The point is...I theorize the Clarity is designed to do everything it can to maintain two bars/SoC ~10% while leaving these electrons available for use as determined by on board computers.

The correlation remains between the SoC gauge and the hondalink bar graph. If you look at the screenshot you will notice the last 10% (I assume) on the bar graph is red. This app/bar graph clearly is designed to show the two bars (aka last 10% SoC) as part of the usable electrons for drive mode...albeit not used often and only as determined by on board computers. Red would be akin to...Will Robinson...danger...danger.

The ancillary benefit of the video...no noticeable engine revving at EV=0/ ~10% SoC. No discernible, elevated noise when RPM's increased by 30%.

I firmly believe no one should be afraid to go to EV=0 if needed during routine driving as the Clarity is designed to perform under those circumstance. Obviously I'm not talking driving over the Rockies...some common sense needed...just routine driving.

I don't fret if I have to allow the car go to EV=0. Obviously I don't do it on regular basis but never a worry as the Clarity I drive responds the same regardless of SoC.

My hope remains this info will assist those who question high revving and reasons behind the cause.

Link: https://drive.google.com/drive/folders/1JWfTcxSUI116s65mx-aaWx9uLgkyhFpe?usp=sharing

 

Clarity_Newbie:

Great video! (Does anyone know of a second OBDII port, to plug in the KIWI and Scan Gauge?)

The starting 1500 rpm is the speed my engine uses for warmup. Then, at 2275, it looks like gear mode. Once you get up to 2800, it is out of gear mode, and your mpg would be taking a hit.

After you hit 2800, you also dropped below 1800: Looks like the rpm control is a little unstable, and seemed to have trouble getting back to gear mode.

I think the experience of us people in the north, with a heater running, would be higher rpm's. I have noticed lower rpm's and better battery management as my temperatures are getting up over 40F.

As you mention, going up a significant hill would also increase the rpm's.

The video does show over 3,000 rpm. 3K rpm noise is not too bad, but the higher rpm's of a heater or hill can get annoying.

Part of the question is whether 3K+ rpm's is acceptable. (The speedometer goes pretty high, too... Is that a good way to run the car?) YMMV

 

That has been my experience. No high revs since weather has warmed up.

 

Perhaps an OBDII splitter would work for you. There a bunch of them on Amazon for under $12.

 

ClarityBill

Questions are great and welcomed when write-up not detailed enough for inquiring minds...but I try to keep it short and if every detail of a run is noted the post would be miles long. I add a few more details below to alleviate your concerns.

Actually the Kiwi is on another Clarity collecting data. I interchange devices primarily as a QC measure. Dependable data is key. Both devices have their place.

This run was impromptu...unplanned. I took advantage of the unexpected EV=0 (due to side trip by wife) and minimal traffic (safety) to video a Clarity's very low SoC at 65 mph RPM response. Visual data instead of dots on a graph.

The RPM's represent getting up to speed while merging...~2200 is what the Clarity I drive runs at 65 mph. The ~2800 - ~3000 RPMs are when the car goes into HV charge mode on its own (theory). Dropping to 1800 RPM's is when I ease up on the throttle to exit highway...the 1800 RPM's at that point indicates to me the HV charge mode is still active...normally the RPM's drop to ~1000 then to EV at that point.

What sticks out to me is how quickly the RPM's go from ~2200 to ~2800...like a switch was thrown. That wasn't throttle.

RPM's are typically very stable...tough to balance holding camera, manage throttle to maintain speed, stay between the ditches, eyes peeled for critters...etc. Any vehicle's RPM's will fluctuate slightly when throttle pressure is uneven...just ask my Subaru.

I doubt seriously if the engine clutch engaged with the low SoC given my belief the Clarity is designed to prioritize SoC maintenance at ~10%...unfortunately looking at the HU screen was not a priority. But that is not really relevant to what I am demonstrating...its about RPM's at SoC ~10%. So much advice on Clarity forums centers around "not letting the SoC drop below this or that" which is BS. This car is designed to run fine at EV=0 under most conditions. Just don't try to climb over the Rockies.

As for the noise at 3000 RPM's...way too subjective...I believe its an Octave thing since everyone's sensitivity to noise is different. The comment about the noise level is just an observation to give folks a perspective if they have issues.

The take-a-way:
It is looking like at a very low SoC the Clarity will increase RPM's substantially to maintain SoC ~10%. Preliminary data shows ~30% increase. This would also explain why folks talk about "sudden high revving" under similar conditions. I believe it is because the Clarity is designed to go into HV charge mode at very low SoC.

I try to offer context and reason for folks who experience issues. Thats why I collect data on the side. The Clarity I drive has none of these issues as of yet...knock on wood...doesn't mean I won't try to help others out.

Perhaps you will collect data after allowing your Clarity to go to EV=0 at high speed...that will help confirm or deny the above...plus add to the data pool.

My theories may be spot on or way off base...dunno...but until I see data that shows a different outcome...this is all I got to go on.

Hope this helps.

 

Insightman

One at a time is enough...lol

 

For sure, the Clarity should run normally through low SOC 2 bars into HV, after all that was the premise of their national TV ad campaign. For a month or so last year, the ads ran non-stop. "The end of your battery charge isn't the end of the world. It runs and electric, and has gas if you need it ... "


On the other hand, if I read your take away correctly, perceived "sudden high revving" at EV battery 2 bars is actually a repeatable about 30% increase in engine RPM at 2 bars. (TBD, I understand your most interesting study is ongoing.)

Therefore, those intentionally keeping some SOC above 2 bars can enjoy a somewhat quieter ride? Or maybe not, because you are going to get charging revs at any SOC.

Maybe your point is that on those longer drives, it matters less where you choose to leave SOC about a previous number of EV bars when HV is intentionally turned on because you are going to eventually experience the higher RPMs one way or the other (either to hold 2 bars, or to hold some higher number of EV bars). Which begs the question, would there by any advantage, short of actual mountains (or, disadvantage) to running at a higher SOC, or even in HV charge mode ("mountain mode") vs. just running at 2 bars? (I'm guessing the preliminary is answer is no, thus the the BS comment.)

So, I for one, like having some EV reserve, at least to use on local roads, when I get "there". But, maybe the point is, that's okay and nice, but don't expect any relation to angry bees.

edited still more

 

Thanks for the video,
Some people have rpm as high as 5200 which is alarming!! Red zone on a normal 4 banger is around 6000 rpm.
My car got stuck on High revs last week for 7 miles, I was trying to see when the engine would turn off and ended up pulling over.
***If someone has the high revs issue, please email me: [email protected], I would like to ask some questions on how your car behaves and provide some answers that will help you resolve the issues (keeping it private for now).

 

FYI - I finally had occasion to drive down the same hill and was able to see the grade on the truck warning sign. It is a 9% grade. As I went down in full paddle regen (all chevrons) I could see the additional tenths of a mile ticking up on the estimated EV mileage guess-o-meter.

 

I've wondered, is it possible that the ACC can provide more regen than 4 chevrons of paddle? You could help answer that question. The next time you go down that 9% grade, set the ACC to see if it gains more regenerated battery power than you can recover with the paddles. Thanks.

 

I will try that next time. I tend not to use ACC around town. My guess is that ACC will provide more regen because the paddles were insufficient to prevent the car from picking up speed and I had to apply the brakes to avoid grossly exceeding the 50 mph speed limit long before I reached the stop light at the bottom of the hill.

 

Having to apply the brake pedal doesn't necessarily mean you're not still regenerating. When you brake up to a certain amount, the brake controller holds off the friction brakes (I believe using some of the antilock brake components) and uses regeneration only, above that it starts to blend friction and regeneration. The systems sound a bit complicated (having to take into account battery state, slippage as the regeneration can only apply to the front wheels, etc), but I suspect that gentle braking to reduce speed down a hill is pure regeneration even beyond the settings the paddles provide. The paddles just provide another convenient way to slow that seems more like a "downshift", especially as people have been taught not to ride the brakes down long hills in cars that just have friction brakes.

That's why most hybrids (and EVs) have varying degrees of "weird" brake pedal feel -- mushiness and inconsistencies as you press harder. The Clarity actually seems to feel the most seamless in the 4 days I've driven it; our Highlander has some abruptness in the feel as you close in on a stop, and the 2 Bolts I test drove had the opposite feel -- it felt like the brakes released a bit right as you came close to a stop, and you had to go "whoa" and press harder all of a sudden (I suppose after getting used to it I wouldn't have gone "whoa" every time!)

 

There is no gentle breaking down the hill I am talking about. It is push hard on the break or run thorough the trafic light and/or miss the right angle turn at the T junction at the bottom.

 

This is an interesting thread, as usual. A couple of comments:

I am the one who reported a battery gauge with zero bars. This has happened to me exactly once, and it was on the trip home from the dealership after picking up the car. I do not know how they managed to accomplish this feat of zero bars, and I can't really say much about how the car drove since it was the second time I'd ever driven a Clarity (the first being the test drive). It was much noisier than I expected based on my experience in the test drive, but I don't think it qualified as "angry bees". But I didn't have to climb a mountain on the way home.

I agree with the basic premise that the controller will make mode changes behind the scene to keep that 10% - two bar - reserve. This is consistent with my experience. And like many others, I use HV on the highway so I can keep the EV for in-town driving.