Why I sold my Clarity after a year.

[MNSteve]

You were using HV charge in a way that’s not recommended. The owners manual indicates that HV charge is best used at highway speeds, and from use, HV Charge is not recommended for any significant uphill. Your outcome is not surprising, and is user error, not a defect with the car.

Sorry, I have to disagree. This is not a driver error, but an error in the way that the car controller is programmed. If a particular combination of modes results in a safety issue, that combination of modes should not be possible for the driver to select. Not having enough power to drive the vehicle normally is a safety issue and should not be happening, no matter what buttons the driver has pushed.

In this case the controller should have detected the need for the power produced by the ICE to be used to propel the car and disengaged any attempt at charging the battery.

 

[ClarityBill]

I could be mis-understanding the phenomenon that OP described, but my personal understanding of how loud the engine becomes seems to be related to some sort of "ev reserve charge" that gets used when in HV and replenished in EV mode. This sounds odd, of course, and not really documented.

But basically if I've been driving on the highway in EV mode and then switch to HV mode, it starts out as pretty quiet. But then when I start to go up a decently long hill, there seems to come a point where the engine starts to sound pretty loud, and then if the upward hill continues on, at some point it becomes very loud. And once I hit it, even though I've already started my downhill descent, the engine stays loud. My solution in this case is to put the car into EV mode for a minute or so, and then switch back to HV mode. Then the engine noise becomes quiet again, but only if I've had it in EV mode for some small period of time. (If I just go into EV and come right back into HV in a few seconds, the engine continues to be louder than normal.)

This led me to believe that there is some sort of reserve EV power that's tapped when needed, and when that power is gone, the engine needs to work by itself, creating noisy and underpowered acceleration.

I think: When you switch to HV mode, the charge on the battery (SOC) becomes a setpoint the engine tries to maintain. When you go up a long hill, the engine cannot keep up, and it rev's to try and charge the battery more. Once you get to the top of the hill, the battery is still lower than 'target', so the engine is still reving to charge it. By switching to EV mode, and waiting, then going back to HV mode, a new setpoint is entered into the engine control logic.

The setpoint in HV mode can make the engine go to high rpm, even though there is plenty of battery power to help out: The system just thinks it has used 'too much' battery already. The engine speed control acts like a simple proportional control, and has to have an offset before the engine even starts to kick in.

 

[insightman]

Although I have not personally explored this (drinking and smoking not in my nature), I think you may be interpreting the chart too literally. It is just a cartoon. If I looked at this chart, I would probably assume that it's scope is limited and it is only trying to show how these 3 modes affect the threshold for invoking the ICE. With your literal interpretation, you are arguing that once you pass the pedal click, there is still more linear range to get even more power? I tend to think the pedal click is 'all she wrote' (ie: there is no more power range beyond that click). Analogous to the old days... the throttle was already wide-open when you hit the kickdown to force the car into a lower gear.

You have perfectly stated my reservations about the accuracy of the chart. SPORT Mode cannot provide greater ICE power beyond what ECON Mode provides when the accelerator is floored, so there's no way to explain the longer length of the ICE activation bar in SPORT Mode.

 

[KentuckyKen]

You have perfectly stated my reservations about the accuracy of the chart. SPORT Mode cannot provide greater ICE power beyond what ECON Mode provides when the accelerator is floored, so there's no way to explain the longer length of the ICE activation bar in SPORT Mode.

Another way to look at that graph is to note that on the x-axis is the point that the click is felt. Therefore I interpret the label of that axis, “driving force”. To actually mean pedal force or position. And that would mean that the length of the EV and Engine bars would have nothing to do with power or torque; just at which point the engine will be called upon. You have to remember that all this is translated from Japanese into English and inevitably there will be something lost in translation.

 

[insightman]

Another way to look at that graph is to note that on the x-axis is the point that the click is felt. Therefore I interpret the label of that axis, “driving force”. To actually mean pedal force or position. And that would mean that the length of the EV and Engine bars would have nothing to do with power or torque; just at which point the engine will be called upon. You have to remember that all this is translated from Japanese into English and inevitably there will be something lost in translation.

So as @Carro con enchufe says, in SPORT Mode the accelerator pedal provides no additional acceleration after passing the click, right? I guess that makes sense because if SPORT Mode changes the accelerator pedal mapping to be more aggressive then it must reach max acceleration before the pedal touches the floor. So ECON Mode must be the only mode where max acceleration requires the pedal to be floored.

 

[JulianClarity]

Sorry, I have to disagree. This is not a driver error, but an error in the way that the car controller is programmed. If a particular combination of modes results in a safety issue, that combination of modes should not be possible for the driver to select. Not having enough power to drive the vehicle normally is a safety issue and should not be happening, no matter what buttons the driver has pushed.

In this case the controller should have detected the need for the power produced by the ICE to be used to propel the car and disengaged any attempt at charging the battery.

You are right, the user can do anything even it is not recommended to the car, but the car should not put a user in danger. The car should not have put extra power charging the battery when itself needs to climb a steep hill.

 

[KentuckyKen]

So as @Carro con enchufe says, in SPORT Mode the accelerator pedal provides no additional acceleration after passing the click, right? I guess that makes sense because if SPORT Mode changes the accelerator pedal mapping to be more aggressive then it must reach max acceleration before the pedal touches the floor. So ECON Mode must be the only mode where max acceleration requires the pedal to be floored.

That could well be. But I am starting to look at that graph as having nothing to do with speed or power or torque on the X axis labeled “driving force”. As in it’s just showing where the engine will be called upon relative to the pedal force or position in each of the three modes depicted in the horizontal bars. And the Y axis labeled “EV drive frequency” makes me think it’s all just showing how to achieve the most EV vs HV and not where the raw or additional power comes from. But I could be all wrong and who knows what the true intent was. I bet it got mangled when it was translated into “Engrish”.

 

[Ray B]

One can argue these charts (Found here: https://www.hondarandd.jp/point.php?pid=1229&lang=en), which are for the Honda Clarity Fuel Cell vehicle, are not directly useful or even relevant, as there is no ICE trigger in that car, but I think they may have some hint about how the different modes are mapped according to accelerator pedal response.



Although I have no information to disprove it, I have the impression that SPORT mode doesn't just remap the pedal input but also may change the performance of the drive components (PCU, VCA, IPU, inverters ... whatever). I could be flat wrong - just a guess.

Perhaps one reason I feel that way is the different regen behavior shown in the same paper which shows that Clarity FCV SPORT mode enables more aggressive regen:



Again - assuming that this FCV regen curve, along with the others, are meaningful to our PHEV under discussion.

 

[neal adkins]

So let me clarify what happened. I was climbing a hill and pressed the accelerator to maintain my speed (around 65). The car revved noticeably, but the speed did not increase. I pressed down a bit harder and heard higher revving and again no increased power, at which time I backed off the accelerator and switched to EV mode.

I think its how the car is designed. I have experienced the same thing. Many dont understand because they dont climb a 6% uphill grade for 18 miles. I think your Clarity actually performed as designed because you never lost speed. The reving is normal. We may not understand or like it but that is by design. When under a heavy load the system detects rapid battery discharge and compensates by commanding the ice to rev and supply power to the generator that charges the battery. This is why your car didn't accelerate. In hv mode the system strives to maintain your current state of charge. The Claritys complex clutch system is not always direct drive so the ice may rev without any increased speed. I do agree that the system should allow more torque from the electric traction motor while in hv mode and climbing a steep grade with a moderate battery state of charge.

 

[JustAnotherPoorDriver]

So as @Carro con enchufe says, in SPORT Mode the accelerator pedal provides no additional acceleration after passing the click, right? I guess that makes sense because if SPORT Mode changes the accelerator pedal mapping to be more aggressive then it must reach max acceleration before the pedal touches the floor. So ECON Mode must be the only mode where max acceleration requires the pedal to be floored.

Only if you assume the pedal is linear. As the fuel cell picture from Ray B shows, it may not be--in that case the pedal still meets the firewall at the same point, but reaches higher power, sooner.

 

[ukon]

so let me understand some of the conclusions,

1) If one is expecting to drive a large hill/steady uphill miles, conserve battery with HV mode
2) then get out of HV mode and drive in regular mode?

I always thought, the better way is HV mode and the clarity uses some battery range for uphill. So in the sense the car in an attempt to maintain charge will be in "HV charge" mode after the uphill or during the uphill?

 

[barnesgj]

Until the 'hill' incident, I could always trust the car to accelerate some when I pushed the accelerator. Maybe not as quickly depending on the conditions, but there was a direct correlation between pedal motion to forward acceleration. Not sure I want to be driving a car that cannot be relied upon to increase its speed when I push the accelerator. Am also still thinking that my car had some kind of incorrect setting which allowed this misbehavior.

 

[ClarityBill]

Ukon,

Depends on your goal... do you want to fiddle and have a quiet ride, or just let the computer handle it?

Definitely want to have maximum battery when approaching a large hill, so drive in HV mode until starting the hill. As the car starts the hill, if the battery charge drops, the HV mode will try to maintain the charge, and the engine may start to scream. It can be loud, even with lots of charge remaining. HV mode only allows the charge to drop a percent or two, from the normal driving range, before the engine will rev up.

If there is lots of charge, and the engine is reving too much; switch to EV mode, and get the engine to calm down. Sometimes it is possible to the finish the hill in EV mode, or switch back to HV, and let the engine charge the battery. When switching back to HV mode, the engine will have a new target charge to maintain, so the engine should start out at a lower rpm, again.

You do want to avoid running to zero battery, with more hill left: If the hill is long, it may be best to just leave it in HV, and let the computer do its best.

'Better way' is always subjective: I like a quiet ride, and most hills can be managed by switching in and out of HV mode.

 

[DC1]

Well i read the

I think: When you switch to HV mode, the charge on the battery (SOC) becomes a setpoint the engine tries to maintain. When you go up a long hill, the engine cannot keep up, and it rev's to try and charge the battery more. Once you get to the top of the hill, the battery is still lower than 'target', so the engine is still reving to charge it. By switching to EV mode, and waiting, then going back to HV mode, a new setpoint is entered into the engine control logic.

The setpoint in HV mode can make the engine go to high rpm, even though there is plenty of battery power to help out: The system just thinks it has used 'too much' battery already. The engine speed control acts like a simple proportional control, and has to have an offset before the engine even starts to kick in.

That's what I thought too, but if this is true, then it should reset the setpoint if I press EV during the uphill climb, but it doesn't seem to do so. Well, anyways, whatever the underlying mechanism, I realize in re-reading the thread that the 'loss of power' wasn't actually a dangerous cutting out of power, but rather a lack of acceleration while going on an extended uphill? I don't think it's much of a safety issue to be honest.

 

[Linkmodo]

Sorry to hear so many issues with heaters and EVs... Pray it doesn't snow in Miami... So far I am loving it after 3 month of ownership and daily commuting in stop n go traffic (20 mile round trip)

 

[Tomrl]

Just passed the 1000 mile mark and have had nothing disconcerting happen yet. The Clarity has been everything we hoped for and more. Have used only around four gallons of gas to this point, couldn't be happier.

 

[The Gadgeteer]

Wouldn't HV mode turned off be better for hill climbing? That way the computer is not trying to maintain battery charge. Instead the computer can freely use whatever engine and battery power is available for locomotion. I imagine trying to charge and move the car up an incline would be very taxing for a such a heavy vehicle with a small engine when battery charge is low.

I agree prior to coming up to a hill having more battery charge by making use of HV or HV Charge will allow the electric motor to do more work to move the car up the hill but once at the hill I would think turning off HV/HV Charge would be best.

As far whether Eco, Normal, or Sport would be better will require some experimentation.

 

[PHEV Newbie]

Wouldn't HV mode turned off be better for hill climbing? That way the computer is not trying to maintain battery charge.

Actually, no. If you're not in HV mode, you'll be running just from the battery if just cruising up hill. If it's a long hill or you just have a partial charge, you could deplete your battery before reaching the top and it'll be pretty unpleasant when it shifts to the ICE with no battery supplementation. In my experience, if there's a major charge in the battery, in HV mode, it can expend a big chunk of the battery to get you to the top. But because it's combined with the ICE (purring quietly in my experience if the battery has a good charge), it depletes very slowly. It does that every time on a nearby mountain grade. Once I get to the top, the ICE stays on to recharge the battery even though it's going gently downhill at that point.

 

[KentuckyKen]

I guess I’m blessed wirh my Clarity. On two 250 mile trips with rolling hills and a couple of steep hill climbs, I started out in HV with 99% SOC and had a great experience. No angry bees, no loss of power, and the SOC pretty much held steady. On the rolling hills the ICE was barely even noticeable and on the steep climbs it only reved up to a pleasant lower mid range hum kind of like my old gas mobile downshifting out of overdrive. Not objectionable at all.
So EV in town and HV on the highway/ Interstate (with plenty of charge) works just fine for me.

 

[craze1cars]

I think there are multiple different interpretations of "loss of power" depending on who's talking, and who's listening. Makes me kinda feel a little bit sorry for Honda, and the dealers, who are forced to field complaints from some customers. It has to be tough for all parties.

"Loss of power" = all electronics shut down and car coasted to stop?
"Loss of power" = car still seems to be running, electronics still on, but car coasted to a stop?
"Loss of power" = the engine got really loud but the car wasn't going any faster?
"Loss of power" = I put my right foot all the way to the floor and the car could only go 30 mph?
"Loss of power" = I put my right foot 3/4 of the way to the floor and the car held a steady speed going up hill but didn't accelerate?
etc
etc
etc....

So so so so many options....and opportunities to misinterpret/miscommunicate.

So am I to understand there are people who have been climbing up steep hills, and if they put their right foot to the floor, the car doesn't accelerate? It actually slows down? Or simply holds speed? If cruise control is being used at 65 mph, the car actually slows down to 55, 45, or 35 mph like a heavily loaded semi-truck that's pulling up a mountain? Or are people just being timid with the gas pedal when they hear the engine get loud and therefore have some mental block against bottoming the go-pedal to the floor?

Every time I put my foot to the floor in my Clarity, it accelerates, just as strong as any 4,500+ pound loaded 180-ish horsepower 4-banger car should be expected to accelerate. If climbing mountains it is certainly not super quick, and certainly not always quiet, but yes it always accelerates. Are there people here actually saying that doesn't happen, and the car actually slows down when climbing a hill while their foot is to the floor? I certainly haven't experienced it, nor have I heard anyone say this yet...though I sure as heck don't read every post on this forum.

I'm feeling there is a disconnect (maybe SEVERAL disconnects) between what people are experiencing, what they're saying, and how others are interpreting what is being said. And I'm not sure where the disconnect is. I know I'm a bit confused, as my car works exactly as I expect it to. But if I have a passenger with me, the car doesn't always work exactly as my passenger expects it to. Because I pretty well understand the car, and my passenger never does. EV mode is easy. HV mode? Ha...it is ALWAYS a fun little conversation as I explain what the car is doing. This is, absolutely, an odd car. It does not work "normal" when compared to other cars. The gas pedal is not in any way attached to the engine itself...in fact the engine essentially ignores the gas pedal at almost every time -- I KNOW some people don't comprehend that fully and have a hard time adjusting. But that doesn't always mean it's not working as designed, nor unsafe. It just makes funny noises at funny times, and some people maybe have a hard time accepting this? But in my experience, no matter what sounds the engine might be making at any moment, the farther I put my foot down on the right pedal, the faster the car goes, without a single exception. In this way, the car is normal. But others apparently disagree? I dunno...