I.C.E. runs everyday - Page 4 - 2018 Honda Clarity Forum
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post #31 of 35 (permalink) Old 06-22-2020, 11:20 PM
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Originally Posted by michaelwei View Post
I have been driving my 2019 Clarity for over a year now, I have been experiencing the ICE coming on after a full charge when I press the brake pedal or when I engage the brake regen, regardless of if the car was going downhill or not. I find this frustrating as I would prefer not to have the ICE comes on at all. I understand that the ICE has to come on once in a while, maybe every few days to do a routine check but to come on every time I have a full charge is very annoying and defeats the purpose of getting a PHEV. Does any know how to switch off the ICE so it won't come on or if other PHEV does the same? I took my car to the dealer and on one has a clue how this happen and how to fix it, they admit that they didn't sell a ton of these and no one bothers to send their technicians for training on this vehicle. However, I love the car, it is quiet, smooth, powerful and I only put in $14.25 worth of gas since I owned it (13 months). Thanks in advance for your comments. Cheers.
Actually system check turning on ICE normally only happens after more than a month or two of no ICE usage. Since March I have only had ICE come on twice, both cases was when I accidentally accelerated past the ICE turn on point. Some people who drive exclusive EV will purposely switch to HV briefly (or gun the accelerator) every couple of weeks to activate ICE because they think it may not be good to go more than a month without ICE running.

For most Clarity owners if ICE comes on every few days it's not maintenance mode kicking in it is the other usual suspects, like accelerating too much which is very easy to do without realizing it since the car is so smooth and quiet, and normally when you do accelerate harder than normal it's because you are in a situation that requires it, and your attention is likely on that so you won't be staring at the dash during the moments of hard acceleration. If you were staring at the dash you would likely see the power indicator go past the blue area in the gray area, maybe just a tiny bit, and maybe just for a second, but that's all it takes to activate ICE, and once it comes on it goes through full warmup which can take several minutes. And again if you weren't watching the dash at the exact moment that you blipped it into the gray, you will only sometime later notice that ICE is running and think that it came on completely randomly for maintenance. To remove some of the mystery about whether or not you momentarily accelerated enough to activate ICE you can drive in Econ mode, in that mode the point where you feel it click past the detent is the point where ICE activates, so it helps you be more aware even without looking at the dash whether you have pressed the accelerator far enough to activate ICE.

The other culprit is what you mentioned, if you have a full battery it has no place to store regen electricity, so if you press the brakes it has to get rid of that energy somehow, so it uses the generated electricity to spin the engine, and the engine then starts up, and yep it now runs several minutes of warmup before shutting off. The reason it always does full warmup is for EPA requirement to not have unburned fuel in a cold catalytic converter. However no one really knows why it has to start ICE in that situation, why not just spin the cold engine without starting it, and any additional braking needed can come from the brake rotor. No real explanation it's just what it does. And it will do it every day if you are in that situation which eliminates the idea that it is doing this for engine check reasons.

Only one car that I know of will stay in EV mode as long as you have battery power, no matter how hard you press the accelerator pedal, and that was the Chevy Volt. Prius Prime apparently is close as it is reportedly hard to get ICE to come on through hard acceleration. Hyundai Ioniq reported goes the other direction and ICE comes on easier than it does in Clarity.

I don't agree though that this defeats the purpose. The purpose of a PHEV is to greatly reduce the amount of gasoline needed and the Clarity does that, and much better than most PHEV's. Other than Volt there are almost no other PHEV's that go as many EV miles per charge as the Clarity. Prius Prime for example only goes half as far per charge. The tiny amount of gasoline used in the cases where ICE comes on briefly is trivial compared to the amount of gasoline saved. People who drive almost exclusively EV in their Clarity (like me currently) experience that even though ICE may occasionally come on for a few minutes, you can still easily go many months without the gas gauge moving even a tiny bit. Hardly defeats the purpose, in my opinion it greatly fulfills the purpose. It's only our sensibilities that get rankled because we can't completely control what the car does in terms of ICE activation.
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post #32 of 35 (permalink) Old 06-25-2020, 10:44 AM
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Quote:
Originally Posted by michaelwei View Post
I have been driving my 2019 Clarity for over a year now, I have been experiencing the ICE coming on after a full charge when I press the brake pedal or when I engage the brake regen, regardless of if the car was going downhill or not. I find this frustrating as I would prefer not to have the ICE comes on at all. I understand that the ICE has to come on once in a while, maybe every few days to do a routine check but to come on every time I have a full charge is very annoying and defeats the purpose of getting a PHEV. Does any know how to switch off the ICE so it won't come on or if other PHEV does the same? I took my car to the dealer and on one has a clue how this happen and how to fix it, they admit that they didn't sell a ton of these and no one bothers to send their technicians for training on this vehicle. However, I love the car, it is quiet, smooth, powerful and I only put in $14.25 worth of gas since I owned it (13 months). Thanks in advance for your comments. Cheers.
If you don't need the full charge to get where you are going, then you could try stopping the charge before the battery is all the way full. That leaves some open capacity in the battery for regen braking when you first start driving, and may reduce the car's desire to use ICE braking. Not the most convenient thing to do, because you would either have to do a timed charge based on an estimate of how long it would take to reach the desired state of charge, or manually stop it before it's full. One of the dings on Clarity is that is lacks a feature to charge to a user-specified state of charge (say, 80 percent).
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post #33 of 35 (permalink) Old 06-26-2020, 11:12 AM
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Did I read somewhere that after a year of not having to fill the gas tank the ICE burns off the old fuel? Is the a possible reason for the ICE operating more continuously? I am in very flat Illinois with a 2020 Clarity. The ICE has never turned on except for battery at 2 bar or HV SET.
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post #34 of 35 (permalink) Old 06-28-2020, 04:47 PM
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Originally Posted by Billb View Post
Did I read somewhere that after a year of not having to fill the gas tank the ICE burns off the old fuel? Is the a possible reason for the ICE operating more continuously? I am in very flat Illinois with a 2020 Clarity. The ICE has never turned on except for battery at 2 bar or HV SET.
That may be true, and if I ever had the fuel sit in mine that long I would expect it to happen. While my driving pattern is mostly EV, I need to go beyond EV range from time to time, so the ICE runs semi-regularly in HV mode and I go through several tanks of gas per year. Most of the reports of unexpected ICE starts are truly unexpected and generally defy logic. That is, the gas tank has been filled recently and ICE ran recently. I had it happen once when the ICE had a long HV run on the highway earlier the same day. The commonality with these unexpected ICE starts is that they happen when the battery is charged to full and then you need to slow down or come to a normal stop after driving a very short distance at low speed. While there is a place for ICE braking, the control system needs a little more patience and allow greater use of the friction brakes before resorting to ICE braking. Maybe Honda got the hint and tweaked the software for the 2020 models.

I have also experienced the opposite end of the spectrum: My Clarity was in winter storage for nearly 6 months. On the first drive out of storage, with battery at about 2/3 full, I would have expected the ICE to start and run on its own due to the extended dormancy. It did not. I had to manually select HV mode to get the ICE to run.

Last edited by 60Hertz; 06-28-2020 at 05:13 PM. Reason: added detail
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post #35 of 35 (permalink) Old 06-29-2020, 03:27 PM
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I have owned my Clarity for over a year, driven hybrids for over eighteen years, and I have also been following forum discussions on this topic for about three years if I include time spent on Prius Prime forums. Based on my experience with my Clarity and reading many other people's experience with their Clarity I have concluded that contrary to popular belief the Clarity is very predictable for ICE startup. Just to list them again in case someone hasn't followed the entire thread.

In no particular order:

#1. Reach 0 EV miles
#2. Press HV button

In the above two scenarios, ICE doesn't always immediately come on, the power semi-circle will change from the usual 75% blue 25% gray to about 25-35% blue. if you are not using a lot of power at that moment it will remain EV for a little while longer, but almost any type of acceleration will push it past the blue into the gray area and ICE will come on.

#3. Hard acceleration. As mentioned, in normal EV mode the power semi-circle is usually about 75% blue. With higher than normal acceleration it's not all that hard to push it into the 25% gray area and activate ICE. However as I mentioned in a previous post it only has to be a tiny bit over for a fraction of a second to activate ICE, and a driver can easily not be aware that they were momentarily at that power level and it is often only sometime later that they notice that ICE is running. Here is one big reason that I think people miss this one, it's because if the engine is cold when you accelerate hard, it normally will add very little power at least for the first few seconds, which is understandable that the system avoids putting a big load on a cold engine. Thus you don't really hear the engine for the brief moment that you are accelerating hard, because the engine is providing only minimal additional power, the battery is still providing most of the power. By the time the engine starts to warm up a few seconds later the heavy acceleration event has likely ended. However now that ICE has started, even though it is no longer needed at the moment it will stay on until it is fully warmed up which can take five or ten minutes depending on conditions, usually either idling or just providing a small amount of power, thus you don't hear it. Then you come to a stop sign or red light, and don't notice the now idling engine. But then the light turns green and you press the pedal and all of a sudden the now warmed up engine comes roaring to life in the annoying high RPM way that it usually does, the driver is startled to hear the engine and assumes that it just came on at that very moment, and it becomes yet another unexplained ICE activation. I really think this happens more often than people realize.

#4. Full battery regen. Battery full or nearly full, a normal stop can easily cause ICE to come on. Sometimes this can be avoided by light braking, but only sure fire way to avoid is to not charge to full if that is an option.

#5. System Check. Completely unknown schedule or pattern. Common belief is that it occurs when ICE has not been run for a long time, but no one can say how long that is. Many have gone for months without ICE activating.

After over a year of my own experience and reading other people's experiences I am fully convinced that the majority of unexplained ICE activation that are blamed on #5 were actually caused by #3 and #4. People claim they didn't accelerate hard, but unless they have a camera pointed at their dash the whole time I am convinced this explains a high percentage of the incidents. As for #4, many people don't know about this quirk with Clarity and thus they don't associate ICE activation with having a full battery or with using regen (who would?) and thus they report it as random ICE startup caused by system check.

There have been a few people who absolutely insist that none of the above is occurring and ICE sometimes starts up completely randomly. For them we reserve explanation #6

#6. Their Clarity acts different than others

It's not impossible that someone could have a software glitch in their car that makes it act differently than others. There was a 2018 owner who engaged in endless debates on this topic, finally everyone agreed that his car just does not act like other people's car. If someone insists that their ICE truly comes on randomly with no explanation, all I can say is that their Clarity does not act like my Clarity or many other people who can easily go months without ICE activation. In fact yesterday I had only my third ICE activation since March, and again it was fully explained, in this case I drove past 0 EV miles for the first time in three months. My previous two activations were both caused by accelerating briefly past the blue area. Back when I was driving more often and also farther it was common for me to reach 0 EV miles and activate ICE, or press HV proactively to control ICE activation when I knew I would be driving past my EV range. The only times that ICE came on unexpectedly, whenever I thought back on my last ten minutes or so of driving I remembered that I had accelerated harder than normal at some point, but I was not watching the power meter at the time, so I felt quite sure that I had probably momentarily blipped it into the gray area.
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