[LenH]

I understand that the I.C.E. will run occasionally. Every night I charge the car using a 32 KW Siemens Versicharge. Every morning within a mile of my home the I.C.E. comes on and will run until I reach my destination and park the car for at least 10 minutes. Turning off the car and restarting it right away has no impact. I went to my selling dealer (Norm Reeves Honda in Irvine CA) and they said the computer does not show any faults. I called American Honda as instructed by my service rep. They could not have been less helpful and more dismissive (must have been trained by an airline's customer service department). They told me to take it to another dealer for a second opinion. I will do that but the second dealer is only going to read the same codes via the OBD2 port.

FRUSTRATED!! Anybody else with a similar experience and information.

 

[obermd]

First question, and this is important because apparently some of the early Clarities had problems with non-Honda EVSEs: Does your car show the battery fully charged in the morning? If the answer is yes then I'd start looking for a different Honda dealership since the one you tried is clueless about the Clarity.

 

[jbellhanson]

I have had the same experience, but only occasionally. I wish I had some helpful information to pass on, but I'm glad to see that I am not the only one. This is one point of frustration I am experiencing because Honda really has not explained well how this car functions.

 

[150MPG]

Hi be sure the car is set to EV mode. It is supposed to default to EV mode on start up. The button on the left on the console. Make sure the battery is charged up. Do not press the throttle all the way to the floor this starts the ICE no matter what mode you are in. If the ICE is running you can switch to EV mode on the fly to turn it off as long as the battery has sufficient charge. If you have only two bars of battery the ICE will start and stop as if you were in HV mode.

 

[Kerbe]

Hi be sure the car is set to EV mode. It is supposed to default to EV mode on start up. The button on the left on the console.

Do you mean "Econ" mode? The Clarity PHEV doesn't have an "EV" button as it defaults to EV if the traction battery has sufficient charge. You can use the the Econ, Sport and HV buttons to map where the "click point" on the throttle will be - the ICE engages when that point is passed. Up until that point - no matter the mode - the ICE should not engage (unless the Clarity decides it needs extra power to climb a hill).

Sorry to be a buzz-kill but, unlike some other PHEVs, Clarity can not be set by the driver to run as an EV only.

 

[Holly]

ICE turns on..

Okay, with my Clarity, the ICE comes on if I have the A/C or Heater going. Also if you have it in EV mode, I think in order to save electricity (because that's what EV mode is for), I believe the ICE may come on then as well. If neither the A/C or Heater nor EV is on, you should just be using Electricity going less than 45 mpg (which also may trigger the ICE to come on). This is my understanding. We are all learning on these PHEV's... Do love my car!

 

[150MPG]

Ok to clarify yes the econ button turns on and off econ mode. ( Econ mode limits throttle response, heating and cooling to conserve battery life) It also assures the car is not in Sport, HV, or HV charge mode. I can drive my car aprox 45 miles on pure electric the ICE never starts until two bars are left on the battery. This is at speeds up to 75 mph with the air or heat blasting. We have gone for months without ever going to the gas station. Are you sure the car is fully charged?

 

[2002]

I understand that the I.C.E. will run occasionally. Every night I charge the car using a 32 KW Siemens Versicharge. Every morning within a mile of my home the I.C.E. comes on and will run until I reach my destination and park the car for at least 10 minutes. Turning off the car and restarting it right away has no impact. I went to my selling dealer (Norm Reeves Honda in Irvine CA) and they said the computer does not show any faults. I called American Honda as instructed by my service rep. They could not have been less helpful and more dismissive (must have been trained by an airline's customer service department). They told me to take it to another dealer for a second opinion. I will do that but the second dealer is only going to read the same codes via the OBD2 port.

FRUSTRATED!! Anybody else with a similar experience and information.

Do you have a downhill slope within a mile of your house? When the battery is full it is not able to do regenerative braking because it has nowhere to store the generated electricity. This means it can only use friction braking (the brake pads) or engine braking to maintain speed during the descent. However to use engine braking it has to turn on the engine (we're not sure why, there are different theories about this). And once the engine is turned on it has to run for several minutes to warm up, this is an emissions requirement. If you don't have a downhill slope, the same thing can happen when stopping at a stop sign or signal light if it causes you to do a lot of regenerating when the battery is full.

Some people solve this by not fully charging the car, which some believe is healthier for the battery anyway. Or if the drive will be partly in HV, then go ahead and start in HV since the engine will come on anyway, then when you are on a stretch of level road where you won't need to slow down then switch to EV, this will use up some EV charge and should keep the engine from coming on the next time you regenerate.

However in any case the engine should only stay on long enough to warm up. You didn't say how far you are driving. If ICE is still running thirty minutes after you have left the house then something is wrong. Also you didn't mention if you have this problem at other times, or only when you leave your house.

 

[tom]

If you press the gas pedal more than 60%-70% it will engage the ICE for added power. Once the ICE is engaged, I believe it stays on for a bit because constant starting/stopping the ICE is unhealthy for it.
Is it possible you are stepping on the gas pedal too much?

 

[LenH]

Best Explanation yet

Thank you for your explanation. This makes sense as the ICE does engage right after stopping at the end of my street. I'm going to try not charging to full and see what happens.:smile:

 

[mowcowbell]

As long as I don't charge above 90%, I don't see the ICE starting up in my Clarity. The few times I have charged the battery 100%, the ICE comes on when I first apply the brakes just a block away from my house at the beginning of my commute.

 

[michaelwei]

I have same issue with my ICE coming on after I charged the Clarity. Why won't it brake with friction braking? Isn't engine braking is usually used on a truck? I called the dealer and they are clueless about the car, he doesn't even know it's a plugged in Hybrid. All he said is 'Make an appointment and he will check it out'. The main reason for me to buy this car is not using fossil fuel and the ICE comes on every few really annoys me. I suppose I have to live with this of just go and get an EV. Thanks for listening.

 

[obermd]

As long as I don't charge above 90%, I don't see the ICE starting up in my Clarity. The few times I have charged the battery 100%, the ICE comes on when I first apply the brakes just a block away from my house at the beginning of my commute.

Something else isn't right then. My wife's Clarity doesn't do this. When possible, the car will use regenerative braking even with the brake pedal, but if the battery is full it goes straight to the friction brakes.

 

[mowcowbell]

Something else isn't right then. My wife's Clarity doesn't do this. When possible, the car will use regenerative braking even with the brake pedal, but if the battery is full it goes straight to the friction brakes.

I don't charge to 100% very often, it is quite possible my car was just engaging the ICE to keep the engine lubricated. Could have been just a odd chance it happened soon after leaving my house.

 

[mikepaynter11]

I don't charge to 100% very often, it is quite possible my car was just engaging the ICE to keep the engine lubricated. Could have been just a odd chance it happened soon after leaving my house.

When your car is fully charged it does not need anymore charging. Therefore you do not get regen braking for a few miles of use. Of course you do not want to overcharge your battery.

 

[2002]

I don't charge to 100% very often, it is quite possible my car was just engaging the ICE to keep the engine lubricated. Could have been just a odd chance it happened soon after leaving my house.

Unless you have gone a long time without using ICE (like weeks or months) it is unlikely that your Clarity is going into System Check which is when ICE will start up and run for a period of time when it hasn't been used for a long time.

Instead what you are almost certainly experienced is exactly what the OP started the thread about, the well known phenomenon that when the battery is full and you do any significant braking or slowing within a mile or so of your house, regen is unavailable because of the full battery, and if the amount of slowing is more than the friction brakes can handle the car uses engine braking, which in the case of Clarity requires starting the engine. We don't know why it can't just spin the cold engine for braking, we just know this is how Clarity works. Although not documented by Honda it is very commonly experienced. In fact when I gave this explanation in post #8 the OP replied in post #10 that this is the likely explanation for their situation as they said ICE comes on when they stop at the end of their street. Unfortunately the OP didn't quote me in their reply so it was probably not clear to everyone that the OP was replying to my explanation.

The other part of it is that once ICE starts it has to run for several minutes to warm up, this is an emissions requirement. Unfortunately this means that even a few seconds of braking/slowing on a full battery will result in several minutes of ICE usage. It's the same as when you press the pedal all the way to accelerate and activate ICE, even though you only need that burst of acceleration for a few seconds, ICE will now stay on for several minutes before shutting off. The gas is not wasted however as it is used to power the car or recharge the battery, but it is disconcerting to those who are on a short trip that in theory could be run entirely in EV and they do not like that some gasoline is used. However the amount of gasoline used in these scenarios is quite small, but I can understand why people don't like it, but that is just how our car works. The Chevy Volt was better in this regard as it would stay in EV until you used up the battery. But the Clarity is so much nicer to drive and is so roomy and comfortable that I don't mind that in these rare situations (for me anyway) that ICE sometimes comes on for a few minutes.

 

[obermd]

if the amount of slowing is more than the friction brakes can handle the car uses engine braking

If this were the case I can 100% guarantee the Clarity would never have passed FVMSS requirements for sale in the US. The friction brakes are required by these standards to be able to stop the car even with the engine providing full power to the transmission.

 

[2002]

If this were the case I can 100% guarantee the Clarity would never have passed FVMSS requirements for sale in the US. The friction brakes are required by these standards to be able to stop the car even with the engine providing full power to the transmission.

I was really thinking of design considerations of the brakes, not that they couldn't actually stop the car if needed. In normal use the friction brakes on an EV or hybrid are used very little which is why brake pads last so long. My Prius was still on the original pads and shoes at 150,000 miles when I traded it with plenty of wear left.

The Clarity is often lauded for the smoothness of its braking compared to many other regenerative systems, although presumably all of them are getting better compared to older systems. In contrast, apparently the friction brakes as designed are not ideal for providing full braking, perhaps for smoothness reasons, perhaps for long term wear reasons. Whatever the reason, in situations where regen is not available because of a full battery the Clarity sometimes utilizes engine braking in addition to the friction brakes.

For an even more mysterious reason the engineers decided that ICE needs to start up in these situations. One theory I have seen tossed out there is that it uses ICE power to in effect fight against the generator, thus providing greater resistance to the motor than just cold spinning. I tend to think more likely is that running ICE is a way to modulate the engine braking force, i.e. as ICE uses more gasoline to turn itself it will reduce the braking force available to the generator, thus providing a level of control. A far fetched theory perhaps, but I have yet to hear a less crazy explanation for why so many people experience ICE coming on when braking or slowing with a full battery.

 

[60Hertz]

This is wild speculation on my part, but I suspect that some part of the Clarity drive software was borrowed from a non-plug in hybrid. Use of engine braking is common in a regular hybrid, because it is very easy to fill up the relatively small battery, for example on a long downhill. Of course, in a regular hybrid you expect to use the ICE every time you drive, so it is not a concern. As a Clarity owner, one comes to accept that the ICE will come on at unexpected times in ways that defy logic and are not repeatable. For example, every day I put on a full charge at work, and then drive ~100 yards down the driveway at 15-20 mph where I have to stop at the street and turn left. I've done that maybe 100+ times since I've purchased the car, and exactly 2 of those times the ICE has started as I'm coming to a stop at the end of the driveway. Absolutely no good reason for the ICE to start in either situation. At that speed, clearly the friction brakes are all that are needed.

Why your Clairty is doing it every time is difficult to say. For sure I would be dissatisfied with the vehicle and make that known to your dealer's service department. The only good news that if it is repeatable, that makes troubleshooting easier. Nevertheless, you will for sure face an uphill battle. Typical response you can expect from your service adviser is to blame the user and/or explain it away, even though they probably understand less about the car than you do. Patience and persistence. Good luck.

 

[obermd]

Yesterday my wife and I took her Clarity out and about. I thought I heard the ICE starting up, but when I checked the propulsion power source display there was no indication of gas being used. In addition, the gas range didn't decrease. Between the car not reporting gas usage and the gas range remaining steady, I suspect what I was really hearing was the oil and (ICE) coolant pump lubricating the ICE engine so it could be safely used to assist with engine braking.

Based on what I saw & heard yesterday, I suspect OP and others who think the ICE is running in this situation are hearing ICE related lubrication and coolant pumps lubricating the gas engine so the car can use it to assist with engine braking.