gas engine coming on at low speeds with full charge?

[CarsonGrey]

I've had two episodes recently where my Clarity was in Eco mode, with a full or mostly full battery and the gas engine came on inexplicably. The first time was several weeks ago. I was stopped at a light and all of a sudden the engine came on and stayed on for a mile or two after I pulled away from the light, before switching off and back into EV mode. As it should have never come out of EV mode while stopped, much less on a full charge, I had the dealer look at it and they ran a diagnostic and checked Honda's internal forums and found nothing.

This afternoon, I floored it up a small hill in Eco mode kind of just playing around and the engine kicked in, as expected. But then it wouldn't go off. For the next 15 minutes, the car would not flip back into EV mode, even though I was driving 35 mph in Eco mode with 75% battery charge and using the regen paddles. Finally, when I thought I was going to have to pull over and turn the car off and then on again, it suddenly switched back to EV mode and then worked fine for the rest of the drive home (15 miles).

Thoughts? Similar experiences?

 

[CarsonGrey]

I've had two episodes recently where my Clarity was in Eco mode, with a full or mostly full battery and the gas engine came on inexplicably. The first time was several weeks ago. I was stopped at a light and all of a sudden the engine came on Speed Test Solitaire essay writer and stayed on for a mile or two after I pulled away from the light, before switching off and back into EV mode. As it should have never come out of EV mode while stopped, much less on a full charge, I had the dealer look at it and they ran a diagnostic and checked Honda's internal forums and found nothing.

This afternoon, I floored it up a small hill in Eco mode kind of just playing around and the engine kicked in, as expected. But then it wouldn't go off. For the next 15 minutes, the car would not flip back into EV mode, even though I was driving 35 mph in Eco mode with 75% battery charge and using the regen paddles. Finally, when I thought I was going to have to pull over and turn the car off and then on again, it suddenly switched back to EV mode and then worked fine for the rest of the drive home (15 miles).

Thoughts? Similar experiences?

thank you my issue has been solved

 

[craze1cars]

For the benefit of others who may come across this, it’s pretty normal behavior for the Clarity to do this, not an indicator of a problem.

 

[mattheo0118]

When the battery is full and you're going on a decline. The engine will kick in because the car can't Regen anymore electricity into the battery.

 

[JCA]

What you noticed the second time (bar going white and car going in and out of EV mode for 15-20 minutes) is likely a "system check" that the car does every few weeks. It is a bit opportunistic; if it's been a couple weeks since the last one and the engine comes on for other reasons (e.g. flooring it or regenerating with full battery), it'll do the system check then. After ~3 weeks if the engine hasn't run at all it can just happen even without a trigger.

 

[Philemon]

but, if the ICE start when the battery is full and we go for regen, I don't see the logic to start the ICE to empty the battery. ICE starting ask for fuel, not electron ?


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[JamesW1988]

This could be due to engine overheating.

 

[neelyang77]

For the benefit of others who may come across this, it’s pretty normal behavior for the Clarity to do this, not an indicator of a problem.

When the battery is full and you're going on a decline. The engine will kick in because the car can't Regen anymore electricity into the battery.

 

[neelyang77]

When the battery is full and you're going on a decline for phd dissertation help. The engine will kick in because the car can't Regen anymore electricity into the battery.

also, we don't know if these are bugs or normal operation, so taking it to Honda is good, but you might need to push dealer to report issue to Honda. Don't expect an immediate fix or anything.

 

[Annawhite]

I've had two episodes recently where my Clarity was in Eco mode, with a full or mostly full battery and the gas engine came on inexplicably. The first time was several weeks ago. I was stopped at a light and all of a sudden the engine came on and stayed on for a mile or two after I pulled away from the light, before switching off and back into EV mode. As it should have never come out of EV mode while stopped, much less on a full charge, I had the dealer look at it and they ran a diagnostic and checked Honda's internal forums and found nothing.

This afternoon, I floored it up a small hill in Eco mode kind of just playing around and the engine kicked in, as expected. But then it wouldn't go off. For the next 15 minutes, the car would not flip back into EV mode, even though I was driving 35 mph in Eco mode with 75% battery charge and using the regen paddles. Finally, when I thought I was going to have to pull over and turn the car off and then on again, it suddenly switched back to EV mode and then worked fine for the rest of the drive home (15 miles). faceshapeapp

Thoughts? Similar experiences?

I’d be curious if this could be related to the engine warming up or the car protecting the battery after the hard acceleration. The fact that it stayed on for 15 minutes despite having plenty of charge is definitely unusual, though. Has anyone else with a Clarity experienced the same thing after flooring it?

 

[insightman]

There are a few things that can cause the engine to run while in EV. Some of them might combine to extend the length of time the engine runs before shutting itself off.

• Pressing the accelerator past its "click" point (about 3/4 of its travel), starts the engine to give you the extra power you need
• Incomprehensible to me, the engine starts up to use up excess regen power when using the brakes with a fully charged traction battery
• When the engine has been dormant for a long time, it starts up to check things out, move some oil around, and use up some old gasoline
• In cold temperatures, the engine may come on to generate more heat than the toaster coils can deliver

 

[Conelite]

• Pressing the accelerator past its "click" point (about 3/4 of its travel), starts the engine to give you the extra power you need

What if you don't go past the 75% detent? Ive noticed I can keep it well below the 75% throttle detent and my engine kicks on under hard acceleration. Super annoying.

Wish there was a way to Force EV mode no matter what.

 

[Joe17]

Mine tends to do the same thing unless in eco mode.

 

[insightman]

What if you don't go past the 75% detent? Ive noticed I can keep it well below the 75% throttle detent and my engine kicks on under hard acceleration. Super annoying.

Wish there was a way to Force EV mode no matter what.

Sorry, I forgot about how the white needle on the curved blue line on the POWER/CHARGE Gauge indicates when the engine will start up, regardless of how far the accelerator pedal is pressed. From the Clarity Owners Manual:

A soft foot on the accelerator pedal while observing the white needle gives you the best way to minimize engine activity.

My wish is for an HV mode switch that persists after you shut off the Clarity. So we're wishing for opposite things. I want to run the engine to conserve charge and you want to run the motor to conserve gas and prevent the annoying sound and vibration of the engine.

 

[Joe17]

That's great and all but I know for a fact if I'm in normal or sport mode the engine will come on before reaching those dashed line (end of blue arc). In eco mode the dashed lines will not move towards the white line under acceleration unlike the other two modes.

 

[megreyhair]

Heavy braking while batt is full will trigger eng to start. It will also start if the engine hasn't start for awhile.

 

[insightman]

That's great and all but I know for a fact if I'm in normal or sport mode the engine will come on before reaching those dashed line (end of blue arc). In eco mode the dashed lines will not move towards the white line under acceleration unlike the other two modes.

My Clarity (delivered in 2017) follows the rules; its engine remains dormant until I need it. Your Clarity isn't following the rules.

I don't know enough to imagine what kind of sensor in your Clarity could be malfunctioning. Other than a visit to your dealer's Clarity specialist (as if) , your only option is to briefly disconnect the 12-Volt battery to reset your Clarity's computer and hope that fixes the problem.

 

[jorgie393]

What if you don't go past the 75% detent? Ive noticed I can keep it well below the 75% throttle detent and my engine kicks on under hard acceleration. Super annoying.

Wish there was a way to Force EV mode no matter what.

My memory from early discussions on this is that the click point only corresponds to engine start when you are [in] Eco mode. That’s when the mapping of the engine start and the click detent line up.

If you are usually driving in standard mode, then you might well kick in the engine by modest pushing of pedal, even if you don’t reach the click, because the mapping to acceleration is more aggressive.

I drive in Eco 100% of the time so I’ve never tested this, and therefore can’t be certain but I remember this was fairly well established in the past.

Edit: this is actually why I keep it in Eco mode, so that it usually is EV all the time except under unusual circumstances, and I don’t accidentally kick on the engine, just when merging, etc.

 

[Joe17]

If the accelerator is pushed quickly, when not in eco mode, the engine will start even if not past the detent.

 

[Dan Albrich]

So I'd just add, some of us that live on a hill experience the gas engine starting almost daily as we drive down our hill. This occurs because we plug in at home, get a full charge. We then head out on a full charge, and the down-hill causes some degree of recharge/regen and the EV system is already full. Something about starting the gas engine (counter intuitive) dissipates the excess charge. So yes, this happens and for me it's an almost daily occurrence. It may also be the reason that some PHEVs (i.e. Volt) have "hill mode." It leaves a buffer so you charge to say 95% intentionally and not 100%, since each day when you head down your hill you get that other 5%.

Mitigating: Of course, don't engage paddles when going down a hill when already full. Using the break peddle is a little less likely to trigger gas engine start but it still happens. While its fall/winter and not obnoxious, I turn the heat to "high" until I get down my hill. If I've using EV capacity at a decent rate (via the heater), I can sometimes avoid starting the gas engine. And of course, you can use a schedule or other method to charge below 100% if you want. AFAIK, there is no built-in method to tell Clarity to limit charge by percent, save time. i.e. it does have a schedule app where you can charge for say 2 hours instead of 2.5 (level2). But if you schedule charge specifically, you "break" auto-charging outside that time window. You can do a combo of schedule and charge start override, but that's something else to manage. I just turn on the heat coming down the hill. There's more than one way to manage it.

One last thing: There's sort of an extreme version of over-charge on Clarity that I sometimes (and thankfully not often) experience only when I forget to turn on the heat and go downhill with a full charge. The whole car stutters. It's as if someone is pumping the breaks repeatedly and is super obnoxious. Anyway, turning on the heat on high fixes this condition, and it doesn't happen often. But there's something about the over-charging that the car doesn't "like." I don't recommend ignoring this, and it may not be good for the car. I don't know, but it only occurs when at a full-charge and going down hill. Finally, my car has always been on the low amp hours measurement compared to other Clarity's so I think i literally have less buffer. But this may be something others will see as their traction battery degrades in time. I say this because this/these issues for me are much more pronounced in Fall/Winter, and almost nonexistent summer when estimated EV range is higher. My estimated EV range is now 22-24 miles total. I sometimes see max 32 miles summer.

Finally this is not to dismiss the other things that are mentioned in this thread that also start the gas engine. i.e. pressing gas peddle hard or past the detent, and maintenance mode that happens automatically from time to time. This car is a hybrid, and yup, the gas engine does engage at various times and it to be expected. BTW, even with this/these issues, i love my Clarity. My commute is about 20 mi daily, so I can run in EV mode mostly.