Low speed engine noise

Thanks. I think the depleted battery is the reason for your angry bees.
If you’ll select HV manually before the charge is depleted you can avoid the angry bees. On a very steep hill with an almost full battery, my ICE only reved up to a mid range rpm low to moderate hum. I’ve never heard the angry bees.

 

Sure, but it’s still abnormal behavior. I’ve done the same hill on a depleted battery without the bees just normal engine noise. It doesn’t make sense to save EV for the last half mile if I’m going on a long trip - I want to fully use it.

 

I’m all for economy, but if you try to squeeze every last allowable electron out of the battery you’re going to have to accept the occasional angry bees’ very high reving.
I’ve found that with a little juice in the battery “bank” I have very low ICE rpm/sound and even on steep hills (at sea level to 1,000 ft) I only get a mid range rpm/ low hum. By not allowing the battery to deplete all the way to zero usable charge, I’ve never heard the angry bees.

 

You won't hurt the engine climbing hills with a depleted battery, but your passengers will notice the contrast from eerie silence.
Thats because it's not possible to hide a 1.5 liter engine running wide open throttle over 3000 RPM with a 13.5 to 1 compression ratio.
If it's called abnormal behavior, there has to be the acknowledgement that its also expected behavior and by design.
The future of gasoline engines will be very small (right-sized), very high compression, and very efficient engines assisted by electric motors.
The science of masking the less pleasant noises will continue to improve.
And the world will probably adjust some of their aural expectations as gas prices rise and over-sized, less-raspy engines fall out of favor with their horrible efficiency.
Personally, I think you can make judicious use of HV mode and get the best of both worlds, 60 MPG on the highway with gas and 50 miles of in-town silence.

 

I own a Clarity. Has about 1500 miles on it. I started to get the revving issues at low and high speeds when it switched out of EV mode. I'd test driven the car at the dealer before purchasing. And drove a neighbor's Clarity too. Neither of those cars exhibited the revving, even when I was in HV Charge mode. After my car started doing the revving, I asked the neighbor if I could drive his again, when his battery was low. I then drove for 40 miles. The battery charge was gone in about 10 miles and yet for the remaining 30 miles I never experienced the revving sound. My car does it and my neighbor's does not. His does make more noise both at low and high speeds when in HV and HV Charge modes but the car never sounds like the engine is revving. I therefore conclude that come of these cars have an issue and others don't have that issue. I've had mine in to the dealer twice and they say there's nothing wrong. What do we do about this?

 

How many times has yours done it? Mine only does it rarely (handful of times in 29,000 miles). However, I don't know how much of that is my wife being used to it and not complaining anymore. It would be interesting if it is different per car. If you can easily recreate have the service tech ride with you.

 

A couple questions for @Mike Koz:
Same software patch revisions on both yours and your neighbors cars?
Both are in Econ mode?

 

Sadly, it only very rarely goes to the angry bees level of noise. I've driven with a dealer mechanic for 20 miles and didn't get the full effect. But still, the regular ICE sound in my neighbor's car is quieter than in mine.

 

The noise seems to be a resonance inside the cabin.
The car is very quiet outside in the front and rear.
Makes me wonder if there is less firewall mass and/or less sound deadening at the front of the cabin or roof, etc.
I will chock it up to optimistic weight savings unless anyone has thoughts otherwise.

 

It could be the ANC? The active noise cancellation. There is some argument if the car even has it or not, but it makes me wonder if it is either not working as it should or somehow amplifying it instead. It might be that it doesn't work as well at higher RPMs, or maybe if the car is resonating some amplifying it.

 

There are reports of Accord Hybrids with ANC failures.
Anyone know how to disable and enable ANC on the Clarity for testing?

 

Disassemble the dash in order to access and and unplug the ANC module. Someone here did it after an audio upgrade that required it...they had photos of the process...can’t find the link right off, maybe someone else can assist in locating it?

 

I searched for Unplug ANC Module and found this post

 

Thar ya go! Thanks mr insightman! Post 56 and 57 is exactly what I was remembering -- with clear photographic instructions on how to disable the ANC module...not to mention rock solid confirmation the system indeed exists on the Clarity.

 

Thanks for reviving the thread Mike. I thought the revving was normal since the other Clarity I've tried at the dealer had it too. I've running the car more on EV mode so it hasn't shown up too much. However, every time I go into HV mode the car revs in stop and go traffic, econ mode and normal, even if I have close to full battery.

To further clarify, it's not an ICE humming noise at test or during a drive. It revs in HV when accelerating from zero to roughly 2/3 bars starting up from a stop light.

I will attempt getting someone to stand outside to listen to it to see if it's a sound only audible inside the cabing or outside as well and if so attempt the ANC fix posted.

 

Have you checked to see if your car has the noise-dampening plugs in place? According to other posts on this forum, some dealers forget to install them/don’t carefully run through the pre-delivery checklist for the car.


Sent from my iPhone using Inside EVs

 

Yes, I have checked under the car and all 4 are there.