High-Pitched Motor Noise

[robxb]

Hey folks, I made an in depth video my my experience with this issue. I have about 12,000kms on my Kona. I recorded multiple instances of the high pitched metallic screeching sound, and put a high-pass filter to eliminate the wind noise. I did this out of the window and under the hood.

I got "exclusive" dashcam footage, with audio, of the dealership's test drives, which was sub-par in my opinion.

Chapters are labeled in the video for your convenience!

 

[R P]

Have you driven in other Kona EVs to see if they make the same noise? I don't hear it in mine, but I know some have said that depends on your hearing frequency sensitivity.

 

[robxb]

Have you driven in other Kona EVs to see if they make the same noise? I don't hear it in mine, but I know some have said that depends on your hearing frequency sensitivity.

No I haven't, but this is the same noise that other people have been sharing with the same description

 

[R P]

No I haven't, but this is the same noise that other people have been sharing with the same description

However, many others have not, like myself. It would be interesting to see if you hear something that others do not.

 

[Anaglypta]

Hey folks, I made an in depth video my my experience with this issue. I have about 12,000kms on my Kona. I recorded multiple instances of the high pitched metallic screeching sound, and put a high-pass filter to eliminate the wind noise. I did this out of the window and under the hood.

I got "exclusive" dashcam footage, with audio, of the dealership's test drives, which was sub-par in my opinion.

Chapters are labeled in the video for your convenience!

First thing to say is that hearing is subjective - it very much depends on your age and how sensitive your hearing is. What I am hearing in your recordings sounds like classic inverter whine, and there's not much you can do about that without redesigning stuff.

https://www.sae.org/publications/technical-papers/content/2020-01-1269/

John.

 

[wizziwig]

If you can hear it in the recording, then you should be able to hear it from the car and it wouldn't be a hearing sensitivity issue. Or is the recording much louder than what the car produces?

 

[R P]

I don't know where Rob lives, but if he was near me, I would invite him to listen to my car. When reading these noise reports, I have listened hard, and asked my wife and son, too, if they could hear something. But no such sound heard by anyone. This includes driving by cement walls, too, with windows open. That's why I recommended to Rob to try another car and see if he hears it, and the other owner doesn't.

 

[wizziwig]

The best way to get your service tech to immediately drop the "blame it on brakes, tires, etc." excuse is to switch car to neutral while it's emitting the noise. If noise stops, you know it's not caused by those components. That's how I isolated the tapping issue coming from my Niro motor.

Regarding this high pitch Kona noise, I don't hear that from inside the Niro, even driving in enclosed underground parking lots (my VESS is disabled). I do hear it in recordings people have made of Niro and Kona motor compartment. Those recordings were made to illustrate the motor tapping noise so difficult to say if a non-tapping Niro motor would also produce the high pitch noise. I suspect they are independent issues and you just don't hear it inside the Niro due to better noise isolation which keeps the noise contained. I do hear a different 3 kHz ringing/chirping sound from inside the cabin when speed hovers around 53 mph. Seems like some kind of resonance from the inverter that starts and stops at specific power draw levels (previously posted links to recordings).

High pitch noises can be more irritating than the low frequency sound of an ICE because our brains are hard-wired to detect them (think baby crying, animals in distress, etc.). This makes them more difficult to tune out and ignore.

 

[Chris-Ca]

Hey folks, I made an in depth video my my experience with this issue. I have about 12,000kms on my Kona. I recorded multiple instances of the high pitched metallic screeching sound, and put a high-pass filter to eliminate the wind noise. I did this out of the window and under the hood.

I got "exclusive" dashcam footage, with audio, of the dealership's test drives, which was sub-par in my opinion.

Chapters are labeled in the video for your convenience!

That’s the exact noise mine makes. I notice it driving down side streets. It’s the only thing I am annoyed about with the car.


Sent from my iPhone using Inside EVs

 

[KiwiME]

Hey folks, I made an in depth video my my experience with this issue.

Thanks for making the video. It's alway good to have a thorough, documented explanation of a complaint. It seems the dealer was looking for something a lot more obvious and traditionally "automotive" in nature. Anyone who's working in automated servo motor or machine tool systems knows the noise those things make when holding position, exactly the same. I sometimes hear this from a passing Leaf or Prius, and occasionally my Kona in the right conditions but with the windows up all is silent other than a slight gear whine under acceleration.

 

[Electric Rich]

Hey folks, I made an in depth video my my experience with this issue. I have about 12,000kms on my Kona. I recorded multiple instances of the high pitched metallic screeching sound, and put a high-pass filter to eliminate the wind noise. I did this out of the window and under the hood.

I got "exclusive" dashcam footage, with audio, of the dealership's test drives, which was sub-par in my opinion.

Chapters are labeled in the video for your convenience!

Hi Rob. I too have this same noise. Totally agree its not meant to be there. Hard to hear unless you have a rebound surface close to the car.
To me it must be metal on metal, thus its an issue.
Interestingly my mate had his motor replaced due to the tapping noise and I was keen to see if he had this noise after the replacement. He did.!
Not as loud as mine but it was there.

 

[Electric Rich]

Hey folks, I made an in depth video my my experience with this issue. I have about 12,000kms on my Kona. I recorded multiple instances of the high pitched metallic screeching sound, and put a high-pass filter to eliminate the wind noise. I did this out of the window and under the hood.

I got "exclusive" dashcam footage, with audio, of the dealership's test drives, which was sub-par in my opinion.

Chapters are labeled in the video for your convenience!

Hi again Rob, just interested when you hear it. EG mine occurs when I accelerate, even mildly, it then disappears at throttle off, then comes back on when you feel the regen cut in. Says to me its drive train related.

 

[KiwiME]

Well, as electromagnetic noise you would expect it to be proportional to current, as you’ve described. There is no question that the source is harmonics from the high frequency switching.

 

[Electric Rich]

Hi Kiwi, I assume you disagree its the motor/drive chain? Electromagnetic noise may increase proportional with current but that doesnt mean the noise couldnt be drive train related. How do you know its harmonics from electromagnetic noise? Why couldnt it be bearing noise when the motor is engaged?
You seem like a clever bloke so I am happy to be convinced but, I'm not sure what your reply exactly means.

 

[KiwiME]

Well, bearings and other rotating drivetrain components with moderate mass and oil lubrication don't normally have resonances at such high frequencies, around 10,000 Hz. Some structural items can "ring" like a bell but the energy must be there to do that, plus the engineers designing such items would have to miss out correcting that. The VESS tops out at around 5,000 Hz while the noise in question is more like 10,000 Hz when analysed.
"Switching" noise is commonly heard in switch-mode power electronics and motors, but is usually harmless. EVs are essentially closed-loop servomotor systems, similar to those which have been used industrially for decades, and since around the '80s using switch-mode amplifiers for efficiency instead of linear types.
For example even at home a subtle switching noise can often be heard from a PC power supply while it's in "sleep" mode.

 

[Electric Rich]

Thanks Kiwi, so it sounds like you don't think its much of an issue, just a slightly annoying noise we have to put up with ?

 

[KiwiME]

Well, I can't discount the possibility that some Konas may make more of this noise than others for reasons currently unknown. There have been a number of complaints and no solutions to those so far.

 

[robxb]

Hi again Rob, just interested when you hear it. EG mine occurs when I accelerate, even mildly, it then disappears at throttle off, then comes back on when you feel the regen cut in. Says to me its drive train related.

I'll have to try a little bit more in depth sometime soon. I have been working from home since covid hit and my wife has been driving it and leaving her ICE car in the garage, so I don't get it often haha. Will report back once I test it a little more.

Is there anyone in the Toronto area that doesn't have the noise? I would be interested in meeting up to compare them and do a couple recording tests.

All this being said, I am disheartened because @Brennan Raposo has had parts changed with nothing solving the issue

 

[robxb]

To those who have their gear reduction unit changed (gearbox/transmission/etc)
First: Was it to silence the high pitched hissing noise as seen @2:08 in the video below? That is the only noise that this thread is about. Not the "card in bike spokes" noise, the brake clunk, etc.
Second: Did this solve the issue?
Third: Did the sound ever return?

Just got my Kona back yesterday after four long weeks in the shop. Gear Drive Unit replacement.
I had almost forgotten what it was like to drive my car without extra noise...I just hope it doesn’t come back. Only time will tell!

@echeck How has it been the past ~3 months? To confirm, you had the hissing noise that can be heard at 2:08 in this video? Has it come back at all (and have you been driving, considering covid isolation, etc)?

So, now I'm wondering how the 'whining' noise fixed by the gearbox replacement relates to the hissing noise (this thread), the ticking noise (the other thread) or possibly a new problem entirely?

@KiwiME I wonder if some people are using whining and hissing synonymously. I always thought they were.

I have a new vibration (it was a whine in winter) that is not the original hiss noise (that is pure harmonic noise) and it doesn't seem to be the tapping noise from the other thread. Dealer says it's a bearing in the gearbox.

@victor_2019 Are they going to replace the gearbox because of it? Are you able to record the sound to share with the community?

So I have read through all 23 pages of the thread to get myself caught back up on the perceived issue (perceived as an issue by many, but not by others). As some other users have noted, they are getting their gearboxes/gear drive units/gear reduction units (I assume all point to the same part?) changed upon thorough inspection, many with black oil coming out of it (pulled out, not leaking). The oil is supposed to be a translucent, golden-brownish colour, as seen here https://blog.naver.com/doohan500/221841433777, and it's thought that there are aluminium or metal filings/dust/pieces that are getting shredded in there, causing the discolouration (no word from Hyundai, as shops are sending the parts back for inspection).

I am wondering how people's driving habits are affecting this. My thought is that perhaps people who have a heavy foot are experiencing it more, as stepping on it in sport mode all the time might (?) be too much for the internal parts to handle, shredding off tiny bits with all of that torque. Do those who always drive economically, basically never putting the pedal to the metal, experience the hissing sound?

I know that @Brennan Raposo had his gear reduction unit swapped (twice, I think?), but the sound continued. Perhaps a flawed unit was installed? I wonder if some of these units coming off of one assembly line or out of one factory might be good and silent while the others are bad.

 

[R P]

I had the reduction gearbox changed because of the tick tick noise. Only worked for about 400 kms and then started again. Eventually had the motor replaced, and so far so good. I never did have the high pitched hissing sound.