Team-BHP > Electric Cars


Reply
 
Thread Tools Search this Thread
Old 13th March 2018, 08:09   #1
Distinguished - BHPian
 
dark.knight's Avatar
 
Join Date: Apr 2013
Location: Beans Town
Posts: 1,840
Thanked: 8,164 Times
Default NVH (cabin noise) issues in Electric Cars - A Study

While electric cars without doubt seem to be the future, there seem to be quite a few issues related to them and in general the whole landscape, in anticipation that they shall become the majority cars everywhere in about 2 decades. The first post that made me aware of Noise Vibration Harshness (NVH) issues in an electric car was actually a post made by BHPian ach1lles during his ride in a Tesla, and he wrote :

Quote:
It was so damn creaky from everywhere. Those cars are not well put together. Also, the road noise that comes in is louder than any engine noise in similarly priced luxury cars.
http://www.team-bhp.com/forum/intern...ml#post4344293

As I read another article, I remembered this post.. turns out that there indeed are issues related to NVH in electric cars, acknowledged by the manufacturers themselves. Part of the reason(s) they give (in defence) are :

- There is no engine which vibrates and generates noise, hence not being able to cancel out the noises of certain squeaks, rattles and wind noise.
- The cooling fan also generates more noise in the absence of the engine.
- The transmission noise, road noise and tyre noises too become prominent when in motion due to the same reason as above.

So far the excuse has been only that of lack of noise cancellation i.e making one noise which is tolerable (white noise-esque), to cancel out the other.. much like how car exhaust mufflers resonate, redistribute and then cancel the noise. This still doesn't excuse them from the part where the whole car squeaks, creaks and rattles as has been reported in almost every Tesla as and when they cross even minor milestones on the odometer.. the disturbances have been reported from the windscreen, seat-belt clips, door panels, seats themselves and almost every conceivable part of the car which can be read through in detail in Tesla forums.

Shows that a tech company that dabbles in cars, focuses purely on the tech and no so much in quality of construction, chassis stiffness, quality of plastics and other aspects. Of course electric cars being highly expensive as a technology, cannot maintain a popular pricing model without sacrificing on other aspects. To me though a rattle is unforgivable.. no car of mine has ever had it.

Quote:
National Electric Vehicle Sweden, the new owner of what used to be Saab Automobile AB, is currently using Altair’s Squeak and Rattle Director, described as “a comprehensive set of software automations that rapidly identify and analyze design alternatives to eliminate the root causes of squeak and rattle in assemblies.” DE recently talked to NVH experts from Altair.
These seem to be popular patch-works to eliminate such noises :

Quote:
NVH sound package for electric vehicle solutions which includes sound design & perception. In order to address the road and wind noise, vehicle integration processes were fine-tuned and controlled. Lightweight structures such as foams butyl pads, rubbers and liquid foams were used to avoid squeak & rattle. HVAC noise was tackled by optimizing the compressor and blower noise system performance, without compromising the cabin comfort.
Electric vehicles have another noise related problem to worry about as well.. that of NOT being able to make noise externally thus being unable to warn pedestrians of its passing-by. Seems to me that there are more that a couple of kinks (legal and otherwise) that need to be worked out until the travel landscape is electrified.

Links:

http://ieeexplore.ieee.org/document/7386867/

http://www.digitaleng.news/virtual_d...tric-vehicles/

Last edited by dark.knight : 13th March 2018 at 08:25.
dark.knight is offline   (8) Thanks
Old 14th March 2018, 17:27   #2
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 61,642
Thanked: 209,994 Times
Default Re: NVH (cabin noise) issues in Electric Cars - A Study

Quote:
Originally Posted by dark.knight View Post
The first post that made me aware of Noise Vibration Harshness (NVH) issues in an electric car was actually a post made by BHPian ach1lles during his ride in a Tesla, and he wrote
I wouldn't consider Tesla as a benchmark as they're a relatively new manufacturer. Even if they built a petrol car, it would still have squeaks & rattles .

Haven't experienced any EVs from high-end manufacturers, but I think they'll easily manage good NVH levels. A 6-cylinder petrol S-Class or E-Class anyway have whisper-quiet engines when cruising at 100 km/h. They could also use noise-cancelling tech inside the cabin (some already do) via speakers.

Quote:
that of NOT being able to make noise externally thus being unable to warn pedestrians of its passing-by
This one is definitely an issue - Related Thread.
GTO is offline   (1) Thanks
Old 14th March 2018, 19:43   #3
BHPian
 
Join Date: Apr 2017
Location: San Jose, CA
Posts: 112
Thanked: 133 Times
Default Re: NVH (cabin noise) issues in Electric Cars - A Study

Quote:
Originally Posted by GTO View Post
I wouldn't consider Tesla as a benchmark as they're a relatively new manufacturer. Even if they built a petrol car, it would still have squeaks & rattles .
Please dont. Too many Model Xs and Ss went out of the shop with niggles and rattles that a normal customer here in the USA would go insane! To this day Tesla still has body issues with door panels, facia panels and dash panels. Dont get me started on the Large Drive Unit NVH issues...
Bhatman510 is offline   (2) Thanks
Reply

Most Viewed
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Copyright 2000 - 2021, Team-BHP.com
Proudly powered by E2E Networks