×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

NVH at the Start of the New Car Development Program

NVH at the Start of the New Car Development Program

NVH at the Start of the New Car Development Program

(OP)
Could any one explain me about "How the NVH is looked at the start of the any New Car Development cycle" ?

RE: NVH at the Start of the New Car Development Program

1) measure competitors NVH
2)set targets
3) break targets down into budgeted performance for each sub system
4) deliver sub system targets in production
5) confirm that this meets overall targets set in 2)
6) take a well earned break and get a pat on the back

Item 1 often goes to plan. After that it gets a bit messy.

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: NVH at the Start of the New Car Development Program

(OP)
Greg,

Thanks for the reply. Could you tell me more about the
1) Measure competitors NVH

What all will be measured in NVH? Is that the tactile responses and the noise intensity at the driver’s ear location? Just only that?

What all targets will be derived from the above measured NVH for the sub systems?

I think I am asking too much in one question. It will be helpful if you through some information on this.

Thanks.

RE: NVH at the Start of the New Car Development Program

Well really that depends on what you are doing. I'm not going to go into specifics, each company probably does it a different way.

But, say, for interior noise I'd be looking at front and rear passenger locations, for the following conditions:

1)
full throttle

light throttle

coast

at all engine speeds in appropriate gears

2) Noise at failry low speed on a coarse chipped surface, and the same on a very smooth surface

3) windnoise at various speeds and yaw angles

4) HVAC noise at avarious operating conditions

5) Noise from hitting a strip on the road (impact noise)

6) Noise at idle

These would then be analysed in various ways and targets set.

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: NVH at the Start of the New Car Development Program

(OP)
What about the tactile responses? Is that done in similar way you explained above for the full throttle, light throttle and Idle? What are the most critical and contributing subsystems for the tactile responses and structure borne noise and how they are dealt with?

RE: NVH at the Start of the New Car Development Program

Yes the tactiles would be similar.

"What are the most critical and contributing subsystems for the tactile responses and structure borne noise and how they are dealt with?"

Aye well, that's for me to know, and you to find out. Sorry, I would describe that sort of info as competitive advantage.

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: NVH at the Start of the New Car Development Program

(OP)
Do you suggest any good NVH books and readings which gives more perspectice on the practical aspects?

Thanks.

RE: NVH at the Start of the New Car Development Program

The lack of a good, general, NVH textbook is an obvious gap in the market. It may be that it is too difficult to write about in a coherent fashion.

Anyway, start with all the free stuff on the B&K website. Then look at SAE papers, particularly the bundled NVH proceedings. The IMechE also has some useful conference papers.

Then you've got acoustics textbooks, like Beranek, and vibration control by Harris.

This is a good one:
Noise and vibration 1982, edited by R. G. White and J. G. Walker.




Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: NVH at the Start of the New Car Development Program

Hey, Greg!
I'm embarking on a completely new vehicle program right now, and am even as I write this in the midst of defining our NVH targets just as you outlined - except I'm not bothering with that benchmark the competitors bit: I know some are better than us,  and I know where we can get to, and where we can't.

Besides,  the Chairman has already said we'd have "Lexus" interior noise levels...   in a Class 8 (U.S.A.) heavy truck!
LOL!
That'll only require dropping interior noise 11 dBA (or more) from where we are today!

Ah,well,  that's job security, eh?

Regards,
Rob

RE: NVH at the Start of the New Car Development Program

Ah, well. The Lexus LS400 was the ONLY car I've really respected as a mobile drawing-room. Nakamichi stereo, woo woo.

11 dBA is a fun task. Hydromounts. Dual mass flywheels. Harmonic absorbers. Intake isolators. Exhaust modes. Intake and exhaust acoustc tuning. Leak paths. Body sensitivity. Heavy glass. Ignition timing optimisation. Stiffen all the ancillary brackets.

That'll get you 3-5 dBA. Then it gets tricky. As my good friend Crowther-san once said, the first 5 dB is easy.

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: NVH at the Start of the New Car Development Program

Actually,  I can get 3 dB with fairly simply barrier and panel damping treatments.
Then such radical ideas as isolating the exhaust system from the frame will be employed...

The engine unfortunately have never been given any NVH treatments,  and our engine suppliers don't at present even have a hemi-anechoic dyno,  nor have they put to use any of their FEA analyses of block structures.

This should be entertaining.
I think I may post periodic updates.
Regards,
 - R

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources