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" ?
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NVH at the Start of the New Car Development Program
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RE: NVH at the Start of the New Car Development Program
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
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RE: NVH at the Start of the New Car Development Program
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
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
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RE: NVH at the Start of the New Car Development Program
RE: NVH at the Start of the New Car Development Program
"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
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RE: NVH at the Start of the New Car Development Program
Thanks.
RE: NVH at the Start of the New Car Development Program
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
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RE: NVH at the Start of the New Car Development Program
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
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
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RE: NVH at the Start of the New Car Development Program
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