Page 664 - Automotive Engineering Powertrain Chassis System and Vehicle Body

20.1
Chapter 20.1

Vehicle refinement: Purpose

and targets

Matthew Harrison

20.1.1 Introduction and definitions low wind noise;
low road noise;
The book opens with one man’s thesis: low engine noise;
idle refinement (low noise and vibration);
‘‘Styling and value sell cars – Quality keeps them sold’’. Lee Iacocca,
Iacocca: An Autobiography * cruising refinement (low noise and vibration, good
ride quality);
To explain, it takes years and millions of US dollars to low transmission noise;
produce a new car. If the styling is attractive and the mar- low levels of shake and vibration;
keting is effective, and if the value for money is good then low levels of squeaks, rattles and tizzes;
that car will probably sell moderately well for the first few low level exterior noise of good quality;
months after launch. However, if the quality is bad then noise which is welcome as a ‘feature’.
word will get round and sales will quickly drop off. It is vital
that good sales are maintained for a significant period if the The term ‘NVH’ is usually taken to cover:
development costs for the car are going to be recouped. noise suppression;
Lee Iacocca was writing from Ford’s and Chrysler’s noise design (altering the character of noise but not
perspective. Both of these already had their own strong necessarily its level);
brand image and so branding was not included in his vibration suppression;
thesis, but it should be when comparing cars from dif- suppression of squeaks, rattles and ‘tizzes’.
ferent manufacturers.
It is useful to introduce some definitions at this point.
The term Vehicle Refinement ** covers: 20.1.2 Scope of this section
noise, vibration and harshness *** (NVH – a well-
known umbrella term in the automotive industry); The scope of this section is illustrated in Fig. 20.1-1.
ride quality; It has been designed to cover the core science, engi-
driveability. neering and technology required by the NVH engineer
with added material on ride quality and driveability.
A refined vehicle has certain attributes, **** they being: Wherever possible, issues that affect the customer’s
high ride quality; buying decision have been emphasised. Refinement is
good driveability; a customer-facing subject as any refinement engineering

* Lee Iacocca, former President of the Ford Motor Company, former President of Chrysler in Iacocca:An Autobiography, Lee Iacocca with William
Novak, Bantam 1984.
** Refine (vb) to make or become free from coarse characteristics; make or become elegant or polished (Collins English Dictionary). Refinement is
both a process (the act of refining) and a description of the eventual state (fineness, polish, etc.).
*** Harsh (adj) rough or grating to the senses (Collins English Dictionary).
****
Attribute (n) a property, quality or feature belonging to or representative of a person or thing (Collins English Dictionary).
Vehicle Refinement; ISBN: 9780750661294
Copyright Ó 2004 Matthew Harrison. All rights of reproduction, in any form, reserved.