The introduction of a Sound Quality Engineering Process to Jaguar Cars : executive summary
Dunne, Gerard T. (2003) The introduction of a Sound Quality Engineering Process to Jaguar Cars : executive summary. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b1655135~S15
The control of the noise and vibration generated by an automobile is referred to as Noise, Vibration
and Harshness (NVH) engineering. It involves identifying the design detail required to reduce the
noise and vibration inside the passenger compartment of the vehicle to levels that are acceptable to
the customer. It also involves delivering an engine or a powertrain sound character that is both
pleasing to the customer and that suits the character of the vehicle. Tuning the sound generated by a
vehicle to deliver a particular character is referred to as Sound Quality Engineering. This document
summarizes the work of the EngD research programme that was aimed at developing a structured
process for engineering the Powertrain Sound Quality of an automobile.
The need for developing a Sound Quality Engineering Process at Jaguar Cars was identified
through a review of customer evaluations of the sound in Jaguar's vehicles and those of its
competitors. This review established that Jaguar's existing vehicles were trailing the leading
competition in terms of the delivery of Powertrain Sound Quality. The reason for this shortfall was
that the NVH Department at Jaguar did not have a focus on delivering the customer requirements.
Without this focus there was no means of using the customer level requirements,
for Sound Quality
to drive the vehicle design process. The EngD research programme resulted in the formulation and
implementation of a Sound Quality Engineering Process at Jaguar Cars that addressed this need.
The first part of the research programme involved developing a means of quantifying the
differences in the subjective Sound Quality character perceived by the customer. It was established
that the subjective nature of the Powertrain Sound Quality could be represented by two underlying
dimensions; a measure of the degree of Refinement and a measure of degree of Powerfulness. An
assessment technique was developed that enabled the subjective Sound Quality character for a
given vehicle to be quantified through its location within a 2-Dimensional Sound Quality Space,
the axes of which were defined by each of the two underlying dimensions of Sound Quality. This 2-
Dimensional Sound Quality Space provided the means of quantifying the differences in the Sound
Quality characters for all of the vehicles competing in the luxury vehicle sectors. It was applied to
define subjective Sound Quality targets for all of the new vehicle programmes at Jaguar Cars.
These targets identified the required improvements to each of the two underlying dimensions of
Sound Quality needed to address the shortfalls in Jaguar Cars' existing vehicles.
The second part of the research programme involved identifying the key acoustic features within
the sound signatures of Jaguar's vehicles that were responsible for determining the differences in
subjective perception between these vehicles and their competitors. The changes to these key
acoustic features were related to the required improvements to each of the two dimensions of
Sound Quality that were established from the subjective target setting process.
The final part of the research programme involved developing techniques that linked these key
acoustic features to the noise sources and paths that were responsible for generating them. Through
this link it was possible to establish the changes to these noise sources and paths that were
necessary to deliver the required changes to the key acoustic features. In this way the required
improvements to each of the two underlying dimensions of Sound Quality were used to define the
vehicle design specification at the concept stage of the vehicle development programme and
consequently drive the vehicle design process. The ability to link the subjective customer level
requirements for Sound Quality to the design detail specification has overcome the previously
identified shortfall within the NVH development process at Jaguar Cars.
The techniques developed during the EngD research programme were formulated into a Sound
Quality Engineering Process. Although the process was developed for Jaguar Cars the findings
from the research and the techniques developed have since been applied by the different brands
within the Ford Motor Company. Within Jaguar Cars the process has been implemented across all
of the new vehicle programmes. It has directly resulted in significantly improved Sound Quality
characters in the new vehicles that have been recently introduced to the luxury vehicle market.
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||T Technology > TL Motor vehicles. Aeronautics. Astronautics|
|Library of Congress Subject Headings (LCSH):||Automobiles -- Power trains -- Noise, Automobiles -- Noise -- Testing, Automobiles -- Design and construction|
|Official Date:||June 2003|
|Institution:||University of Warwick|
|Theses Department:||School of Engineering|
|Supervisor(s)/Advisor:||Jennings, Paul Anthony, 1964-|
|Sponsors:||Engineering and Physical Sciences Research Council (EPSRC)|
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