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Practical approach to enhance Gear Shift Quality in Automatic Transmissions
Technical Paper
2021-01-0688
ISSN: 0148-7191, e-ISSN: 2688-3627
Sector:
Event:
SAE WCX Digital Summit
Language:
English
Abstract
Passenger utility vehicles like car, SUVs, MPVs are used in wide
application all over the world. Luxuries are becoming essential
features of product mix along with comfort and ergonomics. Customer
desires best gearshift quality with emerging technologies like AT,
DCT, CVT, etc. and every OEM is working hard to achieve it. It is
very difficult to satisfy the customer desire because of
diversities in demographics and geographic. Gear shift quality
(GSQ) is very crucial touch point in overall drive feel of vehicle.
GSQ consist of various parameters like shift feel, precision,
comfort, Shift Noise, etc. It demands tradeoff practices among
various parameters as stated. In this paper, Shift system of
Automatic transmission is explained. Various design parameters of
shift system is explained with practical design approach including
detent profile, gearshift mechanism, cable & dampers, etc.
Among various GSQ parameters, In-cabin noise (Shift Noise) during
gear shifting is also one of the crucial parameter. This paper
thoroughly explains inter-relation between different parameter for
GSQ and its effect on shift noise and shift feel; this is explained
with help of various DOEs and relation matrix. In this study
various practical approaches are explained to reduce in-cabin gear
shift noise and to improve shift feel. The intensity and cause
analysis of different parameters with help of 8d and fish bone
diagrams is explained in the later part of paper. This helped to
build an interrelation matrix for elucidating the crucial and
critical contributing areas, how we can optimize costs is also
explained with help of interrelationship matrix. The exercise is
concluded in the last part of paper by referring the
interrelationship matrix to decide the sequence and priority of
contributing factors, critical areas and least important factors to
be deled with while reducing cabin noise.