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Definition of Gearshift Pattern: Innovative Optimization Procedures Using System Simulation
Abstract:
Today's powertrains are becoming more and more complex due
to the increasing number of gear box types requiring gearshift
patterns like conventional (equipped with GSI) and automatic-manual
transmissions (AT, AMT), double clutch and continuous variable
transmissions (DCT, CVT). This increasing variety of gear boxes
requires a higher effort for the overall optimization of the
powertrain. At the same time, it is necessary to assess the impact
of different powertrains and control strategies on CO₂ emissions
very early in the development process. The optimization of Gear
Shift Patterns (G.S.P.) has to fulfill multiple constraints in
terms of objective customers' requirements, like driveability,
NVH, performance, emissions and fuel consumption.
For these reasons, RENAULT and AVL entered an engineering
collaboration in order to develop a dedicated simulation tool:
CRUISE GSP. One of the major tasks of CRUISE GSP is to provide
representative gearshift patterns for all available gearboxes on
the market (including manual transmissions for GSI applications) at
the very early stage of the powertrain development permitting to
discriminate technical solutions.
Once a prototype exists, CRUISE GSP helps to refine and optimize
the gearshift patterns for immediate usage during gear box tuning
in the vehicle.
Being entirely integrated into AVL CRUISE™ (AVL's
simulation tool for vehicle system simulation and driveline
analysis), CRUISE GSP allows the efficient optimization of the
gearbox shift patterns for different driving styles and thus the
reduction of transmission calibration effort in the development
process. By combining AVL CRUISE™ and CRUISE GSP with the engine
tuning optimization tool AVL CAMEO™ a global Powertrain
optimization (i.e., including both engine maps and gearshift
patterns) can now be considered as a future perspective.
AVL powertrain engineering has been using CRUISE GSP on various
calibration projects. For their specific needs AVL have implemented
additional functionality to CRUISE GSP. The GSP WIZARD is a result
of this development. The specific focus of AVL powertrain
engineering is to have a continuous process from simulation to
in-vehicle calibration. In the process the calibration tool is used
by the calibration engineer to speed up the in-vehicle development
and plausibility check results quickly. This helps to avoid a
negative impact on fuel economy and performance while working on
driveability.