17-04-2010, 06:15 PM
Introduction:
This article describes the six-speed automatic transmission used in the North America specification OUTLANDER which was developed by Mitsubishi Motors Corporation. it has the same number of planetary gears as a previously used five-speed automatic transmission.
Development targets:
The main targets are:
-Wide gear range and close gear
ratios
-Wide lockup range
-Low friction
-Lightness and compactness
Some advantages are:
superior fuel
economy, superior power performance
and shift performance, superior
fuel economy and power performance, easy packaging.
Basic structure
6A/T represents a reduction in weight,reduction in overall length,and a reduction in the distance between
the first and third shafts, which means that it is easier to be
packaged.the 6A/T has a wider
gear range and closer ratios between gears,which indicates that it allows better power performance and fuel economy.
A cross-sectional view of the 6A/T shows that its gear train consists of three planetary gear sets:a single-pinion-type front planetary gear set, a doublesun-
gear-type rear planetary gear set and, at the very
back, a double-pinion-type reduction planetary gear set.The clutch system consists of three clutches:a 3-5 reverse clutch , a low clutch ,and a high clutch. The brake system consists of two brakes: a low and
reverse brake and a 2-6 brake.
Hydraulic control system
It is configured using three-way linear solenoids which directly control all clutch and brake pressures,which provides the precise
hydraulic control for smooth shifting.
The linear solenoids of normal low and normal high types are combined with hydraulic switches
to form a compact control valve unit that does not need
to include a fail-safe valve.
Electronic control system
Information from the engine and other parts of the vehicle
is transmitted to the A/T electronic control unit (A/T
ECU) via a Controller Area Network (CAN). This CAN is internationally standardized local area network for incar
communication.
High performance and fuel economy
a) Wide gear range
optimal final gear ratio, the wide gear range yields superior standing-start and acceleration
performance.
Low friction
main friction-minimizing measures are:
1 Reduction of oil pump driving torque by optimized
oil-pump capacity
2 Optimized bearing capacities
3 Use of waved disks
4 Optimal number of rollers in one-way clutch
For more details, refer this report:
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