33
ATF supply and hydraulics
In Mild Hybrid Electric Vehicles (MHEV), the 0D5 transmis-
sion is supplied ATF by two ATF pumps; one mechanically
driven pump on one electric pump. Both pumps draw the
ATF from the ATF intake filter.
Transmission Fluid Auxiliary Hydraulic Pump 1 V475 now
allows the TFSI engine to be shut o under coasting.
Mechanically driven ATF pump
This ATF pump is identical to the twin stroke vane pump
used in the 0BK transmission. It is powered by a chain drive
via the torque converter of the TFSI engine. When the
pump reaches a specified speed of approximately 500 rpm,
it provides a reliable supply of ATF with the auxiliary
hydraulic pump.
662_142
ATF pump,
mechanically driven
Sun gear shaft S1/S2
Brake A
Pump drive hub with spline,
connection to torque converter
Impeller shaft
Chain drive
Transmission Fluid Auxiliary Hydraulic Pump 1 V475
By assisting the mechanically driven ATF pump, V475
provides a reliable supply of ATF for the start-stop func-
tions of the transmission.
If the auxiliary hydraulic pump is unable to circulate ATF
because the overload cut-out has been actuated or a fault
has occurred, the start-stop functions are no longer avail-
able.
If V475 is faulty, the yellow transmission
warning lamp lights up.
V475 operates within an ATF temperature range of 68 -
257 °F (20 -125 °C) and has three output levels. It commu-
nicates with Transmission Control Module J217 via a LIN
bus.
The auxiliary hydraulic pump provides a reliable and quick
supply of ATF. This aids disengagement of the parking lock
and allows delay-free start-up. If the mechanically driven
ATF pump reaches the required speed and is capable of
supplying system pressure by itself, the auxiliary hydraulic
pump receives a signal via LIN bus to stop circulating ATF.
Ground contact for voltage supply
Terminal 30, positive contact
to power supply
LIN bus connector
Brushless
DC motor
G-rotor pump with non-return valve
Connection, pressure
side
ATF suction filter
662_143
Pump electronics –integrated into housing
To Next Page
Loading...
