Z Series E85 Z4 3.0i (M54) ROADST
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Shift travel sensor and selector angle sensor
The gear engaged is recognised from the shift travel sensor and the selector angle sensor:
The shift travel sensor detects the forward/backward movement of the selector shaft in the respective shift
gate.
The selector angle sensor recognises how far the selector shaft turns, and so recognises a change of shift
gate. [more ...]
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Pressure accumulator
The pressure accumulator is fitted on the bottom left of the transmission and makes sure that there is
always sufficient oil pressure for a gearshift to be executed. A piston subdivides the pressure accumulator
into 2 chambers. One chamber is charged with approx. 27 bar nitrogen at -25
°
C. The second chamber
takes up oil from the hydraulic pump. The reservoir volume is approx. 285 cm
3
.
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Pressure sensor
The pressure sensor is installed directly on the valve block and reports the current oil pressure to the SMG
control unit. The hydraulic pump is switched on and off as required.
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Clutch actuator with clutch travel sensor
The clutch actuator executes the coupling/decoupling actions. The release travel is recorded by the clutch
travel sensor. [more ...]
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Hydraulic pump
The hydraulic pump with electric motor builds up a system pressure of up to 55 bar and is actuated by the
SMG control unit.
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Sensor for transmission input speed
The sensor records the transmission input speed for comparison with the engine speed. This comparison
allows the SMG control unit to decide the closing speed of the power flow from the engine to the
transmission via the clutch.
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Expansion tank
The expansion tank makes sure that there is always sufficient hydraulic fluid available in the system. In
addition, the oil is able to expand in the expansion tank. The expansion tank has maximum and minimum
marks for checking the oil level. A filter is integrated into the expansion tank for prefiltering the oil.
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Valve block
The valve block holds the solenoid valves, the pressure sensor, the pressure accumulator, a check valve
and a fine filter.
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Solenoid valves
A total of 4 solenoid valves are installed in the valve block.
3 solenoid valves actuate the clutch actuator and the gearshift actuator for the gearshift movement.
1 solenoid valve actuates the S-Cam brake (S-Cam = bush with S contour) and the gearshift/selector
angle actuator for effecting a change of shift gate. At the same time, the solenoid valve serves as a
pressure relief valve for the hydraulic system.
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SMG control unit
The SMG control unit (GS30) takes the signals received from the sensors and uses these to compute the
actuation signals for the solenoid valves for clutch actions and gear changes. Moreover, the SMG control unit
sends information to various control units, e.g. to the engine speed adjustment, to the transmission program
indicator and to the gear lever position indicator. [more ...]
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Reversing-light relay
The transmission position reverse gear signal is fed by the gearshift travel and selector angle sensors to the
SMG control unit. The SMG control unit generates the signal for the relay. The reversing-light relay is located in
SBT Sequential manual transmission SMG, based on GS6-37BZ E85
BMW AG - TIS
16.02.2013 13:47
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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