BMW 3-series convertible, Полное руководство по автомобилю

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E93 Complete Vehicle Workbook
85
Hydraulic Unit
The movement direction of the hardtop and rear module are determined by corresponding valve positions and by reversing the direction of
rotation of the pump. The hydraulic pump in the hydraulic unit is driven by an electric motor that operates in two directions of rotation.
Both rotation directions are implemented with a relay switch. The pump motor and the five hydraulic valves are activated by the CTM.
The power consumption of the electric motor is about 40 A (safeguarded by a 50 A fuse). The hydraulic pump generates an operating
pressure of 150 to 200 bar.
To prevent the pump motor from overheating if the hardtop is operated frequently, the temperature of the pump motor is measured using
an NTC resistor. The NTC resistor is connected to the CTM via two wires with a floating ground. An open circuit causes an entry in the
fault code memory, but does not prevent the hardtop from moving.
Two temperature values are particularly important. The lower of these is around 90°C and serves as an "early warning". If this tempera-
ture is exceeded, any hardtop movement that has already begun is continued until it as safely come to an end. If the temperature reaches
105°C, the hardtop movement is stopped immediately. It cannot be resumed until the temperature falls back below 90°C.
Index Explanation
1
Reservoir for hydraulic fluid
2
Fill level mark
3 Bleed screw for emergency actuation
4
Hydraulic pump
5
Pump motor
6
Valve 1
7
Valve 3
8 Valve 5
9
Valve 4
10
Valve 2
11
Relay for counter-clockwise operation
12
Relay for clockwise operation