BMW 3: Oil supply
The basic functions of the oil circuit of the GA8P75HZ transmission correspond to those of the GA8HP70Z transmission. The oil has the following tasks:
- Lubrication
- Control of the shift elements
- Cooling
It is a conventional pressure circulating system. In addition to the mechanical transmission oil pump known from the GA8HP70Z, an auxiliary electrical transmission oil pump was integrated into the automatic transmission of the G20 PHEV.
Transmission oil pump GA8P75HZ transmission
- Mechanical transmission oil pump
- Electrical transmission oil pump
The mechanical transmission oil pump is driven by a rolling tooth chain on the transmission input shaft. If the separation clutch is open, drive is accomplished via the electrical machine; if the separation clutch is closed, drive is accomplished through a combination of the combustion engine and the electrical machine.
In operating phases with insufficient speed at the transmission input shaft, the auxiliary electric oil pump compensates for insufficient pressure in the hydraulic system, in order to reduce the response time of the transmission in the event of a load request.
The auxiliary electric transmission oil pump is a vane-type compressor, like the mechanical transmission oil pump. It is driven by a brushless direct current motor. The control electronics are integrated in the housing of the auxiliary electric oil pump and are activated by the electronic transmission control (EGS). The electrical transmission oil pump can be operated as of a transmission oil temperature of -5 ºC (23 ºF). In special cases, such as in the event of a failure of the electrical machine, the electrical transmission oil pump can be operated from a temperature of -15 ºC (5 ºF) in an emergency operation, in order to close the separation clutch. This enables the driver to continue the journey, also in the event of failure of the electrical machine.
In the GA8P75HZ transmission, the electrical oil pump occupies the space of the hydraulic pressure accumulator known from the GA8HP70Z. Like the hydraulic pressure accumulator, the electrical transmission oil pump can also be replaced in the event of a fault.
Installation location of electrical transmission oil pump GA8P75HZ
transmission
- Intake pipe
- Bolting points of the electrical transmission oil pump
- Electrical connection
Oil cooling
Engine oil cooling GA8P75HZ transmission
- Transmission oil cooler
- Electric motor
- Connection of transmission oil lines (for cooling the electrical machine)
- Automatic transmission
- Connection of transmission oil lines (for cooling the automatic transmission)
- Transmission oil thermostat
There is an additional transmission oil cooler in front of the coolant radiator. With the aid of a thermostat, the oil circuit is directed through the transmission oil cooler when corresponding transmission oil temperatures are reached.
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Service information
Electronic emergency gearbox release
As with the conventional 8-speed automatic transmission, the GA8P75HZ also
has an electrical
emergency release option.
In conventional vehicles the starter motor
Introduction
The electrical machine in the G20 PHEV is a permanently excited synchronous
machine. It can convert
electrical energy from the high-voltage battery unit into kinetic energy, by
which the vehicl
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Automatic deactivation of
the front-seat passenger
airbags
Concept
The system reads if the front passenger seat is
occupied by measuring the human body's resistance.
Front, knee, and side airbag on the front passenger's
side are activated or deactivated.
General information
Before transporting a child on the front passenger
seat, refer to the safety inform
Overview
Buttons in the vehicle
Climate control functions
Temperature.
Recirculated-air mode.
Maximum cooling.
AUTO program.
Air flow, manual.
Switching off.
Air distribution, manual.
Defrost and defog the
windshield.
Rear window defroster.
Seat heating
Climate control operation.
Opening t
