Audi A8 Power Transmission – Self-Study Programme 457

Audi A8 2010 Power Transmission - Self-Study Programme 457 PDF

Eight-speed Automatic Gearboxes 0BK and 0BL Rear Axle Drives 0BF and 0BE – Sport Differential – Self-Study Programme 457. The Self-Study Programme teaches the basics of the design and function of new models, automotive components or technologies.

Eight-speed automatic gearboxes 0BK and 0BL belong to the category of conventional multistep torque converter automatic gearboxes.

They have many design and functional features in common with the six-speed automatic gearboxes described in Self-Study Programmes 283, 284 and 385.

These SSPs represent, as it were, the basis for SSP 457. Hence where the technology is identical, reference is made to SSPs 283, 284 and 385. It is, therefore, advisable to have all three booklets ready to hand.

The main focus of development was on:

  • better fuel economy with reduced RPM and drag losses
  • improved performance with shorter gear steps, multiple direct shifts and a low power-to-weight ratio
  • design flexibility in the interior through the use of a shift-by-wire concept

These development efforts are reflected in the new 8-speed automatic gearboxes 0BK and 0BL.

The higher fuel efficiency of the 8HP automatic gearbox generation is due to the following modifications:

  • a wider ratio spread and more gears for better adaptation to ideal engine operating points
  • significantly reduced drag torque in the shift elements (only two open shift elements per gear)
  • use of a more efficient ATF pump (twin-stroke vane pump)
  • improved torsion damping in the converter

Another potentially effective way of improving fuel efficiency is to eliminate idling fuel consumption in the internal combustion engine while the vehicle is at a standstill. This has a very positive impact in city traffic.

To exploit this potential, the 3.0 V6 TDI uses the start-stop function in combination with an automatic gearbox for the first time. Other applications are currently being developed.

It is not a Repair Manual. Figures given are for guidance purposes only and refer to the software version valid at the time of preparation of the SSP.


Power transmission in the Audi A8 ’10

  • New features at a glance

Shift-by-wire shift control system

  • Introduction
  • tiptronic function
  • Features of the shift control system
  • Operating concept
  • Shift schematic – function
  • Selector lever sensors control unit J587
  • Selector lever position sensor G727
  • Functions, networking and interfaces
  • Gear knob/selector lever release button E681
  • Selector lever position indicator unit Y26
  • Function diagram – selector lever E313
  • Gearshift indicators
  • shift-by-wire functions/operation
  • Auto P function (automatic parking lock)
  • Emergency release device for the parking lock

Eight-speed automatic gearbox 0BK/0BL

  • Introduction
  • Specifications
  • Special and common features at a glance
  • Splined prop shaft
  • Centre differential
  • Torque converter
  • ATF supply/ATF pump
  • ATF (Automatic Transmission Fluid)
  • Planetary gearbox
  • Shift elements
  • Brakes
  • Clutches
  • Shift schematic/shift matrix
  • Description of gears – torque characteristic
  • Sectional view of 0BK gearbox
  • Oil system/lubrication/sealing of 0BK gearbox
  • Separate oil systems
  • Common oil system
  • Oil system/lubrication/sealing of 0BL gearbox
  • Gear oil system (common oil system)
  • Common oil system – gear oil circuit
  • Innovative Thermal Management (ITM)
  • Gearbox heating/cooling – V8 FSI engine
  • Gearbox heating/cooling – V8 TDI engine
  • Mechatronics – electro-hydraulic control system
  • Mechatronics/automatic gearbox control unit J217
  • Mechatronics – actuators
  • Pressure regulating valves – solenoid valves
  • Hydraulic interfaces
  • Monitoring of temperature in J217
  • Mechatronics – sensors
  • Gearbox input speed sender G182
  • Gearbox output speed sender G195
  • Parking lock
  • Parking lock – function
  • Parking lock – limp-home functions
  • Parking lock sender G747
  • Functions – neutral idle
  • Functions – gearbox adaption
  • Functions – start-stop system
  • Hydraulic Impulse Storage – HIS
  • Start-stop mode
  • Functions – navigation-based gear selection
  • Functions – displays/warnings
  • Functions – special feature of adaptive cruise control (ACC) mode
  • Functions – encoding the automatic gearbox control unit J217
  • Functions – adapting the gear indicator
  • Functions – limp-home programs and substitute programs
  • Towing

Rear axle drive 0BC/0BF/0BE

  • Conventional rear axle drive/sport differential
  • Rear axle drive 0BE/sport differential
  • Intelligent torque distribution
  • Self-Study Programmes relevant to the Audi A8 ’10

Language: English
Format: PDF
Pages: 68
Size: 6.11 Mb
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