travel sensor
B504
Page 434
Component description for transmission oil temperature sensor
B505
Page 435
Component description for transmission positioner
Y900
Page 492
Component description for pneumatic central clutch release bearing
Page 499
Component description for range groupmodule
GF26.21>W>3010H
Controlling the clutch, function
2.8.11
TRANSMISSION 715 in MODEL 963 with CODE (G5G) Mercedes PowerShift 3
TRANSMISSION 715 in MODEL 964 with CODE (G5G) Mercedes PowerShift 3
W26.21>1122>09
1 Pneumatic central clutch release bearing
A3 Drive control (CPC) control unit A5 Transmission control (TCM) control
unit
A10b Electronic Brake Control (EBS) control unit (Wabco) A10c Electronic Brake Control (EBS)
control unit (Knorr)
CAN 4 Drive train CAN
LIN 3 Multifunction control lever>LIN on the right
P1 Tachograph (TCO)
S23 Right multifunction control lever
Y900 Transmission positioner Y900 b1 Splitter group travel sensor Y900 b2 Gear cylinder travel sensor Y900 b3 Gate cylinder travel sensor B18 Travel and speed sensor
B44 Accelerator pedal sensor B501 Main shaft rpm sensor B502 Countershaft rpm sensor B503 Clutch travel sensor B504 Range group travel sensor B505 Transmission oil temperature
sensor CAN 3 Frame CAN
General information
For transmission automation the clutch is controlled
automatically. This control is integrated in the transmission (TCM) control unit (A5). In this process detection, processing and passing on of all necessary data for the clutch control is realized. The following functions are contained in the clutch control:
f Driving off, driving and stopping function: here all processes are calculated and controlled which are needed for reducing and building up the torque of the clutch.
f Crawl function: here all processes are calculated and controlled which concerns regulation of the clutch and crawling from a standstill and freewheeling.
f Anti Jerking Control: here all processes are calculated and controlled based on drivetrain model which realizes the building up and reduction of the engine before and after shift operation as smoothly and as quickly as possible. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
f Clutch properties: here all data concerning the properties of the clutch are gathered, evaluated and made available to other software functions. To do this the characteristic of the transferable torque is relevant about the actuation travel of the clutch, as well as the engagement point and the temperature behavior of the clutch.
f Clutch operation: here the determined clutch position specified values are implemented in the solenoid actuations and regulates on the basis of the measured clutch sensor values.
i The function of the automated clutch control is achieved for the given conditions, also in back>up mode.
Information from other control units and sensors is also read in and processed in the transmission (TCM) control unit (A5): These include:
f Electronic Brake Control (EBS) control unit (A10b, A10c): speed and activity information, for example: brake regulating system, wheel speeds on the front and rear axle, brake actuation
f Transmission (TCM) control unit (A3): for example accelerator pedal sensor (B44), multifunction control lever on the right (S23)
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
f Main shaft rpm sensor (B501) f Countershaft rpm sensor (B502) f Clutch travel sensor (B503) f Range group travel sensor (B504)
f Transmission oil temperature sensor (B505) f Splitter group travel sensor (Y900 b1) f Gear cylinder travel sensor (Y900 b2) f Gate cylinder travel sensor (Y900 b3) f Travel and speed sensor (B18)
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Actuation of the clutch
The clutch operator takes over calculation of the set variables for actuating the clutch.
The transmission (TCM) control unit (A5) directly actuates the solenoid valves for operation of the clutch over integral output stages:
f Slowly close clutch solenoid valve (Y900 y1) f Slowly open clutch solenoid valve (Y900 y2) f Quickly close clutch solenoid valve (Y900 y3) f Quickly open clutch solenoid valve (Y900 y4)
i The solenoid valves for operation of the pneumatic central clutch release bearing (1) are integrated in the transmission positioner (Y900).
If clutch solenoid valve open slowly (Y900 y2) or clutch solenoid valve open quickly (Y900 y4) is actuated the pneumatic central clutch release bearing (1) has compressed air applied to it over the transmission positioner (Y900) and the clutch opens. i The pneumatic central clutch release bearing is located concentrically around the transmission input shaft.
The clutch regulation monitors opening and closing of the clutch over the sensor connector position (B503) directly read in by the transmission (TCM) control unit (A5).
Component description drive control (CPC) control unit
A3
Page 334
Component description for transmission control (TCM) control unit
A5
Page 337
Component description for Electronic Brake Control control unit (EBS)
A10b, A10c
Page 341
Component description for travel and speed sensor
B18
Page 408
Component description for main shaft rpm sensor
B501
Page 431
Component description for countershaft rpm sensor
B502
Page 432
Component description for clutch travel sensor
B503
Page 433
Component description for range group travel sensor
B504
Page 434
Component description for transmission oil temperature sensor
B505
Page 435
Component description for tachograph (TCO)
P1
Page 459
Component description for transmission positioner
Y900
Page 492
Component description for pneumatic central clutch release bearing
GF26.50>W>3010H
Countershaft brake, function
2.8.11
TRANSMISSION 715 in MODEL 963 with CODE (G5G) Mercedes PowerShift 3
TRANSMISSION 715 in MODEL 964 with CODE (G5G) Mercedes PowerShift 3
General information
For upshifting the countershaft must be braked for rpm compensation between the countershaft and main shaft. The rotational speeds are reported over the countershaft rpm sensor (B502) and the main shaft rpm sensor (B501) to the transmission (TCM) control unit (A5) so that the brake application can be exactly regulated by the transmission (TCM) control unit (A5). For regulation the countershaft brake solenoid valve (Y900 y5) is actuated appropriately.
That is it is possible to change several times between a brake position and release position during a brake application until the rpm between the countershaft and main shaft is compensated. A distinction is made between two function positions of the countershaft brake:
f Brake position f Release position
Brake position of countershaft brake
1 Compressed air duct 2 Piston
3 Internally toothed plates 4 Externally toothed plates 5 Rapid exhaust valve Arrow Brake position
If during upshifting rpm reduction of the countershaft is requested by the transmission (TCM) control unit (A5) the countershaft brake solenoid valve (Y900 y5) is actuated. The compressed air is controlled over a line from the transmission positioner (Y900) to the transmission housing front section and from there through the compressed air duct (1) into the cover on the front side of the piston (2); the mechanical quick vent valve (5) also closes. The air pressure operates on the piston (2) which presses together the internal plates (3) and the external plates (4) and thus brakes the countershaft.
Release position of countershaft brake
1 Compressed air duct 2 Piston
3 Internally toothed plates 4 Externally toothed plates 5 Rapid exhaust valve Arrow Release position
If the rpm between the countershaft and main shaft is compensated or the rpm of the countershaft drop too severely, the countershaft brake solenoid valve (Y900 y5) is no longer actuated.
After the countershaft brake solenoid valve (Y900 y5) is switched off the space upstream of the piston (2) is ventilated compressed air duct (1) and as a result the opens the mechanical quick vent valve (5) and ventilates the space upstream of the piston (2) suddenly.
The centrally located spring>loaded reset pin pushes the piston (2) into the rest position. The internal plates (3) and the external plates (4) are relieved of load. The countershaft can turn again freely.
W26.60>1300>03
Component description for transmission control (TCM) control unit
A5
Page 337
Component description for main shaft rpm sensor
B501
Page 431
Component description for countershaft rpm sensor
B502
Page 432
Component description for transmission positioner