SYSTEM ERRORS
4.5 The pneumatic system
The air supply for the ZF-AS TRONIC shift system is of relevance to the safety of the vehicle. All statutory specifications, such as those regarding the brake system, must therefore be observed.
The air supply can be connected to the vehicle in two ways. Firstly in front of the 4-circuit protective valve (example 1) or secondly after the 4-circuit protective valve on the auxiliary consumer circuit (example 2).
The following should be noted:
➢ In example 1, the air supply takes priority over the shift system for the brake system as a pressure relief valve (> 5 bar) is mounted upstream of the ZF-AS TRONIC air circuit.
➢ In example 2, the air supply has priority over the other auxiliary consumers for the ZF-AS TRONIC as a pressure relief valve is mounted upstream of it (> 5 bar) .
Example 1
Example 2 Transmission
actuator
with pressure sensor
Transmission actuator
with pressure sensor
Clutch actuator Compressor Air dryer Overcurrent valve 5 bar* 4-circuit protective valve Non-return valve 10 L Inner Ø = 9 mm D-I = 9 mm max. 4 m Clutch actuator Compressor Air dryer Over- current valve 5 bar Auxiliary consumer 4-circuit protective valve Non-return valve 10 L D-I = 9 mm D-I = 9 mm max. 4 m 014885 014886
* It is essential that the pressure set on the overflow valve is less than the pressure of the overflow valves in the 4-circuit protective valve for the auxiliary consumers
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Installation4.5
The pneumatic systemAir tank
A separate air tank is provided for the shift system. This has a non-return valve as its failsafe mechanism. No other air consumers may be connected to this pneumatic circuit – with the exception of the ZF-Intarder.
The non-return valve prevents pressure from falling in the tank should a leak occur or should there be no air in the rest of the air system.
Air tank minimum volumes:
➢ AS TRONIC 10 dm3
➢ AS TRONIC + IT 20 dm3
Air pressure
Operating pressure required: 7.0 – 12.0 bar. When operated at the minimum pressure level of 7.0 bar, the shift system shifts and engages in an unreliable manner. For the driver still to be able to perform a few shifts when there is a shortage of air in the system, the ZF-AS TRONIC must have a system pressure of at least 8 bar.
The transmission actuator uses an integrated pressure reducing valve to reduce the air pressure to 7 bar to preserve the shift elements and attain homogeneous shift characteristics.
Air consumption
Air displacement volumes required: at least 5 dm3/min at 8 – 10 bar.
The vehicle’s air system should be designed to ensure that at least the aforementioned volumetric flow of air is available to the ZF-AS TRONIC air circuit.
This assumed requirement is based on the consumption of 9 shifts and 1 starting procedure (“ignition on” with clutch actuator calibration) per minute.
Air lines
The air lines between the ZF-AS TRONIC air tank and transmission actuator and clutch actuator must have a nominal width (inner diameter) of at least 9 mm. Maximum lengths of 4 m must be observed.
Air quality
The compressed air made available by the vehicle must be cleaned, dried and free of condensate. Air particle filter: mesh width 40 microns.
Maximum permitted water content in the compressed air: 15% (relative air humidity).
Ambient Water content
temperature [°C] [g/m3] -20 0.136 -10 0.332 0 0.726 10 1.41 20 2.6 30 4.55 40 7.66 Pressure display/warning
A pressure sensor is integrated in the transmission actuator. This provides the driver with a warning should the pressure fall to below 6.2 bar. This is shown on the ZF display (AL) and/or can be sent as a message on the CAN.
1328 765 101 4-28 2000-09
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Installation4.6
Auxiliary units4.6 Auxiliary units
4.6.1 ZF-Intarder
The ZF-Intarder cannot be attached at a later date. The ZF-Intarder must always be taken into
consideration at the time when the transmission order is placed.
During ZF-Intarder applications, particular attention should be paid to the peripheral components such as attachment of the electronic units, wiring and cooler connection. The number of impulses issued by the speedo sensor differs slightly to that issued when used without the Intarder.
☞ For installation instructions and interface
descriptions, please refer to the ZF-Intarder technical manual (ZF no. 6085 765 004).
The ZF-Intarder electronics unit software takes into consideration the necessary signal exchange with the ZF-AS TRONIC, performed by the CAN bus. ☞ For special features associated with oil filling of
the ZF-AS TRONIC and Intarder combination, please refer to the ZF-Intarder technical manual (ZF no. 6085 765 004).
The initial installation of a ZF-AS TRONIC and ZF- Intarder system combination must be commissioned and approved by ZF.
4.6.2 Externally produced retarders
Whenever attaching externally produced retarders, always consult the technical sales team from ZF. The requirements governing mechanical, pneumatic, electrical interfaces and signal exchange with the ZF-AS TRONIC must be adapted accordingly. Here, it may be necessary to separately consider the system safety of the entire unit and to have the vehicle manufacturer undertake an overall vehicle system FMEA.
If ZF does not expressly issue approval for an externally produced retarder, ZF takes no liability or responsibility for these unit combinations or for the functional and operational safety of the entire system.
4.6.3 ZF PTO units
ZF PTO units can be attached in three ways. Firstly in the plant when the transmission is supplied, secondly at a later date by the vehicle manufacturer or lastly in the end customer’s finished vehicle.
☞ The attachment manual for ZF PTO units,
ZF no. 1328 757 051, provides information on the selection of ZF PTO units and on the attachment specifications.
This manual pays particular attention to the fact that when a PTO unit is mechanically attached, the electronics unit in the ZF-AS TRONIC will also require additional programming to ensure the operational safety of the system used in conjunction with the automated clutch. If the vehicle
manufacturer is to attach the PTO units, the data set required should be clarified with the technical sales team. If supplied vehicles are to be retrofitted, this task is undertaken by the ZF service centres. If the PTO unit is attached and the ZF attachment specifications (e.g. program changes to the
electronics unit) are not taken into consideration, then ZF takes no responsibility for this unit combination or the functional and operational safety of the entire system.
The peripheral parts (wiring harness etc.) required for the ZF PTO units must be provided by the vehicle manufacturer. When retrofitting a vehicle which has already been supplied, the ZF service centres are available to offer their assistance.
4.6.4 PTO units produced by external companies
When attaching PTO units produced by external companies, the assistance of the ZF technical sales team should always be obtained. The requirements governing mechanical, pneumatic and electrical interfaces to the ZF-AS TRONIC must be adapted accordingly. Here, it may be necessary to separately consider the system safety of the entire unit and to have the vehicle manufacturer undertake an overall vehicle system FMEA to ensure operational safety of the system used in conjunction with the automated clutch.
4
Installation4.7
Transm. installation on assembly line If ZF does not expressly issue approval for anexternally produced PTO unit, ZF takes no liability or responsibility for these unit combinations or the functional and operational safety of the entire system.