General information about the pneumatic system

Transcription

1 Definitions It is important to be aware of the following definitions and concepts in relation to the vehicle's pneumatic system: Compressed air tank A pressurised tank containing compressed air. This is used in the brake system and for other systems which require compressed air, i.e. auxiliary tanks. These tanks are marked so that they can be identified. APS (Air Processing System) The part of the pneumatic system the supplies the entire system with compressed air. The APS comprises a protection valve and air dryer, and also controls the compressor. The Air Processing System (APS) is available in 2 different versions: Air Management (standard version) High Capacity APS (high capacity version). A vehicle that does not have an APS unit with a compressed air tank for regeneration can be upgraded in various ways depending on when it was manufactured. More information on Air Processing System APS can be found in the document Additional compressed air. More information on pneumatic system modification is available in the document Modifying the pneumatic system. Air consumer A component which uses compressed air. ABS and EBS are examples of components in the brake system which use air. ABS and EBS The brake control system comprises valves and other components. The compressed air is distributed from here to the brakes at the wheels. 03:50-01 Issue 6 en-gb 1 (8)

2 Location of the compressed air tanks The compressed air tanks can be located in different positions depending on the following: Vehicle type Configuration. More information on the location of the compressed air tanks can be found on the ICD. Instructions for ordering and tools for interpreting the ICD are found under Drawings. Identifying compressed air tanks Each compressed air tank is marked with one of the following function symbols: Brake system tank, front circuit Brake system tank, rear circuit Brake system tank, parking Air suspension tank 03:50-01 Issue 6 en-gb 2 (8)

3 Pneumatic system circuits The pneumatic system consists of 5 different circuits with different system pressures. Brakes, rear circuit Brakes, front circuit Parking and trailer Compressed air circuit for accessory systems Air suspension. The compressed air circuits are supplied with compressed air from the compressor, which is controlled by the APS. The circuits can work directly from the APS or can contain air storage in the form of pressure tanks. Generally, the more pressure tanks a circuit has, the longer it takes to fill the system and the longer the compressor and the APS need to operate. The optimal system design therefore varies depending on the air consumption and driving cycle. IMPORTANT! If the air supply is insufficient, the brakes will be actuated, which will result in protection systems being activated, warnings triggered, etc. 03:50-01 Issue 6 en-gb 3 (8)

4 Component A B APS Designation Double check valve Overflow valve Air Processing System Circuit Max. pressure Connection in APS Brakes, rear circuit Brakes, front circuit Parking and trailer Compressed air circuit for accessory systems Air suspension Schematic diagram of the pneumatic system for leaf spring suspension or for a vehicle with air suspension without an extra tank. Schematic diagram of the pneumatic system for a vehicle with air suspension with an extra compressed air tank for the air suspension. 03:50-01 Issue 6 en-gb 4 (8)

5 Air consumption Note: The information about air consumption applies to the Air Management APS (standard version). For the High Capacity version, the below values plus 15% apply. The highest permitted continuous output of compressed air from each compressor is shown below at different engine speeds and with a system pressure of 10 bar. Engine speed (rpm) 600 cc (l/min) 636 cc (l/min) 720 cc (l/min) , , Note: The air that can be supplied contains oil particles resulting from oil carryover from the compressor and should therefore not be used in a manner that could cause damage. IMPORTANT! To ensure that the APS is able to carry out regeneration, the compressor running time should not exceed 50% of the engine operating time. This is to allow the desiccant in the air dryer to be adequately dehumidified. 03:50-01 Issue 6 en-gb 5 (8)

6 Operating the pneumatic system Operating the pneumatic system Charging compressed air External charging of the pneumatic system must only be carried out via the union located under the front grille panel immediately above the left headlamp. The maximum charging pressure for the vehicle is 9.3 bar. Note: Before charging, check that the external compressed air is free from oil and water :50-01 Issue 6 en-gb 6 (8)

7 Operating the pneumatic system Couplings The compressed air pipes may have connector unions made of brass or composite material. Information about connection and renewing unions can be found in the document Modifying the pneumatic system. Different methods are required for connecting and removing compressed air pipes depending on whether the connector unions are made of brass or composite material. It is important that the compressed air pipes are a high quality. The compressed air pipes and compressed air valves must be purchased from a Scania dealer. IMPORTANT! The compressed air pipes of the brake circuits and trailer brake circuits may only be joined using composite unions which are approved by Scania. 03:50-01 Issue 6 en-gb 7 (8)

8 Operating the pneumatic system Connecting an air consumer Connect the compressed air equipment to manifold fitting 65 1 The manifold fitting can be located in several positions on the vehicle. The most easily accessible manifold fittings are located on the right frame side member and rear crossmember. The rear position is only available on vehicles with a differential lock or ABS. The manifold fittings may look different and many connections may already be occupied by chassis components. There will always be at least one vacant connection for compressed air pipes (12 x 1.5 mm). If there are not enough vacant connections, it is possible to fit additional manifold fittings such as manifold fitting (illustration). Note: Valves and couplings can be purchased from Scania dealers. Pneumatic diagrams can be obtained from a Scania workshop. Example of the appearance and location of a manifold fitting More information on air consumer connection is available in the document Modifying the pneumatic system. Example of how manifold fitting 65 is shown on a pneumatic diagram is the manifold fitting's number on Scania's pneumatic diagrams. 03:50-01 Issue 6 en-gb 8 (8)