Compressor, as-built configuration

W13.30-1150-12

Location

1 Compressor

The compressor (1) is attached to the left side of the engine on the cylinder crankcase.

General information

The compressor (1) is a compact 1-cylinder reciprocating piston pump which is driven by means of a gearwheel drive by the engine.

The cylinder head for the compressor (1) is cooled by the coolant from the engine coolant circuit.

Lubrication takes place as circulation lubrication through the feed and drain bore over which the compressor (1) obtains oil from the engine oil circuit.

Parameters

Displacement 353 cm3

Delivery volume: up to about 420 l/min for the rated speed and a 12 bar back pressure

The compressor (1) is fitted with an energy saving system.

As soon as the vehicle air brake system is adequately charged, the power absorption capacity of the compressor (1) is significantly reduced by this system, which in turn results in fuel savings for the veh..

W13.30-1156-12

Design

1 Compressor (housing)

2 Sealing rings

3 Suction lamella

4 Sliding plate

5 Valve intermediate plate (with pressure disk)

6 Gasket

7 Gasket

8 Bolts

9 Cylinder head cover

10 Gasket

W13.30-1154-81

Function - general points

Driving of the compressor (1) takes place over a gear attached to the camshaft. It is therefore always driven when the engine is running. The air is delivered by the compressor (1) over the pressure line to the pressure regulator and compressed air reservoirs.

The pressure regulator which determines the pressure in the compressed air system also serves to actuate the energy saving system which switches the compressor (1), according to the charge level of the compressed air reservoir, into loaded movement and idle .

1) Loaded movement (delivery phase)

In loaded movement the function of the compressor (1) in the main represents that of a conventional compressor without an energy saving system. During the intake stroke the compressor (1) suctions in the air over the air inlet on the cylinder head which flows through the suction lamella (3) into the cylinder.

At this point in time the pressure disk is closed in the valve intermediate plate (5). When the compressor then changes over into the intake stroke the suction lamella (3), and the pressure disk opens from a particular pressure so that the compressed air can flow out of the cylinder to the compressed air outlet in the direction pressure regulator and compressed air reservoir.

During this period a spring holds the shift pistons (11) together with the associated sliding plate (4) on the outer end stop. In this way the sliding plate (4) closes the openings (12) to an additional clearance volume, the activation space.

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2) Idle (energy-saving-phase)

Once the shutoff pressure of the pressure regulator is reached this switches the compressor (1) over to idle mode. To do this the shift piston (11) has compressed air applied to it over a control line between the pressure regulator and the compressor (1). The shift piston (11) is now pressed axially against the force of the spring to the inner end stop and therefore also moves the sliding plate (4) connected with it. Thus the sliding plate (4) frees up the openings (12) to the activation space.

The additional volume of the activation space lowers the compression pressure for the downstroke of the piston and thus also the power absorption capacity of the compressor (1). Conversely the pre-compressed air in the activation space expands for the downstroke of the piston and thus contributes to energy recovery.

 In contrast to a conventional compressor which is not fitted with the energy saving system, in idle just about 1/3 of the compressed air is blown over the pressure regulator instead of the whole compressed air.