DAF 95XF. Manual - part 398

4

XF ENGINE INLET AND EXHAUST SYSTEM

General

95

XF series

2-2

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95

XF series

General

XF ENGINE INLET AND EXHAUST SYSTEM

2-3

 1.

Inlet hose

 2.

Turbocharger

 3.

Wastegate diaphragm

 4.

Inlet pipe

 5.

Exhaust bend

 6.

Butterfly valve

 7.

Flexible exhaust pipe

 8.

Inlet manifold

 9.

Intercooler

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XF ENGINE INLET AND EXHAUST SYSTEM

General

95

XF series

2-4

2.2

DESCRIPTION OF TURBOCHARGER SYSTEM WITH WASTEGATE

Wastegate
To make the engine more responsive at lower
engine speeds, a turbocharger is used that
produces a better fill ratio at such speeds.
If no special provisions were made, the boost
pressure yielded by such a turbocharger would
be too high at maximum engine speeds. This is
prevented by using a wastegate.
The turbocharger’s compression housing has an
air coupling connected with a diaphragm. The
boost pressure yielded by the turbocharger
operates the diaphragm and the control rod
connected to it.
The control rod operates a valve in the turbine
housing.
The valve in the turbine housing is opened when
the maximum allowable pressure has been
reached.
When the valve is opened, some of the exhaust
gases will be discharged to the exhaust pipe
rather than being used to propel the
turbocharger’s turbine wheel.

Compression housing by-pass
At higher boost pressures, the compressor of
the turbocharger tends to allow this pressure to
return to the inlet underpressure area. To
prevent this, the compression housing of the
turbocharger has been adapted.
This adaptation consists of bypass ducts and a
stop plate.
Boost pressure attempting to return to the inlet
area, will do so at the outer circumference of the
compression housing.
Providing the compression housing with an air
slot forces this pressure to flow through special
air ducts on the outside until it is arrested by the
stop plate.

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Inspection and adjustment

XF ENGINE INLET AND EXHAUST SYSTEM

3-1

3.  INSPECTION AND ADJUSTMENT

3.1

CHECKING AND ADJUSTING THE WASTEGATE TURBOCHARGER

1.

Remove the heat shield from the
turbocharger.

2.

Remove the air supply connector (1) from
the diaphragm housing (2).

3.

Remove the retaining clip (3) and remove
the control rod (4) from the wastegate lever.

4.

Using a pressure-reducing valve, apply the
required pressure setting to the diaphragm
housing connection, see main group
“Technical data”.

5.

Push the wastegate lever fully to the left to
close the wastegate valve.

6.

Adjust the length of the control rod (4),
making sure it fits exactly on to the lever at
the set pressure.

7.

Check the wastegate setting at the specified
pressure, see main group “Technical data”.

8.

Install the retaining clip (3).

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