DAF CF65, Service Manual

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200324 2-5
General
XE ENGINE, ENGINE BRAKE
CF65/75/85 series
4
10
2.4 SYSTEM DESCRIPTION, ENGINE BRAKE, GENERAL
The collective designation 'engine brake' includes
the engine brake (butterfly valve) and the DAF
Engine Brake (DEB).
With the introduction of the DAF 12.6 litre engine,
a new type of engine brake was introduced for
DAF, which could also be applied to XE engines.
This is the DAF Engine Brake or DEB for short.
Every XE engine has a factory-fitted exhaust
brake.
At the request of the customer, the DEB can be
fitted at the factory or at a later date.
If the driver activates the engine brake by means
of the engine brake control switch on the cab
floor, both the exhaust brake and the DEB are
engaged. Therefore, the DEB always works in
conjunction with the exhaust brake.
As the UPEC electronic unit checks the activation
of the engine brake, it will disengage the engine
brake below a certain engine speed (see UPEC
system manual).
2.5 SYSTEM DESCRIPTION, DEB
The DEB consists of two different housings, each
cylinder head having its own DEB housing.
Each housing contains various valves, pistons,
and a solenoid valve.
When the DEB is activated, fuel ceases to be
injected and one exhaust valve will be opened
hydraulically at the end of the compression
stroke. This means that the compressed air can
escape to the exhaust system, so that during the
working stroke this pressure does not help the
piston to fall.
i 400160
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