CITROEN CX - Page 86

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OPERATION
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ALL
CX VEHICLES
ANTI-POLLUTION
SYSTEM (SWEDISH MARKET)
-
CX 2200
The
object of the
system
is to
reduce the
amount of unburnt hydrocarbons and the
amount
of CO in
the exhaust
2 to
3 .
of
CO
)
by
injecting air under
pressure
inta
the exhoust manifold
OPERATION
As
the engine
rototes air pump
(1) supplies the air
injectors
(4)
situated ciose to the
exhaust
valves:
flap
(
3)
prevents
the
exhaust
fumes from entering the
air pump
(1
)
ond valve (2) assembly
There
are two cases
when
it is
necessary
to
stop
the
injection of
air
inta
the
exhaust manifold
1.
During
deceleration
During
fast decelerations,
the mixture
becomes
richer
combustion is incomplete
and the
injection of air
is
stopped
in order to avoid
a second
combustion taking place
in
the exhaust
system
(
which would result
in
back
firing
)
During deceleration
there
is
extreme
low
pressure
downstream of the butterfly
(8). This in tum draws
in
f
or
a
short period of time the
diaphragm in
valve
(2)
The
air
supplied
by
pump
(1) is releosed
into the atmosphere the
calibrated hole
a
»
on the
diaphragm
balancesthe
pressure
on either
side of it,
and the
diaphraqm
returns
to its initial
position allowinq
air to
be
once more
injected
into
the exhaust manifold.
2.
With the
choke out
With
the
choke in
this position, the quantities
of
unburned
hydrocarbons
and
CO
are
very
considerable.
It is
theref
are
necessary
to stop the
injection of air
inta
the exhaust manifold
sa as
to avoid an
excessive
increase of temperature
in the manifoid.
With the
choke out, lever (5)
connects relay
(7) to earth.
The
«
WEBER
»
electric
contact is energized
The air pressure at
the outlet of air
pump
(1
)
increases the
effect of the
low pressure
on
the
diaphragm in valve
(2)
(
the air-pressure
is
felt
above the
diaphragm and
the
low
pressure
produced
by
the
carburettor (8) is felt below
the diophroqm
).
the
sliding
volve
in volve
unit (2)
changes position, and the
air
is
expelled
inta the
atmosphere.
If
choke
(5)
is pushed
back
in
air
is once again injected
inta the exhaust
manif
old.
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