Downloaded from www.Manualslib.com manuals search engine OPERATION No MA. 642-W : ~Thnracteristics o/ thy, e I:Ko/I) - -70 3 hc,nriug s, stew Op. MA. 642-00 3
When starting : capsule is subjected to vacuum
Vacuum capsule
Westaflex tube
c J
J
COLD AIR
Closing plate for
SUPPLY SHUT OFF warm air supply
,
Flap B
I
to air filter
DIAGRAM.No. 1
‘acuum capsule not under vacuum
Flap
DIAGRAM No. 2
to air filter
Situated at the air-filter inlet. the vacuum capsule controls a flap and a closing plate allowing simultaneously supply
or no supply of warm air and no supply or supply of cold air. When starting ( Diagram 1 ) the capsule is subjected to
vacuum, the flap stops the supply of cold air, and the closing plate allows the supply of warm air to the air filter.
When the effect of the vacuum ceases, the capsule returns to length Ll ( Diagram 2 ) : the flap.opens, allowing supply
of cold air and the closing plate stops the supp[y of warm air.
The vacuum capsule operates via a thermal sensor.
Downloaded from www.Manualslib.com manuals search engine B. THERMAL SENSOR
This is situated in the duct linking the air filter to the carburettor ( see diagram below ).
__
Depending on the temperature of the inlet air. it allows or not vacuum to reach the control capsule for the flap and
the closing plate.
It consists of a number of valves and bi-metallic strips.
To inlet manifoldb-yTu-4
I To vacuum capsule Operating principle :
For an inlet air temperature below 6’ C, the position of the bi-metallic strips and the valves is such that vacuum in
the inlet manifold is communicated to the capsule (see para. A, diagram No. 1 )
For an inlet air temperature above 19” C, the bi-metallic strips change shape. and the position of the valves stops
the vacuum from reaching the capsule ( see para A. diagram No.2 ).
For an inlet air temperature between 6 and 19” C, the positions of valves and bi-metallic strips allow the action of
the vacuum on the capsule to be regulated. In this case, the flap and the closing plate are in an intermediate position,
allowing simultaneous supply of warm and cold air.
