GB1370069A - Carburettor - Google Patents

Abstract

1370069 Spray carburetters FORD MOTOR CO Ltd 11 Oct 1972 [1 Nov 1971] 46825/72 Heading F1B A carburetter has a throttle 22 rotatably mounted across an induction passage and movable from a closed position 34 through an idle speed position 36 to a wide open throttle position, throttle control means including a plunger connected to a flexible diaphragm 50 which divides a hollow shell into two chambers 46, 48 each connected to the engine intake manifold by conduits 52, 54, a flow restrictor 88 in conduit 52 between a reservoir 90 and the manifold, a first spring 78 biasing the valve towards the wide open position and a second spring 70 biasing the throttle towards the idle position, arranged so that an increase of the manifold vacuum overcomes the second spring to move the throttle to position 37 and on engine shutdown the reservoir vacuum temporarily closes the throttle and decay of the reservoir vacuum permits the first spring to return the throttle to the idle position. When the engine is cranked, the turning of the ignition key energizes solenoid 98 to position valve 92 as shown. If the engine has been accelerated to move lever 38 away from plunger 62 and the accelerator pedal is released spring 40 biases the throttle 22 to the closed position 34. Inlet manifold vacuum increases and diaphragm 50 moves plunger 62 rightwards until the shoulder abuts sleeve 66 to move the throttle into position 37 permitting greater air and fuel flow sufficient to scavenge the combustion chambers. The subsequent vacuum decrease permits repositioning of the throttle into the idle position 36. When ignition is switched off solenoid 98 is de-energized thereby bleeding line 54 to atmosphere. Flow restrictor 88 delays the decay of vacuum in reservoir 90 thereby permitting the vacuum in chamber 46 to retract plunger 62 and closure of the throttle to position 34 to prevent "running-on". When the vacuum in reservoir 66 does decay the pressures in chambers 46, 48 equalize allowing the springs 70 and 78 to return the throttle to position 36.