GB303924A - Improvements in or relating to carburettors for internal combustion engines - Google Patents

Abstract

303,924. Boonzaier, G. J. Oct. 13, 1927. Spray-carburettors. - The fuel needle-valve is actuated from the throttle valve through the medium of a cam having a flexible and adjustable blade profile, the blade being mounted on a base-plate provided with means for local flexing of the blade to vary the rate of throw, the baseplate being adjustable as a whole to varv the total throw. A variable air aperture concentric with the nozzle is produced by an iris diaphragm or geared shutters which may also he actuated from the throttle valve and, at times, independently thereof. The body A has a flange A<1> for connection to the intake manifold, and a single air inlet A<4> in which is a nozzle A<2> fed from an annular float chamber B. The iris diaphragm D is actuated through a spider D<1> and a metal tube O to which an arm N is secured. This arm is associated with the main throttle lever L through a ball joint N<1> and a spring-loaded sliding member M<1> provided with a stop pin M<3>. The arm N may be actuated independently of the throttle valve by a separate rod to decrease the area around the nozzle at starting. Upon release of the rod, the pin M<3> is drawn back against the lever L for simultaneous actuation of the throttle, diaphragm and needle valve. The nozzle aperture is regulated bv a needle, valve F which passes axially through the tube O and is threaded through a pinion G, the valve being prevented from rotating by its square upper end sliding through a guide P. The pinion G is rotated by a toothed quadrant H pivoted on a stud H<3> and carrying at its other end a swivelling washer H<2>, a slot in which is engaged by the blade K<1> of a cam mounted in a baseplate K which is adjustably secured to the cranked end L<1> of the throttle spindle by a bolt L<3>. The blade can be flexed between its extremities K<3>, Fig. 1, by means of set-screws K<2> and the total throw of the cam can be varied by releasing the bolt L<3> and tilting the baseplate. The washer H<2> is retained in position by a plate H<1> held by the stud H<3>. The cam may act on the needle valve either directly or through other mechanism. Minor adjustments of the level in the float chamber may be effected by a screw B<3> which loads the float through a spring B<4> and flanged tickler B<2>. In a modification, the iris diaphragm is replaced by a pair of geared metal shutters, Figs. 3 and 6 (not shown).