Carbureters
AssigneeThe Zenith Carburetor Company Limited
InventorThomas James Ullman
Life of this patent
Estimating the term…
Abstract
A twin air valve carbureter has a single bar which extends diametrically across the two draught tubes upstream thereof, and two air valve flaps which are mounted on opposite sides of the bar, so as to extend across both draught tubes, and are hinged at their ends remote from the bar. Both the flaps co-operate with the bar to define a throat of variable area. The fuel discharge ports are formed in the bar and comprise outwardly-divergent slot ports. A depression responsive fluid pressure motor is linked to each of the flaps to provide compensation for the effect of the reduction of the effective area of each flap as that flap opens. A novel linkage is disclosed for linking a fuel metering needle to one of the flaps.
Claims24
An air valve carburetter of the pivoted flap air valve type comprising body, a branched through passage extending through the body, the branched through passage comprising a single upstream passage portion, a pair of downstream passage portions and a junction passage portion in communication with both the downstream passage portions;
- a bar that is supported by the body within a part of the through passage which is upstream of the two downstream passage portions whereby it extends substantially diametrically with respect to the two downstream passage portions;
- at least one throttle valve in the through passage downstream of the bar for controlling air flow through the two downstream passage portions;
- a pair of air valve flaps disposed within the through passage upstream of the downstream passage portions, said valve flaps being mounted pivotally within the body on opposite sides of the bar that extends between them, each of the pair of pivoted air valve flaps extending across the upstream ends of both the downstream passage portions co-operating with the bar to form a throat of variable area between itself and the bar and being disposed to pivot in response to a tendency for a depression established within either downstream passage portion between the bar and the throttle valve that controls air flow through that downstream passage portion to vary and thus to oppose a tendency for that depression to vary;
- and a fuel supply system operable to supply metered quantities of fuel from a respective fuel metering orifice to that part of the branched through passage between the bar and said at least one throttle valve through at least one fuel discharge nozzle in the bar.
An air valve carburetter of the pivoted flap air valve type comprising a body, a branched through passage extending through the body, the branched through passage comprising a single upstream passage portion, a pair of downstream passage portions and a junction passage portion which places the single upstream passage portion in communication with both downstream passage portions;
- a bar which is supported by the body within a part of the through passage which is upstream of the two downstream passage portions whereby it extends diametrically with respect to the two downstream passage portions;
- at least one throttle valve in the through passage downstream of the bar for controlling air flow through the two downstream passage portions;
- a pair of air valve flaps disposed within the through passage upstream of the downstream passage portions, said valve flaps being mounted pivotally within the body on opposite sides of the bar that extends between them, each of the pair of pivoted air valve flaps extending across the upstream ends of both the downstream passage portions having a surface which is curved convexly and which co-operates with the bar to form a throat of variable area between itself and the bar, and being disposed to pivot in response to a tendency for a depression established within either downstream passage portion between the bar and the throttle valve that controls air flow through that downstream passage portion to vary and thus to oppose a tendency for that depression to vary;
- and a fuel supply system comprising at least one fuel discharge nozzle in each side of the bar for supplying metered volumes of fuel to the variable area throat that is formed between the respective side of the bar and the adjacent air valve flaps, each fuel discharge nozzle being disposed with its upstream edge positioned adjacent to the convexly curved surface of the adjacent air valve flap when the latter is in its closed position.
An air valve carburetter of the pivotted flap air valve type comprising a body with a through passage formed in it, a throttle valve for controlling air flow through the through passage, an air valve flap mounted pivotally within the body upstream of the throttle valve, part of the air valve flap co-operating with adjacent structure to define a throat of variable area, the air valve flap being hinged to the body at a point which is opposite said part of that air valve flap, and being disposed to pivot in response to a tendency for a depression established within the induction passage downstream of the air valve flap to vary and thus to oppose any tendency for the said depression to vary and so that said part of that flap is drawn towards the respective throttle valve by such a depression when the carburetter is fitted to an engine for use, and a fuel supply system which includes a fuel metering orifice and a fuel discharge nozzle and which is operable to supply metered quantities of fuel through the fuel discharge nozzle to that part of the through passage between the pivoted flap and the throttle valve, a profiled needle which projects through the fuel metering orifice, a linkage which connects the needle to the pivoted flap such that the needle moves relative to the fuel metering orifice with movement of the pivoted flap so that the effective area of the fuel metering orifice is varied in accordance with variations in the area of the variable area throat, and guide means which guide the needle for coaxial rectilinear movement relative to the fuel metering orifice, wherein an aperture is formed in the wall of the through passage adjacent to the pivot mounting of the flap, another part of the flap projects from the pivot mounting of the flap through the aperture and is bifurcated outside the through passage, and the linkage comprises a U-shaped angled link, the free end of each of the U-shaped angled link being pinned to a respective one of the branches of said bifurcated flap part and a point on the angled link which is spaced from the free ends of the arms of the angled link is hinged to the profiled needle by a flexible hinge.
Dependencies are inferred from the claim text.