US1732666A - Carburetor for internal-combustion engines - Google Patents

Description

06. 22, 1929. Q. SVENSSON 6 1,732,666

GARBURETOR FOR INTERNAL-COMBUSTION ENGINES Filed Nov. 22, 1926 AM I Patented Oct. 22, 1929 PATET OFFlQli'.

OSKAR S'VENSSON, OF DAGLOS'EN, SWEDEN GABBURETOE FOE INTERNAL-COMBUSTION ENGINES Application filed November 22, 1926, Serial No. 150,067, and in Sweden December 19, 1925.

This invention relates to carburetors for internal combustion engines of that type, which comprises a controlling member, gen erally a swingable plate, which against the action of a spring is shifted by the air current passing to or sucked into the working cylinder of the engine and at which an inlet opening for the fuel is provided in such a manner, that the fuel is carried away with he air passing the plate and mingled with the same. The object of the said plate is that the same, every time the mixture of fuel and air is sucked into the working cylinder, should be brought into a certain position dependent on the number of revolutions of the engine and the intensity oi the sucking operation dependent on the said number of revolutions, in order that a mixture containing an unvariable percentage of fuel may be produced for each stroke of the working piston. The said plate acted upon by the impact of the air in the one direction and by the spring in the opposite direction, is caused to oscillate. The said plate, however, acted upon by its own weight and by the spring has a natural oscillation and for that reason it may happen that the plate does not perfectly cmply with the impulses resulting from air impacts but may, for instance, already have started on its way from its closed position, as the sucking operation is started, which results in the plate being opened through too great a distance, which on the other hand results in too small a quantity of fuel being carried with the air current and the mixture being too poor. It may also happen that the plate returns towards its closed position while the mixture is sucked into the cylinder, which results in the area of the air passage becoming too small and thus the suction too forcible, which results in too rich a mixture. The object of the present invention is to remove the said and similar disturbances at the mixing of the fuel charges. This is ettected by a retarding mechanism being combined with the controlling. member or the plate which mechanism is so constructed that it permits the plate to be freely opened through the distance, required by the air current, but retards the return stroke oi: the plate and thus prevents the same from falling backwards between the suction operations. Owing to this tact the plate will be held in a position substantially unvariable tor the number of revolutions respectively and at the transition for instance from a greater to a smaller number of revolutions the plate, acted upon by the retarding mechanism, will gradually move to a position corresponding to the new, less -forcible suction or slighter pressure of the entering air.

1 in the accompanying drawing shows in a side view an internal combustion engine provided with a carburetor arranged in accordance with this invention. Fig. 2 shows in a side view the retarding mechanism.

1, Figs. 1. and 2, is the ordinary air tube leading to the working cylinder of the engine, 2 is the controlling member or swing-- able plate, acted upon by a spring 3, which tends to move the plate to its closed position. At the part of the tube 1 against wl'iich plate 2 bears when being in its closed position a conduit i for the tliuel, benzine, opens, said conduit extending from a receptacle 5 which is provided with the ordinary needle valve 7 controlled by a float 6 and regulating the level of the fuel provided in the receptacle 5. According to the invention a rack 16, movable in guides 15, is connected with the arm 8 of the controlling plate by means of a ink 1st, said rack 16 meshing with a toothed wheel 18, which is rotatable on a shaft 17. On the said toothed wheel 18 a pawl 19 is provided, which engages a ratchet wheel 20 fixed on the said shaft 17, to which two wings 21 also are fixed.

The described mechanism operates in the following manner. While air is sucked into the working cylinder of the engine, bringing with itself fuel from the conduit 4, plate 2 is opened in a degree corresponding to the intensity of the suction or to the pressure of the air current and rack 16 is moved downwards, while pawl 16 runs freely on the ratchet wheel 20. As the suction of the mixture of air and fuel into the working cylinder ceases, spring 3 moves the plate 2 towards its closed position and, consequently, the rack 16 is moved upwaii'ds. Paw], 19 then causes the ratchet Wheel 20 and the wings 21 to rotate, which latter have a retarding influence on the return movement of the plate. During the operation of the engine, plate 2 is subjected to repeated impulses effected by the air passing to the Working cylinder and for that reason will remain in a substantially unvariable position, corresponding to the intensity of the suction operation. For that reason the mixture of air and fuel remains constant. At the transition to another number of revolutions plate 2 adjusts itself into the position corresponding to the intensity of the suction, which then prevails. 1

The retarding device described above is simple and cheap and comprises no valves, which may be stopped up and get out of order. The device is not altered through variations of the temperature and moves easily while the plate is opened, because pawl 19 then runs idle.

I claim:

In a carburetor for internal combustion engines the combination of a controlling member shifted by the air current passing to the Working cylinder 01": the en ine, a yielding device adapted to return the said controlling member, a supply conduit for the fuel and a retarding device for said controlling member, comprising a Wing-wheel, a ratchet-mechanism connected to itsspindle and a motion transmitting device between the said controlling member and the ratchet-mechanism, said retarding device permitting the controlling member to be freely opened but retarding its return movement towards its closed position, in order that the controlling member may remain in substantially unvariable position between air impulses of the same intensity and the mixture of air and fuel thus kept constant.

In testimony whereof I have hereunto atfixed my signature.

OSKAR SVENSSON.

Images