US2297550A - Carburetor - Google Patents

Description

Sept, 2%, 1942.

P. X. A. GISTUCCI CARBURETOR INV EN TOR. BY 75 GL5 TUCC/ 7004 XH V/fE. flaws Original Filed Aug. 22, 1935 e 2 v ATTORNEY.

Patented Sept. 29, 1942 7 2,291,550 cmmmsroa Paul Xavier Auguste Gistucci, Paris, France, assignor to Societe Generale Des Carburateurs Zenith,'Geneva, Switzerland, a corporation of Switzerland Original application August 22, 1935, Serial No. 37,274. Divided and this application August 4,

1939, Serial No. 288,278.

Claims.

The present invention relates to an altimetric control device applicable to carburetors fed with fuel from a fuel chamber in which the pressure is adjusted by means of a diaphragm forming one of the walls of said chamber and operatively connected with the valve that controls the inflow of fuel to said chamber.

This application is a division of my copending application, Serial Number 37,274, filed August 22, 1935, which issued March 4, 1941, as Patent No. 2,234,001.

The altimetric control device according to the present invention comprises a chamber connected both with the induction passage of the carburetor and with the atmosphere or the air intake of the carburetor through two separate passages, the relative sections of which can be varied by means of a manually or barometrically controlled valve. This chamber is separated from the fuel chamber by the diaphragm above referred to, or by a movable wall (diaphragm or piston) which is mechanically connected with said diaphragm.

' Adjustment of the mixture richness to compensate for changes in air density due to changes in altitude is accomplished by actuating said mov- In Belgium August able wall in accordance with the pressure in the induction passage adjacent the main fuel jet,

'said pressure being modified by the position of tion varying in accordance with the degree of opening of the throttle to act on the outer surface of the diaphragm closing the fuel chamber. This known arrangement, in which the suction acting on the diaphragm depends merely upon the degree of opening of the throttle, does not permit of varying the fuel pressure when the altitude varies, and therefore does not permit of attaining an altimetric control.

In the present invention, the valve which varies the relative sections of the respective passages that connect the chamber with the induction passage of the carburetor and with the atmosphere or the air intake respectively, is adapted to be actuated both by the means for controlling the position of the throttle and by control means acting independently of said throttle, thereby providing an altimetric control device.

The following description, with reference to the appended drawing, given merely by way of example, will explain how the invention may be carried out.

Figures 1 and 2 are diagrammatic views of two embodiments of the present invention.

The carburetor shown in Figure 1 is of the anterior throttle type and includes an induction passage l controlled by a throttle valve 2 through a lever 3. Passage I is fed with air through, an air intake 4 and with fuel through a fuel outlet 6 opening into the venturi 1 posterior to the throttle 2. The fuel outlet 6 is controlled by a needle 8, the position of which is controlled by a lever 3 through a lever 9 and a connecting rod It. This fuel outlet receives fuel through a conduit 10 connected to the outlet of chamber H.

The chamber ll receives fuel through-a conduit I2, the inflow of fuel to said chamber being controlled by a valve I3. The valve I3 is connected to a rod l4 with the diaphragm it which serves to control the fuel pressure in chamber II. The diaphragm I5 is loaded by a spring l6, and separates the chamber II from a chamber H. The chamber I1 is connected on the one hand with the air intake 4 through an orifice l8, and on the other hand with the induction passage of the carburetor through a conduit IS. The conduit l9 opens at 5 into the venturi adjacent the fuel outlet 6. The end 5 of the conduit I9 is thus subjected to a suction which is substantially the same as that acting on fuel outlet 6. In the conduit 19 there is provided an orifice 20 controlled by a valve 2|. The head 22 of the valve 2| is subjected to the action of a compression spring 23 bearing upon a collar'24 so as to urge said head against the extension 42 of lever 43. The

[lever 43 is pivoted at 44 to the connecting rod I0 and the lever B and is provided with a slot 45 in which is engaged a pin 46 carried by a lever 4| pivoted about a, pin 41. The valve 2| is thereby adapted to be controlled jointly by the lever 3 that controls the throttle valve and needle 8, and by the independent lever 4!. The lever 4| can be connected at its lower end by a cable or link thereby to permit remote control of said lever from the pilot's cockpit.

The fuel outlet 6 is fed under the pressure existing in the chamber II and its rate of feed depends upon this pressure. The pressure existing in the chamber H depends upon the pressure existing in the chamber ll, since the diaphragm is and the valve i3 take a position of equilibrium for which the pressure exerted by the fuel of chamber H on diaphragm l5 balances the combined action of the spring l6 and the pressure exerted by the air present in the chamber ll on the outerface of the diaphragm IS.

The conduit l9 transmits suction to the chamber ll, but this suction islower than the suction at point 5 of the venturi due to the provision of the orifice l8 between the chamber l1 and the atmosphere. For any given operating condition, the suction transmitted to the chamber IT increases as the relative section of the orifice 20 is made greater with respect to the section of orifice l8. As the suction transmitted to the chamber I1 is increased the fuel pressure in chamber I is reduced, which produces a reduction in the rate of fuel feed through the outlet 6 and a consequent reduction in the mixture richness.

When the lever 4| occupies a fixed position and the pilot actuates the lever 3 in a direction to close the throttle valve 2, the movement of the lever 3 is transmitted through the connecting rod ID, on the one hand to the lever 9 which produces a displacement of the needle in the direction that reduces'the section of the fuel outlet 6, and on the other hand to the lever 43. This lever pivots about the pin 46 in such manner as tofcause the valve 2| to move away from the orifice 20, under the action of its spring, thus increasing the section of flow through said orifice 20. An increased depression is thus transmitted to the chamber When the pilot operates the lever 4| in the direction of the arrow 48, the pin 46 moves in the slot 45 causing the lever 43 to pivot about the pivot pin 44 in the direction of the arrow 49. The valve 2| is moved inthe direction that increases the section of flow through the orifice 20 and the suction transmitted to the chamber ll increases. This operation therefore corresponds to an increased altitude. The reverse operation would correspond to a reduced altitude.

At the same time as the pin 46 moves in the slot 45 and therefore causes the valve 2| to be moved away from its seat, it modifies the ratio of the two arms of lever 43 on either side of the pin 46. It therefore modifies the axial displacement of the valve 2| that corresponds to a given displacement of the throttle valve 2. The modi-' fication of this ratio is such that, when the position of the lever 4| has been adjusted for a given altitude, the composition of the mixture remains correct for all positions of the throttle valve at that altitude.

In Figure 2, the lever 4| is automatically controlled according to the altitude by means of a barometric capsule 50 mounted in a chamber 5| connected to the air intake of the carburetor through a passage 52.

, The invention is obviously not limited to any particular form of carburetor or of diaphragm chamber, as theseelements are known in themselves and do not constitute the invention. Although there is shown a carburetor in which the liquid fuel is fed to a single fuel outlet mechanically controlled in accordance with the position of the throttle valve and located posterior to said throttle valve, the invention may also be applied to other kinds of carburetors, for instance to carburetors having one or more fuel outlets, fed either with liquid fuel or with aerated fuel located either anterior or posterior to the throttle, and to carburetors having no mechanical regulating means.

In a like manner the fuel chamber may include several diaphragms connected with one another and with the fuel valve through suitable mechanical connections. Although the diaphragm has been shown as subjected to the action of a spring, this spring may be eliminated. Finally, the invention is not l mited to the snecific embod ments shown in the drawing. The

mechanical connections as well as the shape of the expansible capsule or of the members that control the valve sections of flow may be modifled in various manners without departing from the principle of the invention; for instance, instead of varying the section of the orifice of communication with the induction passage of the carburetor, as shown by the drawing, the section of the passage of communication with the atmosphere or the air intake, or both of these passages simultaneously, may be varied.

I claim:

1. A charge forming device for an internal combustion'engine comprising an induction passage, a throttle therein, a fuel duct discharging into the passage, a fuel chamber communicating with said duct, a variable pressure chamber, valve means controlling the inflow of fuel to said fuel chamber to thereby control the supply of fuel to the engine, means including a diaphragm responsive to the pressures in said chambers for controlling the valvemeans, conduits connecting said variable pressure chamber to a region of depression in said passage and to a source of substantially atmospheric pressure, throttle operated valve means for varying the relative effective cross sections of said conduits, and means operable independently of the throttle for varying the position of the last-named valve means at a given position of the throttle to thereby vary the rate at which the relative effective cross sections of the conduits are varied by the throttle operated means.

2. A charge forming device for an internal combustion engine including an air supply passage, a throttle therein, a fuel chamber closed by a diaphragm, a fuel duct leading from the fuel chamber to the air passage, a throttle controlled variable restriction in said duct arranged to be subjected to suctions derived from the restricting effect of said throttle, a suction chamber closed by said diaphragm, a valve connected to said diaphragm for controlling the admission of fuel to the fuel chamber, passages connecting said suction chamber to the air passage respectively anterior to the throttle and to a point adjacent said variable restriction thereby to subject said last named passage and the variable restriction to substantially equal or proportional suctions, valve means for varying the relative areas of said passages to thereby vary the suction in the suction chamber, and means controlled conjointly by manually operated means actuated independently of the throttle and by means actuated by the throttle for controlling said valve means.

3. In a charge forming device for an internal combustion engine, an induction passage, means including a throttle for creating a region of depression in said passage, a fuel passage discharging into said region, a throttle controlled variable restriction in said fuel passage and subjected to suction derived from said region, a fuel chamber communicating with said fuel passage, a variable pressure chamber, a conduit leading from the variable pressure chamber and having an outlet in one of said passages whereby the variable restriction and said outlet will be subjected to substantially proportional suctions, a conduit for bleeding air into the variable pressure chamber, valve means for varying the relative fiow capacities of said conduits, means adapted to be moved without corresponding movement of the throttle for positioning said valve means, means actuated by the throttle for modifying the position of the valve means as determined by said last named means upon change in the position of the throttle, and means responsive to the pressures in the fuel chamber and in the variable pressure chamber for controlling the inflow of fuel to the fuel chamber.

4. A charge forming device for internal combustion engines comprising a throttle controlled air passage, a fuel chamber having an inlet, a fuel duct leading from said chamber to the passage posterior to the throttle for supplying fuel thereto, and means for variably restricting the inflow of fuel to said chamber to control the richness of the mixture comprising a valve in said inlet, a variable pressure air chamber, diaphragm means responsive to the pressures in said air and fuel chambers for controlling said valve, means connecting said variable pressure air chamber with a region of depression in the induction passage, air bleeding means for partially destroying the depression in said air chamber, and means for varying the relative effectiveness of said bleeding means and said connecting means to control the pressure in the air chamber comprising a sealed capsule having a movable wall responsive to variations in the density of the air in the induction passage anterior to the throttle, a member movable with the throttle, and valve means controlled by said movable wall and said member.

, transmitting suction from a region of depression in said air passage to the variable pressure chamber, means for bleeding air into said chamber, and means for varying the relative effectiveness of said transmitting means and said bleeding means to control the pressure in the air chamber comprising a sealed chamber having a yielding. wall responsive to variations in the density of the air in the supply passage resulting from variations in altitude, a member controlled in accordance with throttle position, and valve means actuated by said yielding wall and by said member whereby the pressure in the air chamber will be varied by change in altitude and by change in throttle position.

PAUL XAVIER AUGUSTE GISTUCCI.

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