Carburetor with feedback means and system

• US 3,906,910 A
• Filed: 04/23/1973
• Issued: 09/23/1975
• Est. Priority Date: 04/23/1973
• Status: Expired due to Term

• Current Assignee: Coltec Industries Incorporated (Enpro Industries Incorporated)
• Original Assignee: Emil Szlaga Jr
• Inventors: Szlaga, Emil Jr.
• Primary Examiner(s): Burns, Wendell E.
• Assistant Examiner(s): Cranson, Jr., James Winthrop
• Application Number:
  US05/353,579
• Time in Patent Office: 883 Days
• Field of Search: 261/121B,5A 123/139AW,14MC,32EA,97B,127,119R
• US Class Current: 123/677
• CPC Class Codes: F02D 35/0061 Controlling the emulsifying air only F02D35/0076, F02D35/0084 take precedence
• CPC Class Codes: F02M 7/24 Controlling flow of aerating air

Abstract

A carburetor having a fuel metering restriction is provided with air bleed valving means for varying the pressure at one side of the metering restriction to thereby change the metering pressure differential across the metering restriction and consequently vary the fuel-air ratio of the combustible mixture discharged by the carburetor to reflect changes in engine operating parameters.

Claims

1. In a carburetor type fuel metering device, for an internal combustion engine, of the type having induction passage means with venturi means carried therein for creating a reduced first pressure proportional to the square of the flow of air therethrough, a fuel bowl, a fuel passage between the fuel bowl and an orifice for discharging fuel adjacent the venturi and a throttle valve disposed in the inducation passage downstream from the venturi means for controlling the flow of a fuel-air mixture to the engine and wherein said first pressure is employed in combination with a relatively high, substantially atmospheric second pressure in the fuel bowl as the only means for causing metered main fuel to flow to said induction passage means, said device being free of main fuel flow pressurizing means for pressurizing main fuel at pressures appreciably above atmospheric pressure, the improvement of providing additional means responsive to indicia of engine operation, said additional means being effective for at times modifying the effective magnitude of said first pressure in response to said indicia of engine operation in order to thereby correspondingly modify the effect of said first pressure on the rate of metered fuel flow and thereby cause said rate of metered fuel flow, at any air flow during such modification of the effect of said first pressure, to be reflective of said indicia of engine operation.

2. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine deceleration.

3. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine speed.

4. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions indicative of engine shut-down.

5. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine intake manifold pressure.

6. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to the presence of oxygen within the exhaust gases of said engine.

7. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine deceleration and engine speed.

8. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine deceleration, engine speed and engine shut-down.

9. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to conditions of engine deceleration, engine speed, engIne shut-down and the presence of oxygen within the exhaust gases of said engine.

10. A fuel metering device according to claim 1 wherein said indicia comprises means responsive to atmospheric pressure.

11. A fuel metering device according to claim 1 and further comprising further manually adjustable means for manually modifying the effective magnitude of said first pressure.

12. A fuel metering device according to claim 1 wherein said additional means comprises air-bleed means communicating generally between a source of relatively high pressure air and the vicinity in which said first pressure exists.

13. A fuel metering device according to claim 1 wherein said additional means comprises air-bleed means communicating generally between a source of relatively high pressure air and the vicinity in which said first pressure exists, and valving means responsive to said indicia of engine operation for variably opening and closing said air-bleed means generally in accordance with said indicia of engine operation.

14. A fuel metering device according to claim 1 wherein said venturi means comprises variable venturi means.

15. A carburetor for an internal combustion engine, comprising body means, induction passage means with a venturi restriction formed through said body means and having air inlet means formed at one end thereof and outlet means formed at another end thereof, a throttle valve disposed in said inducation passage downstream from said venturi restriction, first means for creating a fuel metering pressure by creating a first relatively low metering pressure of variable magnitude proportional to the square of the velocity of flow of air through said induction passage venturi restriction means, fuel metering means communicating between a source of fuel and said induction passage means, said fuel metering means being so positioned as to have one end thereof generally exposed to said fuel metering pressure in order to in response to the magnitude thereof cause a metered rate of fuel flow to said inducation passage means, said carburetor being free of fuel pressurizing means for pressuring said main fuel at pressures appreciably above atmospheric pressure, and air bleed means communicating generally between a source of relatively high, substantially atmospheric pressure air and said one end of said fuel metering means, said air bleed means being effective to bleed said high pressure air in order to effectively increase the magnitude of said fuel metering pressure, thereby decreasing the metering depression, without modifying the magnitude of said first relatively low pressure and thereby reduce the rate of metered fuel flow to said induction passage.

16. A carburetor according to claim 15, wherein said first means comprises variably openable venturi means.

17. A carburetor according to claim 15, wherein said first means comprises variably openable venturi means operatively connected to throttle valve means situated in said induction passage means downstream thereof.

18. A carburetor according to claim 15, wherein said first means comprises fixed venturi means.

19. A carburetor according to claim 15, wherein said air bleed means comprises variably openable air bleed passage means the effective opening of which is controlled generally in response to atmospheric pressure.

20. A carburetor according to claim 15, wherein said air bleed means comprises variably openable air bleed means the effective opening of which is controlled generally in response to the degree of presence of oxygen in exhaust gases of said engine.

21. A carburetor according to claim 15, wherein said air bleed means comprises openable air bleed means the opening of which is controlled in response to conditions of engine deceleration.

22. A carburetor according to claim 15, wherein said air bleed means comprises openable air bleed means the opening of which is controlled in response to engine speed.

23. In a carburetor type fuel meterinG system, for an internal combustion engine, wherein fuel is metered through calibrated restriction means from a source of fuel to induction passage means communicating with said engine, wherein a first relatively high, substantially atmospheric pressure is applied to said source of fuel, wherein a second relatively low, subatmospheric pressure of variable magnitude is created to be indicative of the air flowing to said engine, and wherein the difference in magnitudes between said first and second pressures is employed for creating a fuel metering pressure differential generally across said source of fuel and said calibrated restriction means causing metered fuel flow, the improvement of forming chamber-like means generally downstream of said calibrated restriction means and at least at times variably bleeding air thereto so as to thereby create a third pressure within said chamber-like means with said third pressure being greater in magnitude than said second pressure, and means responsive to conditions of engine operation for controlling the degree of such air bled to said chamber-like means.

24. A fuel metering system according to claim 23 wherein said calibrated restriction means comprises a portion of the idle fuel delivery system of a carburetor structure.

25. In an internal combustion engine carburetor of the type having induction passage means, associated fuel reservoir means containing fuel to be metered into said induction passage means, venturi means defined within said induction passage means for creating a first pressure of relatively reduced magnitude in response to the flow of air therethrough and a throttle valve disposed downstream of the venturi means, and wherein said first pressure is employed for creating a fuel-metering pressure differential generally across said fuel within said fuel reservoir means to thereby cause a corresponding rate of metered flow of said fuel into said induction passage means, the improvement of providing additional means responsive to indicia of engine operation, said additional means being effective for at times effectively modifying the magnitude of said first pressure in response to said indicia of engine operation in order to thereby correspondingly modify the magnitude of said fuel-metering pressure differential and thereby correspondingly alter said rate of metered flow of said fuel into said induction passage means even during conditions of engine operation wherein the rate of flow of air through said induction passage means has remained substantially constant.