Claims
- 1. An automatic control system for supplying a fuel-air mixture to the intake manifold of the internal combustion engine of a vehicle for regulating the ratio of air to fuel so that this ratio is optimized for prevailing conditions of engine speed and load, said system comprising:
- A. a variable Venturi structure whose inlet is coupled to a source of incoming combustion air and whose outlet is coupled to said intake manifold, said structure including concentric passages constituted by a primary Venturi passage having a throat and leading to a secondary Venturi passage having a variable area throat, and a tertiary Venturi passage having a throat, incoming air flowing through an inlet into all three passages to said intake manifold, and a mechanism for adjusting said variable area throat;
- B. a servo motor operatively coupled to said mechanism to adjust said variable throat area;
- C. means to supply fuel into said primary passage to intermingle with the air passing therethrough to produce an air-fuel mixture;
- D. means communicating with said inlet and the throat of the tertiary passage to sense the pressure difference between that of the air at the inlet and that at the tertiary passage throat to produce a command signal that depends on the velocity of air flow through the Venturi structure; and
- E. a controller responsive to said command signal to govern said servo motor to adjust the area of the variable area throat and thereby change said air velocity so as to bring about the desired ratio of air and fuel in said mixture.
- 2. A system as set forth in claim 1, wherein said primary passage is defined by a cylindrical booster whose interior surface has a Venturi formation and said secondary passage is defined by an axially-shiftable spool whose interior surface has a Venturi formation, the variable area throat being formed between the interior surface of the spool and the exterior surface of the booster.
- 3. A system as set forth in claim 2, wherein said tertiary passage is formed by a ring having a Venturi formation mounted on a cylindrical casing surrounding said spool and said booster.
- 4. A system as set forth in claim 3, wherein said spool is provided at diametrically opposed positions with ribs which slide in channels formed in said ring.
- 5. A system as set forth in claim 4, wherein one of said ribs is provided with a pin projecting through said casing, in a slot therein, said pin being driven by said servo motor.
- 6. A system as set forth in claim 2, wherein said fuel is drawn from a chamber having a vertical fuel tube therein whose lower end is provided with a jet opening, the upper end of the tube being coupled by a duct to a nozzle disposed in said booster and having openings therein which spray the fuel into the booster.
- 7. A system as set forth in claim 6, wherein said duct feeds said fuel tangentially into the nozzle to create a vortex therein.
- 8. A system as set forth in claim 6, further including an air tube disposed within the fuel tube, the lower end of the air tube being immersed in the fuel in the tube, the upper end of the air tube communicating with the inlet to the Venturi structure whereby air is induced by said air tube into the fuel to disperse the fuel before it is conducted into the nozzle.
- 9. A system as set forth in claim 6, wherein said nozzle has an open horn formation and openings in the throat thereof, and is seated within the booster.
- 10. A system as set forth in claim 6, further including an air input throttle disposed in the inlet of the Venturi structure.
- 11. A system as set forth in claim 2, wherein said fuel is pumped from a tank through a fuel pressure regulator into a fuel injector which sprays the fuel into an air passage communicating with the primary Venturi passage.
- 12. A system as set forth in claim 11, further including means to operate said fuel regulator as a function of said pressure difference.
- 13. A system as set forth in claim 1, wherein said controller is an electronic control module and said command signal is produced by a transducer which converts said pressure difference into a corresponding electrical value that is applied to said module.
- 14. A system as set forth in claim 13, wherein also applied to said electronic module is an auxiliary signal which is derived by a transducer from the intake manifold pressure, said auxiliary signal modulating the command signal to effect control as a function of changing engine conditions as reflected by said manifold pressure.
- 15. A system as set forth in claim 14, wherein said module includes a differential amplifier having a non-inverting input and an inverting input whose output acts to govern said servo motor, said auxiliary signal being applied to said inverting input and said command signal to said non-inverting input.
- 16. A system as set forth in claim 15, further including a sensor positioned in the exhaust of said engine to provide a sensor signal that depends on the air-fuel ratio of the mixture, and means to apply said sensor signal to said differential amplifier in a manner maintaining said ratio at a value approaching the stoichiometric ratio of the mixture.
- 17. A system as set forth in claim 16, wherein said last-named means includes a pair of amplifiers, each comparing the sensor signal with a separate reference voltage to provide in one amplifier an enrichment signal representing the deviation in one direction of the sensor signal from the stoichiometric ratio, and in the other amplifier a leaning signal representing the deviation in the other direction, said enrichment signal being applied to said non-inverting input and said leaning signal being applied to the inverting input of the differential amplifier.
RELATED APPLICATIONS
This application is a continuation-in-part of a pending application Ser. No. 962,883, filed Nov. 22, 1978, now U.S. Pat. No. 4,187,805 which in turn is a continuation-in-part of a pending application Ser. No. 919,541, filed June 27, 1978.
US Referenced Citations (15)
Foreign Referenced Citations (2)
Number |
Date |
Country |
2014140 |
Oct 1970 |
DEX |
2219880 |
Oct 1973 |
DEX |
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
962883 |
Nov 1978 |
|
Parent |
919541 |
Jun 1978 |
|