Single point fuel dispersion system using a low profile carburetor

• US 4,231,333 A
• Filed: 01/12/1978
• Issued: 11/04/1980
• Est. Priority Date: 01/12/1978
• Status: Expired due to Term

• Current Assignee: Arthur K. Thatcher
• Original Assignee: Arthur K. Thatcher
• Inventors: Thatcher, Arthur K., McCarter, Ed R.
• Primary Examiner(s): Burns, Wendell E.
• Application Number:
  US05/868,825
• Time in Patent Office: 1,027 Days
• Field of Search: 123/139 AW, 123/179 B, 123/119 R, 123/32 EA, 123/25 R
• US Class Current: 123/676
• CPC Class Codes: F02B 1/00 Engines characterised by fuel-air mixture compression characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition F02B11/00
• CPC Class Codes: F02B 3/00 Engines characterised by air compression and subsequent fuel addition characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition F02B11/00
• CPC Class Codes: F02D 41/04 Introducing corrections for particular operating conditions F02D41/14 takes precedence
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: F02M 27/08 by sonic or ultrasonic waves
• CPC Class Codes: F02M 69/041 having vibrating means for atomizing the fuel, e.g. with sonic or ultrasonic vibrations

Abstract

This invention relates to a computer controlled fuel system for an internal combustion engine including a low profile carburetor for permitting engine operation on very lean fuel/air ratios without sacrificing engine performance during critical engine operations such as start up, warm-up and acceleration. The low profile carburetor provides a single point source fuel dispersion and includes one or more throttle controlled, sliding plates for increasing fuel entrainment at low engine speeds by increasing the velocity of the airstream flow through the carburetor just before the dispersion point and by maximizing the lateral distance between the point of fuel dispersion and the carburetor airstream. The computer controlled system includes various threshold circuits for providing additional fuel and/or water injection into the carburetor airstream upon detection of predetermined engine conditions.

Claims

1. A computer controlled fuel system for an internal combustion engine having a combustion area, an intake manifold for conducting air and fuel to the combustion area, an air source for providing an airstream for entry into the intake manifold, an exhaust manifold for removing exhaust gases from the combustion area, and a fuel source, said computer controlled fuel system comprising

(A) fuel input means connected to supply fuel from the fuel source to the airstream, said fuel input means including

(1) fuel dispersion means for receiving fuel at a point adjacent the path of the airstream and for dispersing the fuel so received into the airstream at an angle relative to the direction of flow of the airstream and toward the center of the airstream at a point before the airstream reaches the combustion area of the engine, said fuel dispersion means being mounted in a predetermined orientation adjacent the path of the airstream, and

(2) fuel injection means for receiving fuel from the fuel source and for directing a flow of fuel so received to said fuel dispersion means for dispersion into the airstream;

and

(B) a fuel computer means connected with said fuel input means for controlling the flow of fuel from said fuel injection means to supply a predetermined fuel-air ratio to the intake manifold in response to sensed engine conditions as long as such engine conditions remain within predetermined limits, said fuel computer means including threshold means for providing additional fuel flow to said fuel dispersion means from said fuel injection means whenever a sensed engine condition goes beyond a predetermined threshold level.

2. A computer controlled fuel system as defined in claim 1, wherein said threshold means includes a first threshold circuit responsive to a temperature condition of the internal combustion engine for increasing the flow of fuel to said fuel dispersion means from said fuel injection means when said temperature condition falls below a predetermined condition.

3. A computer controlled fuel system as defined in claim 2, wherein said first threshold circuit includes a start-up circuit means responsive to the initial energization of the internal combustion engine during start-up operations to cause additional fuel flow to said fuel dispersion means from said fuel injection means.

4. A computer controlled fuel system as defined in claim 2, wherein said first threshold circuit includes a first temperature sensor mounted to sense the temperature of the exhaust gases in the exhaust manifold and a second temperature sensor mounted to sense the temperature of the airstream passing through the intake manifold.

5. A computer controlled fuel system as defined in claim 4, wherein the internal combustion engine is liquid cooled and wherein said first threshold circuit includes a third temperature sensor mounted to sense the temperature of the liquid coolant of the engine.

6. A computer controlled fuel system as defined in claim 1, wherein said threshold means includes a second threshold circuit responsive to the pressure in the intake manifold to increase fuel flow to said fuel dispersion means from said fuel injection means whenever the pressure within the intake manifold rises above a predetermined level.

7. A computer controlled fuel system as defined in claim 6, further including water injecting means for injecting water into said airstream, and wherein said second threshold circuit means operates said water injecting means to inject water into said airstream whenever the pressure within said intake manifold rises above a predetermined level.

8. A computer controlled fuel system as defined in claim 6, wherein said second threshold circuit includes a temperature dependent circuit means for increasing the amount of fuel enrichment resulting from the operation of said second threshold circuit when the engine is operating below a predetermined temperature.

9. A computer controlled fuel system as defined in claim 8 wherein said temperature dependent circuit is dependent upon the temperature of the airstream within said intake manifold.

10. A computer controlled fuel system as defined in claim 1, wherein said threshold means includes a rate of pressure change circuit means responsive to the rate of change of pressure within said intake manifold to enhance the flow of fuel to said airstream by said fuel injecting means proportional to the rate of change of pressure within said intake manifold.

11. A computer controlled fuel system as defined in claim 10, wherein said threshold means further includes a low engine speed circuit means for increasing the fuel enrichment when the engine is accelerating above a predetermined rate and the engine speed is below a predetermined rpm.

12. A computer controlled fuel system as defined in claim 11, wherein said threshold means includes a pre-set engine speed cut off circuit means for holding open said fuel injection means during acceleration when said engine speed is below a predetermined rpm, and the pressure conditions of claim 1 are satisfied.

13. A computer controlled fuel system as defined in claim 1, wherein said rate of pressure change circuit means produces output pulses and wherein said threshold means includes a pulse stretcher circuit means for time stretching the pulses from said rate of pressure change circuit means.

14. A computer controlled fuel system as defined in claim 13, wherein said pulse stretcher circuit means include first circuit means for time stretching negative pulses and second circuit means for time stretching positive pulses.

15. A computer controlled fuel system as defined in claim 1, further including carburetor means for mixing air and fuel at a point upstream from said intake manifold in accordance with the setting of a throttle control and said fuel computer means, said carburetor means including

(a) passage means for forming an airstream passage for directing an airstream into the intake manifold;

(b) fuel injection means for injecting fuel toward a dispersion point located within the airstream passage at which the fuel may be dispersed, and

(c) airstream control means for displacing the airstream within said passage to increase the distance between said dispersion point and said airstream when the throttle control is adjusted so as to produce less engine speed and for permitting a decrease in the distance between said dispersion point and the airstream when the throttle control is adjusted so as to increase engine speed.

16. A computer controlled fuel system as defined in claim 15, wherein said airstream control means includes

(a) linkage means for mechanically connecting the throttle control with said airstream control means, said linkage means including a spring for transmitting a force to said airstream control means proportional to the displacement of the throttle control and a dash pot means for time delaying the response of said airstream control means;

(b) anticipation transducer means connected with said linkage means for producing a signal anticipating the response of said airstream control means following changes in the displacement of the throttle control; and

(c) means connecting said anticipation signal to said fuel computer means to modify the fuel flow to said airstream.

17. A computer controlled fuel system as defined in claim 16, wherein said anticipation transducer means includes a displacement transducer connected with said spring in response to the relative movement of the ends of said spring.

18. A computer controlled fuel system as defined in claim 16, wherein sand anticipation transducer means includes a pressure transducer for measuring the pressure within said dash pot means to produce said signal.

19. A computer controlled fuel system as defined in claim 6 wherein said second threshold circuit means includes starter de-enrichment circuit means to reduce fuel input to said fuel injection means during the time that the engine is being started when the engine is hot.

20. A computer controlled fuel system as defined in claim 6 wherein said second threshold circuit means includes an early warm-up circuit means for providing additional fuel to said fuel injection means while the engine is cold.

21. A computer controlled fuel system as defined in claim 1 including a clamping circuit means for preventing excessively lean air-fuel ratios during engine deceleration.

22. A computer controlled fuel system as defined in claim 1 wherein said fuel injection means includes valve means for forming fuel pulses of varying volume dependent upon the length of time the valve means is open, said fuel computer means including integrator circuit means operable in response to pulse control signals for controlling the length of time said valve means is open, said threshold means including idle and acceleration time constant modification circuit means for varying the length of time said valve means is open in response to a voltage signal representative of the pressure in the intake manifold of the engine.

23. A computer controlled fuel system as defined in claim 3 for use with an engine having an ignition system which provides electrical timing pulses proportional to the speed of engine rotation, wherein said fuel injection means includes valve means connected to the engine ignition system for responding to the timing pulses to form fuel pulses at a rate directly proportional to the engine ignition pulses, said fuel computer means including circuit means connected with said fuel injection means to pulse width modulate the fuel pulses in response to engine conditions, to meter the correct amount of fuel to the engine for each sensed engine condition.

24. The computer controlled fuel system as defined in claim 4, wherein said first temperature sensor includes a thermistor mounted in indirect contact with the exhaust manifold.

25. A computer controlled fuel system as defined in claim 24, wherein said thermistor is formed with cooling fins which limit the maximum temperature in the thermistor to a safe value.

26. A computer controlled fuel system for an internal combustion engine having an intake manifold, an air source for providing an airstream for entry into said intake manifold, and a fuel source for said internal combustion engine, said computer controlled fuel system comprising fuel input means connected to supply fuel from said fuel source to said airstream at a point before said intake manifold reaches the combustion area of said engine, said fuel input means including fuel dispersion means having at least one fuel receiving surface for receiving fuel and providing a fuel dispersion to said airstream, said fuel dispersion means being mounted at a point adjacent the path of said airstream, means for directing fuel onto said fuel receiving surface, said fuel receiving surface being formed to redirect said fuel toward the center of the airstream, fuel control means to control the flow of fuel from said fuel source to said fuel directing means and fuel receiving surface, said computer controlled fuel system also comprising fuel computer means connected to control the operation of said fuel control means to provide a fuel flow to said fuel receiving surface which varies as a function of variations in the operation of said internal combustion engine, said fuel computer means including threshold means for increasing the flow of fuel from said fuel input means to said fuel receiving surface whenever a sensed engine condition goes beyond a predetermined threshold level.

27. A computer controlled fuel system for an internal combustion engine having a plurality of cylinders, an intake manifold including a central passageway joined to a plurality of branch passageways in respective fluid communication with the plurality of cylinders for conducting air and fuel thereto, an air source for providing an airstream which passes through the central passageway of the intake manifold and is divided by the branch passageways into separate airflows for entry into the cylinders, an exhaust manifold for removing exhaust gases from the cylinders, and a fuel source, said computer controlled fuel system comprising pulsed fuel input means connected to supply pulses of fuel from the fuel source to the airstream at a point before the branch passageways divide the airstream into separate airflows, said pulsed fuel input means including both a fuel dispersion means for receiving and dispersing said pulses of fuel into the airstream at said point before the branch passageways divide the airstream into separate airflows and a fuel injection means for directing said pulses of fuel from the fuel source toward said fuel dispersion means for dispersion into the airstream, said computer controlled fuel system also comprising a fuel computer means connected with said fuel input means for controlling the duration of said pulses of fuel dispersed into the airstream to provide a predetermined fuel-air ratio in the intake manifold in response to sensed engine conditions as long as such engine conditions remain within predetermined limits, said fuel computer means including threshold means for increasing the duration of said fuel pulses dispersed into the airstream whenever a sensed engine condition goes beyond a predetermined threshold level.