Adaptive charge forming system for controlling the air/fuel mixture supplied to an internal combustion engine

• US 4,368,707 A
• Filed: 07/28/1980
• Issued: 01/18/1983
• Est. Priority Date: 11/22/1976
• Status: Expired due to Term

• Current Assignee: Fuel Injection Development Corporation
• Original Assignee: Fuel Injection Development Corporation
• Inventors: Leshner, Ervin, Leshner, Michael D.
• Primary Examiner(s): Cox, Ronald B.
• Application Number:
  US06/172,665
• Time in Patent Office: 904 Days
• Field of Search: 123/436, 123/440, 123/438, 123/419, 123/585, 123/437
• US Class Current: 123/436
• 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: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 41/005 according to engine operating conditions
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: F02M 26/54 Rotary actuators, e.g. step motors
• CPC Class Codes: F02M 31/18 to vaporise fuel
• CPC Class Codes: F02M 69/18 the means being metering valves throttling fuel passages to injectors or by-pass valves throttling overflow passages, the metering valves being actuated by a device responsive to the engine working parameters, e.g. engine load, speed, temperature or quantity of air the means varying fuel pressure in a fuel by-pass passage, the pressure acting on a throttle valve against the action of metered or throttled fuel pressure for variably throttling fuel flow to injection nozzles F02M69/26
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An adaptive charge forming system for an internal combustion engine is disclosed which monitors a parameter of engine combustion efficiency, such as power output, and derives a signal indicating the direction and amplitude of power change. The fuel mixture control system responds to changes in power output, regardless of their source, to maintain the engine air/fuel ratio in a preferred region. In a preferred embodiment, engine crankshaft angular acceleration is monitored to maintain the air/fuel mixture at the lean limit. A stepping motor is used to control a value for bleeding additional air into the charge; a clock provides steady pulses to the motor, tending to lean the mixture, while enrichment is effected upon the detection of each weak combustion event. The clock frequency thus sets the equilibrium rate of weak combustion events, defining the optimal mixture to be supplied to the engine.

Claims

1. Apparatus for controlling valve means for altering the ratio of the fuel/air mixture supplied to an engine to equal an optimum ratio varying in accordance with the instantaneous power output of said engine, comprising:

means for providing a first fixed signal for controlling said valve means to alter said mixture in a first direction;

means for providing a second variable signal proportional to departure of said mixture from said optimum ratio to cause said valve means to alter said mixture in a second opposite direction; and

means for controlling said valve means adapted to alter said ratio at a rate proportional to the difference between said first and second signals.

2. The apparatus of claim 1 wherein said second variable signal proportional to departure of the ratio of said mixture from said optimum ratio is generated by means for monitoring the instantaneous power output of said engine.

3. The apparatus of claim 2 wherein said means for monitoring comprises means for differentiating a signal proportional to the instantaneous crankshaft speed of said engine.

4. The apparatus of claim 1 wherein said first direction is the direction of leaning said mixture and said second direction is the direction of enrichening said mixture.

5. An adaptive system for altering the fuel/air ratio of the charge supplied to an engine comprising means for monitoring operation of said engine and for detecting when the rate of change of power output by said engine exceeds a predetermined negative value, means for gradually and continually leaning the charge supplied to said engine, and means for instantaneously richening said charge, at a rate proportional to the rate of change of power output by said engine in response to signals output by said means for monitoring operation of said engine, upon said detection.

6. The system of claim 5 wherein said means for monitoring operation of said engine measures the angular velocity of the crankshaft of said engine.

7. The system of claim 5 wherein said charge is altered by valve means controlled to bleed a variable quantity of air into said charge.

8. The system of claim 7 in which said valve means is operated by electric servomotor means.

9. The system of claim 8 wherein said servomotor means is a stepping motor, and said means for gradually and continually leaning said charge comprises clock means for supplying a steady train of pulses to said stepping motor, whereby said valve means is gradually controlled to bleed more air into said charge.

10. The system of claim 9 wherein said means for richening said charge comprise means for applying pulses to said stepping motor in response to said detection, whereby said valve means is instantaneously controlled to bleed less air into said charge.

11. Apparatus for the controlling of the ratio of the fuel/air mixture supplied to an internal-combustion engine, comprising:

means for providing a first signal indicative of the power output by said engine;

means for differentiating said first signal and for producing a second signal indicative of the rate of change of said first signal; and

means for altering said fuel/air ratio in response to said second signal exceeding a predetermined level, wherein said means for altering said fuel/air ratio is controlled to alter said ratio at a rate dependent on the amount by which said second signal exceeds said predetermined level.

12. The apparatus of claim 11 wherein a third signal comprising a series of pulses is produced by said second signal exceeding said predetermined level and is used to control said means for altering said fuel/air ratio.

13. The apparatus of claim 12 wherein the frequency of the pulses comprising said third signal depends on the degree to which said second signal exceeds said predetermined level.

14. The apparatus of any of claims 11, 12 or 13 wherein said means for altering said fuel/air ratio is controlled to alter said ratio only when said second signal is negative.

15. Apparatus for controlling the fuel/air ratio of the charge supplied to an internal combustion engine, comprising:

valve means for controllably varying the ratio of the charge;

electric servo motor means for controlling said valve means;

first signal source means for applying a first bias signal to said servo motor for biasing variation of the ratio of said charge in a first direction; and

second signal source means for applying a varying second signal, generated in response to sensed engine operating parameters, to said servo motor to cause variation of the ratio of said charge in a second direction opposite said first direction,

whereby equilibrium operation is reached by said servo motor means when said first bias signal is substantially equalled by said varying second signal, thus controlling said ratio in order to control said operating parameters.

16. The apparatus of claim 15 wherein said servo motor means comprises a stepping motor.

17. The apparatus of claim 15 wherein said first signal source means is a clock for applying a steady stream of pulses to said servo motor means.

18. The apparatus of claim 15 wherein said second signal source means comprises means for supplying pulses to said servo motor means in response to detection that the rate of change of the power output of said engine exceeds a predetermined rate.

19. The apparatus of claim 18, comprising:

means for producing a first signal dependent on the instantaneous power output by said engine;

means for producing a second signal in response to differentiation of said first signal; and

means for outputting a pulse when said second signal exceeds a predetermined level.

20. The apparatus of claim 19 wherein instantaneous engine angular velocity is input to said means for producing a first signal dependent on instantaneous power output by said engine.

21. Apparatus for controllably varying the fuel/air ratio of the charge supplied to an internal combustion engine, comprising:

means for detecting weak combustion events, and outputting first pulses in response thereto;

means for generating a steady stream of pulses; and

means for varying the air/fuel ratio of said charge in response to said pulses, said first pulses being applied to vary said ratio in a first sense and said stream of pulses applied to vary said ratio in the opposite sense, whereby the fuel/air ratio is urged toward an equilibrium point at which the average rate of said weak combustion events is substantially equal to the rate of said steady stream of clock pulses.

22. The apparatus of claim 21 wherein said means for varying the air/fuel ratio of said charge comprises servo motor means controlled to vary said charge in response to said pulses.

23. The apparatus of claim 21 wherein said means for detecting weak combustion events comprises means for differentiating the instantaneous crankshaft velocity.

24. The apparatus of claim 21 wherein said equilibrium point is preset at a selected lean mixture combustion limit for said engine.