Circuit for providing electronic enrichment fuel compensation in an electronic fuel control system

Claim 2

In an internal combustion engine fuel control system of the type having an intake manifold for providing air to the engine, sensor means including means for generating a signal indicative of engine load, and computing means responsive to the sensor means for providing a train of fuel delivery command signals varying from an engine speed determined first value to a second value determined at least in part by said signal indicating engine load, the durations of said fuel delivery command signals between said engine speed determined first value and said second valve determining quantities of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined engine load at which the air pressure in the intake manifold is within ten percent of atmospheric pressure; and means for compariNg the reference and load indicating signals and changing the duration of the fuel delivery command signals in response to load indicating signal values having a predetermined relationship with respect to said reference signal.

Claim 3

The fuel control system of claim 1 in which: said means for changing the duration of said fuel delivery command signals comprise: current sink means; and switching means responsive to the reference and engine load indicating signals for switchingly connecting said current sink means to drain energy from the means for providing said fuel delivery command signals and thereby increase the time required for a command signal to reach said second value.

Claim 4

The fuel control system of claim 2 in which: the means for providing said train of fuel delivery command signals comprise a capacitor, and means for intermittently charging and discharging said capacitor; and said switching means comprise means for connecting said current sink means to drain energy from said capacitor in response to an engine load indicating signal having a value greater than the value of said reference signal.

Claim 5

In an internal combustion engine fuel control system of the type having sensor means including means for generating a signal indicative of engine load, and computing means responsive to the sensor means for producing a train of fuel delivery command signals that vary from an engine speed determined first value to a second value, said signal indicating engine load determining said second value and thereby determining at least in part the time required for a fuel delivery command signal to reach said second value, the durations of said fuel delivery command signals between said engine speed determined first value and said second value determining the quantity of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined engine load; and means for comparing the reference and fuel delivery command signals and reducing the variation rate of each fuel delivery command signal reaching said reference value to thereby increase the quantity of fuel being supplied to the engine.

Claim 6

In an internal combustion engine fuel control system of the type having sensor means including means for generating a signal indicative of engine load, and computing means responsive to the sensor means for producing a train of fuel delivery command signals that vary from an engine speed determined first value to a second value, said signal indicating engine load determining said second value and thereby determining at least in part the time required for a fuel delivery command signal to reach said second value, the durations of said fuel delivery command signals between said engine speed determined first value and said second value determining the quantity of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined engine load; and means for comparing the reference and fuel delivery command signals and reducing the variation rate of each fuel delivery command signal reaching said reference value to thereby increase the quantity of fuel being supplied to the engine.

Claim 7

The fuel control system of claim 4 in which: The means for providing said train of fuel delivery command signals comprise a capacitor and current source means for intermittently charging and discharging said capacitor; and said means for reducing the variation of said fuel delivery command signals comprise: current sink means for draining energy from said capacitor; and switching means responsive to the reference and fuel delivery command signals for switchingly connecting said current sink means to said capacitor in response to a fuel delivery command signal reaching said reference value.

Claim 8

In an internal combustion engine fuel control system of the type having sensor means, including means to generate a signal indicative of engine load, responsive to engine conditions operative to produce signals indicative of engine operating parameters, computing means responsive to the sensor means signals operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal operative to supply the engine with fuel in relation to the fuel delivery command signal, wherein the computing means comprise waveform generating means operative to generate a composite waveform signal having an initializing portion defining an engine speed determined initializing level and a computing portion having a predetermined slope increasing from said initializing level and threshold means receiving said waveform on one of said sensor signals operative to establish a sensor signal determined threshold level, and further operative to generate an output signal whenever the computing portion of the waveform signal has a level which has a selected relationship with the established threshold, the improvement comprising: electronic circuit means responsive to the sensor means signal indicative of a condition of engine loading in excess of a predetermined amount operative to generate a signal indicative of a need for full load enrichment, wherein said electronic circuit means comprise switching means having a pair of stable states responsive to the computing portion of the waveform signal having attained a preselected value operative to switch from one state to the other to generate a signal indicative of the instantaneous relationship between the computing portion and said preselected value, and means responsive to said enrichment signal operative to modify the fuel delivery command signal to cause the fuel supply means to increase the delivery of fuel to the engine, said enrichment signal responsive means being responsive to said switching means indication of a predetermined relationship between the computing portion and the preselected value and are operative to alter the slope of the computing means signal.

Claim 9

In an internal combustion engine fuel control system of the type having sensor means, including means to generate a signal indicative of engine load, responsive to engine conditions operative to produce signals indicative of engine operating parameters, computing means responsive to the sensor means signals operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal operative to supply the engine with fuel in relation to the fuel delivery command signal, wherein the computing means comprise waveform generating means operative to generate a composite waveform signal having an initializing portion defining an engine speed determined initializing level and a computing portion having a predetermined slope increasing from said initializing level and threshold means receiving said waveform on one of said sensor signals operative to establish a sensor signal determined threshold level, and further operative to generate an output signal whenever the computing portion of the waveform signal has a level which has a selected relationship with the established threshold, the improvement comprising: electronic circuit means responsive to the sensor means signal indicative of a condition of engine loading in excess of a predetermined amount operative to generate a signal indicative of a need for full load enrichment, wherein said electronic circuit means comprise switching means having a pair of stable states responsive to the computing portion of the waveform signal having attained a preselected value operative to switch from one state to the other to generate a signal indicative of the instantaneous relationship between the computing portion and said preselected value, and means responsive to said enrichment signal operative to modify the fuel delivery command signal to cause the fuel supply means to increase the delivery of fuel to the engine, said enrichment signal responsive means being responsive to said switching means indication of a predetermined relationship between the computing portion and the preselected value and are operative to alter the slope of the computing means signal.

Claim 10

The system as claimed in claim 6 wherein said waveform generating means comprise current source means operative to generate an electrical current and receiving means intermittently receiving said current source means current operative to generate a signal having a level indicative of the duration said current has been received and said enrichment signal responsive means comprise current sink means operative when actuated to reduce the level of current being received by said receiving means.

Claim 11

In an internal combustion engine fuel control system of the type having a plurality of sensor means responsive to engine conditions operative to generate signals indicative of engine operating parameters, computing means responsive to the sensor means signals operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal operative to supply the engine with fuel in relation to the fuel delivery command signal wherein the computing means comprises first generating means for generating a voltage signal waveform having predeterminable first and second waveform portions and second generating means for generating the fuel delivery command signal while the second waveform portion remains below a sensor means signal controlled second value, said first portion defining a first value varying with engine speeds and said second portion commencing at said first value and increasing towards said second value the improvement to said computing means comprising: circuit means responsive to at least one of said plurality of sensor means operative to generate a signal indicative of engine operation within a selected range of engine conditions coupled to the computing means first generating means operative to controllably vary the slope of the second waveform portion in response to the degree of engine operation within said selected range.

Claim 12

In an internal combustion engine fuel control system of the type having a plurality of sensor means responsive to engine conditions operative to generate signals indicative of engine operating parameters, computing means responsive to the sensor means signals operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal operative to supply the engine with fuel in relation to the fuel delivery command signal wherein the computing means comprises first generating means for generating a voltage signal waveform having predeterminable first and second waveform portions and second generating means for generating the fuel delivery command signal while the second waveform portion remains below a sensor means signal controlled second value, said first portion defining a first value varying with engine speeds and said second portion commencing at said first value and increasing towards said second value the improvement to said computing means comprising: circuit means responsive to at least one of said plurality of sensor means operative to generate a signal indicative of engine operation within a selected range of engine conditions coupled to the computing means first generating means operative to controllably vary the slope of the second waveform portion in response to the degree of engine operation within said selected range.

Claim 13

The system as claimed in claim 8 wherein the first generating means comprise capacitor means, at least two current source means and switching means to sequentially apply the currents generated by the current source means to the capacitor means, the first current source operative to generate the first waveform portion across the capacitor means and the second current source means operative to generate the second waveform portion across the capacitor means and said circuit means comprise means for generating a control signal in response to engine operation within a selected range of engine operating conditions and means for applying said control signal to the second current source means, said control signal operative to control the magnitude of the current generated by the second current source means.

Claim 14

The system as claimed in claim 9 wherein said control signal is operative to terminate the communication of current generated by said second current source means.

Claim 15

In an internal combustion engine fUel control system of the type having sensor means responsive to engine conditions operative to produce at least one signal indicative of engine operating parameters, computing means responsive to the sensor means signal operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal, the computing means including first means for generating a predeterminable waveshape signal and second means for generating a threshold level and responsive to the generated waveshape operative to produce as output signal the fuel delivery command signal while the generated waveshape bears a preselected relationship to the threshold level wherein the first generating means comprise capacitor means, at least two current source means and switching means to sequentially apply the current generated by the current source means to the capacitor means, the first current source operative to generate an engine speed determined first waveform portion across the capacitor means and the second current source means operative to generate a second waveform portion across the capacitor means increasing from said first portion the improvement comprising: circuit means coupled to said first means and responsive to selected conditions of the generated waveshape operative to controllably alter the waveshape and said circuit means comprising means for generating a control signal in response to engine operation within a selected range of engine operating conditions and means for applying said control signal to the second current source means, said control signal operative to control the magnitude of the current generated by the second current source means.

Claim 16

In an internal combustion engine fUel control system of the type having sensor means responsive to engine conditions operative to produce at least one signal indicative of engine operating parameters, computing means responsive to the sensor means signal operative to produce a fuel delivery command signal indicative of the engine fuel requirement and fuel supply means responsive to the fuel delivery command signal, the computing means including first means for generating a predeterminable waveshape signal and second means for generating a threshold level and responsive to the generated waveshape operative to produce as output signal the fuel delivery command signal while the generated waveshape bears a preselected relationship to the threshold level wherein the first generating means comprise capacitor means, at least two current source means and switching means to sequentially apply the current generated by the current source means to the capacitor means, the first current source operative to generate an engine speed determined first waveform portion across the capacitor means and the second current source means operative to generate a second waveform portion across the capacitor means increasing from said first portion the improvement comprising: circuit means coupled to said first means and responsive to selected conditions of the generated waveshape operative to controllably alter the waveshape and said circuit means comprising means for generating a control signal in response to engine operation within a selected range of engine operating conditions and means for applying said control signal to the second current source means, said control signal operative to control the magnitude of the current generated by the second current source means.

Claim 17

The system as claimed in claim 11 wherein said control signal is operative to terminate the communication of current generated by said second current source means.

Claim 18

In an internal combustion engine fuel control system of the type having an intake manifold for providing fuel to the engine, sensor means including means for generating a load signal indicative of intake manifold air pressure, and computing means responsive to the sensor means for providing a train of fuel delivery command signals having durations determined at least in part by said signal indicating manifold air pressure, the durations of said fuel delivery command signals determining quantities of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined relationship with respect to atmospheric pressure and for varying said reference signal in accordance with atmospheric pressure variation; and means for comparing the reference and load indicating signals and changing the duration of the fuel delivery command signals in response to load indicating signal values having a predetermined relationship with respect to said reference signal.

Claim 19

In an internal combustion engine fuel control system of the type having an intake manifold for providing fuel to the engine, sensor means including means for generating a load signal indicative of intake manifold air pressure, and computing means responsive to the sensor means for providing a train of fuel delivery command signals having durations determined at least in part by said signal indicating manifold air pressure, the durations of said fuel delivery command signals determining quantities of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined relationship with respect to atmospheric pressure and for varying said reference signal in accordance with atmospheric pressure variation; and means for comparing the reference and load indicating signals and changing the duration of the fuel delivery command signals in response to load indicating signal values having a predetermined relationship with respect to said reference signal.

Claim 20

In an internal combustion engine fuel control system of the type having an intake manifold for providing fuel to the engine, sensor means including means for generating a load signal indicative of intake manifold air pressure, and computing means responsive to the sensor means for producing a train of fuel delivery command signals that vary from an engine speed determined first value to a second value, said load signal indicating manifold air pressure determining said second value and thereby determining at least in part the time required for a fuel delivery command signal to reach said second value, the durations of said fuel delivery command signals between said first and second values determining the quantity of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined relationship with respect to atmospheric pressure and for varying said reference signal in accordance with atmospheric pressure variation; and means for comparing the reference and fuel delivery command signals and reducing the variation rate of each fuel delivery command signal reaching said reference value to thereby increase the quantity of fuel being supplied to the engine.

Claim 21

In an internal combustion engine fuel control system of the type having an intake manifold for providing fuel to the engine, sensor means including means for generating a load signal indicative of intake manifold air pressure, and computing means responsive to the sensor means for producing a train of fuel delivery command signals that vary from an engine speed determined first value to a second value, said load signal indicating manifold air pressure determining said second value and thereby determining at least in part the time required for a fuel delivery command signal to reach said second value, the durations of said fuel delivery command signals between said first and second values determining the quantity of fuel supplied to the engine, the improvement comprising a full load enrichment circuit having: means for providing a reference signal representing a predetermined relationship with respect to atmospheric pressure and for varying said reference signal in accordance with atmospheric pressure variation; and means for comparing the reference and fuel delivery command signals and reducing the variation rate of each fuel delivery command signal reaching said reference value to thereby increase the quantity of fuel being supplied to the engine.

Claim 22

In an internal combustion engine fuel control system of the type having a plurality of sensor means each responsive to a different engine operating condition to generate a respective engine operating parameter signal, electronic fuel command signal computing means comprising: a. capacitor means; b. first and second current source means for generating respective currents; c. switch means for alternately coupling said capacitor means to said first and second current sources whereby a first waveform is provided by said capacitor means while said first current source is coupled thereto and a second waveform having successive first and second slopes is generated by said capacitor means when said second current source is coupled thereto; d. first and second reference means for providing respective first and second reference signals varying in accordance with respective first and second engine operating parameter signals; and e. first and second comparator means each having a first input, a second input and an output, said first input coupled to said capacitor means, said second input coupled to a different one of said first and second reference means, said output of said first comparator means operative to provide a fuel injection command signal commencing when said capacitor means is switched from said first current source means to said second current source means and terminating when said second waveform exceeds said first reference signal, and said output of said second comparator means coupled to said second current source means to vary the current generated thereby from said first slope to said second slope said second waveform exceeds said second reference signal; wherein said second waveform increases along said first slope as long as said second waveform is less than said second reference signal whereafter said second waveform increases along said second slope so that after said second waveform exceeds said second reference signal the time required to reach said first reference signal is changed from it would have been if said second comparator means had not varied the current generated by the second source means.

Claim 23

In an internal combustion engine fuel control system of the type having a plurality of sensor means each responsive to a different engine operating condition to generate a respective engine operating parameter signal, electronic fuel command signal computing means comprising: a. capacitor means; b. first and second current source means for generating respective currents; c. switch means for alternately coupling said capacitor means to said first and second current sources whereby a first waveform is provided by said capacitor means while said first current source is coupled thereto and a second waveform having successive first and second slopes is generated by said capacitor means when said second current source is coupled thereto; d. first and second reference means for providing respective first and second reference signals varying in accordance with respective first and second engine operating parameter signals; and e. first and second comparator means each having a first input, a second input and an output, said first input coupled to said capacitor means, said second input coupled to a different one of said first and second reference means, said output of said first comparator means operative to provide a fuel injection command signal commencing when said capacitor means is switched from said first current source means to said second current source means and terminating when said second waveform exceeds said first reference signal, and said output of said second comparator means coupled to said second current source means to vary the current generated thereby from said first slope to said second slope said second waveform exceeds said second reference signal; wherein said second waveform increases along said first slope as long as said second waveform is less than said second reference signal whereafter said second waveform increases along said second slope so that after said second waveform exceeds said second reference signal the time required to reach said first reference signal is changed from it would have been if said second comparator means had not varied the current generated by the second source means.

Claim 24

In the electronic fuel command computing circuit of claim 15 said switching means operative to effect selective discharge and charge of said capacitor means when coupled to one of said first and second current source means in accordance with the time elapsed from the switching of said capacitor means from said second current source means to said first current source means and said second comparator output operative to decrease the current generated by said second current source means to effect fuel enrichment when said first reference signal is greater than said second reference signal.