Claims
- 1. An engine control system including engine idle speed control apparatus, comprising:
- means for providing an error signal related to the difference between actual sensed engine speed and a desired engine idle speed;
- means coupled to said error signal providing means for implementing, when enabled, a closed loop engine idle speed control in accordance with a control signal related to at least the magnitude of said error signal; and
- means coupled to said engine idle speed control means for selectively enabling said closed loop idle speed control means in response to at least the magnitude of said actual speed being substantially equal to said desired engine idle speed, and disabling and closed loop control means whenever said actual speed is above a predetermined speed which is greater than said desired speed,
- wherein said closed loop idle speed control means includes means for positioning air-fuel mixture control apparatus in accordance with said control signal, and means for storing, until said closed loop idle speed control means is enabled, the magnitude of a signal related to the position of said control apparatus at a magnitude related to the magnitude which existed when said closed loop idle speed control means was last enabled, and utilizing said stored magnitude to implement initial closed loop control of said air-fuel mixture control apparatus by initially determining said control signal when said idle speed control means is enabled.
- 2. An engine control system according to claim 1 wherein said closed loop idle speed control means also comprises means for developing a signal varying substantially in direct proportion to said error signal, said control signal being a function of both said direct proportion signal and the integral of said error signal.
- 3. An engine control system according to claim 1 wherein said control means includes an integrator means for developing an output signal representative of the integral of said error signal, wherein said control signal is determined in accordance with at least the magnitude of said output integral signal, and wherein said storing means includes means for holding, when said control means is disabled, the magnitude of said output integral signal constant at a magnitude related to the magnitude which existed when the closed loop control means was last enabled.
- 4. An engine control system according to claim 1 wherein said enabling means includes means for enabling said closed loop engine idle speed control means in response to a throttle positioin sensor signal having a magnitude indicative of a closed throttle position, in addition to said actual speed being substantially equal to said desired idle speed.
- 5. An engine control system according to claim 4 wherein said enabling means includes means for disabling said closed loop engine speed control means in response to any one of said error signal being outside of a predetermined range about zero magnitude and said throttle position signal indicating other than a closed throttle position.
- 6. An engine control system according to claim 1 wherein said enabling and disabling means includes a flip-flop means providing an output signal controlling the enabling and disabling of said closed loop control means.
- 7. An engine control system according to claim 6 wherein said flip-flop means includes a reset terminal coupled to an output of a comparator which receives, as one input, said error signal and which receives, as another input, a reference potential.
- 8. An engine control system according to claim 7 wherein said flip-flop means has a clock terminal coupled to an output terminal of a comparator which receives, as its inputs, a signal related to said actual engine speed and a signal related to said desired engine speed, and wherein said comparator provides a digital output signal to said flip-flop clock terminal.
- 9. An engine control system including engine idle speed control apparatus, comprising:
- means for providing an error signal related to the difference between actual sensed engine speed and a desired engine idle speed;
- means coupled to said error signal providing means for implementing, when enabled, a closed loop engine idle speed control in accordance with a control signal related to at least the magnitude of said error signal;
- means coupled to said idle speed control means for selectively enabling said closed loop idle speed control means in response to at least the magnitude of said error signal being within a predetermined range about zero magnitude;
- sensor means for developing a signal related to the amount of fuel consumption of said engine;
- means coupled to said sensor means and said error signal providing means for (1) developing a signal related to the amount of engine fuel consumption during an engine idle condition by effectively sampling the sensed fuel consumption signal whenever the engine speed error signal is within a predetermined range about zero magnitude and, (2) storing said signal related to the engine fuel consumption during engine idle when the engine speed error signal exceeds said predetermined range; and
- means coupled to said idle speed fuel consumption signal providing means for utilizing said stored sensed idle speed fuel consumption signal for engine control at times other than when said idle speed control means is enabled.
- 10. An engine control system according to claim 9 wherein said fuel consumption signal corresponds to a signal related to the amount of air utilized in the engine fuel mixture.
- 11. An engine control system according to claim 10 wherein said closed loop engine idle speed control means includes means for selectively receiving said idle speed control signal related to the magnitude of said error signal when said idle speed control means is enabled and providing in response thereto at least a controlled amount of air, related to the magnitude of said control signal, to the engine fuel mixture to implement engine idle speed control.
- 12. An engine control system according to claim 10 wherein said utilizing means includes means for providing an engine torque polarity signal related to the difference between sensed engine manifold air pressure and a predetermined level of air pressure related to idle speed air pressure, and means for selectively, in response to engine operating conditions, causing said controlled air means to provide air to the engine fuel mixture in accordance with the magnitude of said torque polarity signal rather than said idle speed control signal.
Parent Case Info
This is a continuation of application Ser. No. 630,480, filed July 13, 1985 now abandoned.
US Referenced Citations (22)
Continuations (1)
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Number |
Date |
Country |
Parent |
630480 |
Jul 1984 |
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