Adaptive air fuel control using hydrocarbon variability feedback
First Claim
1. A method for controlling engine operation at a lean fuel air ratio including the steps of:
- applying a fuel injector control signal to fuel injectors of the engine as a function of a stored schedule of fuel air ratio command signals;
observing the normalized variability in engine hydrocarbon emissions;
establishing a reference normalized hydrocarbon variabililty;
generating a feedback signal as a function of the difference betweem the observed normalized variability in engine hydrocarbon emissions and a reference normalized hydrocarbon variability;
generating a signal indicative of the airflow into the engine; and
modifying the fuel injector control signal as a function of the feedback signal and the airflow signal.
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Abstract
An apparatus for controlling operation of an internal combustion engine at lean air fuel ratios includes a fuel controller for generating a fuel injector drive signal. The apparatus also includes a memory table means, a hydrocarbon sensor means, an airflow indication means, and a compensation means. Memory table means stores a schedule of fuel air ratio commands as a function of engine operating conditions. The hydrocarbon sensor means is coupled to the engine for measuring variations in the engine exhaust hydrocarbon emissions and generating an output signal as a function of such variations in hydrocarbon emissions. The airflow indication means generates a signal indicative of airflow into the engine. The compensation means is coupled to the hydrocarbon sensor, the memory table means, and the airflow indicator means for modifying the fuel air ratio control commands stored in the memory table means as a function of airflow and engine exhaust hydrocarbon variation. The compensation means is also coupled to the fuel controller means for applying a fuel command signal to the fuel controller means, thereby permitting engine operation at the lean air fuel ratio limit.
41 Citations
2 Claims
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1. A method for controlling engine operation at a lean fuel air ratio including the steps of:
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applying a fuel injector control signal to fuel injectors of the engine as a function of a stored schedule of fuel air ratio command signals; observing the normalized variability in engine hydrocarbon emissions; establishing a reference normalized hydrocarbon variabililty; generating a feedback signal as a function of the difference betweem the observed normalized variability in engine hydrocarbon emissions and a reference normalized hydrocarbon variability; generating a signal indicative of the airflow into the engine; and modifying the fuel injector control signal as a function of the feedback signal and the airflow signal. - View Dependent Claims (2)
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