A new method to estimate instantaneous A/F ratio and use the estimation as a feedback signal to control AFR during cold transients, before the oxygen sensor is functional, has been realized by a on-board PCM for a vehicle with a 4.6L, V8, PFI engine [4, 6]. Different AFRs cause variations in flame propagation, causing fluctuations in the effective torque. When a known AFR disturbance is induced into an engine system, a corresponding crankshaft angular velocity fluctuation can be detected. A variable derived from this physical phenomenon can be used to characterize the problem. The optimal fuel perturbation signal is designed by a relaxation concept, and the system model is determined by employing a dual-direction screening multivariate stepwise regression analysis. The estimated AFR is used by the PCM in a closed loop control to correct the fuel during cold transients.


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    Title :

    Optimal A/F Ratio Estimation Model (Synthetic UEGO) for SI Engine Cold Transient AFR Feedback Control


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    International Congress & Exposition ; 1998



    Publication date :

    1998-02-23




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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