An Algorithm for the Calibration of Wall-Wetting Model Parameters 2003-01-1054
Spark-ignited engines equipped by a three-way catalyst require a precise control of the air fuel ratio fed to the combustion chamber. A stoichiometric mixture is necessary for the proper working of the catalyst in order to meet the legislation requirement.
A critical part of the air fuel ratio control is the feed-forward compensation of the fuel dynamics. Conventional strategies are based on a simplified model of the wall-wetting phenomena whose parameters are stored in off-line computed look-up tables. Unfortunately, errors in the parameters calibration over the whole engine map deteriorate the control performances in terms of emissions.
In this paper an automatic procedure for a rapid and efficient identification of the wall-wetting parameters is presented. The whole procedure has been experimentally tested on a vehicle by using a test bench. Using the identified parameters values, a significant reduction in the air fuel ratio excursion has been achieved during rapid throttle transients with respect to the same vehicle equipped by a commercial ECU with resident engine maps computed by traditional calibration activity. Moreover, the algorithm can be also on-line used to improve air-fuel ratio control performances.
Alessandro di Gaeta, Stefania Santini, Luigi Glielmo, Ferdinando De Cristofaro, Carlo Di Giuseppe, Antonello Caraceni
Dipartimento di Informatica e Sistemistica, Università degli Studi Napoli Federico II, Napoli, ITALY, Dipartimento di Ingegneria, Universitàdel Sannio in Benevento, ITALY, Elasis SCpA Control Systems Department, Napoli, ITALY
SAE 2003 World Congress & Exhibition
Electronic Engine Control Technologies, 2nd Edition-PT-110, Electronic Engine Controls 2003-SP-1749