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Experimental Results on Dual-UEGO Active Catalyst Control
Technical Paper
2004-35-0026
Sector:
Language:
English
Abstract
This paper describes active control of an aftertreatment system for a spark ignition engine equipped with a three-way catalyst and pre- and post-catalyst oxygen sensors. The control objective is to maximize the simultaneous conversion efficiencies of oxides of nitrogen and unburned hydrocarbons. Linear exhaust gas oxygen sensors are used to measure pre- and post-catalyst air-fuel ratio. A series controller configuration is adopted. The upstream controller provides relatively rapid response to disturbances on the basis of the pre-catalyst measurement, while the downstream controller uses the pre- and post- catalyst air-fuel ratio measurements to compensate for the bias corrupting the pre-catalyst air-fuel ratio measurement. The control strategy is tested on a 5:4L engine and compared with an existing proprietary controller that is based on the more common switching-type air-fuel ratio sensors.