Air-fuel ratio control device for internal combustion engine

Abstract

Abstract PURPOSE:To enable control of an air-fuel ratio to a true theoretical value, by a method wherein an air-fuel ratio feedback correction factor and a learning correction factor at each running region are set by means of an O2 sensor having a nitrogen oxide reduction catalyst layer, and oxygen concentration in exhaust gas containing an oxygen content in a nitrogen oxide is detected. CONSTITUTION:Detecting values from an airflow meter 13, a crank angle sensor 14, a water temperature sensor 15, and an O2 sensor 16 are inputted to a control unit 12, and the opening time of a fuel injection valve 16 is computed and processed. A rhodium catalyst layer 24, having titanium oxide serving as a carrier outside a platinum catalyst layer 23 and functioning as an NOX reduction catalyst, is formed on the O2 sensor 16, and the O2 sensor reduces NOX in exhaust gas to detect oxygen concentration in exhaust gas containing an oxygen content in NOX. The control unit 12 calculates a fundamental fuel injection amount from an intake air amount and the number of revolutions, calculates a feedback correction factor based on a detecting value from the O2 sensor 16, and updates a learning correction factor at each running region.

Inventors

• 👤 Shinpei Nakaniwa

Bibliographic Details