Patent ID: 6019094
Filing Date: 2000-02-01
Classification: F02D,Y02T

Abstract:
An exhaust recirculation device for use with an engine comprising an intake passage, exhaust passage and combustion chamber, said device comprising:an exhaust recirculation passage for recirculating a part of exhaust discharged from said combustion chamber into said intake passage,an exhaust recirculation valve provided in said exhaust recirculation passage,a sensor for detecting a fresh air amount aspirated into said engine through said intake passage,a sensor for detecting an intake pressure of said engine,a sensor for detecting an exhaust pressure of said engine, anda microprocessor programmed to:determine a target exhaust recirculation rate based on an engine running state,calculate a required flowpath cross-sectional area of said exhaust recirculation passage from said target exhaust recirculation rate, fresh air amount, intake pressure and exhaust pressure,calculate a coefficient specifying a relation between said required flowpath cross-sectional area and the opening area of said exhaust recirculation valve,determine a target opening area of said exhaust recirculation valve from said required flowpath cross-sectional area and said coefficient, andcontrol the opening area of said exhaust recirculation valve to said target opening area.