Ford Global Technolgoies, LLC

Ford Motor Company Limited

Shailesh Natwarlal Patel

David Karl Bidner

Alexander Y Gopp

Vipon K Sharma

Dave G Farmer

A method and apparatus for monitoring an EGR system during normal vehicle operations is disclosed. An EGR valve located in an EGR passage controls the flow of exhaust gas to an intake manifold, and a sensor disposed in the air intake manifold downstream of air and EGR confluence point, monitors temperature of the mixture. A controller calculates a correlation function between a calculated desired EGR flow and the output of the manifold temperature sensor. If the value of correlation function is lower than a reference level, the monitoring system deterioration of EGR flow rate is indicated.

Method and apparatus for monitoring EGR system flow

An Electronic Engine Controller (EEC) is calibratable to control the rate at which fuel is delivered to an intake of an internal combustion engine in order to achieve a bias in the air/fuel ratio combusted by the engine. The EEC operates under closed-loop control to alter the fuel delivery rate in response to an output of an oxygen sensor which detects the concentration in exhaust gas produced by the engine. The EEC achieves a predetermined bias, in the air/fuel ratio, which is in a rich or lean direction from stoichiometry, by maintaining the fuel delivery rate at a jump value upon the indication by the oxygen sensor of an air/fuel ratio in the same direction from stoichiometry as the desired bias. The fuel delivery rate is maintained at the jump value for a variable period of time, which preferably depends upon the engine speed and load. Upon expiration of the variable period of time, the fuel delivery rate is abruptly altered to a fuel delivery rate corresponding to a predetermined air/fuel ratio. The fuel delivery rate is thereafter progressively altered until the indication by the oxygen sensor of an air/fuel ratio in the same direction from stoichiometry as the desired bias.

Growing community of inventors

Garden City, MI, United States of America

Shailesh Natwarlal Patel