Patent ID: 6729123
Filing Date: 2004-05-04
Classification: F01N,F02D,Y02T

Abstract:
An exhaust gas purifying device for an in-cylinder injection spark ignition type internal combustion engine including an injection valve for injecting fuel directly into a combustion chamber, fuel injection control means for controlling the injection of fuel by the injection valve, and air/fuel ratio control means for controlling burn air/fuel ratio, said exhaust gas purifying device comprising:a catalytic converter arranged in an exhaust passage, for purifying harmful matter in exhaust gas; catalyst activation determining means for determining an activated state of said catalytic converter; compression-stroke slight-lean operation means for causing the air/fuel ratio control means to control the burn air/fuel ratio to produce a slight lean air/fuel mixture equivalent to or slightly leaner than a stoichiometric air/fuel mixture and also causing the fuel injection control means to inject fuel in a compression stroke, to thereby carry out a compression-stroke slight-lean operation in which residual oxygen and CO are made to react with each other in an exhaust system of the engine; and exhaust gas flow control means for restraining an exhaust gas flow in the exhaust passage, wherein when it is judged by said catalyst activation determining means that said catalytic converter is not in the activated state, the compression-stroke slight-lean operation is performed by said compression-stroke slight-lean operation means and also the exhaust gas flow in the exhaust passage is restrained by said exhaust gas flow control means.