Abstract: An exhaust gas purifying apparatus for an internal combustion engine having a NOx removing device provided in an exhaust system of the engine and at least one fuel injector for injecting fuel into a combustion chamber of the engine. A temperature of the NOx removing device is detected and a regeneration process, which removes sulfur oxide accumulated in the NOx removing device, is performed. The regeneration process is performed by performing at least one post injection after performing a main injection by the at least one fuel injector to raise a temperature of the NOx removing device or by increasing a main injection amount of fuel to raise the temperature of the NOx removing device without performing the post injection. The exhaust gases are then controlled to flow into the NOx removing device in the reducing state.

Abstract: An exhaust gas purifying device for an internal combustion engine, comprises: a first catalyst (TWC 7, example) having a reducing capability; a second catalyst (LNC 9, example) provided downstream of the first catalyst, the second catalyst is adapted to trap NOx in a lean condition of air fuel ratio of an exhaust gas and reduce the trapped NOx in a rich condition of air fuel ratio of the exhaust gas; and an exhaust air fuel ratio control means for controlling an exhaust air fuel ratio to decrease the NOx in the first and second catalysts, wherein the exhaust air fuel ratio control means conducts NOx decreasing control suitable for the first catalyst when the second catalyst is in an inactive state and the first catalyst is in an active state, and wherein the exhaust air fuel ratio control means conducts NOx decreasing control suitable for the second catalyst after the second catalyst is activated.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine having a NOx removing device provided in an exhaust system of the engine and at least one fuel injector for injecting fuel into a combustion chamber of the engine. A temperature of the NOx removing device is detected and a regeneration process, which removes sulfur oxide accumulated in the NOx removing device, is performed. The regeneration process is performed by performing at least one post injection after performing a main injection by the at least one fuel injector to raise a temperature of the NOx removing device or by increasing a main injection amount of fuel to raise the temperature of the NOx removing device without performing the post injection. The exhaust gases are then controlled to flow into the NOx removing device in the reducing state.

Abstract: Provided is a control device for an internal combustion engine that can execute a sulfur purge in a favorable manner under all conditions without complicating the control action or the engine structure. The process comprises detecting a temperature of the NOx catalytic converter, detecting an exhaust air fuel ratio in the catalytic converter, computing a target exhaust air fuel ratio according to a detected temperature of the NOx catalytic converter, and controlling a fuel injection valve so as to make an actual exhaust fuel ratio agree with the target exhaust air fuel ratio. If the temperature of the NOx catalytic converter is not high enough to enable a sulfur purge, a temperature increase control is executed to increase the temperature of the NOx catalytic converter by suitably changing various engine parameters.

Abstract: In a control device for an internal combustion engine provided with a NOX catalytic converter in an exhaust passage thereof, the progress of sulfur purging is computed from the consumption of reducing agent contained in the exhaust gas in the NOX catalytic converter. This computation may be based on the air fuel ratio of exhaust gas upstream of the NOX catalytic converter and the estimated consumption of the reducing agent contained in the exhaust gas or on the difference between the air fuel ratios of exhaust gas upstream and downstream of the NOX catalytic converter. In either case, the accuracy can be improved by taking into account the space velocity of the exhaust gas.