Internal combustion engine control device

Abstract

An internal combustion engine control device includes a NOx adsorber catalyst disposed in an exhaust passage, an EGR passage, a reducing agent adding device, a torque fluctuation reducing device, and a fuel injection device. The EGR passage draws a portion of exhaust gas from the exhaust passage downstream of the NOx adsorber catalyst and recirculates the exhaust gas into the intake passage. The reducing agent adding device adds a reducing agent to exhaust gas upstream of the NOx adsorber catalyst to reduce substances adsorbed by the NOx adsorber catalyst. When or after the reducing agent adding device adds the reducing agent, the torque fluctuation reducing device advances the timing of the fuel injection device or carries out a pilot injection to reduce a fluctuation in engine torque. The reducing agent adding device adds less reducing agent while the torque fluctuation reducing device is operating.

Description

technical field [0001] The invention relates to a control device for an internal combustion engine. Background technique [0002] Some internal combustion engines are provided with a turbocharger and a low-pressure EGR passage for passing a part of the exhaust gas as low-pressure EGR gas from downstream of the turbine of the turbocharger and downstream of the NOx storage catalyst (hereinafter simply referred to as "NOx catalyst") The exhaust passage of the turbocharger is introduced into the intake passage upstream of the compressor of the turbocharger. This internal combustion engine is also provided with a high-pressure EGR passage for recirculating a portion of the exhaust gas as high-pressure EGR gas from the exhaust passage upstream of the turbine and recirculating this high-pressure EGR gas to the intake air downstream of the compressor channel. A technique is described in JP-A-2005-076456 to control the amount of low-pressure EGR gas flowing through the low-pressure...

AI Technical Summary

Problems solved by technology

However, as described above, if overfeeding is performed during the reduction of the torque fluctuation of the internal combustion engine, the torque fluctuation increases to an uncontrollable level, and combustion in the internal combustion engine becomes unstable

Moreover, if the torque fluctuation of the internal combustion engine is reduced as described above, the internal combustion engine produces a greater amount of smoke and uncontrollable combustion noise

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