| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique for reliably preventing combustion fluctuation, in an exhaust emission control system of an internal combustion engine that controls a low pressure EGR device not to generate the combustion fluctuation when a reducing agent is supplied to an exhaust emission control device from a supply device of the reducing agent. <P>SOLUTION: The exhaust emission control system of the internal combustion engine performs an adjusting step of adjusting an EGR rate not to change oxygen concentration of a gas inhaled into a cylinder before or after supply of the reducing agent when the reducing agent is supplied from the supply device. When the combustion fluctuation is generated by performing the adjusting step, the system determines whether a factor of the combustion fluctuation is a performing timing of the adjusting step or controlled variable of the EGR rate at the adjusting step on the basis of a history of combustion state. The system further correct the performing timing of the adjusting step or the controlled variable of the EGR rate at the adjusting step, depending on the determined result. <P>COPYRIGHT: (C)2012,JPO&INPIT |
