Exhaust gas cleaning apparatus

An exhaust gas cleaning apparatus comprising:

• an exhaust gas particulate filter arranged in an exhaust passage of an internal combustion engine for capturing particulate matter in exhaust gas from the internal combustion engine;
• an oxidation catalytic converter arranged upstream of the exhaust gas particulate filter in the exhaust passage;
• a regeneration control component configured to control an exhaust gas recirculation rate and a temperature of recirculated exhaust gas being recirculated to an air induction system of the internal combustion engine for controlling a temperature of the exhaust gas particulate filter and a concentration of nitrogen dioxide in the exhaust gas particulate filter such that nitrogen dioxide generated by the oxidation catalytic converter is used to burn the particulate matter captured in the exhaust gas particulate filter;
• an exhaust gas recirculation passage arranged to recirculate the exhaust gas to the air induction system;
• an exhaust gas recirculation control valve arranged in the exhaust gas recirculation passage to control the recirculation rate of the recirculated exhaust gas being recirculated to the air induction system;
• a cooler arranged in the exhaust gas recirculation passage to cool the recirculated exhaust gas;
• a bypass passage arranged to allow the recirculated exhaust gas to bypass the cooler;
• and
• a selector valve arranged to change a ratio of an amount of the recirculated exhaust gas that passes through the cooler and an amount of the recirculated exhaust gas that bypasses the cooler,
• the regeneration control component being further configured to control the temperature of the recirculated exhaust gas being recirculated to the air induction system by controlling the selector valve so as to change the ratio and to control the recirculation rate of the recirculated exhaust gas being recirculated to the air induction system by controlling the exhaust gas recirculation control valve.

An exhaust gas cleaning apparatus comprising:

• an exhaust gas particulate filter arranged in an exhaust passage of an internal combustion engine for capturing particulate matter in exhaust gas from the internal combustion engine;
• an oxidation catalytic converter arranged upstream of the exhaust gas particulate filter in the exhaust passage;
• a regeneration control component configured to control an exhaust gas recirculation rate and a temperature of recirculated exhaust gas being recirculated to an air induction system of the internal combustion engine for controlling a temperature of the exhaust gas particulate filter and a concentration of nitrogen dioxide in the exhaust gas particulate filter such that nitrogen dioxide generated by the oxidation catalytic converter is used to burn the particulate matter captured in the exhaust gas particulate filter;
• a comparing component configured to compare a rate at which the particulate matter will accumulate in the exhaust gas particulate filter if the regeneration control component does not control the temperature and the concentration of the nitrogen dioxide to a rate at which the particulate matter will accumulate in the exhaust gas particulate filter if the regeneration control component does control the temperature and the concentration of the nitrogen dioxide;
• and
• an operation permitting component configured to permit operation of the regeneration control component when a comparison result obtained by the comparing component indicates that the rate at which the particulate matter accumulates will decrease more if the regeneration control component controls the temperature and the concentration of nitrogen dioxide than if the regeneration control component does not control the temperature and the concentration of the nitrogen dioxide.

A method of cleaning exhaust gas comprising:

• passing exhaust gas from an internal combustion engine through an oxidation catalytic converter and an exhaust gas particulate filter arranged downstream of the oxidation catalytic converter;
• and
• controlling an exhaust gas recirculation rate and a temperature of recirculated exhaust gas being recirculated to an air induction system of the internal combustion engine for controlling a temperature of the exhaust gas particulate filter and a concentration of nitrogen dioxide in the exhaust gas particulate filter such that nitrogen dioxide generated by the oxidation catalytic converter is used to burn the particulate matter captured in the exhaust gas particulate filter,
• the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas including controlling the temperature of the recirculated exhaust gas being recirculated to the air induction system via an exhaust gas recirculation passage arranged to recirculate the exhaust gas to the air induction system by controlling a selector valve so as to change a ratio of an amount of the recirculated exhaust gas that passes through a cooler disposed in the exhaust gas recirculation passage and an amount of the recirculated exhaust gas that bypasses the cooler, and
• the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas further including controlling the recirculation rate of the recirculated exhaust gas being recirculated to the air induction system by controlling an exhaust gas recirculation control valve disposed in the exhaust gas recirculation passage.

A method of cleaning exhaust gas comprising:

• passing exhaust gas from an internal combustion engine through an oxidation catalytic converter and an exhaust gas particulate filter arranged downstream of the oxidation catalytic converter;
• controlling an exhaust gas recirculation rate and a temperature of recirculated exhaust gas being recirculated to an air induction system of the internal combustion engine for controlling a temperature of the exhaust gas particulate filter and a concentration of nitrogen dioxide in the exhaust gas particulate filter such that nitrogen dioxide generated by the oxidation catalytic converter is used to burn the particulate matter captured in the exhaust gas particulate filter;
• comparing a rate at which the particulate matter will accumulate in the exhaust gas particulate filter if the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas is not performed to control the temperature and the concentration of the nitrogen dioxide to a rate at which the particulate matter will accumulate in the exhaust gas particulate filter if the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas is performed to control the temperature and the concentration of the nitrogen dioxide so as to obtain a comparison result;
• and
• permitting the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas to be performed when the comparison result indicates that the rate at which the particulate matter accumulates will decrease more if the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas is performed to control the temperature and the concentration of the nitrogen dioxide than if the controlling of the exhaust gas recirculation rate and the temperature of recirculated exhaust gas is not performed to control the temperature and the concentration of the nitrogen dioxide.

An exhaust gas cleaning apparatus comprising:

• an exhaust gas particulate filter arranged in an exhaust passage of an internal combustion engine for capturing particulate matter in exhaust gas from the internal combustion engine;
• an oxidation catalytic converter arranged upstream of the exhaust gas particulate filter in the exhaust passage;
• and
• a regeneration control component configured to control simultaneously both an exhaust gas recirculation rate and a temperature of recirculated exhaust gas being recirculated to an air induction system of the internal combustion engine for controlling a temperature of the exhaust gas particulate filter and a concentration of nitrogen dioxide in the exhaust gas particulate filter to respective target values such that nitrogen dioxide generated by the oxidation catalytic converter is used to burn the particulate matter captured in the exhaust gas particulate filter, the temperature of the recirculated exhaust gas being controlled by variably adjusting a mixture rate of a first part of the exhaust gas and a second part of the exhaust gas that is cooled more than the first part of the exhaust gas.