Exhaust discharge control device for internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsShinya Hirota, Toshiaki Tanaka, Satoshi Iguchi
Life of this patent
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Abstract
An NOx absorbent is arranged in an engine exhaust passage absorbs NOx when the air-fuel ratio of inflowing exhaust gas is lean and discharges absorbed NOx or SOx when the oxygen concentration of inflowing exhaust gas decreases. When the air-fuel ratio of the exhaust gas flowing into the NOx absorbent is rich, previously absorbed NOx or SOx is discharged from the NOx absorbent. When NOx or SOx is to be discharged from the NOx absorbent, oxygen is left in the exhaust gas flowing into the NOx absorbent and the oxygen concentration of this exhaust gas is maintained within a predetermined range.
Claims15
An exhaust discharge control device for an internal combustion engine comprising:
- an NOx absorbent located in an exhaust gas passage of the engine, wherein exhaust gas flows through the exhaust gas passage from upstream to downstream, the NOx absorbent absorbing NOx when an air-fuel ratio of exhaust gas flowing into the NOx absorbent is lean and discharging absorbed NOx when an oxygen concentration of the inflowing exhaust gas decreases;
- oxygen concentration control means for allowing oxygen to remain in inflowing exhaust gas when one of NOx and SOx is to be discharged from the NOx absorbent and for maintaining the oxygen concentration of the exhaust gas within a predetermined range;
- and
- means for determining an amount of hydrocarbons adhered to the NOx absorbent, wherein the oxygen concentration control means increases the oxygen concentration of inflowing exhaust gas to increase an amount of one of NOx and SOx discharged from the NOx absorbent as the hydrocarbon amount increases.
An exhaust discharge control device for an internal combustion engine comprising:
- an occluding and reducing type NOx catalyst disposed in an exhaust gas passage of the engine, wherein exhaust gas travels through the exhaust passage from upstream to downstream, the occluding and reducing type NOx catalyst absorbing NOx in the exhaust gas flowing therein when an air-fuel ratio of inflowing exhaust gas is lean and discharging absorbed NOx therefrom when the air-fuel ratio of inflowing exhaust gas is one of stoichiometric and rich;
- regeneration means for making the air-fuel ratio of in flowing exhaust gas one of stoichiometric and rich when SOx absorbed by the occluding and reducing type NOx catalyst during NOx absorption is discharged from the occluding and reducing type NOx catalyst;
- rich atmosphere providing means for supplying and maintaining a predetermined amount of oxygen in an SOx absorption region of the occluding and reducing NOx catalyst when the regeneration means executes SOx discharge;
- and
- means for determining an amount of hydrocarbons adhered to the NOx catalyst, wherein the rich atmosphere providing means increases the oxygen concentration of inflowing exhaust gas to increase an amount of one of NOx and SOx discharged from the NOx catalyst as the hydrocarbon amount increases.
An exhaust discharge control device for an internal combustion engine comprising:
- an occluding and reducing type NOx catalyst disposed in an exhaust gas passage of the engine, wherein exhaust gas travels through the exhaust passage from upstream to downstream, the occluding and reducing type NOx catalyst absorbing NOx in the exhaust gas when an air-fuel ratio of inflowing exhaust gas is lean, and discharging absorbed NOx when the air-fuel ratio of inflowing exhaust gas is one of stoichiometric and rich;
- an SOx absorbent arranged in said exhaust passage upstream of the occluding and reducing type NOx catalyst, the SOx absorbent absorbing SOx when the air-fuel ratio of inflowing exhaust gas is lean and discharging the absorbed SOx when the air-fuel ratio of inflowing exhaust gas is one of stoichiometric and rich;
- regeneration means for making the air-fuel ratio of the exhaust gas one of stoichiometric and rich when the SOx previously absorbed by the SOx absorbent is to be discharged from the SOx absorbent;
- rich atmosphere providing means for controlling an oxygen content of inflowing exhaust gas so that a predetermined amount of oxygen enters an SOx absorption region of said SOx absorbent when the regeneration means executes SOx discharge;
- and
- means for determining an amount of hydrocarbons adhered to the NOx catalyst, wherein the rich atmosphere providing means increases the oxygen concentration of inflowing exhaust gas to increase an amount of one of NOx and SOx discharged from the NOx catalyst as the hydrocarbon amount increases.
Dependencies are inferred from the claim text.