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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKoichiro Nakatani, Terutoshi Tomoda, Shinobu Ishiyama, Tomoyuki Ono, Tomoyuki Kogo, Katsuhiro Ito
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Disclosed is a technology that enables better reduction of NOx stored in an NOx catalyst in an exhaust gas purification system for an internal combustion engine. When NOx stored in an NOx catalyst is to be reduced, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to a target air-fuel ratio by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine. In doing so, if the temperature of the NOx catalyst is not lower than a specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to the target air-fuel ratio while bringing the combustion state into low temperature combustion. On the other hand, if the temperature of the NOx catalyst is lower than the specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased to the target air-fuel ratio while decreasing the quantity of EGR gas in a cylinder so that the amount of generated smoke is kept within an allowable range.
An exhaust gas purification system for an internal combustion engine comprising:
An electronic control unit (ECU) configured to control an internal combustion engine having an exhaust gas purification system that includes a NOx storage reduction catalyst provided in an exhaust passage of the internal combustion engine, the ECU including control logic configured to control the internal combustion engine, so that when the NOx storage reduction catalyst is active and NOx stored in the NOx storage reduction catalyst is to be reduced, the ECU instructs the internal combustion engine to:
Dependencies are inferred from the claim text.