| 摘要 |
In an internal combustion engine, a hydrocarbon feed valve (15), NOx storage catalyst (13), particulate filter (14), and electric resistance type sensor (29) are arranged in an engine exhaust passage in this order from an upstream side. The electric resistance type sensor (29) generates an output value corresponding to the amounts of deposition of particulate matter and hydrocarbons which are contained in the exhaust gas and deposited at the sensor part thereof. From the change of the output value of the electric resistance type sensor (29), it is judged if the hydrocarbons have slipped through the NOx storage catalyst (13) and if the particulate matter has slipped through the particulate filter (14). |
| 主权项 |
1. An abnormality detection system of an engine exhaust system in an internal combustion engine in which an NOx storage catalyst able to store NOx when an air-fuel ratio of exhaust gas is lean and able to release stored NOx by making the air-fuel ratio of the exhaust gas rich is arranged in an engine exhaust passage, a hydrocarbon feed valve is arranged in the engine exhaust passage upstream of the NOx storage catalyst, a particulate filter for trapping particulate matter contained in the exhaust gas is arranged in the engine exhaust passage downstream of the NOx storage catalyst, and hydrocarbons are injected from the hydrocarbon feed valve to make the air-fuel ratio of the exhaust gas flowing into the NOx storage catalyst rich when NOx should be released from the storage catalyst, wherein
an electric resistance type sensor having a sensor part to which particulate matter and hydrocarbons which are contained in exhaust gas deposit and generating an output value corresponding to an amount of deposition of the particulate matter and hydrocarbons to said sensor part is arranged in the engine exhaust passage downstream of the particulate filter, the output value of the electric resistance type sensor when hydrocarbons are injected from the hydrocarbon feed valve to release NOx from the NOx storage catalyst and when hydrocarbons slip through the NOx storage catalyst exhibits a behavior which changes by a faster speed compared with when particulate matter slips through the particulate filter, then changes in direction of change to an opposite direction, and, when the output value of the electric resistance type sensor changes, it is judged if hydrocarbons have slipped through the NOx storage catalyst when hydrocarbons are injected from the hydrocarbon feed valve or particulate matter has slipped through the particulate filter from the difference in behavior of the output value of the electric resistance type sensor. |
