{
  "$type": "site.standard.document",
  "description": "An exhaust emission control device includes a NOx purification catalyst, a three-way catalyst provided upstream of the NOx purification catalyst, a first air-fuel ratio sensor provided upstream of the three-way catalyst, a second air-fuel ratio provided downstream of the NOx purification catalyst…",
  "path": "/patents/1000168",
  "publishedAt": "2012-07-25T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F01N3/0842",
    "NISSAN MOTOR [JP]"
  ],
  "textContent": "An exhaust emission control device includes a NOx purification catalyst, a three-way catalyst provided upstream of the NOx purification catalyst, a first air-fuel ratio sensor provided upstream of the three-way catalyst, a second air-fuel ratio provided downstream of the NOx purification catalyst, a rich spike unit for changing an exhaust gas air-fuel ratio from lean to rich for a predetermined period to reduce and purify NOx adsorbed by the NOx purification catalyst, a first detection unit for detecting a NOx adsorption amount and an oxygen storage amount of the three-way catalyst and the NOx purification catalyst during rich spike, a second detection unit for detecting the oxygen storage amount of the three-way catalyst and the NOx purification catalyst until the output of the second air-fuel sensor becomes lean after the rich spike, and a deterioration determination unit for determining deterioration of the NOx purification catalyst based on a detected value of the first detection unit and that of the second detection unit.",
  "title": "EXHAUST GAS PURIFYING DEVICE FOR INTERNAL COMBUSTION ENGINE AND METHOD FOR DETERMINING NOx PURIFYING CATALYST DETERIORATION"
}