{
  "$type": "site.standard.document",
  "description": "In a process to operate a lean-burn internal combustion engine, the exhaust system has a pre-catalytic converter discharging to a NOx storage catalytic converter. In the process, the storage activity is determined, together with temperature values for both catalytic converters to determine a…",
  "path": "/patents/1089421",
  "publishedAt": "2004-02-25T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F01N11/00",
    "VOLKSWAGEN AG [DE]"
  ],
  "textContent": "In a process to operate a lean-burn internal combustion engine, the exhaust system has a pre-catalytic converter discharging to a NOx storage catalytic converter. In the process, the storage activity is determined, together with temperature values for both catalytic converters to determine a pattern of correlation between the two. The values are compared with a standard sample to determine the actual condition within the pre-catalytic converter. Further in the process the NOx storage activity is determined at a temperature within a given diagnostic temperature range +/- 10K. These values are determined in conjunction with the pre-catalyst temperature and a correlation is established between the two and compared with a known standard sample. The pre-catalytic converter condition is derived by a comparison of the values measured with the sample. Further claimed is a lean-burn engine incorporating this diagnostic system.",
  "title": "Method for operating a lean burn internal combustion engine having an exhaust gas purification system"
}