{
  "$type": "site.standard.document",
  "description": "An automotive piston engine has an exhaust gas system with first and second NOx storage catalytic converters which, prior to start up, are below an initial pre-defined threshold temperature. In the start-up process, the engine operates with a stoichiometric fuel-air ratio, accompanied by continual…",
  "path": "/patents/1084554",
  "publishedAt": "2004-08-25T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B01D53/9431",
    "BAYERISCHE MOTOREN WERKE AG [DE]"
  ],
  "textContent": "An automotive piston engine has an exhaust gas system with first and second NOx storage catalytic converters which, prior to start up, are below an initial pre-defined threshold temperature. In the start-up process, the engine operates with a stoichiometric fuel-air ratio, accompanied by continual monitoring of the temperature in the first catalyst. When the temperature in the first NOx catalytic converter passes a second operating threshold in the first catalyst, the motor is then operated with a lean mixture. The NOx catalytic converters are regenerated when the temperature in the first converter is above the second activation temperature. Also claimed is a commensurate operating process for an automotive engine.",
  "title": "Engine control method having an exhaust system comprising two NOx-catalysts in series"
}