{
  "$type": "site.standard.document",
  "description": "The invention relates to a method for determining the efficiency of an exhaust gas purification device (2) of an internal combustion engine, in particular a diesel internal combustion engine (1), in particular for motor vehicles, with a first NOx sensor (7) upstream of an oxidation catalyst (3)…",
  "path": "/patents/952453",
  "publishedAt": "2015-02-04T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F01N11/00",
    "MAN TRUCK & BUS AG [DE]"
  ],
  "textContent": "The invention relates to a method for determining the efficiency of an exhaust gas purification device (2) of an internal combustion engine, in particular a diesel internal combustion engine (1), in particular for motor vehicles, with a first NOx sensor (7) upstream of an oxidation catalyst (3) and/or a particle filter (4) and a second NOx sensor (8) arranged downstream of a reduction catalyst (5), as well as with a device (10) for metered supply of a reducing agent, wherein the signals of the two NOx sensors (7, 8) are supplied to a control unit (9), by means of which at least one supply quantity of the reducing agent is specified. According to the invention, it is provided that for the determination of an efficiency, in particular a NO2 formation efficiency, at least of the oxidation catalyst (3) and/or the particle filter (4), the control unit (9) determines the NO and NO2 concentration and/or the NO2/NO ratio of the exhaust gas stream at the measuring position of the second NOx sensor (7) and/or downstream of the reduction catalyst (5) solely on the basis of the signal values acquired by the two NOx sensors (7, 8). Furthermore, a suitable apparatus for carrying out such a method is proposed.",
  "title": "Method and device for determining the efficiency of an exhaust gas purifying device"
}