{
  "$type": "site.standard.document",
  "description": "For combustion engines with a three way catalyst it is necessary to implement an air/fuel ratio control to keep the air/fuel ration within a rather narrow range for best catalyst efficiency. The present invention describes an air/fuel ratio controller (6) and a method that uses an upstream control…",
  "path": "/patents/984893",
  "publishedAt": "2013-06-05T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F02D41/1402",
    "HOERBIGER KOMPRESSORTECH HOLD [AT]"
  ],
  "textContent": "For combustion engines with a three way catalyst it is necessary to implement an air/fuel ratio control to keep the air/fuel ration within a rather narrow range for best catalyst efficiency. The present invention describes an air/fuel ratio controller (6) and a method that uses an upstream control loop to maintain a given optimum air/fuel ratio (» opt ), whereas the optimum air/fuel ratio (» opt ) is determined in the controller (6) in an downstream control loop by adding incremental offset (») to the air/fuel ratio set-point (» SP ) of an upstream control loop whilst monitoring a NOx sensor (10) output. The air/fuel ratio set-points (» SP ) at two turning points (SP1, SP2) in the NOx sensor (10) output are used to calculate a new optimum air/fuel ratio set-point (» opt ) as mean value of the air/fuel ratio set-points (» SP1 , » SP2 ) at the turning points (SP1, SP2).",
  "title": "Air/fuel ratio controller and control method"
}