{
  "$type": "site.standard.document",
  "coverImage": {
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  "description": "A system and method for detecting leakage from a evaporative emission space of an automotive vehicle fuel system. A reciprocating pump is operated in a pressurizing mode to build pressure in the space toward a nominal test pressure. The pressurizing mode involves operating the pump in a repeating…",
  "path": "/patents/1112223",
  "publishedAt": "2001-06-20T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F02M25/0818",
    "SIEMENS CANADA LTD [CA]"
  ],
  "textContent": "A system and method for detecting leakage from a evaporative emission space of an automotive vehicle fuel system. A reciprocating pump is operated in a pressurizing mode to build pressure in the space toward a nominal test pressure. The pressurizing mode involves operating the pump in a repeating cycle wherein the pump operates alternately in an accelerated pumping mode and a natural frequency pumping mode. During the pressurizing mode, a characteristic of successive occurrences of the natural frequency pumping mode indicative of pressure in the space is measured. The number of times the cycle repeats is counted and compared to a predefined reference. When the cycle count exceeds the predefined reference, the test continues at a lower resolution for detecting leakage, and when the cycle count does not exceed the predefined reference and a measurement of the characteristic of successive occurrences of the natural frequency pumping mode indicative of pressure in the space exceeds a predetermined reference pressure, the test continues at a higher resolution for detecting leakage. The invention is useful when overall test time is limited.",
  "title": "Method and system for aggressive cycling of leak detection pump to ascertain vapor leak size"
}