{
  "$type": "site.standard.document",
  "description": "An engine fuel control system includes a fuel metering valve operable to control the flow of fuel between a supply line and a delivery line. The fuel control system further includes a pressure drop control arrangement operable to regulate a pressure drop across the metering valve, the pressure drop…",
  "path": "/patents/971555",
  "publishedAt": "2014-08-06T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F02C7/232",
    "ROLLS ROYCE CONTROLS & DATA SERVICES LTD [GB]"
  ],
  "textContent": "An engine fuel control system includes a fuel metering valve operable to control the flow of fuel between a supply line and a delivery line. The fuel control system further includes a pressure drop control arrangement operable to regulate a pressure drop across the metering valve, the pressure drop control arrangement maintaining in normal use a substantially constant pressure drop across the metering valve. The fuel control system further includes an electro-mechanical backup control system which, in the event of an engine overthrust event, is controllable by an electrical pullback signal to operate the pressure drop control arrangement, such that increasing the pullback signal reduces the flow of fuel between the supply line and the delivery line. The fuel control system further includes a detector arrangement which detects a start of an engine overthrust event, and detects a time at which an upward runaway caused by the overthrust event is arrested. The fuel control system further includes a controller which (i) determines, at the time of the overthrust detection, a rate of increase of the pullback signal and an offset of the pullback signal, (ii) sends the pullback signal to the backup control system at the determined rate of increase, and (iii), when the upward runaway is arrested, reduces the pullback signal sent to the backup control system by the determined offset.",
  "title": "ENGINE FUEL CONTROL SYSTEM"
}