{
  "$type": "site.standard.document",
  "description": "Aircraft Auxiliary Power Unit (APU) controllers and related methods are described herein. An example APU controller includes a sensor interface to receive a signal from a speed sensor. The signal includes pulses representing a rotational speed of an engine of an APU. The APU controller also…",
  "path": "/patents/1352668",
  "publishedAt": "2023-10-12T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F02D41/042",
    "The Boeing Company"
  ],
  "textContent": "Aircraft Auxiliary Power Unit (APU) controllers and related methods are described herein. An example APU controller includes a sensor interface to receive a signal from a speed sensor. The signal includes pulses representing a rotational speed of an engine of an APU. The APU controller also includes an overspeed detection circuit including a counter to count a number of pulses from the signal occurring within a time interval, a digital-to-analog converter (DAC) to convert the number of pulses into an analog voltage signal and a comparator to: compare the analog voltage signal to an overspeed threshold signal and generate a shutdown command in response to the analog voltage signal exceeding the overspeed threshold signal. The APU controller also includes a valve driver to, in response to receiving the shutdown command, cause a fuel shutoff valve to cease fuel flow to the engine of the APU.",
  "title": "AIRCRAFT AUXILIARY POWER UNIT (APU) CONTROLLERS AND RELATED METHODS"
}