{
  "$type": "site.standard.document",
  "description": "An ECU obtains two data values (a peak value and a waveform correlation coefficient) that show the characteristics of a knock from the output of a knock sensor. The ECU approximately obtains the mean of each data value by smoothing each data value, and approximately obtains a variance by smoothing…",
  "path": "/patents/1073233",
  "publishedAt": "2005-10-19T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F02D35/027",
    "TOYOTA MOTOR CO LTD [JP]"
  ],
  "textContent": "An ECU obtains two data values (a peak value and a waveform correlation coefficient) that show the characteristics of a knock from the output of a knock sensor. The ECU approximately obtains the mean of each data value by smoothing each data value, and approximately obtains a variance by smoothing the squared deviation between the data values before and after the smoothing process. The ECU then computes the square root of the variance to approximately obtain a standard deviation. The ECU normalizes each data value using the mean and the standard deviation, obtains a distribution of the normalized two data values, and calculates a correlation coefficient that shows the correlation between the obtained distribution and an ideal knock distribution. Based on the correlation coefficient, the ECU corrects a knock determination threshold value. Therefore, the mean and the standard deviation of the data values are computed with a small RAM capacity.",
  "title": "Apparatus and method for controlling internal combustion engine"
}