| 摘要 |
The maximum cylinder pressure angle in an internal combustion engine is approximated by inputting the output of a cylinder pressure sensor to a window comparator, comparing the sensor output with predetermined reference values, determining intersection points of the sensor output with the reference values from the pulses output by the comparator, determining the time lapse between a predetermined reference point such as piston TDC and the intersection points, calculating the midpoints between the respective intersection point pairs, extending the line connecting the midpoints, determining the arc tangent of the extension as an indicator of the slope thereof, determining the product of the arc tangent and a separately determined maximum cylinder pressure and using this product to determine the total time lapse from the predetermined reference point up to the intersection of the extension with the sensor output, multiplying this total time by a time/angle conversion factor, and defining the so-obtained angle as the approximate maximum cylinder pressure angle.
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