| 摘要 |
PURPOSE:To detect knocking from pressure variation within a low frequency range without providing a special circuit by detecting the pressure in an engine combustion chamber, and then detecting the knocking from the value obtained by imposing secondary differentiation upon the pressure in terms of a crank angle or time. CONSTITUTION:The pressure in an engine combustion chamber is detected and the value obtained by imposing secondary differentiation upon the detected pressure interms of a crank angle or time is used to detect knocking. After the pressure (p) in the combustion chamber with the crank angle theta of, for example, 0- 720 degrees is stored in a storage part via an A/D converter, when it is judged in a step 22 that knocking (d<2>p/dtheta<2>>k) exceeding prescribed amplitude, an ignition point of time is set to a knocking limit in steps 23-25. In a step 27, when the (p) is judged to be thetapmax 18 deg. ATDC, MBT feedback control is performed in steps 28 and 29, and when not, the ignition period is advanced by a 1 deg. crank angle in a step 30 at 400ms intervals. |
