| 摘要 |
PROBLEM TO BE SOLVED: To provide an evaluation system of a knocking level which properly evaluates an abnormal sound including knocking while responding to the functionality of human beings.SOLUTION: An evaluation system of a knocking level comprises a sound pressure detection part 2 which detects a sound issued by a reciprocation-type internal combustion engine 100, an angle detection part 3 which detects a rotation angle of a crankshaft 102, and a knocking level detection device 1. The device 1 extracts a maximum amplitude around immediately after a top dead point from sound pressure data which are obtained by synchronizing a sound pressure signal and an angle signal in a prescribed frequency range, and on the basis of a magnitude of the maximum amplitude, quantizes a functionality level of the abnormal sound which is generated by a prescribed cycle number. The system creates descending-order data in which a prescribed number of the maximum amplitudes are aligned in an order of large-number amplitude values. The evaluation system calculates dark noise which is obtained by averaging the maximum amplitudes from a small-number amplitude value up to a prescribed order in the descending-order data. The evaluation system extracts the maximum amplitude of the prescribed order from the larger amplitude value in the descending-order data, and calculates a difference between the dark noise and the extracted maximum amplitude (abnormal sound pressure). The evaluation system determines the functionality level of the abnormal sound pressure by collating the abnormal sound pressure and functionality evaluation.SELECTED DRAWING: Figure 1 |
