System and method for detecting damage to bearing of engine using knocking sensor

A method for detecting damage to a bearing of an engine using a knocking sensor, the method comprising:

• a data storing step, which stores a vibration signal output from a knocking sensor installed in an engine in a data storing unit;
• a by-frequency amplitude calculating step, which performs, by a frequency amplitude calculating unit, Fast Fourier Transform (FFT) for the vibration signal input to the data storing unit and calculates an amplitude for each frequency;
• a detection frequency integrating step, which obtains a detection frequency integration value by adding all amplitudes of detection frequencies selected by a detection frequency selecting unit;
• a noise determining step, which determines, by a noise determining unit, whether the vibration signal of the knocking sensor is the vibration signal irrelevant to damage to a bearing by determining whether exclusion frequencies for detecting knockout selected by an exclusion frequency selecting unit correspond to a preset condition;
• a counter increasing step, which increases a damage counter, when the detection frequency integration value is greater than a preset damage threshold, if the vibration signal of the knocking sensor is the vibration signal due to the damage to the bearing;
• and
• a damage confirming step, which confirms that the bearing is damaged, when the damage counter is greater than or equal to a preset confirmation counter;
• wherein the noise determining step determines the vibration signal of knocking sensor as the vibration signal due to the damage to the bearing, when a value obtained by summing all amplitudes of the exclusion frequencies does not exceed a preset reference, when an exclusion frequency with the largest amplitude among the exclusion frequencies is not within a predetermined ranking among al frequencies, and when a ratio between an exclusion frequency with the largest amplitude among the exclusion frequencies and the detection frequency does not exceed a predetermined ratio.