To provide an examination method of a fuel pump highly accurately detecting abnormality of the fuel pump using a capacitor for inhibiting discharge between a brush and a segment.
The fuel pump is operated by applying an examination voltage lower than a minimum operation voltage of the fuel pump 10. An abnormality examination of the fuel pump 10 is carried out with the fuel pump 10 brought in a dry condition before the fuel pump 10 is operated in examination fluid and a discharge rate, etc, of the fuel pump 10 are measured. Noises are first eliminated from an electric current detected by applying the voltage lower than the minimum operation voltage. Duration, start levels and end levels of one cycle of drive currents corresponding to respective segments 72 are then coincided. The drive currents at a time lapse t in the one cycle are compared and an area difference between wave forms of a maximum current connecting maximum values and a minimum current connecting minimum values at the time lapse t in the one cycle are obtained. Abnormality of the fuel pump is detected by judging the area difference.
Dai Yoshida
South Island Noboru
Next Patent: SUPERCHARGING PRESSURE VARIABLE TURBOCHARGER