| 摘要 |
PURPOSE:To measure correct revolutions of the engine by a method wherein vibrations exceeding a specified value in the amplitude detected and integrated from among those generated by the fuel injection thereof and the revolutions are displayed based on the frequency at which the integrated value exceeds a specified value. CONSTITUTION:A sensor 1 is mounted to a fuel injection system pipe and obtains a signal of vibration at each injection attributted to vibrations generated when a needle of a fuel injection valve gets in contact with a stopper after the end of the injection and those by the impact of a delivery valve through an amplifier 2 and a filter 3. the output of the filter 3 is compared with the reference voltage SL1 by a comparator 4 and when it is larger than the value SL1, an output signal is produced. The output signal is integrated by a specified time constant with an integration circuit 5 and then, the results are compared by a comparator 6 to yield one pulse at each injection of the engine. The pulse is integrated with an integration circuit 7 to display the number of pulses, namely, the revolutions of the engine. Thus, correct revolutions can be measured. |
