| 摘要 |
PURPOSE:To detect a fuel flow rate or an abnormality in a fuel system, by detecting mechanical oscillation in the diameter direction of a fuel jet pipe, etc. of a Diesel engine, by a piezoelectric element, and measuring a valve opening time from an oscillation period, a pipe sectional area and fuel pressure. CONSTITUTION:On a part of the outside circumference of a fuel jet pipe 1 placed just in front of the jet valve of a Diesel engine, a piezoelectric element 2 is made to tightly adhere onto the outside circumferential surface of the pipe and is provided so as to cover its almost semicircle, and to the remaining almost semicircle which is not covered with the element 2, an insulator 3 having high rigidity is made to tightly adhere, and the element 2 and the insulator 3 are installed to the jet pipe 1 with a cover 5. An output signal of the element 2 is supplied to an electronic circuit 9 by a lead wire 8 and an earth wire 10. In a circuit 9, an electric signal v1 emitted by a fuel pressure variation only is outputted as a peak value at the time of both start of jet and end of jet, the signal v1 is integrated and is compared with a signal of a mean value, and an interval of obtained output pulses is measured. Also, a fuel flow rate or an abnormality in the fuel system is detected by calculating from a pipe sectional area and fuel pressure. |
