| 摘要 |
PURPOSE:To supply fuel exactly even at the starting time of an engine, by detecting an occurring frequency of Karman's vortex street by a frequency vortex street detector and outputting a fixed frequency at the time when said detected frequency comes to below the frequency of an oscillator which is higher than the stably occurring frequency of Karman's vortex street. CONSTITUTION:Ultrasonic wave is radiated from a ultrasonic transmitter 3 by an output of a unltrasonic osillator 5 and receives phase modulation by Karman's vortex street across a flow path 1 and reaches a ultrasonic receiver 4. The output is transferred to a vortex street detector 6 and the Karman's vortex street is simultaneously detected from a phase difference from the transmitting wave transferred from an oscillator 5, and the output is transferred to a frequency discriminator 7 and an AND gate 8. The output of the discriminator 7 is transferred to an AND gate 10 via the gate 8 and an invertor 9. The frequency which is higher than the stably occurring frequency of the vortex is transferred from an oscillator 11 to the gate 10, and when the output frequency from the discriminator 7 is lower than the above mentioned frequency, a fixed frequency is outputted T via an OR gate 12 and fuel is exactly supplied even at the starting time of an engine. |
