METHOD AND DEVICE FOR MEASURING PROPERTY OF FUEL AND FUEL INJECTION QUANTITY CONTROLLER USING THE DEVICE

摘要

PURPOSE: To obtain a small-sized highly accurate device which can quickly respond and can be suitably mounted on a vehicle by generating bubbles in fuel by cavitation by irradiating the fuel with ultrasonic waves or using an orifice and introducing the fuel containing the bubbles to a bubbles passage. ;CONSTITUTION: A fuel property measuring instrument 10 is provided with an ultrasonic vibrator 4 fitted to a position counterposed to the front end of a detecting electrode 1 in a cylindrical case 14. When the vibrator 4 is driven in a state where a fuel tank 12 is filled up with fuel, bubbles 18 are generated in the fuel near the vibrator 4 by cavitation and the bubbles 18 ascend through a pore passage 13 and are diffused in the tank 12 from a fuel exit 8. Since the dielectric constant of the fuel passing through the passage 13 decreases as the total amount of generated bubbles 18 increases, the capacitance between the detecting electrode 1 and common electrode 3 decreases. Therefore, when the capacitance is measured, the dielectric constant of the fuel containing the bubbles 18 can be recognized and, accordingly, the total amount of the generated bubbles 18 and, in turn, the vapor pressure of the fuel can be recognized.;COPYRIGHT: (C)1995,JPO