| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid level detector for vehicle which ensures highly accurate liquid level detection by devising the constitution of a cylinder. SOLUTION: A guide pipe 4 and a guide pipe 5 are made a cylindrical shape with the same inner diameters and the thickness dimensions d<SB>1</SB>and d<SB>2</SB>of the guide pipes 4 and 5 are so set that sound velocities c<SB>1</SB>and c<SB>2</SB>in fuel 8 in the guide pipes 4 and 5 are equal. By this method, transmission energy reduction of ultrasonic due to ultrasonic wave interference at 4 corners in the guide pipes with rectangular cross section in a conventional liquid level detector is prevented. Also, a transmission velocity change of ultrasonic waves is not caused when the ultrasonic wave transits from the guide pipe 4 to the guide pipe 5, and from the guide pipe 5 to the guide pipe 4 and so, a detection signal level which an ultrasonic oscillator element generates by reflection wave from the liquid level is raised and a fuel level detector 1 capable of accurate liquid level detection is realized. COPYRIGHT: (C)2005,JPO&NCIPI |
