| 초록 |
This work is an experimental research to investigate the gas fuel (CH4) characteristics necessary for natural gas vehicles based on ultrasonic-assisted measurement using two different ultrasonic sensors. This paper offers the technical methods including energy transfer process, ultrasonic propagation, sensitivity, amplitude signal, and relationship of CH4 density and ultrasonic signal. The experiment is composed of a constant volume chamber (CVC), two different sensors (AUS and HSUS), and gas fuel (methane). The experimental conditions are set by 1 ~ 4 bar of initial pressure, 7 Hz of pulse rate, 53.7 kHz of resonant frequency, and 0.45 ~ 0.85 m of measurement distance in natural gas space. As a result, HSUS is measured by 0.92 V of the height, 4 cm of main width, 12.7 cm of full width, and 42.8º of slope angle. The important thing is to highly increase the height and slope angle of HSUS model comparing with AUS model. Consequently, this experiment is shown that ultrasonic signal is gradually diminished as distances increases, the amplitude is improved as initial pressure increases, and ultrasonic sensor capable of transferring longitudinal wave is significantly affected by distance difference in CH4 gas space. |
