Characteristics of fabricated catalytic combustible micro gas sensor with low power consumption for detecting methane leakage of compressed natural gas bus

For keeping the safety of compressed natural gas-powered buses (CNG, CH₄), a small sized and low power consumption gas sensor is needed for the fuel leakage alarm system. So catalytic combustible micro gas sensors were designed and fabricated by microelectromechanical systems (MEMS) technology and the sensors were measured output voltage potential of the sensor circuit as sensitivities to methane. The sensor was consisted of a sensing platform and a compensation platform, and the length and width of the fabricated platform were 3 mm by 3 mm. The output voltage of a fabricated micro sensor were 0.727 mV, 0.548 mV, 0.45 mV, and 0.29 mV at methane concentrations of 4,630 ppm, 3,473 ppm, 2,315 ppm, and 1,158 ppm respectively, at the input power of 104 mW. Fabricated micro gas sensors could be operated at low power consumption and showed good selectivity. For further study, the long-term stability of micro sensors will be done before applying to CNG powered buses.