Abstract: An oil detecting system for detecting a leakage oil by optical fluorescence measurement means even in the presence of external fluorescent light, for example, from parts and equipments of a vehicle and a plant comprises an irradiation apparatus for irradiating a light including an absorption wavelength of an oil to be detected and exciting molecules of the oil to make the oil fluoresce, a wavelength selection apparatus operatively connected to the irradiation apparatus and adapted to select a fluorescence wavelength of the leakage oil fluoresced by the irradiation apparatus, and an observation apparatus for detecting the fluorescence of the leakage oil and selecting only a period of observing fluorescing of the leakage oil over substantially the same time period that the leakage oil fluoresces light. A processing apparatus may be further provided so as to be operatively connected to the observation apparatus and adapted to process an image or a signal from the observation apparatus.

Abstract: Concentration of hydrogen gas generated during a process of electrically recharging a battery of an electric vehicle is maintained by discharging the hydrogen gas during the process. An electric fan is installed inside a control unit box for accommodating a motor, an electric recharger and a control apparatus. The electric fan communicates ambient air to a motor through ducts. The air is further communicated to batteries through a duct and a nozzle member. Air directed by the electric fan during operation of the electric vehicle cools the motor driver and the motor. On the other hand, air communicated by the electric fan during a process of electrically recharging the batteries cools the electric recharger and then flows from the nozzle member to the batteries, blowing off hydrogen gas generated by the batteries during the electrical recharging process.