1. Field
The present application relates to a fuel-level measuring apparatus that measures the fuel level in a fuel tank installed in a vehicle.
2. Description of the Related Art
In a vehicle that uses gasoline or light oil as fuel, it is necessary to indicate the fuel level in a fuel tank so that the driver can know when the tank needs to be refilled and how far the car can drive.
A known fuel-level measuring apparatus that measures the fuel level in a fuel tank is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2013-50410. The apparatus disclosed therein includes a float provided in a fuel tank, the float moving up and down with the surface level of the fuel, and, by making a float arm of the float slide over a resistor plate and converting the surface level into an electric potential difference, the apparatus measures the height of the surface and indicates the fuel level calculated from the height of the surface to a driver.
However, the technique disclosed in Japanese Unexamined Patent Application Publication No. 2013-50410 has the following problems: because the fuel-level measuring apparatus, such as the float, is disposed in the fuel tank, the capacity of the fuel tank decreases by an amount corresponding to the volume of the fuel-level measuring apparatus; because the fuel-level measuring apparatus needs to be disposed in the fuel tank, the shape of the fuel tank is restricted and cannot be thin or complicated; and, because the surface level of the fuel in the tank changes significantly depending on the orientation and driving conditions of the vehicle, it is impossible to measure the accurate fuel level.