To improve measurement accuracy for liquid quantity, to enable reliable measurement with the consumption of electric power suppressed, and further to prevent the effects of covering with a liquid as much as possible.
A volume measuring device 12 is installed on the upper part of a fuel tank 11. The volume measuring device 12 measures the volume of air in the fuel tank 11 through the use of acoustic effects. A remaining fuel operating means 13 measures remaining fuel in the fuel tank 11 from the volume of air measured by the volume measuring device 12. A fuel consumption operating means 16 operates the consumption of fuel on the basis of the amount of injected fuel detected by an injected fuel amount detecting means 14. A remaining fuel judging means 18 concludes that a value operated by the remaining fuel operating means 13 is remaining fuel when judging that a vehicle is stopping on the basis of the speed of the vehicle detected by a vehicle speed detecting means 17, and concludes that a value obtained by subtracting the consumption of fuel operated by the fuel consumption operating means 16 from a value calculated last time when judging that the vehicle is moving.
YAMADA KOICHI
OKADA MINORU
OKAMOTO YOSHIYUKI
