Abstract: A fuel consumption measuring device is provided with a flow meter which is mounted on a fuel feeding passage extending from a fuel tank to an engine, wherein a return fuel which is not consumed by the engine is returned to a passage in the downstream of the flow meter through a return passage so as to measure a fuel consumption in the engine by the flow meter. The fuel feeding passage is provided with a pressure reducing valve for maintaining a confluence of the fuel feeding passage and the return passage at atmospheric pressure. Therefore, the fuel consumption measuring device has high measuring accuracy and high security, and is suitable for a vehicle.

Abstract: A measuring apparatus of a volume of a fluid injected from an injection valve. A fluid having a volume V is injected from an injection valve into an injection chamber containing a fluid, same kind as that of the injected fluid, and having a predetermined pressure and volume. A back pressure chamber is formed separately in the injection chamber with a parting plate having an effective under-pressure area A and a bellow sealed and connected, at one end thereof, to the parting plate. In the back pressure chamber a non-contact displacement sensor having a thermal compensation device is disposed with a clearance from the parting plate and the bellow and the back pressure chamber is filled with another fluid having same pressure as that of fluid in the injection chamber. By the injection of the fluid into the injection chamber, the parting plate moves toward the non-contact displacement sensor by a distance S which is equal to V/A. Distance S is detected by the non-contact displacement sensor.

Abstract: A measuring device for measuring a fuel injection quantity comprising fuel volume sensing means including a fuel injection chamber connected to a fuel injection valve and receiving the fuel injection quantity therefrom, a back pressure chamber which faces the fuel injection chamber, bulkhead means located between the fuel injection chamber and the back pressure chamber as an intercept therebetween and responsive to the fuel injection quantity for generating a displacement, sensing means for sensing the displacement of the bulkhead means, pressure means for holding a pressure of the back pressure chamber to be of a constant value, fuel injection quantity computing means responsive to the sensing means for determining a fuel injection quantity, discharging means including fuel discharging means for discharging the injected fuel quantity from the fuel injection chamber to its exterior, discharging quantity computing means responsive to the fuel injection quantity computing means for computing a discharged quanti