Patent ID: 7845216

Claim:
An instantaneous flow rate measurement instrument of a gaseous fuel injector comprising: a gaseous fuel injector including an electromagnetic valve inside and injected with a gaseous fuel; an injector drive means for controlling opening and closing of the electromagnetic valve; a measuring portion thin tube connected to the gaseous fuel injector and supplied with the gaseous fuel from said gaseous fuel injector; a nozzle provided in the measuring portion thin tube and having cross section which changes from a small area to a large area from said gaseous fuel injector side to the downstream side of the measuring portion thin tube; an extension thin tube provided at a downstream side end of said measuring portion thin tube; a pressure measuring means arranged close to a small hole provided in said measuring portion thin tube; and a means for transducing the pressure in said measuring portion thin tube which has been measured by said pressure measuring means into flow rate of the gaseous fuel flowing in said measuring portion thin tube based on a predetermined conversion formula.