APPLICATION OF A LASER TECHNIQUE TO THE VELOCITY MEASUREMENT OF THE LIQUID-FUEL FILM WITHIN THE INTAKE PIPE OF INTERNAL COMBUSTION ENGINES.

Utilizing a flash photolysis method, a non-disturbing technique was developed to measure the flow velocity of liquid-fuel film formed on the surface of the intake pipe of internal combustion engines. A tracer, in the form of a blue line, was generated instantaneously by applying a high energy laser beam to the liquid film of a fuel which contains very dilute 2-(2,4-dinitro-benzyl)-pyridine. AN//2 pulse laser with 900 kW peak power was used as the light source. The arrival of the tracer was detected by the He-Ne laser and photodiode system at an appropriate fixed point located a short distance downstream from the tracer generating point. The flow velocity of the film was determined from the time the tracer required to travel the distance between the two points. It was disclosed that the film flow velocity is of the order of 1/100 of the mean air velocity within the intake pipe.