Fuel Atomization and Spray Behavior in an Intake Manifold of Gasoline Engine. 1st Report. In a Steady Air Flow.

Abstract

A new single-point injector which is a impingement-type twin-fluid injector was developed, and the spray characteristics of it and spray behavior in a steady air flow were investigated. Newly designed injector has two kinds of atomizing air supply. At low rotational speed, the fuel is atomized by the air inhaled through the injector by the pressure difference between the atomospheric pressure and the vacuum pressure in an intake manifold. At high rotational speed, the fuel is atomized by high speed air stream inhaled through the throttle valve. The spray characteristics can be improved by new injector compared to conventional pressure injector, especially at low rotational speed. The deposition rate of fuel droplets to the inner wall of intake manifold increases with increase of rotational speed, and it is influenced by the intensity of the recirculation zone on the inner wall.