A new twin-fluid injector applicable to a single-point injector for ga
soline engine was developed. Using this injector's transient spray cha
racteristics, the mixing mechanism of spray particles and the depositi
on mechanism on the inner wall of an intake manifold were investigated
. The measurements of spray particle sizes, velocities and deposition
rates were experimentally conducted in a pulsating air flow. The parti
cle deposition takes place due to the particle inertia at high air flo
w rates. At low air flow rates it comes due to the recirculation appea
ring on the inner wall at the entrance of the intake manifold. On the
other hand, the deposition rate of spray particles is strongly influen
ced by air pulsation. The behavior of spray particle is mainly influen
ced by air pulsation when the velocity of the atomizing air is low and
when the velocity of the air flow around the injector is high. Single
small particles follow the air flow more easily than large particles,
and this causes the spatial particle size distribution in the spray c
lump. As the spray particles approach to the tip of a spray clump, the
size of particles.