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Flow characteristics and influence of swirl flow interactions on spray for direct-injection diesel engine
Technical Paper
2000-05-0101
Sector:
Language:
English
Abstract
Since it is well known that the flow and spray characteristics
are critical factors on the performance and emission in a
direct-injection diesel engine, this study aims to investigate the
interaction between flow and spray characteristics. At first,
in-cylinder flow distributions in swirl/tumble adapter for 4-valve
cylinder head of DI diesel engine were investigated under steady
conditions with different SCV angles mounted on the cylinder head
by using 2-D LDV. It was found that swirl flow is more dominant
than tumble on spray interaction in the engine. For the analysis,
the in-cylinder flow was quantified in terms of non-dimensional rig
swirl/tumble, mean flow coefficient, swirl ratio/tumble ratio. It
was confirmed that the swirl ratio is controlled between 2.3 and
3.8 by changing SCV angles.
Spray characteristics of the intermittent injection also were
investigated by using PDA system to measure droplet size and
velocity. The analyses of the PDA results were carried out with
Time Dividing Method. It was found that there is a correlation
between the swirl flow and SMD. The droplet size and the velocity
were found to be nearly constant value with SCV angles, while the
swirl ratio becomes higher with smaller SMD. The swirl ratio was
found to be helpful factor to the atomization of droplet.