Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
Nozzle Assembly For Controlled Spray
Technical Field
This invention relates generally to a nozzle
assembly for controllably spraying a li~uid in a
substantially columnar form and, more particularly, to
a nozzle assembly for spraying a stream of cooling
liquid into a reciprocating piston passage.
Background Art
In using a nozzle to spray a liquid, the
pattern of the stream leaving the nozzle is important
; to assure that the liquid is delivered to the precise
location desired. For example, a nozzle is commonly
used to spray a cooling liquid such as engine oi~L
upwardly against the piston as it reciprocates in order
to cool it. In longer stroke engines particularly, the
oil must be sprayed a relatively long distance toward
the piston when it is at its top dead center position.
~1 The pattern of the spray is therefore important so that
the oil reaches the desired por~ion of the piston for
direct cooling. The oil can then drip or be deflected
downwardly to cool the remaining portion of the piston.
Heretofore, the nozzles in such engines have
utilized a single opening having a sufficiently large
; cross-sectional area to deliver the desired volume of
oil for a given period of time. However, over the
~ distances which the oil is directed, it tends to spread
-~ out or have an excessively wide spray pattern. This
reduces the effectiveness of the cooling oil in that
sufficient amounts do not reach the piston crown area.
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One attempted experimental solution was to
taper the outlet passageway in the nozzle to better
concentrate the stream leaving the nozzle. However,
the manifold construction and tapered nozzle imparted
an undesirable rotation and turbulence to the oil
particles so -that an unacceptable diverging spray
pattern still resulted.
The present invention is directed to
overcoming one or more of the problems as set forth
above.
Disclosure of Invention
In one aspect of the present invention, a
nozzle assembly for controllably spraying a liquid in a
columnar form has substantially axially aligned inlet
and outlet portions, with the inlet portion defining an
opening therethrough. First passage means is provided
for communicating a first liquid flow from the opening
through the outlet portion and outwardly thereof at a
first velocity, and second passage means is provided
for communicating a second liquid flow from the opening
through the outlet portion and outwardly thereof along
a plurality of paths generally encircling the first
passage means and individually having a second velocity
less than the first velocity.
In another aspect of the present invention, a
nozzle assembly is provided for controllably spraying a
cooling liquid toward a reciprocating engine piston in
a precise spray pattern. More specifically, a straight
passage is defined in the piston leading to an upper
cooling chamber, and the nozzle assembly controllably
sprays the cooling liquid in a columnar form into the
passage and thereby to the chamber.
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In yet another aspect of the present
invention, a method is disclosed for spraying a liquid
from a nozzle assembly. The steps of the method
include initiating liquid flow through an opening in an
inlet portion of the nozzle assembly, and controlling
the liquid flow from the inle-t portion at an outlet
portion defining a primary, centrally located passage
and a plurality of secondary, peripherally located
passages such that the liquid exits from the primary
passage at a first velocity and from the secondary
passages at a second velocity to maintain a columnar
spray pattern.
Advantageously, the liquid spray pattern of
the present nozzle assembly is maintained in a columnar
form rather than being widely dispersed. Irhis is
achieved by providing different liquid flow paths, such
as centrally from a primary outlet passage and
peripherally from a plurality of secondary ou~let
passages which cooperate to maintain the spraying
pattern relatively compact and free from such
dispersing effects.
Brief Description of the Drawings
FigO 1 is a diagrammatic elevational view of
an engine with a portion broken open and sectioned
showing one embodiment of the nozzle assembly of the
~` present invention for spraying a cooling liquid in
columnar form into a passage in a piston of the engine;
Fig. 2 is a diagrammatic and greatly enlarged
cross-sectional view of the nozzle assembly of Fig. l;
and
Fig. 3 is a diagrammatic, outlet end
elevational view of the nozzle assembly taken along
line III--III of Fig. 2.
Best Mode For Carrying Out the Invention
Referriny to the drawings, and particularly to
Fig. 1, a nozzle assembly 10 is shown associated with
an internal combustion engine 12. The engine has a
block 14 in which a cylinder liner 16 i5 carried. A
piston 18 is positioned in the cylinder liner and
reciprocates, as is known in the art, within the
cylinder liner. The block 14 has a passageway 20l and
a liquid distribution manifold 22 is releasably
connected to the block in communication with the
passageway. The nozzle assembly 10 receives a cooling
liquid, such as engine oil, under pressure from the
passageway and the manifold, which is then sprayed
upwardly toward the piston as it reciprocates in a
liquid column as is illustrated and identified by the
letter "A".
The piston 18 has a profiled downwardly Eacing
and stepped opening 24 and a straight passage 26
connected to the opening which extends upwardly to an
internal annular chamber 28 located at the crown area
thereof. A plurali~y of generally radially e~tending
passages 30 serve to communicate cooling liquid in the
annular chamber with a centrally disposed cavity 32.
- From the cavity the liquid can descend by gravity
through a central port 34 to the region of the
connection between the connecting rod 36 and pin 38 for
lubrication thereof.
As best seen in Fig. 2, the nozzle assembly 10
generally includes an inlet portion 40 and an outlet
portion 42 releasably secured thereon. In the instant
example the inlet portion is an integral outlet part of
the manifold 22 and has a substantially cylindrical
inner wall 44 at the outlet thereof defining an opening
46 through which the cooling liquid flows generally
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along a first central axis 48. The inlet portion
further has external connecting threads 50 and an end
face 52, and the outlet portion has internal connecting
threads 54 and a pocket 56 for screwthreadably
receiving the inlet portion.
The outlet portion 42 of the nozzle assembly
lO includes a planar inner end face 58 and a planar
outer end face 60 parallel thereto defining a
preselected length "L" therebetween as is illustrated
in Fig. 2. More specifically, a cylindrical outlet
passage 62 having a preselected diameter "Dl" is
defined between the end faces and is disposed on a
second central axis 64 generally aligned with the first
central axis 4~ of the inlet portion 4Q. Moreover, a
plurality of cylindrical outlet passages 66 are also
defined between the end faces and individually have a
diameter "D2". The passages 66 are preferably
aligned along a plurality of individual axes 68 which
are parallel to the central axis 64 and symmetrically
located a radial distance therefrom to establish a
radial separation distance "S" between the central
passage 62 and the surrounding passages 66 as is
illustrated in Fig. 3. It is theoriæed that the
minimal radial separation distance "S" should be about
1 mm, or one half the diameter "D2", whichever is
greater.
Thus, the central outlet passage 62
constitutes a primary or first passage means 70 for
communicating a first liquid flow from the opening 46
through the outlet portion 42, and the encircling
passages 66 constitute a secondary or second passage
means 72 for communicating a second liquid flow from
the opening 46 through the outlet portion.
Advantageously, the first liquid flow has a flow rate
along the central axis 64 at a first velocity, and the
second liquid flow has a flow rate in the individual
passages 66 at a second velocity less than the first
- velocity.
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The velocities of the individual outward
liquid flow paths from the nozzle assembly 10 are at
least in part based upon a relationship to the boundary
layer Elow conditions adjacent the inner wall 44 of the
opening 46 in the inlet portion 40. ~s is known in the
art, the boundary layer flow through a pipe, such as
the manifold 22 might represent, is a region adjacent
the wall of decreased liquid velocity owing to the
viscous drag of the liquid thereat.
In the nozzle assembly 10, the primary outlet
passage 62 is spaced radially inwardly of the axial
extension of the boundary layer within opening 46 in
order to achieve the first desired velocity. Where the
outlet passage is positioned centrally as shown, such
first velocity will basically be the highest velocity
through the inlet portion 40 and the highest velocity
through the nozzle assembly. The reduced second
velocity desired from the secondary outlet passages 66
is established in the instant embodiment by locating
them at least in part in substantial axial alignment
with the boundary layer flow along the inner wall 44.
This can be accomplished by positioning the radially
outermost portion of the secondary outlet passages 66
in axial alignment with the inner wall 44 of the
opening 30. In other words, the radially outer edges
of the peripherally grouped outlet passages are
constructed axially flush with the inner wall such that
liquid at a decreased velocity will enter the secondary
outlet passages.
It should be understood that the nozzle
assembly 10, and particularly the outlet passages 62,66
can be of other configurations without departing from
the invention. For example, the outlet passages can be
formed of individual tubes, not shown, attached to the
inlet portion 40. Also, the shape, orientation, number
and size of the outlet passages can be varied as long
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as the cross-section thereof is basically symmetrical
to assure columnar flow. For another example, a
plurality of arcuately shaped outlet passages, not
shown, can be formed in an annular relationship about
the primary outlet passage. However, it is believed
that the illus~rated configuration represents the most
desirable and economical nozzle assembly contemplated.
Industrial Applicability
In use, the nozzle assembly lO sprays a
substantially columnar stream pattern "A" upwardly into
the profiled opening 24 and the passage 26 formed in
the reciprocating piston 18. Whereupon the oil enters
the annular chamber 28 substantially at the same flow
rate as it had leaving the nozzle assembly. In other
words, the oil stream makes substantially no contact
with the walls of the opening 24 so that there is no
loss of cooling oil before the stream enters the
interior of the passage 26. When the piston i9 at
bottom dead center as is indicated by the phantom line
in Fig. 1, the outlet portion 42 of the nozzle assembly
is telescopingly received in the profiled opening 24 in
the piston with but a minimum of clearance. But when
it is at top dead center as shown, the stream is
delivered for the greatest distance in columnar form
directly into the passage 26.
It has been found that the use of multiple
elongate passages 66 encircling the elongate central
passage 62 greatly reduces any rotational turbulence of
the oil in the inlet portion 40 of the manifold 22.
This is in part due to the relatively significant ratio
of the length "L" of the outlet passages 62,66 to the
cross-section areas thereof as represented by the
respective diameters Dl and D2. It is theorized
that the L/D ratio for the central passage 62 should
preferably be in a range of from about 3.75 to about
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6Ø Similarly, the L/D ratio for the outer passages
66 should preferable be in a range of from about 7.5 to
about 13Ø It is further theorized -that these two L/D
ratios are related and should preferably not be less
than 2:1 or greater than 3:1, and with the minimum
individual ratio being above about 3.75.
In one preferred embodiment the distance "L"
was 15 mm, Dl was 2.5 mm, D2 was 1.15 mm, and the
radial distance "S" between the central passage and the
eight peripherically located passages was 1 mm.
A suficient quantity of oil must be available
within a preselected pressure range above a minimum
value of about 140 KPa in the inlet manifold 22. For
example, in one instance oil under a pressure of abo~t
480 KPa was available in the manifold sufficient for
the subject nozzle assembly 10 to desirably supply
about 18 liters/minute to the piston passage 26. ~ven
though the oil in the manifold was in a fluid vortex
state at the inlet portion 40 of the nozzle assembly,
the plurality of relatively long straight passages
62,66 served to divide the swirling flow into a
plurality of individual and straightened streams. Due
to the viscosity of the air medium between the central
stream and the plurality of encircling streams
traveling at a lesser velocity than the central stream,
the outlying streams have a tendency to be pulled
radially inwardly toward the central axis 64 through a
suction phenomena aided by atmospheric pressure, all of
which factors maintain the liquid stream pattern "A" in
columnar form for a substantially significant overall
distance, for example about 400 mm.
It is also to be noted that space is at a
premium in the interior of an engine, so that it was
desired to maintain the overall length "~" of the
outlet portion 42 in Fig. 2 to below 25 mm in order to
assure sufficient operating clearance from the piston
18.
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Thus it is apparent that the nozæle assembly
of ~he present invention is relatively compact and
simple in operation, and can advantageously direct a
columnar stream of oil into a linear passage in a
reciprocating piston so that it can cool the crown
portion thereof. This is accomplished without
resorting to a complicated series oE pressurized oil
passages through the crankshaft and c:onnecting rod,
which costly alternative also tends to weaken these
components in relatively critical areas.
Other aspects, objects and advantages of this
invention can be obtained from a study oE the drawings,
the disclosure and the appended claims.
