U.S. patent number 3,872,916 [Application Number 05/348,436] was granted by the patent office on 1975-03-25 for fan shroud exit structure.
This patent grant is currently assigned to International Harvester Company. Invention is credited to Harold D. Beck.
United States Patent |
3,872,916 |
Beck |
March 25, 1975 |
FAN SHROUD EXIT STRUCTURE
Abstract
An internal combustion engine, having a heat exchange cooling
system, a fan for moving air therethrough and a shroud and shroud
exit section for controlling the air path. The shroud exit encloses
the fan and includes throat (CF) radial expander (R) and radial
flat (RF) sections whereby air is drawn through the heat exchanger
axially and expelled radially along said exit sections. The fan has
a projected axial width (AW) such that a general relationship
exists with the shroud exit sections: CF = AW/3, RF = AW/3, and R =
2AW/3.
Inventors: |
Beck; Harold D. (Downers Grove,
IL) |
Assignee: |
International Harvester Company
(Chicago, IL)
|
Family
ID: |
23368047 |
Appl.
No.: |
05/348,436 |
Filed: |
April 5, 1973 |
Current U.S.
Class: |
165/51;
123/41.49; 180/68.1; 415/207; 415/222; 165/122; 415/211.1 |
Current CPC
Class: |
F04D
29/545 (20130101); F01P 5/06 (20130101) |
Current International
Class: |
F04D
29/40 (20060101); F01P 5/02 (20060101); F01P
5/06 (20060101); F04D 29/54 (20060101); F28d
021/00 () |
Field of
Search: |
;123/41.48,41.49
;180/54A,68R ;415/210,219R,DIG.1 ;165/1,51,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
485,410 |
|
Oct 1953 |
|
IT |
|
107,876 |
|
Jul 1939 |
|
AU |
|
770,848 |
|
Mar 1957 |
|
GB |
|
569,241 |
|
Jan 1933 |
|
DD |
|
Other References
Applications of the Coanda Effect, Imants Reba, Scientific
American, Vol. 214, No. 6, 6-66, pps 84-92..
|
Primary Examiner: Davis, Jr.; Albert W.
Assistant Examiner: Richter; S. J.
Attorney, Agent or Firm: Krubel; Frederick J. Harman; Floyd
B. Schaerli; John A.
Claims
What is claimed is:
1. A method of transferring internal combustion engine produced
heat for cooling said engine comprising the steps of:
transferring the engine generated heat to a coolant;
passing said heated coolant through a heat exchange means;
generating an air stream with a fan means;
drawing the air stream through the heat exchanger transferring heat
thereto;
guiding the heated air stream from said heat exchanger to said fan
with a shroud; and
expelling the heated air stream from the fan means over a contoured
fan shroud configured to produce a Coanda effect directing the air
stream generally radially outward, said fan shroud being positioned
generally around said fan.
2. A method for dissipating internal combustion engine produced
heat comprising the steps of:
absorbing said heat in a liquid media;
transporting heated liquid media to a heat exchanger means;
circulating said heated liquid media through said heat
exchanger;
generating an air stream with a fan means;
drawing the air stream through said heat exchanger to effect heat
transfer therebetween and expelling the heated air from the fan
means over a fan shroud configured to produce a Coanda effect
directing the air stream generally radially outward, said fan
shroud being positioned generally around said fan.
3. A method of moving air to dissipate the heat generated by a
liquid cooled internal combustion engine such that a Coanda effect
is achieved comprising the steps of:
passing liquid from said internal combustion engine through a heat
exchanger means;
generating an air stream with a fan means;
drawing the air stream through the heat exchanger;
guiding the air stream from the heat exchanger to the fan means;
and
expelling the air stream from the fan over a contoured fan shroud
configured to produce a Coanda effect directing the air stream
generally radially outward, said fan shroud generally surrounding
said fan.
4. A method of handling air for cooling a water jacketed internal
combustion engine such that a Coanda effect is achieved comprising
the steps of:
generating an air stream with a fan means;
drawing the air stream through a heat exchanger;
guiding the air stream from said heat exchanger with a shroud
means; and
expelling the air stream over a contoured fan shroud means
configured to produce a Coanda effect directing said air stream
generally radially outward.
5. A heat transfer system for an internal combustion engine
comprising:
a heat exchanger including a front and a rear section;
a shroud having a forward section arranged to enclose said rear
section of said heat exchanger, and a rearwardly extending unitary
contoured exit section including a cylindrical throat, radial
expanding section and a radial flat portion;
a fan assembly including a plurality of fan blades having leading
and trailing edges, said leading edges positioned adjacent said
heat exchanger wherein the following relationship within plus or
minus 12 percent of AW exists: RF = AW/3, CF = AW/3, and R = 2AW/3
where RF is the length of the radial flat portion, CF is the length
of the cylindrical throat, R is the radius of the radial expanding
section and AW is the projected axial width of the fan means
whereby fan generated noise and horsepower requirements of said
engine are reduced.
6. The heat transfer system of claim 5 wherein the trailing edge of
said fan forms a plane parallel, plus or minus 12 percent, with
said radial flat portion, whereby the fan induced stream of air is
converged and directed out parallel to the radial flat portion.
7. A heat transfer system for an internal combustion engine
comprising:
a heat exchanger having a front and a rear section;
a shroud having a forward section arranged to enclose said rear
section, and a rearwardly extending unitary contoured exit section
including means defining a cylindrical throat, means defining a
radial expanding section and a radial flat portion;
a fan assembly including a plurality of fan blades each having a
leading and a trailing edge, said leading edge being positioned
adjacent said heat exchanger, wherein the following relationship
exists: RF = AW/3, CF = AW/3, and R = 2 AW/3 where RF is the length
of the radial flat portion, CF is the length of the cylindrical
throat, R is the radius of the radial expanding section and AW is
the projected axial width of the fan whereby fan generated noise
and horsepower requirements are reduced.
8. A cooling system for an internal combustion engine
comprising:
a radiator including means defining a tube and means defining a
rearward area;
a shroud having a forward section arranged to include said rearward
area of said radiator, and means defining a rearwardly extending
unitary contoured exit section including a cylindrical throat, a
radial expanding section and a radial flat portion;
a fan assembly including a plurality of fan blades each having
leading and trailing edges, said leading edges being positioned
adjacent said radiator, wherein the following relationship plus or
minus 12 percent exists: RF = AW/3, CF = AW/3 and R = 2 AW/3 where
RF is the length of the radial flat portion, CF is the length of
the cylindrical throat, R is the radius of the radial expanding
section and AW is the projected axial width of the fan whereby the
fan induced stream of air is converged and directed out generally
parallel to the radial flat portion.
9. The cooling system of claim 8 wherein:
said radiator includes means defining a rearwardly extending
perforated area;
said shroud enclosing said perforated area, and
said trailing edges of said fan blades are coextensive plus or
minus 12 percent with said radial flat portion wherein the
following relationship exists: RF = AW/3, CF = AW/3, and R = 2AW/3
where CF is the length of the cylindrical throat, R is the radius
of the radial expanding section and AW is the projected axial width
of the fan.
10. A vehicle having an operator station, an internal combustion
engine, a radiator for cooling fluid from said engine an axial flow
fan axially facing said radiator and including a plurality of
angular blades drawing air rearwardly through said radiator, and a
shroud rearwardly extending from said radiator wherein the
improvement comprises:
a unitary shroud exit section closely surrounding said fan and
extending in the same direction as said shroud including a tubular
portion forming the leading edge thereof, an arcuate portion
extending generally rearwardly and outwardly from said tubular
portion and terminating in a flat flange portion forming the
trailing edge of said shroud and lying in a plane perpendicular to
said tubular portion, said fan disposed within at least a portion
of said shroud exit section wherein the following relationship plus
or minus 12 percent exists: RF=AW/3, CF=AW/3 and R=2 AW/3 where RF
is the length of the flat flange portion, CF is the length of the
tubular portion, R is the radius of the arcuate portion and AW is
the projected axial width of the fan whereby fan generated noise
and horsepower requirement of said engine are reduced.
11. The shroud exit section of claim 10 wherein said fan has a
front plane which intersects said tubular portion and a rear plane
which intersects, plus or minus 12 percent, said flat flange
portion whereby a stream of air is converged and directed outwardly
parallel to said flat flange portion to prevent the passage of dust
and particle laden air against said engine, and engine heat against
said operator station.
12. The shroud exit section of claim 11 wherein said tubular
portion is secured to said shroud around the entire circumference
thereof forming a junction section; and
said front plane struck out by said fan intersects said junction
section.
13. A vehicle having an operator station and an internal combustion
engine, a radiator for cooling fluid from said engine, an axial
flow fan axially facing said radiator and including a plurality of
angular blades drawing air rearwardly through said radiator, and a
shroud rearwardly extending from said radiator wherein the
improvement comprises:
a unitary fan shroud exit portion secured to said shroud and
extending rearwardly thereof including; a cylindrical throat
defining a leading edge, a radially expanding portion, and a radial
flat portion defining a trailing edge; said fan being enclosed
therein, said blade means defining a front plane coextensive with
said leading edge wherein the following relationship exists: RF =
AW/3, CF = AW/3, and R = 2 AW/3 where RF is the radial flat
portion, CF is the cylindrical throat, R is the radius of the
radial expanding section and AW is the projected axial width of the
fan whereby fan generated noise and horsepower requirements of said
internal combustion engine are reduced.
14. The improvement of claim 13 wherein:
said fan shroud exit portion is secured to said shroud around its
entire circumference; and
said blade means defines a rear plane, said plane being coextensive
with said radial flat means plus or minus 12 percent.
Description
This invention relates to a cooling assembly and more particularly
to a contoured fan shroud exit section and a fan located
therein.
Most vehicles in general use today are driven by internal
combustion engines. These engines being heat producing are for the
most part water cooled, that is the engine is jacketed for
circulation of water which takes up the heat and subsequently
transfers it to the atmosphere. The radiator is used for cooling
the liquid circulating through the engine by dissipating the heat
to an air stream. The air flowing through the radiator absorbs the
heat and carries it out into the atmosphere. Different types of fan
systems are used to achieve the necessary air velocity through the
radiator. That is, some fan assemblies draw air from the atmosphere
through the radiator and back over the engine thereafter exiting to
the atmosphere. This type of fan is known as an axial flow suction
fan, drawing air axially through the radiator and discharging it
into the engine compartment. Other fans work in the reversed
manner, that is, they draw air from the engine compartment
wherefrom it is blown forwardly through the radiator to achieve the
necessary radiator cooling. This latter system is often employed
when the vehicle is performing tasks that generate large amounts of
dust or air borne particles, to keep such material from settling in
the engine compartment or where thermal and/or air pollution are
detrimental to operator environment. This dust problem is found in
many cases to have a detrimental effect upon the engine and its
performance while heat and noise reduce the efficiency of the
operator. Baffle systems are often involved to redirect the air
drawn rearwardly by the suction fan, however, such devices are
often complicated and as is apparent employ additional parts,
labor, and services. The reverse or forwardly blown air through the
radiator also suffered from the fact that the air was often heated
substantially by the passage around the hot engine and, depending
upon how fast the vehicle was moving forwardly necessitated
additional fan power to overcome the rearward vehicle generated air
stream. With the increase in power delivered to the fan, fuel
consumption increased and noise pollution increased.
It is thus apparent that both above methods possess characteristics
which are far from that which are desirable. It is therefore an
object of this invention to provide a cooling assembly which
directs dust and air borne particles so as to enhance their
expulsion from the engine compartment. Yet another object of this
invention is to provide an air exit section for a fan shroud
whereby maximizing air flow and improving operator environment by
reducing thermal, noise, and air pollution. Still another object of
this invention is to provide a fan shroud exit section and a fan
having a relationship whereby optimum air flow and noise values are
achieved. Another object of this invention is to provide a fan
shroud exit section and a fan oriented therein whereby the air flow
discharge path can be tailored and, if so desired, bent to exit
radially. A further object of this invention is to provide a fan
shroud with an exit section which is capable of producing the
Coanda effect. Still another object of this invention is to provide
an air exit section and a fan having a relationship whereby the
Coanda effect can be maintained over a substantial range of fan
speeds. Still another object of this invention is to provide an
engine cooling assembly which does not direct heated air toward the
operator station.
In accordance with the preferred embodiment of this invention a
vehicle is provided having a liquid cooled internal combustion
engine and a radiator cooling system for dissipating the heat
produced. The radiator cooling system includes a standard radiator,
an axial flow fan facing the radiator and having a plurality of
angular blades whereby air is drawn rearwardly through the
radiator. A shroud rearwardly extends from the back face of the
radiator to channel air through the radiator and hamper the fan
from drawing air which has not passed through or at least come in
contact with the perforated heat exchanging surfaces of the
radiator. For the most part the shroud encloses the entire
perforated heat exchanging rear area of the radiator. A fan shroud
exit means is also provided having secured to the backwardly
extending portion of the fan shroud and extending rearwardly
thereof as well as outwardly. As will be later explained it is the
particular contour of this exit section in combination with an
axial flow fan located therein, the location thereof also being
important, which allows the air stream to be converged and directed
radially away from the engine compartment. As is apparent this
invention is also applicable to a stationary engine where it is
desired to direct the air stream.
Other objects and advantages of the invention will become apparent
upon reading the following detailed description and upon reference
to the drawings, in which;
FIG. 1 is a side elevation of an internal combustion engine showing
the device of my invention attached to a vehicle;
FIG. 2 is a fragmentary vertical section showing the relationship
of the fan to the contoured exit section;
FIG. 3 is a top view of a tractor showing the air stream of the
prior art fan assemblies; and
FIG. 4 is a top view of a tractor showing the directed air stream
achieved with the radiator cooling assembly herein disclosed.
While the invention will be described in connection with a
preferred embodiment, it will be understood that it is not intended
to limit the invention to that embodiment. On the contrary, it is
intended to cover all alternatives, modifications and equivalents
as may be included within the spirit and scope of this invention as
defined by the appended claims.
Turning first to FIG. 1 there is shown a conventional water cooled
heat producing internal combustion engine means 10 forwardly
carried on longitudinally extending parallel support means 12 of
vehicle means 14. As shown herein vehicle means 14 is a tractor,
however, as will hereafter become more apparent this invention can
be applied to any type of vehicle employing a heat generating
internal combustion engine or any other portable or stationary
device requiring an air moving fan. Forwardly mounted is a water
cooling radiator means 16 employed to dissipate the engine
generated heat. Water flows between the water jacket on the engine
(not shown) and the radiator through a series of fluid
communicating means 18 and 20. In this particular embodiment sheet
metal means 22 encircles engine means 10 thereby forming the engine
compartment area means 24.
Carried at the forward end of engine means 10 is a fan shaft means
26 whereby power is delivered to drive fan means 28. As is
apparent, the particular mode whereby power is transmitted thereto
is not critical and belts and pulleys could also be employed. As
employed here, fan means 28 is a rotatable suction fan positioned
opposite the radiator means 16, and normally creating a flow of air
or drawing in a stream of cooling air rearwardly through the
radiator with a subsequent axial discharge thereof. This axial flow
of air is directed to the fan means by a shroud means 30. The
particular shape of the forward section 32 is dependent upon the
shape and design of the perforated heat exchanging design of the
radiator. The nature of the connection between the leading edge of
32 and the rear face 34 of the radiator will be dependent upon the
particular characteristics of these components, that is, some
connections being provided with air gaps while others are
substantially sealed over the entire circumference of the
enclosure. In the preferred form of this invention the entire
perforated area is substantially sealed against the passage of air
from any other direction except through the radiator. From the
forward edges the shroud means 30 (be it a taper transition as
shown or a box type) converges rearwardly to a circular rear
section 36.
Referring now to FIG. 2 wherein is more clearly shown a shroud exit
means 38 extending rearwardly and outwardly from shroud edge 36.
The connection between the shroud and the shroud exit can be
achieved by any suitable means, however, it is desirable that such
connection be relatively free of gaps or spaces which would allow
the passage of air. Exit shroud means 38 includes a tubular means
40, an arcuated means portion 42 and a flat flange portion means
44. For the most part tubular means portion 40 forms the leading
edge of the exit shroud means while arcuated means portion 42 still
extending generally rearwardly simultaneously extends outwardly
around an arch the reference point of which is defined as point 46.
That is, arcuated section 42 has a general bell-shaped appearance
being a section of a transition surface or some approximation
thereof. In the preferred embodiment arcuated section 42 is a
section of a constant radius arch. Flat flange portion 44 forms the
trailing edge of exit shroud means 38 and has a major plane
perpendicular to that of tubular section 40. For purposes of
simplicity, tubular means 40 will be hereafter referred to as the
cylindrical throat means, arcuated portion 42 will be referred to
as the radial expanding means and flat flange portion 44 will be
referred to as radial flat means. Overall the entire fan shroud
exit means 38 has a horn-like configuration.
As previously stated, fan means 28 is rotatingly carried adjacent
said radiator means and operably to establish a flow of cooling air
therethrough. Fan means 28 includes a plurality of fan blade means
48 (only one shown) as is well known in the art. As shown in FIG. 2
fan means 28 is surrounded by said contoured fan shroud exit
section 38. The enclosure of the fan means 28 within shroud means
30 is such that a front plane struck out by the leading edge 50 is
coextensive and passes through the leading section of throat means
40 and a rear plane struck out by trailing edge 52 is about
coextensive and parallel with said radial flat portion 44. It
should be noted, however, that there is a plus or minus error
factor involved in both of these values of about 12 percent of AW.
That is, the respective planes formed by the blade means can be
within about 12 percent of optimum and still function
satisfactorily within the scope of this invention. Thus, within
this range the direction air stream will still be substantially
radial.
It has been determined, however, that best results are obtained
when the front plane struck out by leading edge means 50 passes
through the juncture point between converging shroud 36 and the
throat section 40. Even more determinative on the result is the
relationship between the rear plane struck out by trailing edge
means 52 and the radial flat portion 44. Overall performance is
achieved when the rear plane and the radial flat portion 44 are
coextensive and parallel. Deviations from this orientation cause
the air stream to change more rapidly than corresponding percentage
changes in the front plane location.
The following relationship exists between these parameters: RF =
AW/3, CF = AW/3, and R = 2AW/3 where RF is the length of the radial
flat portion 44, CF is the length of the cylindrical throat section
40 and R is a radius of the radial expanding section 42 or distance
from the reference point to the transistion surface and AW is the
projected axial width of fan 28.
Although not obvious from a simple consideration of the layout the
cooling assembly embodied herein, horsepower savings and noise
reduction are realized. The geometry of the shroud exit and
positioning of the fan therein so effects the cooling
characteristics of the assembly that fewer rpms of the fan are
necessary to achieve the same temperature reduction of the coolant.
Hence, decreasing the fan speed yields a reduction of fan generated
noise and power required to drive the fan. Because of the radial
discharge of the air stream dust and particle matter are swept away
from the operator and not back on him. The same is true for the
heat which has been passed to the air, it issues away from the
operator station.
FIGS. 3 and 4 show the path in which air is dispersed by the fan
means comprising again a standard assembly and the improved
assembly, thus, the achieved is apparent.
In actual tests on an International Harvester tractor model number
F-1026 equipped with the improved cooling assembly provided the
same cooling capacity while making a number of improvements. These
included about a 20 percent reduction in fan drive power, about a
6dB reduction in actual fan noise, 4dB reduction of overall vehicle
noise at operator station and operator station temperature
reductions of 20.degree.F at his feet, 8.degree.F at his head and
5.degree.F at the steering wheel. It thus is apparent that shroud
exit geometry and fan relationships can make substantial
improvements in the air flow and its discharge direction, noise,
and required fan drive power characteristics of a cooling fan.
Louver means 56 can also be provided to allow the easy and quick
dissipation of the radially discharged air. can be achieved by
having X.sub.E about equal to plus or minus 12 percent of AW. That
is, as explained previously when the plane swept out by the rear
edge is coextensive with the surface of the radial flat or within
the tolerance set forth. By changing the orientation of the fan
with respect to the fan exit section it is also possible to direct
the air stream, straight back, at an angle off radial, etc.,
depending on preference and need.
Thus it is apparent that there has been provided a heat exchange
system including, a heat exchange means such as a radiator, a fan
shroud and a fan shroud exit section with a fan therein. An exit
section includes, in order, a cylindrical throat section, a radial
expanding section, and a radial flat portion. The leading edge of
the cylindrical throat section being secured to the shroud around
its entire circumference. The fan assembly carried in the shroud
exit section includes a plurality of fan blades having front or
leading edges and trailing or rear edges. These edge means sweep
out planes as they rotate, that is, a front and rear plane. The
front plane for the most part should intersect the junction between
the shroud end and the cylindrical throat while the rear plane
should be parallel to and coextensive with the radial flat portion.
By experimentation it has been determined that the relationship of
the rear plane to the radial flat is the more critical of the two
parameters. In the assembly the following relationship plus or
minus 12 percent of AW exists: RF = AW divided by 3, CF = AW
divided by 3, and R = 2AW divided by 3 where RF is the length of
the radial flat portion, CF is the length of the cylindrical
throat, R is the distance from the reference point to the radial
expanding section and AW is the projected axial width of the fan.
As has been pointed out previously the R value in the preferred
embodiment is the radius of the radial expanding section, that is,
the radial expanding section is a part of a circle. However, as is
apparent it may deviate from this preferred form. Accordingly, the
fan induced stream of air is converged and directed out of the
shroud exit parallel to the radial flat portion thus avoiding the
passage of dust and particle laden air currents against the engine
and subsequently against the operator station.
Thus it is apparent that there has been provided, in accordance
with the invention, a shroud exit means that fully satisfies the
objects, aims, and advantages set forth above. While the invention
has been described in conjunction with specific embodiments
thereof, it is evident that many alternatives, modifications, and
variations will be apparent to those skilled in the art in light of
the foregoing description. Accordingly, it is intended to embrace
all such alternatives, modifications, and variations as fall within
the spirit and broad scope of the appended claims.
* * * * *