U.S. patent application number 15/295624 was filed with the patent office on 2017-02-02 for air management system for under-hood heat control.
The applicant listed for this patent is Enviro-Cool, Inc.. Invention is credited to Edward M. Murray, George R. Sturmon.
Application Number | 20170030256 15/295624 |
Document ID | / |
Family ID | 39345079 |
Filed Date | 2017-02-02 |
United States Patent
Application |
20170030256 |
Kind Code |
A1 |
Sturmon; George R. ; et
al. |
February 2, 2017 |
AIR MANAGEMENT SYSTEM FOR UNDER-HOOD HEAT CONTROL
Abstract
A system for removing heat from the engine compartment (9) of a
heavy duty truck. A first ventilating system removes heat from the
radiator. It is isolated from a second ventilating system that
removes heat from the engine compartment. The first system takes
heat from the radiator through a plenum by centrifugal squirrel
cage blowers, and is directs it out to ambient by ductwork. The
second system draws ambient air generally from back to front of the
engine compartment, preferably by cowl induction, without the use
of ram air from the vicinity of the radiator. The exits of the two
systems are into a slip stream of the heavy duty truck, and the
exit of the second ventilating system is into a slip stream of the
first, to scavenge air out of the engine compartment.
Inventors: |
Sturmon; George R.; (St.
Charles, MO) ; Murray; Edward M.; (Fenton,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Enviro-Cool, Inc. |
Sullivan |
MO |
US |
|
|
Family ID: |
39345079 |
Appl. No.: |
15/295624 |
Filed: |
October 17, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14247069 |
Apr 7, 2014 |
9470135 |
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15295624 |
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13590616 |
Aug 21, 2012 |
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14247069 |
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12427400 |
Apr 21, 2009 |
8556013 |
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13590616 |
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11932393 |
Oct 31, 2007 |
7537072 |
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12427400 |
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PCT/US07/83190 |
Oct 31, 2007 |
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12427400 |
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60863740 |
Oct 31, 2006 |
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60863740 |
Oct 31, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60Y 2200/14 20130101;
B60K 11/08 20130101; B60Y 2200/142 20130101; F01P 11/10 20130101;
F01P 1/06 20130101; F01P 2001/005 20130101 |
International
Class: |
F01P 11/10 20060101
F01P011/10; B60K 11/08 20060101 B60K011/08 |
Claims
1. A vehicle capable of on-road highway travel, the vehicle
comprising an operator compartment; an engine compartment, the
engine compartment being defined at least in part by a raisable
hood having a top and sides; an engine in the engine compartment; a
radiator, the radiator receiving coolant from the engine; a first
ventilating system downstream of the radiator, the first
ventilating system comprising ducting having an exhaust exit to
ambient through the hood and at least one electric or hydraulic fan
adapted to draw air through the radiator, through the ducting, and
out the exhaust exit of the first ventilating system, the first
ventilating system being constructed to prevent air drawn through
the radiator from entering the engine compartment; and a second
ventilating system constructed to remove heat from the engine
compartment, the second ventilating system being constructed to
flow ambient air into a rear part of the engine compartment and to
exhaust air heated by the engine compartment out of an exhaust exit
toward a forward part of the engine compartment through the
hood.
2. The vehicle of claim 1 wherein the second ventilating system
further comprises air induction structure on at least one of the
top or sides of the engine compartment, the air induction structure
being adapted to flow ambient air into the engine compartment when
the vehicle is moving forward.
3. The vehicle of claim 1 wherein the exhaust exit of the second
ventilating system is positioned in a low pressure area of the
first ventilating system, the system being so constructed and
arranged that exhaust air from the first ventilating system draws
air out the exit of the second ventilating system.
4. The vehicle of claim 1 wherein the vehicle has a gross vehicle
weight of at least 6350 kilograms and is capable of a highway speed
of ninety-seven kilometers per hour.
5. The vehicle of claim 4 wherein the vehicle is a heavy duty truck
having a gross vehicle weight of at least 11,794 kilograms.
6. The vehicle of claim 5 wherein the vehicle is a vocational heavy
duty truck adapted for off-road use as well as on-road highway
travel.
7. The vehicle of claim 5 wherein the vehicle is a tractor portion
of a tractor-trailer over-the-road rig.
8. The vehicle of claim 1 wherein the second ventilating system
comprises an air outlet in a wall of the engine compartment.
9. A vehicle capable of on-road highway travel, the vehicle
comprising an operator compartment; an engine compartment; a hood
defining at least a part of the engine compartment, the hood being
rotatably mounted to a body of the vehicle, an engine in the engine
compartment; a radiator in front of the engine, the radiator
receiving coolant from the engine; a ventilating system behind the
radiator, the ventilating system comprising ducting having an
exhaust exit to ambient through the hood, and at least one powered
fan adapted to draw air through the radiator, through the ducting,
and out the exhaust exit, the ducting comprising a first section
fixed with respect to the radiator and a second section attached to
the hood.
10. The vehicle of claim 9 further comprising a gasket between the
first section and the second section of the ducting.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of pending U.S.
Non-Provisional application Ser. No. 14/247,069, filed Apr. 7,
2014, which is a continuation of U.S. Non-Provisional application
Ser. No. 13/590,616, filed Aug. 21, 2012, now abandoned, which is a
continuation of U.S. Non-Provisional application Ser. No.
12/427,400, filed Apr. 21, 2009, now U.S. Pat. No. 8,556,013 which
is a continuation of U.S. Non-Provisional application Ser. No.
11/932,393, filed Oct. 31, 2007, now U.S. Pat. No. 7,537,072, and
PCT/US07/83190 filed Oct. 31, 2007, and is related to and claims
the benefit of U.S. Provisional Application 60/863,740, filed Oct.
31, 2006, the disclosures of all which are hereby incorporated by
reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] This invention relates to systems for reducing temperatures
under the hood of a vehicle. It has particular, but not exclusive,
application to such systems for use in a heavy duty truck, more
particularly to the tractor portion of a tractor-trailer rig. Heavy
duty trucks are typically over-the-road and vocational vehicles
considered as weight class 4 to 8. Class 4 is generally considered
to include vehicles with a gross vehicle weight of 14,001 lb to
16,000 lb (6350 kg to 7257 kg). The invention is particularly
useful with weight class 6 to 8 vehicles, most particularly class 7
to 8 vehicles. Class 6 includes vehicles with a gross vehicle
weight of 19,501 lb to 26,000 lb (8846 kg to 11,793 kg). Class 7
vehicles have a gross vehicle weight of 26,001 lb to 33,000 lb
(11,794 kg to 14,969 kg).
[0004] Vocational heavy duty trucks are adapted for various
off-road jobs such as concrete mixer trucks, log-hauling trucks and
other trucks which carry heavy loads and are required to operate
over rough and uneven ground under off-road conditions. Such trucks
are generally also capable of on-road highway travel.
[0005] The internal combustion engine of a heavy duty truck
produces great quantities of heat. Heat is taken from the engine
block by a liquid coolant system, including a radiator spaced in
front of the engine block. The heat is dissipated by natural
convection, primarily by air flow caused by motion of the vehicle,
and by the air which is blown through the radiator and over the
engine by an axial fan. In most trucks, the axial fan is run
directly from the engine crank shaft, through a clutch. In other
vehicles, the fan is electric. In either, the efficiency of the fan
is relatively low, frequently on the order of forty percent. This
is caused in part by the natural inefficiency of the fan itself.
The short distance between the fan and the engine block is also a
factor; the engine block forms a natural barrier to air flow and
creates a dead space between the fan and the engine block in which
positive pressure tends to prevent air flow. A heavy duty truck
engine may produce on the order of 1.5 million BTUs (1.6 million
kilojoules) an hour at a speed of sixty miles per hour (97 km/hr),
producing less than twelve miles per gallon (5 km/I) of fuel usage,
and may utilize up to a thirty-two inch (0.8 m) diameter fan
nominally pulling 9,500 cubic feet (270 cubic meters) per minute to
disperse the heat put out by the radiator. It is estimated that
roughly one-third of the output of the engine is utilized to propel
the truck, one-third is in the heated exhaust (as heat and unburned
fuel), and one-third must be handled by the cooling system.
[0006] In addition to the heat carried from the engine block to the
radiator by the coolant, the engine block itself radiates
substantial heat, estimated to be up to about 20,000 BTUs (22,000
kJ) an hour at highway speeds.
[0007] Recently, large diesel trucks have begun to include exhaust
gas recirculation (EGR) systems. Trucks equipped with engines over
250 horsepower (186 kW) have consequently begun to experience
severe under-hood heat problems. The EGR system recirculates a
portion (typically about 15%-30%) of the exhaust gas to the engine
air intake. Because the exhaust gas has a temperature of about
1200.degree. F. to about 1500.degree. F. (about 650.degree. C. to
about 815.degree. C.), it is cooled to about 600.degree. F.
(315.degree. C.) by running it through an EGR heat exchanger before
introducing it into the cylinders of the engine. The EGR system
adds about thirty percent to the cooling system heat load, about
150,000 BTUs (160,000 kJ) per hour, most of which must be dispersed
by the radiator. Because much of this heat is directed back into
the engine compartment, under-hood heat loads are dramatically
increased. The EGR system itself also radiates heat directly into
the engine compartment.
[0008] Other auxiliary devices are run by the engine and generate
further heat. For example, an air compressor is required for
operation of brakes and other components. The air compressor may
have a surface temperature on the order of 250.degree. F.
(121.degree. C.).
[0009] To meet environmental standards and to increase efficiency,
a number of other devices have been added to the engine. A
turbocharger, powered by the exhaust gasses, generates further
heat, estimated to be on the order of 32,000 BTUs (34,000 kJ) per
hour. The turbocharger may have an operating surface temperature of
about 800.degree. F. to 1200.degree. F. (425.degree. C. to
650.degree. C.).
[0010] The additional heat produced under the hood of a modern
heavy duty truck has raised temperatures under the hood to
unacceptable levels. The additional heat and temperature reduce the
lives of components in the engine compartment and reduce engine
efficiency. They sometimes melt plastic components and overheat
fluids in the engine compartment. The heat also can transfer into
the vehicle operator cab and can make both the air temperature in
the cab and surface temperatures on the floor and front wall of the
cab uncomfortably high. Attempts to enlarge the radiator, by
repositioning it, tilting it, or splitting it, have not been
sufficient. Enlarging the fan is likewise impractical and would
increase the power requirements for running it.
[0011] A modern heavy duty truck requires aerodynamic design
considerations that sometimes make the hood design smaller. Packing
more equipment in the engine compartment further makes airflow more
difficult. All of these considerations require a completely new
approach to under-hood air management.
[0012] Various attempts have been made to solve somewhat similar
problems with automobiles and off-highway vehicles. For example,
Charles, U.S. Pat. Nos. 4,979,584 and 5,495,909 disclose an
automotive engine bay ventilation system using ram air through
openings around the radiator of a transverse-engine automobile.
Likewise, Corwin et al., U.S. Pat. No. 6,216,778, discloses a
cooling system for an off-highway vehicle which is stationary or
moves at very low ground speed. These systems are not easily
adaptable to the needs of a heavy duty truck.
BRIEF SUMMARY OF THE INVENTION
[0013] Briefly stated, the present invention provides a system for
removing heat from the engine compartment of a vehicle by isolating
heat from the radiator from the engine compartment (above and to
the sides of the engine block). The invention provides a new design
which separates the heat loads and provides separate exhaust exits,
but allows the systems to operate together or separately as
needed.
[0014] Heat from the radiator is taken from a plenum behind the
radiator, preferably by centrifugal squirrel cage blowers, and is
directed out of the engine compartment, rather than against the
engine block. The blowers are preferably controlled
thermostatically to allow some or all of the blowers to operate as
needed. The use of predictive computer control of the blowers is
also contemplated.
[0015] The engine block and its associated devices (such as the EGR
valve and the turbocharger) are cooled by a separate system which
draws ambient air generally from back to front of the engine
compartment, preferably by cowl induction, without the use of ram
air from the vicinity of the radiator.
[0016] Both the radiator ventilating system and the engine
compartment ventilating system preferably exit to ambient through
side walls of the engine compartment, near the front of the engine
compartment. The exits are preferably configured to exhaust hot air
into the slip stream of the truck, which tends to draw air from the
system. Further, the exit of the engine compartment ventilating
system is preferably behind the exit of the radiator ventilating
system and is configured to utilize the flow of air from the
radiator ventilating system to ambient to draw air out of the
engine compartment. Air flow around each exit is preferably
primarily laminar.
[0017] The systems of the invention may include one or more
standard radiator, plenum and blower packages sized for particular
classes of vehicles or engine sizes. It may also include a standard
cowl induction system also sized for particular classes of vehicles
or engine sizes. Ducting for each system, however, is likely to be
dependent on particular vehicle designs, including such
considerations as available space in the engine compartment,
internal configuration of the engine compartment and placement of
engine components inside the engine compartment affecting air flow
within the engine compartment, combustion air intake configuration
of the engine, and air flow patterns around the outside of the
engine compartment.
[0018] The foregoing and other objects, features, and advantages of
the invention as well as presently preferred embodiments thereof
will become more apparent from the reading of the following
description in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0019] In the accompanying drawings which form part of the
specification:
[0020] FIG. 1 is a schematic sectional view in side elevation of an
internal combustion engine compartment in a heavy duty truck,
modified in accordance with one embodiment of the present
invention.
[0021] FIG. 2 is a view in top plan, showing air flow through a
part of an illustrative embodiment of the system of FIG. 1.
[0022] FIG. 3 is a view in rear elevation, showing an illustrative
radiator cooling system package of the present invention.
[0023] FIG. 4 is a view in side elevation of the package of FIG.
3.
[0024] FIG. 5 is a view in perspective of parts of the system of
FIGS. 2-4, taken along line 5-5 of FIG. 2.
[0025] FIG. 6 is a view in perspective of an engine compartment air
outlet of the system of FIGS. 2-5.
[0026] FIG. 7 is a schematic view in perspective showing a cowl
induction scoop in accordance with an embodiment of another part of
the invention.
[0027] FIG. 8 is a view in perspective of an over-the-road truck
incorporating the embodiment of FIGS. 1-7.
[0028] Corresponding reference numerals indicate corresponding
parts throughout the several figures of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] The following detailed description illustrates the invention
by way of example and not by way of limitation. The description
clearly enables one skilled in the art to make and use the
invention, describes several embodiments, adaptations, variations,
alternatives, and uses of the invention, including what is
presently believed to be the best mode of carrying out the
invention.
[0030] As shown in the FIGURES, an internal combustion engine in a
large heavy duty truck 2 (FIGS. 1 and 8) includes the engine block
3, air intake 5, and a radiator 7 which cools coolant circulated
from inside the engine block 3 through passages 8. All of these
components of the engine are contained in an engine compartment 9
having a front 10 (usually at or just ahead of the radiator), a top
11, and sides 12. The top and much of the sides are generally
formed as a raisable hood 13 (FIG. 8), which is typically hinged to
the body of the truck in the area of a lower front end of the
truck. At the back of the engine compartment 9, a fire wall 14
separates the engine compartment from an operator cab 15. A
turbocharger 16, exhaust piping 17, and an air compressor 19 add to
the heat load in the engine compartment 9. In a conventional heavy
duty truck, the heat radiated by the engine and the heat blown back
into the engine compartment by an axial fan raise the temperature
of the engine compartment. In recent years, an exhaust gas
recirculation (EGR) system, including an EGR valve 20, adds further
to the heat load on the radiator and the temperature in the engine
compartment, particularly because the EGR system typically
circulates on the order of 15% to on the order of 30% of the hot
exhaust gas back into the engine. The total heat load in the engine
compartment 9 of a modern heavy duty truck 2, other than that
emitted by the radiator 7, is estimated to be about 60,000 BTUs
(63,000 kJ) per hour.
[0031] This illustrative embodiment of the invention removes the
axial fan and replaces it with an isolated radiator ventilating
system 21 including a plenum 23 mounted to the back of the radiator
7, preferably in sealing relationship with the radiator. Therefore,
all ram air reaching the radiator 7 when the truck is in forward
motion is directed through the radiator 7 and is concentrated in
the plenum 23. Mounted on the plenum 23, preferably on its back,
are multiple motors 25 driving squirrel cage (centrifugal) fans 27
behind the plenum 23. The squirrel cage fans 27 draw heated air
axially from the plenum and redirect the air 90.degree. to
discharge it outwardly (laterally) into air ducts 43 as described
hereinafter.
[0032] If desired, the back side of the plenum 23, the fans 27, and
air ducts 43 may be provided with insulating material in the form
of a coating or a separate insulative layer or barrier. As
indicated by broken line 33, this arrangement effectively shields
the engine, its components, and add-ons in the engine compartment 9
from the approximately 650,000 BTUs (700,000 kJ) or more per hour
being dissipated to ambient by the radiator 7 when the truck 2 is
at highway speed. Exhausting the heated air in this fashion will
remove the constant reinforcement of heat into the engine
compartment. The problem of heat generation in the engine
compartment is thus reduced to the 60,000 BTUs (63,000 kJ) per hour
generated under the hood by the turbocharger 16, EGR 20, engine
block 3, and other engine compartment components.
[0033] The motors 25 are operated thermostatically, with individual
motors or groups of motors being operated only when required.
Predictive algorithms for controlling the operation of the cooling
fans 27 will be apparent to those skilled in the art. Such
algorithms may include such factors as engine coolant temperature,
rate of rise of coolant temperature, engine surface or oil
temperature, engine compartment temperature, ambient temperature,
engine speed, and truck speed, for example.
[0034] The arrangement thus far described has the further
advantages that it reduces the power (estimated to be sixty-five
horsepower) required to operate a bladed fan. This could provide
considerable fuel savings (7-9%). It also eliminates the fan clutch
that has shown to be a high maintenance item. The electric squirrel
cage fan blowers 27 are far more efficient in removing heat from
the radiator 7 than the bladed axial fan. Because plural fan
blowers 27 are preferably provided, air flow can be stepped up and
down and controlled more effectively by controlling which blowers
are powered. Moreover, the fan blower's DC motor can become a
generator when it is off and free wheeling from ram air, thereby
charging the truck's batteries.
[0035] The isolated radiator ventilating system 21 described thus
far may be implemented in a standard package 35; a few such
packages will accommodate a wide range of heavy duty trucks. The
package 35 may include a radiator 7, a plenum 23, and a plurality
of fans 27. Such a package may include a radiator 7 having a height
of from about two to three feet (0.5 m to one meter) and a width of
about 18'' to about 36'' (0.4 m to one meter), with a plenum 23
about one to two inches (2.5 cm to 5 cm) deep, sized to fit the
back of the radiator. The package 35 may be mated to a ductwork
system which is tailored to a particular truck style to create both
the radiator ventilating system 21 and a part of an engine
compartment ventilating system.
[0036] As shown in FIGS. 2-7, for example, a radiator and plenum
33'' (84 cm) tall by 22'' (56 cm) wide may be provided as a
standard package 35. The radiator 7 is illustratively 6'' (15 cm)
deep with a flange 36 extending around its periphery, and the
plenum is 1.25'' (3 cm) deep and includes a peripheral flange 37
attached to the flange 36 of the radiator. As best seen in FIG. 3,
attached to the plenum are six squirrel cage fans 27A, 27B, 27C,
27A', 27B', and 27C', each including a motor 25A, 25B, 25C, 25A',
25B', and 25C', respectively, a squirrel cage impeller 26, and a
housing 38 having a side outlet 39. Illustratively, each fan draws
530 cfm (15 cubic meters per minute) of air, and has a brushless
3'' (7.6 cm) diameter, 3,000 rpm, 24 volt DC motor. The draws of
the centrifugal fans are sized for particular applications. The
housing 38 of each fan 27 is about 9'' wide by about 10'' tall by
about 4'' deep (22.5.times.25.5.times.10 cm), and each housing has
a 4'' (10 cm) square outlet 39. It will be seen that the upper left
fan 27A and the two lower right fans 27B' and 27C' have the same
handedness (clockwise rotation), and that the upper right fan 27A'
and the two lower left fans 27B and 27C have the opposite
handedness (counterclockwise rotation). The lowermost fans 27C and
27C' have extended outlets 39', exiting between the exits of the
two fans above them, so that all of the outlets on each side of the
plenum align vertically to form a 12'' by 4'' (30.times.10 cm)
rectangular outlet 40 on each side of the package.
[0037] As shown particularly in FIG. 3, each motor 25 is
individually electrically connected to a control system 41 having
inputs, illustratively T1 representing coolant temperature, T2
representing engine compartment temperature, RPM representing
engine speed, MPG representing instantaneous or integrated fuel
consumption, and MPH representing vehicle speed. These inputs
permit the controller to operate the fans 27 individually or in
groups in order to insure that engine temperature remains in a
desired range, in accordance with algorithms which will be easily
applied by those skilled in the art. In simplest form, the fans are
turned on in pairs as the temperature of the coolant, represented
by T1, exceeds predetermined values and turned off when T1 drops
below a second value. They also permit operation of the fans in
unusual circumstances when T2 exceeds a predetermined value while
T1 is relatively low, to cool the engine compartment 9, as
described hereinafter. Inputs RPM, MPG and MPH permit predictive
operation of some or all of the fans 27, to begin drawing ram air
through the radiator to provide cooling while the temperature of
the coolant is still rising. The controller will also make possible
the regenerative use of the fans to charge the battery of the truck
when ram air is flowing through them and they are not
energized.
[0038] This radiator cooling package 35 is mated to a duct system
43. At least the rearward portion of duct system 43 is preferably,
but not necessarily, mounted on the inside of the hood 13. The
juncture between the hood-mounted ducts 43 and the package 35 may
be sealed in any known manner. For example, as shown solely in
FIGS. 2 and 3, the rectangular outlet 40 of the package 35 may
terminate in a compound bevel 42 having a gasket on its open
(upper) face to seal with a complementarily sloped bevel on the
hood-mounted ducts. This arrangement permits unimpeded opening of
the hood 13 and seals the duct system 43 to the package 35 when the
hood 13 is closed. Alternatively, an end section of the package
duct or the hood-mounted duct may be longitudinally moveable via an
automatic or manual operating mechanism to mate with the other
section of the duct. Likewise, the duct system may be permanently
attached to the radiator ventilating system package 35 and may
simply align with an opening in each side 12 of the hood.
[0039] The duct system 43 of this illustrative embodiment includes
a curved outside wall 44 mated to a forward wall of the outlet 40
and a curved inside wall 45 mated to a rearward wall of the outlet
40. The outside wall 44 terminates in a generally flat vertical
rectangular opening 46 having a peripheral edge 47 aligned with a
rectangular opening of similar size in the side wall 12 of the hood
of the truck. It will be noted that the shape of this opening will
be to some extent dictated by the contour of the truck's hood. In
this embodiment, the opening 46 is substantially twelve inches (30
cm) tall, the same height as the outlet 40 of the radiator
ventilating package. The inside wall 45 of the duct system 43 is
spaced four inches from the outside wall 44 along a curved inlet
portion attached to the outlet 40. When the inside wall 45 reaches
a position opposite the opening 46, it then curves gently outward
into the rear edge 47 of the opening 46. The outside and inside
walls 44 and 45 are connected to each other by upper and lower
horizontal walls 48. It will be seen that the walls 44, 45 and 48
form a smooth open channel guiding air exhausted from the radiator
ventilating system 21 into the ambient slip stream of the heavy
duty truck when the truck is moving forward.
[0040] To cool the engine block 3 and its associated under-hood
components in the engine compartment, a separate engine compartment
ventilating system 51 is provided. The second ventilating system 51
in this illustrative embodiment is sized to remove the
approximately 60,000 BTUs (63,000 kJ) per hour of heat produced in
the engine compartment. In brief, the 60,000 BTUs (63,000 kJ) per
hour can be effectively controlled by cowl air induction
strategically located on top of the hood, using the high pressure
area at the windshield to flow cool ram air into the engine
compartment and causing the engine compartment air to exit through
hood side ducts arranged to draw air into a low pressure area
adjacent the exit of radiator fan air into ambient. As shown in
FIGS. 1, 2, and 8, the engine compartment ventilating system 51
includes an induction cowl 53 in front of the windshield 55 of the
truck 2. Cowl induction systems have long been used in race cars,
but their use in a heavy duty truck is believed to be novel. As is
known, the rear 56 of the cowl 53, adjacent the windshield, is open
to the engine compartment. At operating speeds, even relatively low
operating speeds, air is compressed at the base of the windshield
55 and is drawn into the engine compartment through the rear of the
cowl 53 as shown at 56.
[0041] Air within the engine compartment 9 is expelled through air
exit ducts 57 mounted on the inside walls 45 of the ducts 43, as
shown particularly in FIGS. 2-6. As seen particularly in FIGS. 3
and 4, the exit ducts 57 are in this embodiment about nine inches
high and three inches wide (23 cm.times.8 cm) at their mouths 59,
and are vertically centered on the inside walls 45 of the ducts 43.
The inside walls 45 of the ducts 43 include rectangular openings 61
into which exit ducts 57 empty. Each exit duct 57 includes a
vertical inner wall 63, which curves to meet the inside wall 45 at
its rear, and upper and lower horizontal walls 65 which join the
inner wall 63 of the exit duct to the inner wall 45 of the radiator
ventilating duct 43. Although the exit ducts 57 are entirely open
to ambient, they are also in the slip stream of the hot air being
forcibly expelled through the exits 46 of the radiator ventilating
system 21 and in the slip stream of the truck. Therefore, air is
further drawn out of the engine compartment by a venturi effect
created by the flow of hot air from the plenum through the exits
46. Forward movement of the truck 2 will also create a slip stream
tending to pull hot air from both the exits 46 of the ducts 43 and
the exits 57 from the engine compartment 9. In the unlikely
circumstance that the engine compartment were to reach an
undesirable temperature while the fans 27 are turned off, the fan
motors 25 can be turned on to draw air through the ducts 43 and
suck air out of the engine compartment 9.
[0042] As shown in FIGS. 1 and 2, ram air represented by arrows R
at the front of the heavy duty truck, is directed entirely through
the radiator 7 and into the radiator ventilating system 21, while
the engine compartment 9 is cooled by cowl induction air,
represented by the arrows C, moving generally from the rear to the
front of the engine compartment. Movement of air from back to front
of the engine compartment 9 also removes heat from the area of the
fire wall 14 and reduces the heat load on the cab 15.
[0043] Appropriate guards are preferably provided over all
accessible openings. Numerous such guards are well known and may
include, for example, thin horizontal vanes.
[0044] Numerous variations in the vehicle under-hood temperature
control system of the invention, within the scope of the appended
claims, will occur to those skilled in the art in light of the
foregoing disclosure. Merely by way of example, other closed
systems for cooling the radiator may be provided. As previously
noted, the configuration and size of the exhaust ducts will of
course be varied somewhat to accommodate the geometries and engine
compartments of different trucks, as exemplified in FIG. 8. The
engine compartment cooling system may include other air inlets in
the top or sides of the engine compartment, including induction air
systems and ram air inlets. Preferably, the air inlets are spaced
away from the front of the truck. Ram air inlets in general are not
presently preferred except for use in a cab-over design. The engine
compartment cooling system may include other exhaust ports and may
include powered fans of various sorts if desired. For example,
powered fans could be provided at the outlets of the engine
compartment ventilating system. Many temperature-controlled systems
are known or easily adapted for controlling the operation of the
fans, or for moving baffles and the like. In the illustrative
embodiment, other motors, including for example variable speed
motors and, less desirably, hydraulic motors may be used to operate
the squirrel cage fans; the size and number of fans may be altered
as required for an application; and the shapes, numbers and sizes
of the blades of the squirrel cage fan may be changed to suit the
requirements of particular applications. Electric fan motors may be
driven from different voltages, illustratively 12V to 42V. The
bottom of the engine compartment may be enclosed for aerodynamic or
internal air flow purposes. These variations are merely
illustrative.
[0045] As various changes could be made in the above constructions
without departing from the scope of the invention, it is intended
that all matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
[0046] All patents and patent applications mentioned herein are
hereby incorporated by reference.
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