Note: Descriptions are shown in the official language in which they were submitted.
CA 02623578 2008-02-28
FLEX STACK
BACKGROUND
Semi-trailer trucks typically include at least one vertical exhaust stack
positioned rear
of or alongside the truck cab. The vertical exhaust stack is normally secured
to a side or rear
surface of the truck cab. Other portions of the exhaust system, such as
exhaust
after-treatment devices, are often attached to the vehicle frame. Because the
truck cab is
moveably mounted to the frame of the vehicle, when the semi-trailer truck is
in motion, there
is necessarily relative movement between the exhaust stack and those exhaust
system
components that are mounted to the frame.
Some vehicles include an exhaust system support assembly that allows for a
certain
amount of relative motion between the exhaust stack and the vehicle cab. Thus,
the exhaust
stack is free to move with the frame-mounted exhaust system components free
from the
restriction that would result from rigidly mounting the exhaust stack to the
vehicle cab.
Nonetheless, these support assemblies often restrict the motion of the cab at
the extreme
positions of cab movement during jounce and rebound. This restriction can
cause the
exhaust system support assembly to be torn away from the truck cab when the
truck cab
moves beyond the limits to which the support assembly is designed to
accommodate.
Other known exhaust systems include a section of flexible hose between the
frame-mounted and cab-mounted portions of the exhaust system. The flexible
hose provides
a conduit from the frame-mounted portion to the cab-mounted portion, while
allowing for
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relative motion therebetween. Still, such exhaust systems are not without
disadvantages. For example, many vehicle operators take great pride in the
appearance of their vehicles, often outfitting the vehicles with highly
polished
chrome exhaust system components. For these systems, a flexible hose, which
can not be chromed and polished to match the other exhaust components,
detracts from the overall appearance of the vehicle.
Operators of semi-trailer trucks would find desirable an exhaust
system assembly that allows for relative motion between the cab-mounted
exhaust stack and the frame-mounted exhaust components during jounce and
rebound, while providing an aesthetically pleasing appearance.
SUMMARY
According to one aspect of the present invention, there is provided a
flexible exhaust stack for a vehicle having a cab movably mounted to a frame
and
exhaust system components fixedly mounted to the frame so that relative motion
lo occurs between the cab and the frame-mounted exhaust system components, the
flexible exhaust stack comprising: (a) a pipe having an inlet end and a
discharge
end, the pipe being mountable to the cab; (b) a collar secured to an interior
portion of the pipe between the inlet end and the discharge end; (c) a
flexible
hose at least partially disposed within the pipe, a discharge end of the
flexible
hose being secured to the collar and disposed in fluid communication with the
discharge end of the pipe, an inlet end of the flexible hose being capable of
receiving exhaust gases discharged from the exhaust system, wherein the
flexible
hose allows for relative motion between the cab and the exhaust system; and
(d)
a heat shield at least partially surrounding the pipe.
According to another aspect, there is provided a flexible exhaust
stack for a vehicle having a cab movably mounted to a frame and exhaust system
components fixedly mounted to the frame so that relative motion occurs between
the cab and the frame-mounted exhaust system components, the flexible exhaust
stack comprising: (a) a pipe having an inlet end and a discharge end, the pipe
being mountable to the cab; (b) a collar secured to an interior portion of the
pipe
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between the inlet end and the discharge end; (c) a flexible hose at least
partially
disposed within the pipe, a discharge end of the flexible hose being secured
to the
collar and disposed in fluid communication with the discharge end of the pipe,
an
inlet end of the flexible hose being capable of receiving exhaust gases
discharged
from the exhaust system, the flexible hose allowing for relative motion
between
the cab and the exhaust system, wherein the pipe is mounted to the cab, and
the
inlet end of the hose is disposed in fluid communication with the frame-
mounted
exhaust system components so that the exhaust stack receives exhaust gases
from the frame-mounted exhaust system components and discharges the exhaust
lo gases from the discharge end of the pipe.
According to a further aspect, there is provided a flexible exhaust
stack for a vehicle having a cab movably mounted to a frame and an exhaust
system components fixedly mounted to the frame so that relative motion occurs
between the cab and the frame-mounted exhaust system components, the flexible
exhaust stack comprising: (a) an inlet pipe having an inlet end and a
discharge
end; (b) a discharge pipe having an inlet end and a discharge end, the inlet
end of
the discharge pipe being attached to the discharge end of the inlet pipe to
define a
joint therebetween so that the inlet pipe is in fluid communication with the
discharge pipe; (c) a collar disposed within at least one of the inlet pipe
and the
2 o discharge pipe, the collar being secured to the at least one of the inlet
pipe and
the discharge pipe at the joint; and (d) a flexible hose at least partially
disposed
within the inlet pipe, a discharge end of the hose being secured to the collar
so
that the discharge end of the hose is in fluid communication with the
discharge
end of the discharge pipe, an inlet end of the hose being in fluid
communication
with the exhaust system so that the exhaust stack receives exhaust gases from
the exhaust system and discharges the exhaust gases from the discharge end of
the discharge pipe, wherein the flexible hose allows for relative motion
between
the cab and the exhaust system.
This summary is provided to introduce a selection of concepts in a
simplified form that are further described below in the Detailed Description.
This
summary is not intended to identify key features of the claimed subject
matter, nor
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is it intended to be used as an aid in determining the scope of the claimed
subject
matter.
DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this
invention will become more readily appreciated by reference to the following
detailed description, when taken in conjunction with the accompanying
drawings,
wherein:
FIGURE 1 is a side view of an exemplary embodiment of a disclosed
flexible exhaust stack mounted to a vehicle according to the present
disclosure;
FIGURE 2 is an isometric cutaway view of a flexible exhaust stack
insert of the flexible exhaust stack shown in FIGURE 1;
FIGURE 3 is a partial cross-sectional view of the flexible exhaust
stack shown in FIGURE 1; and
FIGURE 4 is a partial cross-sectional view of a first alternate
embodiment of the flexible exhaust stack shown in FIGURE 1.
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DETAILED DESCRIPTION
Embodiments of the present invention will now be described with reference to
the
drawings where like numerals correspond to like elements. Embodiments of the
disclosed
subject matter and appended claims are generally directed to an exhaust system
suitable for
use with vehicles such as Class 8 trucks. More particularly, the disclosed
subject matter and
appended claims are directed to a flexible exhaust stack that allows for
relative motion
between the cab of the vehicle, to which the exhaust stack is mounted, and the
vehicle frame,
to which other exhaust system components are mounted.
Although exemplary embodiments of the present disclosure and appended claims
will
be described hereinafter with reference to Class 8 trucks, it will be
appreciated that aspects of
the claimed subject matter have wide application, and therefore, may be
suitable for use with
many types of vehicles that produce exhaust gases. Accordingly, the following
descriptions
and illustrations herein should be considered illustrative in nature, and
thus, not limiting the
scope of the present disclosure, as claimed.
In the following description, numerous specific details are set forth in order
to
provide a thorough understanding of exemplary embodiments of the disclosed and
claimed
subject matter. It will be apparent to one skilled in the art, however, that
many embodiments
of the claimed subject matter may be practiced without some or all of the
specified details.
Although a vehicle such as depicted in FIGURE 1 represents one of the possible
applications
for the disclosed and claimed subject matter, it should be appreciated that
aspects of the
subject matter transcend any particular type of vehicle to include any vehicle
having an
exhaust system in which a flexible component of the exhaust system would be
advantageous.
As shown in FIGURE 1, a vehicle 10, such as a Class 8 truck, includes a frame
12
supported by a plurality of wheels 14 rotatably mounted thereto. A cab 16 is
moveable
secured to the frame 12 by a suspension system to provide a sheltered
enclosure from which
an operator controls the vehicle 10. The suspension system provides a smoother
ride for the
vehicle operator by allowing relative motion between the cab 16 and the frame
12 so that the
operator is isolated from some of the motion of the frame 12 during vehicle
operation.
An internal combustion engine (not shown) is mounted to the frame 12 to drive
the
wheels 14 of the vehicle 10. During operation, the internal combustion engine
produces
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exhaust gases, which are at least partially discharged to the environment
through an exhaust
system 18.
The exhaust system 18 includes a frame-mounted portion 20 in fluid
communication
with the engine to receive exhaust gases discharged from the engine. Various
aftertreatment
devices, such as mufflers and diesel particulate filters (DPF's), are
optionally included in the
frame-mounted portion 20 of the exhaust system 18. One or more rigid pipes
form a
discharge end 22 of the frame-mounted portion 20, through which exhaust gases
from the
engine are discharged.
The exhaust system 18 further includes a cab-mounted exhaust stack 24 with an
inlet
end 26 and a discharge end 28. The inlet end 26 of the exhaust stack 24
receives exhaust
gases from the frame-mounted portion 20. The exhaust gases pass through the
exhaust
stack 24 and are discharged from the discharge end 28 into the atmosphere.
Because the
exhaust stack 24 is mounted to the cab 16, relative movement occurs between
the exhaust
stack an the frame-mounted portion 20 as the cab 16 moves relative to the
frame 12 during
vehicle operation.
Referring to FIGURE 2, the exhaust stack 24 includes a flexible insert 30 that
provides a flexible connection between the frame-mounted portion 20 of the
exhaust
system 18 and the exhaust stack. The insert 30 includes an annular collar 32
and a flexible
hose 34 having a discharge end 46 and an inlet end 48. A suitable flexible
hose 34 is capable
of stretching, compressing, and otherwise deflecting such that the hose does
not unduly
restrict the movement of the components to which it is coupled when relative
motion occurs
therebetween. Additionally, a suitable hose can accommodate relative motion
that occurs
between exhaust components during vehicle operation without damaging the
components,
the hose, or the structure to which they are mounted, and without causing
leaks in the exhaust
system.
The collar 32 is secured to the discharge end 46 of the flexible hose 34 by a
band
clamp 35, mechanical fasteners, high temperature adhesives, welding, or any
other suitable
method. In the disclosed embodiment, the collar 32 is formed of a heat
resistant metal, such
a stainless steel; but it should be appreciated that any material having
suitable structural
properties when subjected to hot exhaust gases may be used. Similarly, the
flexible hose 34
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is formed from a heat resistant metal, such as stainless steel; however, it
should also be
appreciated that any material having suitable structural properties at exhaust
gas
temperatures may also be used provided the material is capable of being formed
into a
flexible hose. The flexible hose may also be formed of a combination of
materials to provide
suitable attributes, such as strength, flexibility, and thermal resistance.
As shown in FIGURES 1 and 3, the exhaust stack 24 includes a generally
straight
portion of rigid pipe 36 having an inlet end 42 and a discharge end 44. The
rigid pipe 36 is
mounted to an exterior portion of the vehicle cab 16 in a substantially
vertical position.
Alternate embodiments wherein the shape and orientation of the rigid pipe vary
are also
contemplated and should be considered within the scope of the present
disclosure and the
appended claims. The illustrated embodiment also includes an optional heat
shield 38
surrounding at least a portion of the pipe 36 to increase operator safety when
in the area of
the stack 24. In addition, the illustrated embodiment includes an access
handle 40 attached
to the rigid pipe 36 or the heat shield 38 to assist with ingress to and
egress from the cab 16.
Referring now to FIGURE 3, the flexible insert 30 is disposed within the rigid
pipe 36 so that the flexible hose 34 extends toward the inlet end 26 of the
exhaust stack 24.
The insert 30 is secured to the rigid pipe 36 by welding the annular collar 32
of the insert 30
to the interior surface of the pipe 36. Alternately, the collar 32 may be
secured to the pipe
using high temperature adhesives, mechanical fasteners, interference fit, or
any other suitable
means.
The exhaust stack 24 is mounted to the vehicle cab 16, and the flexible hose
34 is
secured to the discharge end 22 of the frame-mounted portion 20 of the exhaust
system 18.
When so mounted, the frame-mounted portion 20 and the exhaust stack 24 are in
fluid
communication so that exhaust gases discharged from the discharge end 22 of
the
frame-mounted portion 20 are received by the inlet end 26 of the exhaust stack
24 and
discharged from the discharge end 28 of the exhaust stack 24 into the
atmosphere. In the
disclosed embodiment, the flexible hose 34 is removably secured to the
discharge end 22 of
the frame-mounted portion 20 with a clamp, such as a band clamp 35, however,
it should be
appreciated that welding, high temperature adhesives, mechanical fasteners,
interference fit,
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or any other suitable means for providing a fluid connection between the
flexible hose 34 and
the discharge end 28 of the frame-mounted portion 20 may be used.
As best shown in FIGURE 3, the connection between the flexible hose 34 and the
discharge end 22 of the frame-mounted portion 20 is positioned within the
exhaust stack so
that the entire flexible hose 34 is disposed within the rigid pipe 36. As a
result, the flexible
hose 34 is not visible when the exhaust stack 24 is viewed from the side of
the vehicle 10.
Thus, the disclosed exhaust stack 24 provides a flexible connection between
the
frame-mounted portion 20 of the exhaust system 18 and the cab-mounted exhaust
stack 24,
wherein all visible components, i.e., rigid pipes, heat shields, handles,
etc., can have a
common, aesthetically pleasing appearance, such as is provided by a chrome
finish, while the
flexible hose 34, which may be difficult to chrome, is hidden from view. It
should be
appreciated that embodiments in which finishes other than chrome are applied
to the exhaust
components would also enjoy an aesthetic benefit from obscuring the flexible
hose 34 from
view.
FIGURE 4 shows an alternate embodiment of the disclosed exhaust stack 24
wherein
the single rigid pipe 36 that surrounds the flexible insert 30 is replaced by
an inlet pipe 50,
which has an inlet end 51 and a discharge end 52, and a discharge pipe 54,
which also has an
inlet end 55 and a discharge end 56. The inlet end 55 of the discharge pipe 54
is flared and
sized to receive the discharge end 52 of the inlet pipe 50. A plurality of
mechanical
fasteners 66 secure the inlet pipe 50 to the discharge pipe 54. The mechanical
fasteners 66
also secure the collar 32 of the flexible insert 30 to the inlet pipe 50 and
the discharge
pipe 54 so that the flexible insert 30 is fixedly positioned within the
exhaust stack 24 with the
collar 321ocated at the joint between the inlet pipe 50 and the discharge pipe
54.
While illustrative embodiments have been illustrated and described, it will be
appreciated that various changes can be made therein without departing from
the spirit and
scope of the disclosure and the appended claims.
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