U.S. patent application number 10/316268 was filed with the patent office on 2004-06-17 for waste gate valve actuator.
Invention is credited to Lilly, Daryl A., Riley, David D..
Application Number | 20040112051 10/316268 |
Document ID | / |
Family ID | 32392943 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040112051 |
Kind Code |
A1 |
Riley, David D. ; et
al. |
June 17, 2004 |
WASTE GATE VALVE ACTUATOR
Abstract
A waste gate valve actuator is provided for use with a
turbocharger having a flexible and durable thin non-fabric
diaphragm substantially uniform in thickness. The actuator
comprises a cover and a bottom can joined at a crimp to the cover
to form an interior cavity. A piston is located in the interior of
the actuator comprising a piston cup located at an upper end and a
rod depending downward to a lower end. A spring is captured between
the piston cup and the bottom can for exerting a biasing force on
the piston. Also provided is a non-fabric durable and flexible
diaphragm of substantially uniform thickness, with a crimp end for
air tight securement within the crimp, a top, and a convoluted side
therebetween, wherein the diaphragm divides the interior of the
actuator into an upper pressure chamber and a lower chamber at
atmosphere with the piston located in the lower chamber. An air
inlet introduces a pressurized substance into the pressure chamber
whereby the introduction of a sufficient amount of the pressurized
substance will exert sufficient pressure on the diaphragm to
overcome the biasing force of the spring and force the piston
downward a sufficient distance to actuate the waste gate valve of
the turbocharger.
Inventors: |
Riley, David D.; (Creston,
IA) ; Lilly, Daryl A.; (Creston, IA) |
Correspondence
Address: |
Davis, Brown, Koehn, Shors & Roberts, P.C.
The Financial Center
Suite 2500
666 Walnut Street
Des Moines
IA
50309-3993
US
|
Family ID: |
32392943 |
Appl. No.: |
10/316268 |
Filed: |
December 11, 2002 |
Current U.S.
Class: |
60/602 |
Current CPC
Class: |
F16J 3/02 20130101; F02B
37/186 20130101; Y02T 10/144 20130101; Y02T 10/12 20130101; Y10T
428/24521 20150115 |
Class at
Publication: |
060/602 |
International
Class: |
F02D 023/00 |
Claims
1. A waste gate valve actuator for use with a turbocharger having a
flexible and durable thin non-fabric diaphragm substantially
uniform in thickness, said actuator comprising: a cover; a bottom
can joined at a crimp to said cover to form an interior cavity; a
piston located in said interior of said actuator comprising a
piston cup located at an upper end and a rod depending downward to
a lower end; a spring captured between said piston cup and said
bottom can for exerting a biasing force on said piston and said
diaphragm; a non-fabric durable and flexible diaphragm of
substantially uniform thickness, with a crimp end for air tight
securement within said crimp, a top, and a convoluted side
therebetween, wherein the diaphragm divides said interior of said
actuator into an upper pressure chamber and a lower chamber at
atmosphere with said piston located in said lower chamber; an air
inlet for the introduction of a pressurized substance into said
pressure chamber whereby the introduction of a sufficient amount of
said pressurized substance will exert sufficient pressure on said
diaphragm and said piston to overcome the biasing force of said
spring and force said piston downward a sufficient distance to
actuate the waste gate valve of the turbocharger.
2. The invention in accordance with claim 1 wherein said diaphragm
is a convoluted diaphragm.
3. The invention in accordance with claim 1 wherein said convoluted
side of said diaphragm includes strengthening ribs.
4. The invention in accordance with claim 1 wherein said diaphragm
in substantial portion is about 0.022 inches thick.
5. The invention in accordance with claim 1 wherein said diaphragm
is made entirely of a thermoset or thermoplastic fluorocarbon
material.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a waste gate valve actuator
for a turbocharger, and in particular to a waste gate valve
actuator for a turbocharger having a fabricless diaphragm with
certain other unique and advantageous properties.
[0003] 2. Background
[0004] Turbochargers are commonly used with various types of
engines for the purpose of providing a relatively high pressure
charge of a fluid or gas, like air, to an internal combustion
engine. The turbocharger operates in conjunction with the engine,
typically by channeling engine exhaust gas from the engine into a
rotateably driven compressor that in turn drives a compressor for
compressing air or fluid for return to the engine. The return flow
boosts the power of the engine, which among other things increases
the flow exhaust gas to the turbocharger
[0005] Thus, the speed of the turbocharger increases as the speed
of the engine that it supports increases. This feedback loop can
create an overload condition for either the turbocharger or the
engine. In other words, safe operation of the engine and
turbocharger requires a mechanism for the controlled release of
pressure under extreme operating conditions to prevent damage to
the system. The prior art teaches the use of a variety of devices
to limit the rotational capacity of the turbocharger compressor,
and thereby the amount of boost provided to the engine by the
turbocharger. These devices include compressor inlet control
valves, turbine bypass mechanism, blow-off valves, and waste gate
valves. In each case the operation of the various devices includes
the use of a pressure selective device divert some portion of the
exhaust gas that drives the turbocharger to an alternative
passageway.
[0006] In particular, waste gate valves open and close a passage
way that diverts some portion of the exhaust gas away from the
turbine or compressor. Thus, under load conditions that approach
excessive levels a sufficient portion of the exhaust gas that
drives the turbine flows through a bypass route thereby
interrupting the feedback loop to avert dangerous operating
conditions. In this manner, the boost pressure that the
turbocharger provides to the engine is capped at predetermined
maximum level to avoid damage to the engine or turbocharger.
[0007] Waste gate valves are controlled by a waste gate valve
actuator, which is designed to open and/or close the valve under
certain predetermined conditions. The actuator typically includes a
housing that surrounds a pressure driven piston and depending rod,
the motion of which opens and closes the waste gate valve. A
resilient diaphragm is flexibly captured within interior of the
housing. An inlet pressure source provides pressure to the actuator
in proportion to the pressure levels of the exhaust gas that feeds
the turbocharger. A spring provides selective resistance to the
pressure and under normal conditions biases the diaphragm to a
position that closes the bypass route. When the pressure builds to
a maximum predetermined level during heavy load conditions, the
pressure in the actuator overcomes the biasing force of the spring
and displaces the diaphragm a sufficient distance to move the
piston and rod enough to trigger the waste gate valve to allow the
diversion of some portion of the exhaust gas.
[0008] In operation, the waste gate actuator undergoes substantial
stress due to the nature of the conditions under which the
turbocharger operates. In addition to the normal wear and tear
associated with engines, the exhaust gases have corrosive
properties that tend to deteriorate the diaphragm. Another
important source of stress particularly on waste gate actuator
diaphragms comprises operational vibration. Vibration can cause the
edges of the diaphragm nearest to the housing to prematurely wear
through contact between the diaphragm and the housing. Perhaps even
more importantly, the repetitive operational displacement of the
diaphragm comprises a substantial influence on the deterioration
and subsequent failure of diaphragms. Thus, the diaphragm must both
be flexible and durable, which has proved a troublesome combination
for prior art designs. In particular, many prior art diaphragms for
waste gate actuators are comprised of a combination of a
proprietary fabric material like Nomex.RTM. and a thermoplastic or
rubber material. The former provides flexibility while the latter
provides durability. However, in practice even this design is
subject to failure through repetitive use. Also, the combination is
expensive and difficult to manufacture due to the combination of
the two materials and the expensive of the woven fabric like
materials. Other prior art attempts to improve the useful life of
waste gate actuator diaphragms include increasing the thickness to
improve durability, however, this comes at the expense of
flexibility. In addition, some prior art diaphragms selectively
vary the thickness of the diaphragm in order strengthen those
portions that are most susceptible to failure. This approach,
however, increases the cost and difficulty of manufacture.
[0009] Thus, a need exists for an improved diaphragm for a
turbocharger waste gate valve actuator.
SUMMARY OF THE INVENTION
[0010] An object of the present invention comprises providing a
waste gate valve actuator for use with a turbocharger having a
flexible and durable thin non-fabric diaphragm substantially
uniform in thickness.
[0011] These and other objects of the present invention will become
apparent to those skilled in the art upon reference to the
following specification, drawings, and claims.
[0012] The present invention intends to overcome the difficulties
encountered heretofore. To that end, a waste gate valve actuator is
provided for use with a turbocharger having a flexible and durable
thin non-fabric diaphragm substantially uniform in thickness. The
actuator comprises a cover and a bottom can joined at a crimp to
the cover to form an interior cavity. A piston is located in the
interior of the actuator comprising a piston cup located at an
upper end and a rod depending downward to a lower end. A spring is
captured between the piston cup and the bottom can for exerting a
biasing force on the piston. Also provided is a non-fabric durable
and flexible diaphragm of substantially uniform thickness, with a
crimp end for air tight securement within the crimp, a top, and a
convoluted side therebetween, wherein the diaphragm divides the
interior of the actuator into an upper pressure chamber and a lower
chamber at atmosphere with the piston located in the lower chamber.
An air inlet introduces a pressurized substance into the pressure
chamber whereby the introduction of a sufficient amount of the
pressurized substance will exert sufficient pressure on the
diaphragm to overcome the biasing force of the spring and force the
piston downward a sufficient distance to actuate the waste gate
valve of the turbocharger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1a shows a top view of a waste gate valve actuator for
a turbocharger.
[0014] FIG. 1b shows a side cross sectional view of the waste gate
valve actuator taken along the line A-A shown in FIG. 1a.
[0015] FIG. 2a is a bottom view of a diaphragm of the waste gate
valve actuator.
[0016] FIG. 2b is a side cross sectional view of the diaphragm
taken along the line A-A shown in FIG. 2a.
[0017] FIG. 2c is a cross sectional view of a ribbed portion of the
diaphragm taken along the line B-B shown in FIG. 2b.
[0018] FIG. 3 is a reproduction of a photograph of the waste gate
actuator in operational position on the turbocharger.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In the Figures, FIG. 1 shows a waste gate valve actuator 10
for a turbocharger (shown partially in FIG. 3). The actuator 10
comprises a cover 12 and bottom can 14 that define the perimeter
and interior of the actuator 10. The cover 12 and bottom can 14 are
joined by crimp 36 extending around the circumference of the
actuator 10, whereby an upward extending portion 46 of an outward
lip 50 on the bottom can 14 is crimped downward and around a mating
lip 48 on the cover 12 to from the circumferential crimp 36.
[0020] The interior of the actuator 10 is divided in two generally
by a diaphragm 22 into a pressure chamber 20 and a lower chamber 50
at atmosphere. An air inlet 18 provides a fluid communication port
of the introduction into the pressure chamber 20 of a pressurized
substance like air, engine exhaust, and the like.
[0021] The interior of the actuator 10 also includes a piston 15
with a piston rod 16 descending downward therefrom. The piston 15
at its upward end further comprises a piston cup 30 to define a top
of the piston 15. A washer 28 comprises the actual point of
contract between upward end of the piston 15 and the piston cup 30.
A piston rod 16 extends downward from the piston 15 and out of the
bottom of the actuator 10 for connection to a lever (not shown) or
similar device for the purpose of operating a waste gate valve (not
shown). A spring 26 is located within the interior of the lower
chamber 50 of the actuator 10, and is secured on its upward end
within the piston cup 30 and is captured at its lower end by a cup
shaped liner 34 located along the bottom of the can 14.
[0022] Finally, threaded leads 32 extend downward from the bottom
of the can 14 of the actuator and allow for securement of the
actuator 10 through the attachment of treaded bolts (not
shown).
[0023] Returning now to the diaphragm 22, as shown best in FIG. 1b,
the diaphragm 22 is flexibly secured within the interior of the
actuator 10 at the crimp 36. In particular, a crimp end 44 of the
diaphragm 22 fits between the lip 48 of the cover 12 and the bottom
of the lip 50 of the bottom can 14. This point of connection is
sufficiently secure to ensure that the pressure chamber 20 remains
air tight. Otherwise, the diaphragm 22 generally conforms in shape
to the piston cup 30, with the exception of a portion of a
convoluted side 42.
[0024] In operation, a pressurized substance enters the pressure
chamber 20 and exerts a downward pressure on the piston 15, which
is resisted by the upward biasing force of the spring 26. However,
once the pressure in the pressure chamber 20 overcomes the
resistance of the spring 26, the piston 15 is forced downward
through the rolling of the convoluted side 42 of the diaphragm 22.
Eventually, the piston rod 16 is displaced downward a sufficient
distance to actuate the waste gate valve. As noted hereinabove, the
waste gate valve opens a route to bypass the turbocharger
compressor thereby limiting the boost power to the engine and in
turn limiting the inlet pressure enough to allow the waste gat
valve to under the biasing force of the spring 26. Upon closing,
the spring 26 returns the diaphragm 22 to its neutral position by
reversing the roll of the convoluted side 42 of the diaphragm
22.
[0025] FIGS. 2a-c show in detail the construction of the diaphragm
22, which is a diaphragm type commonly referred to as a convoluted
diaphragm. The diaphragm 22 is comprised entirely of a thermoset
fluorocarbon material, and is substantially uniform in thickness.
The material used for construction of the diaphragm 22 is
sufficiently rubber like, or pliant, to provide the required
resilience while at the same time is satisfactorily durable. The
diaphragm as will be described in detail hereinbelow is not only
substantially uniform in thickness but is comparatively thin. It
has been found for example that diaphragms constructed of
thermoplastic materials cannot provide the required combination of
resilience and durability. The diaphragm 22 of the present
invention has the advantage of eliminating the need for composite
construction common to prior art diaphragms, and in particular
eliminating the use of a fabric combination diaphragm. Also, the
diaphragm 22 can be more easily and inexpensively manufactured by
virtue of its substantialy uniform thickness and is relative thin
in profile. In detail, the top 40 of the diaphragm 22 varies
between 0.022 and 0.030 inches in thickness, and the convoluted
side 32 varies between 0.017 and 0.022 inches in thickness. Thus,
the top 40 and convoluted side 32 can be a uniform thickness if
desired, but in any event are substantially of the same thickness.
The crimp end 44 of the diaphragm 22, however, is of a slightly
greater thickness of between 0.034 and 0.041 inches to support the
pressure of the crimp 36. In addition, the interior of the
convoluted side 42 that lies between the line C-C shown in FIG. 2b
is ribbed for additional strength. As shown in FIG. 2c the ribs
vary in height from between 0.004 and 0.008 inches.
[0026] In the preferred embodiment, the diaphragm 22 in its neutral
state is 2.244 inches between the crimp ends 44, and the top is
1.438 inches in diameter. Of course, those of ordinary skill in the
art will understand that the size of the diaphragm 22 can and will
vary depending on the desired application. For example, the
convoluted side 42 of the diaphragm 22 is 0.646 inches form top to
bottom, and between 0.495 and 0.522 inches from the top 40 and the
crimp end 44. The design of the convoluted side 42, or course, will
vary depending on the necessary stroke of the piston rod 16 needed
to actuator the waste gate valve.
[0027] The waste gate valve actuator 10 and its internal diaphragm
22 substantially eliminate the problems of the prior art by
providing for the use of a diaphragm 22 that is of a uniform
non-composite design which eliminates the need for the use of an
expensive fabric material like Nomex. Furthermore, the
substantially uniform thickness and general thin nature of the
diaphragm allows for easier and less expensive manufacturing. The
present invention accomplishes these advantages while not
sacrificing either resilience or durability over the prior art
design. In fact, it is believed that the actuator 10 incorporating
the diaphragm 22 is superior in both aspects of prior art
diaphragms.
[0028] The foregoing description and drawings comprise illustrative
embodiments of the present inventions. The foregoing embodiments
and the methods described herein may vary based on the ability,
experience, and preference of those skilled in the art. Merely
listing the steps of the method in a certain order does not
constitute any limitation on the order of the steps of the method.
The foregoing description and drawings merely explain and
illustrate the invention, and the invention is not limited thereto,
except insofar as the claims are so limited. Those skilled in the
art that have the disclosure before them will be able to make
modifications and variations therein without departing from the
scope of the invention.
* * * * *