U.S. patent application number 09/745022 was filed with the patent office on 2002-06-20 for thermally controlled valve and fuel system using same.
Invention is credited to Duffer, Bradly G., Loer, Daniel L., Mueller, Jeffrey J..
Application Number | 20020074419 09/745022 |
Document ID | / |
Family ID | 24994908 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020074419 |
Kind Code |
A1 |
Duffer, Bradly G. ; et
al. |
June 20, 2002 |
THERMALLY CONTROLLED VALVE AND FUEL SYSTEM USING SAME
Abstract
A dual temperature valve positioned in a bypass passageway can
move to an open position when two temperature conditions are met.
When opened, the dual temperature valve can allow warm fluid from a
first line to mix with cold fluid from a second line to heat the
same. The valve is preferably utilized in an engine fuel system and
positioned in a bypass passageway extending between a fuel supply
line and a fuel return line. In this application, the dual
temperature valve can prevent possible fuel transfer problems, such
as cold start gaseous circulation.
Inventors: |
Duffer, Bradly G.; (East
Peoria, IL) ; Loer, Daniel L.; (Brimfield, IL)
; Mueller, Jeffrey J.; (Normal, IL) |
Correspondence
Address: |
LIELL & MCNEIL
ATTN: Michael B. McNeil
511 S. Madison St.
P.O. Box 2417
Bloomington
IN
47402
US
|
Family ID: |
24994908 |
Appl. No.: |
09/745022 |
Filed: |
December 20, 2000 |
Current U.S.
Class: |
236/99K ;
239/397.5 |
Current CPC
Class: |
G05D 23/1366 20130101;
B01D 35/18 20130101; F02M 37/20 20130101; F02M 37/48 20190101; B01D
35/147 20130101 |
Class at
Publication: |
236/99.00K ;
239/397.5 |
International
Class: |
B05B 015/00 |
Claims
1. A dual temperature actuated valve comprising: a valve housing
defining a passageway extending between an inlet and an outlet; at
least one valve member being movably positioned in said passageway;
a first temperature sensor being positioned adjacent said inlet; a
second temperature sensor being positioned adjacent said outlet;
said at least one valve member opening said passageway when a first
temperature sensed by said first temperature sensor is greater than
a first predetermined temperature and a second temperature sensed
by said second temperature sensor is less than a second
predetermined temperature; and said at least one valve member
closing said passageway when at least one of said first temperature
is less than said first predetermined temperature and said second
temperature is greater than said second predetermined
temperature.
2. The dual temperature actuated valve of claim 1 wherein said at
least one valve member includes a first valve member movable
between an open position and a closed position and a second valve
member movable between an open position and a closed position; and
said passageway being at least partially open when said first valve
member is away from said closed position and said second valve
member is away from said closed position.
3. The dual temperature actuated valve of claim 1 wherein said
passageway includes a first segment and a second segment; said
first segment is open when said first temperature is greater than
said first predetermined temperature; and said second segment is
open when said second temperature is less than said second
predetermined temperature.
4. The dual temperature actuated valve of claim 3 wherein said
passageway is open when said first segment and said second segment
are open; and said passageway is closed when at least one of said
first segment is closed and said second segment is closed.
5. The dual temperature actuated valve of claim 1 wherein said
inlet is a first inlet and said valve housing defines a second
inlet in fluid communication with said outlet.
6. The dual temperature actuated valve of claim 1 wherein said
outlet is a first outlet and said valve housing defines a second
outlet in fluid communication with said inlet.
7. The dual temperature actuated valve of claim 1 wherein said
first temperature sensor is a portion of a first wax motor and said
second temperature sensor is a portion of a second wax motor; and
said first wax motor and said second wax motor are operably coupled
to said at least one valve member.
8. A fuel system comprising: a fuel tank and at least one fuel
injector; a supply line extending between an outlet of said fuel
tank and an inlet of said at least one fuel injector; a return line
extending between an outlet of said at least one fuel injector and
an inlet of said fuel tank; a bypass passageway extending between
said supply line and said return line; a valve positioned in said
bypass passageway; said valve being movable toward an open position
when fluid in said return line is relatively warm and fluid in said
supply line is relatively cold; and said valve being movable toward
a closed position when at least one of fluid in said return line is
relatively cold and fluid in said supply line is relatively
warm.
9. The fuel system of claim 8 including a fuel pump being operably
positioned in said supply line.
10. The fuel system of claim 9 wherein said bypass passageway
includes a first segment and a second segment; and a first valve
member is positioned in said first segment and at least partially
positioned in said valve and a second valve member is positioned in
said second segment and at least partially positioned in said
valve.
11. The fuel system of claim 10 wherein a first wax motor is
operably coupled to said first valve member and a second wax motor
is operably coupled to said second valve member.
12. The fuel system of claim 11 including a filter, wherein said
valve is mounted on said filter.
13. The fuel system of claim 12 including a first temperature
sensor in said supply line and a second temperature sensor in said
return line.
14. The fuel system of claim 13 wherein said fuel tank outlet is
fluidly connected to said at least one fuel injector inlet when
said valve is in said closed position and away from said closed
position; and said at least one fuel injector outlet is fluidly
connected to said fuel tank inlet when said valve is in said closed
position and away from said closed position.
15. A method of controlling a bypass passageway comprising:
providing a bypass valve positioned in a passageway between a first
line and a second line; opening said passageway when fluid in said
second line is relatively warm and fluid in said first line is
relatively cold; and closing said passageway when at least one of
fluid in said second line is relatively cold and fluid in said
first line is relatively warm.
16. The method of claim 15 wherein said step of opening said
passageway includes moving said valve toward an open position; and
said step of closing said passageway includes moving said valve
toward a closed position.
17. The method of claim 15 wherein said bypass valve includes a
first valve member and a second valve member; said step of opening
said passageway includes moving said first valve member away from a
closed position and moving said second valve member away from a
closed position; and said step of closing said passageway includes
at least one of moving said first valve member toward a closed
position and moving said second valve member toward a closed
position.
18. The method of claim 15 including mixing fluid in said first
line with fluid in said passageway.
19. The method of claim 15 including maintaining fluid
communication between said first line and said second line when
said bypass valve is in said closed position and away from said
closed position.
20. The method of claim 16 wherein said bypass valve includes a
first valve member and a second valve member; and operably coupling
a first wax motor to said first valve member and a second wax motor
to said second valve member.
Description
TECHNICAL FIELD
[0001] This invention relates generally to dual temperature
actuated valves, and more particularly to fuel systems utilizing
dual temperature actuated valves.
BACKGROUND ART
[0002] One property of diesel fuel that can be altered by refining
is the temperature at which paraffins will precipitate. The
temperature at which this precipitation occurs is referred to as
the "cloud point" of the fuel, and is often varied by distillers
depending upon the geographic region in which the fuel is intended
for use. For instance, fuel that is intended for use in colder
climates will typically have a lower cloud point than fuel intended
for use in warmer regions. Because it is undesirable to have
paraffin precipitates clogging up fuel system components, fuel
systems are often designed with a means to circulate warm fuel
through the system as soon as possible after cold start. One method
for dealing with this problem is the positioning of a temperature
sensitive valve in the return line between the fuel injectors and
the fuel tank. When the temperature of fuel flowing through the
supply line is relatively low, the fuel is directed from the return
line to the supply line to be recirculated through the fuel system
to warm the relatively cold fuel. When the fuel temperature is
relatively high, the fuel is directed back to the fuel tank. While
these valves have performed adequately, there is still room for
improvement.
[0003] For instance, a fuel transfer problem can occur when the
fuel system is evacuated and the fuel lines become filled with cool
gaseous vapors. If this occurs when the detected temperature in the
supply line is relatively cold, the bypass valve will connect the
fuel supply to the fuel return line, thus allowing the fuel pump to
continue to circulate the vapors through the fuel system while
preventing the pump from pulling fuel from the fuel tank to prime
the system. In turn, the engine will be prevented from
starting.
[0004] The present invention is directed to overcoming one or more
of the problems as set forth above.
DISCLOSURE OF THE INVENTION
[0005] In one aspect of the present invention, a dual temperature
actuated valve includes a valve housing that defines a passageway
extending between an inlet and an outlet. At least one valve member
is movably positioned in the passageway. Positioned adjacent the
inlet is a first temperature sensor. A second temperature sensor is
positioned adjacent the outlet. The valve member(s) opens the
passageway when a first temperature sensed by the first temperature
sensor is greater than a first predetermined temperature and a
second temperature sensed by the second temperature sensor is less
than a second predetermined temperature. The valve member(s) closes
the passageway when at least one of the first temperature is less
than the first predetermined temperature and the second temperature
is greater than the second predetermined temperature.
[0006] In another aspect of the present invention, a fuel system
includes a fuel tank and at least one fuel injector. A supply line
extends between an outlet of the fuel tank and an inlet of the fuel
injector(s). A return line extends between an outlet of the fuel
injector(s) and an inlet of the fuel tank. A bypass passageway
extends between the supply line and the return line. Positioned in
the bypass passageway is a valve. The valve is movable toward an
open position when fluid in the return line is relatively warm and
fluid in the supply line is relatively cold. The valve is movable
toward a closed position when at least one of fluid in the return
line is relatively cold and fluid in the supply line is relatively
warm.
[0007] In yet another aspect of the present invention, a method of
controlling a bypass passageway includes providing a bypass valve
that is positioned in a passageway between a first line and a
second line. The passageway is opened when fluid in the second line
is relatively warm and fluid in the first line is relatively cold.
The passageway is closed when at least one of fluid in the second
line is relatively cold and fluid in the first line is relatively
warm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic representation of a fuel system
according to the present invention;
[0009] FIG. 2 is a diagrammatic representation of a fuel filter and
bypass valve according to the present invention for use with the
fuel system of FIG. 1; and
[0010] FIG. 3 is a diagrammatic representation of the bypass valve
of FIG. 2.
BEST MODE FOR CARRYING OUT THE INVENTION
[0011] Referring to FIG. 1, there is shown a schematic
representation of a fuel system 10 according to the present
invention. A fuel tank 12 is provided in fuel system 10 that has an
outlet 13 in fluid communication with a fuel supply line 14. Fuel
tank 12 also has an inlet 28 that is in fluid communication with a
fuel return line 24. A fuel filter 16 is positioned in supply line
14 and acts to trap precipitates and other solids from fuel flowing
through supply line 14. Also positioned in supply line 14 is a fuel
pump 18 that draws fuel out of fuel tank 12 to circulate fuel to at
least one fuel injector 20 provided within fuel system 10. Fuel
injector 20 has a fuel inlet 19 in fluid communication with supply
line 14 and a fuel outlet 21 in fluid communication with return
line 24. A valve filter assembly 17 is provided in fuel system 10,
and provides a supply temperature sensor 15 that is positioned in
supply line 14. Supply temperature sensor 15 is capable of sensing
the temperature of fluid, such as liquid fuel and/or gaseous vapor,
in the same. A return temperature sensor 25 is also provided in
valve filter assembly 17 and positioned in return line 24 and is
capable of sensing the temperature of fluid in the same. Extending
between supply line 14 and return line 24 is a bypass passageway
51.
[0012] Referring to FIGS. 2 and 3, valve filter assembly 17 is
shown in greater detail. A bypass valve 40 having a valve housing
41 is mounted on fuel filter 16. Valve housing 41 defines a return
inlet 43 that is in fluid communication with return line 24. Return
inlet 43 is capable of fluid communication with a supply outlet 59,
defined by valve housing 41, when bypass passageway 51 is open.
Return inlet 43 is in continuous fluid communication with a return
outlet 44, defined by valve housing 41. Therefore, some or all of
fuel flowing into return inlet 43 from return line 24 will be
directed to fuel tank 12 via return outlet 44 regardless of when
bypass passageway 51 is open or closed respectively. Valve housing
41 also defines a supply inlet 58 that is in fluid communication
with supply line 14. Fuel entering bypass valve 40 through supply
inlet 58 can flow out of supply outlet 59 and flow through fuel
filter 16.
[0013] Returning to bypass valve 40, a first valve member 47 and a
second valve member 53 are positioned in a first segment 48 and a
second segment 55 of bypass passageway 51, respectively. First
valve member 47 is movable between a closed position in contact
with a valve seat 49, defined by bypass valve 40, and an open
position out of contact with valve seat 49. First valve member 47
is biased toward its closed position by a biasing spring 45. When
first valve member 47 is in its closed position, return inlet 43 is
blocked from first segment 48, and all of the fuel entering return
inlet 43 will be returned to fuel tank 12 via return outlet 44.
When first valve member 47 is away from its closed position, return
inlet 43 is open to first segment 48 and capable of fluid
communication with both first segment 48 and return outlet 44.
[0014] Similarly, second valve member 53 is movable between a
closed position in contact with a valve seat 52, defined by bypass
valve 40, and an open position out of contact with valve seat 52.
When second valve member 53 is in its closed position, first
segment 48 is blocked from second segment 55, thus preventing any
fuel in first segment 48 from flowing through second segment 55 and
exiting bypass valve 40 via supply outlet 59. When second valve
member 53 is away from its closed position, first segment 48 is
open to second segment 55. It should be appreciated that bypass
passageway 51 is not open unless both first valve member 47 and
second valve member 53 are away from their respective closed
positions. In other words, return inlet 43 is blocked from fluid
communication with supply outlet 59 unless both first valve member
47 and second valve member 53 are away from their respective closed
positions.
[0015] First valve member 47 and second valve member 53 are
actuated in their movement by a first wax motor 50 and a second wax
motor 56, respectively. Wax motors such as first wax motor 50 and
second wax motor 56 are known in the art and include a collection
of a substance, typically a particular type of wax, that will
expand and contract in response to temperature. In other words, the
term "wax motor" is intended to mean anything that changes shape in
response to a change in temperature and is capable of functioning
as both a temperature sensor and an actuator for a valve member.
The temperature at which expansion and contraction occur can be
varied depending upon the type and amount of temperature sensitive
substance used in the wax motor. For instance, while one wax motor
may be constructed to begin expanding at a temperature greater than
20.degree. C., a different wax motor may be constructed such that
expansion does not begin to occur until it is exposed to a
temperature greater than 50.degree. C. In addition, while the wax
motor may begin expanding at a first temperature, it may not reach
its fully expanded size until it is exposed to a substantially
higher temperature. Therefore, a wax motor may begin expanding when
exposed to a temperature greater than 20.degree. C., but not reach
its fully expanded size until it is exposed to a temperature
greater than 40.degree. C.
[0016] Returning to bypass valve 40, first wax motor 50 serves as
both an actuator for first valve member 47 and return temperature
sensor 25. Similarly, second wax motor 56 serves as both an
actuator for second valve member 53 and as supply temperature
sensor 15. As illustrated, second wax motor 56 is suspended in
bypass valve 40 by biasing spring 54 and 57, which maintain second
wax motor 56 in its desired position attached to second valve
member 53, while allowing the same to expand and contract at the
appropriate temperatures. While the present invention has been
illustrated utilizing wax motors to actuate first valve member 47
and second valve member 55, it should be appreciated that other
actuators could be substituted. For instance return temperature
sensor 25 and supply temperature sensor 15 could be independent
components that communicate fuel temperature to an electronic
control module provided in fuel system 10. Temperature information
relayed to the electronic control module could then be utilized for
actuation of electronically controlled actuators coupled to first
valve member 47 and second valve member 53.
[0017] First wax motor 50 does not begin expanding to move first
valve member 47 toward its open position until the temperature of
fluid in return line 24 is above a minimum return actuation
temperature. In the embodiment illustrated herein, the minimum
return actuation temperature is preferably at least 50.degree. C.
Therefore, when return temperature sensor 25 detects a fuel
temperature in return line 24 that exceeds 50.degree. C., wax motor
50 begins to expand to move first valve member 47 away from its
closed position. Complete expansion of first wax motor 50 to move
first valve member 47 to its fully open position preferably does
not occur until return temperature sensor 25 senses a maximum
return actuation temperature. In the illustrated embodiment, this
maximum return actuation temperature is preferably about 70.degree.
C. Therefore, first wax motor 50 does not expand to its full size
to move first valve member 47 to its fully open position until
return temperature sensor 25 senses a fuel temperature above
70.degree. C. It should be appreciated, however, that first segment
48 will be fluidly connected to return inlet 43 so long as first
valve member 47 is away from its closed position. However, flow
area past valve seat 49, and therefore the amount of fuel from
return inlet 43 that can enter first segment 48 will be affected by
the location of first valve member 47 between its closed and open
positions.
[0018] In order for first segment 48 to be open to second segment
55, second valve member 53 must be away from its closed position.
Second valve member 53 is in its closed position blocking first
segment 48 from second segment 55 when second wax motor 56 is fully
expanded, and moves toward its open position when second wax motor
56 begins to contract. Second wax motor 56 begins to contract when
the temperature of fuel in supply line 14 falls below a maximum
supply actuation temperature. As illustrated herein, the maximum
supply actuation temperature is preferably about 10.degree. C.
Thus, when supply temperature sensor 15 detects a fuel temperature
in supply line 14 that is below 10.degree. C., second wax motor 56
begins to contract to allow second valve member 53 to move away
from its closed position. Second wax motor 56 preferably does not
contract sufficiently for second valve member 53 to be moved to its
fully open position until the temperature of fuel in supply line 14
falls to a minimum supply actuation temperature. As illustrated
herein, this minimum supply actuation temperature is preferably
substantially less than the maximum supply actuation temperature,
and is on the order of -10.degree. C. Thus, second valve member 53
will be moved to its fully open position only after supply
temperature sensor 15 detects a fuel temperature that is around
-10.degree. C. Therefore, for the embodiment of the present
invention disclosed herein, bypass passageway 51 will be open to
allow warm fuel from return line 24 to mix with cool fuel from
supply inlet 58 when return temperature sensor 25 detects a fuel
temperature above 50.degree. C. and supply temperature sensor 15
detects a fuel temperature below 10.degree. C.
[0019] While values for the minimum return actuation temperature,
the maximum return actuation temperature, the maximum supply
actuation temperature and the minimum supply actuation temperature
have been provided, it should be appreciated that these values have
been provided for illustrative purposes only. The present invention
contemplates selecting these temperatures to be any values which
allow bypass valve 40 to perform its desired function of reducing
the risk fuel filter 16 becoming clogged with paraffin
precipitates. However, it is preferable that the difference between
the minimum return actuation temperature and the maximum supply
actuation temperature is at least 20.degree. C. Factors to consider
when selecting these temperature values include the cloud point of
fuel to be used in fuel system 10 and the geographic region in
which fuel system 10 is contemplated for use will influence the
values of these temperatures. For instance, if fuel system 10 is to
be used predominately in a warm climate, with fuel having a
relatively high cloud point, the temperatures at which first wax
motor 50 and second wax motor 56 expand and contract to open bypass
passageway 51 should be higher than if fuel system 10 was to be
used predominately in a cold climate, with fuel having a relatively
low cloud point. Further, these temperatures should be selected
such that an unduly high amount of precipitates are not permitted
to clog fuel filter 16 before temperatures in the system rise
enough to melt paraffins in the filter.
INDUSTRIAL APPLICABILITY
[0020] Referring to FIGS. 1-3, just prior to activation of fuel
system 10 under cold start conditions, first valve member 47 is
positioned in its biased, closed position such that return line 24
is blocked from bypass passageway 51. Second valve member 53 is in
its open position, such that first segment 48 is open to second
segment 55. Activation of fuel system 10 is followed by activation
of fuel pump 18 which begins to draw fuel from supply line 14 for
use in fuel system 10. Because bypass passageway 51 is closed, fuel
pump 18 is only drawing fuel from fuel tank 12. In addition, fuel
flowing into bypass valve 40 from return line 24 is prevented from
flowing through bypass passageway 51, and instead is returned to
fuel tank 12 via return outlet 44.
[0021] As operation of fuel system 10 continues, the temperature of
fuel in return line 24 increases as a result of circulation near
the warming engine cylinders. In addition, because all of the fuel
from return line 24 is being directed toward fuel tank 12 while
bypass passageway 51 remains closed, the temperature of fuel in
supply line 14 is also increasing, although at a slower rate. When
the fuel temperature in return line 24 exceeds the minimum return
actuation temperature, first wax motor 50 begins to expand to move
first valve member 47 toward its open position. As first valve
member 47 moves away from valve seat 49, a portion of the fuel
flowing into bypass valve 40 via return inlet 43 can flow into
first segment 48 of bypass passageway 51.
[0022] Recall that under cold start conditions, second valve member
53 will be in its open position when fuel system 10 is activated.
If the fuel temperature in supply line 14 detected by supply
temperature sensor 15 remains below the minimum supply actuation
temperature, second valve member 53 will remain away from its
closed position and relatively warm fuel from return line 24 will
be permitted to flow through bypass passageway 51 to mix with
relatively cold fuel from supply line 14 and exit bypass valve 40
via supply outlet 59. Because warmer fuel is now flowing through
fuel filter 16, there is less risk that fuel filter 16 will become
clogged with paraffin precipitates before the entire system warms
up. As fuel system 10 continues to operate, fuel temperature within
return line 24 will continue to increase, thus allowing first valve
member 47 to continue moving toward its fully open position,
maximizing the flow area past valve seat 49. In addition, fuel
temperature within fuel tank 12 will continue to increase as a
portion of the warm fuel in return line 24 is continually returned
to fuel tank 12 via return outlet 44. As the fuel temperature in
supply line 14 increases, second wax motor 56 continues to expand
to move second valve member 53 toward its closed position. Once the
fuel temperature in supply line 14 exceeds the maximum supply
actuation temperature, second wax motor 56 will fully expand to
move second valve member 53 to its closed position to block first
segment 48 from second segment 55.
[0023] It should be appreciated that bypass passageway 51 will
remain closed for the duration of the operation of fuel system 10
so long as the fuel temperature in supply line 14 remains above the
predetermined maximum supply temperature. Further, if the
temperature of fuel in return line 24 should fall below the
predetermined return temperature, it should be appreciated that
first valve member 47 will be returned to its closed position, thus
preventing fluid communication between return inlet 43 and first
segment 48. In addition, if fuel system 10 is deactivated and then
reactivated before fuel in fuel tank 12 has cooled sufficiently,
second valve member 53 will remain in the closed position at fuel
system activation.
[0024] The present invention can improve engine performance over
bypass valves previously installed in fuel systems. Because bypass
valve 40 includes a supply inlet 58 that is always open to supply
outlet 59, fuel pump 18 will be capable of drawing fuel from fuel
tank 12 even upon a cold start after the fuel system was evacuated
of fuel. Recall that with previous bypass valves, if the engine was
started under cold start conditions after it had been evacuated of
fuel, the valve would continue to circulate gaseous vapors through
the fuel system instead of pulling fuel from the fuel tank.
[0025] It should be appreciated that a number of modifications
could be made to bypass valve 40 without departing from the scope
of the present invention. For instance, while the bypass valve of
the present invention has been illustrated utilizing two separate
valve members, it should be appreciated that a single valve member
having the ability to open the bypass passageway only when
temperature in the return line is above a specified temperature and
temperature in the supply line is below a specified temperature
could instead be substituted. Further, while the valve members of
the present invention have been illustrated as being actuated by
wax motors, it should be appreciated that any suitable actuation
means could be substituted. For instance, supply temperature sensor
15 and return temperature sensor 25 could be operably connected to
an electronic control module included in fuel system 10. The
electronic control module could then communicate a control signal
to an electronic or digital actuator operably connected to the
valve members to open or close the same. Further, while bypass
valve 40 has been illustrated as being mounted on fuel filter 16,
it should be appreciated that it could be attached to fuel filter
16 in any conventional manner, or alternatively could be located at
some other suitable position within fuel system 10.
[0026] In addition to the above indicated modifications, it should
be appreciated that the minimum return actuation temperature,
maximum return actuation temperature, minimum supply actuation
temperature and maximum supply actuation temperature are not
intended to be limited to the values indicated herein, which were
intended for illustrative purposes only. Recall that factors such
as geographic region in which the bypass valve will be used and
cloud point of the fuel to be used will influence selection of
these values. In addition, these temperatures should be selected
such that fuel filter 16 does not become unduly clogged with
paraffin precipitates prior to the bypass passageway being opened.
Further, while the present invention has been illustrated for use
in a fuel system, it should be appreciated that it could find use
in any fluid system having a first fluid line including a
relatively high temperature fluid and a second fluid line including
a relatively low temperature fluid, wherein heating of the
relatively low temperature fluid is desirable under certain
conditions.
[0027] Thus, those skilled in the art will appreciate that other
aspects, objects and advantages of this invention can be obtained
from a study of the drawings, the disclosure and the appended
claims.
* * * * *