U.S. patent application number 11/858738 was filed with the patent office on 2009-03-26 for electric motor driven lubrication supply system shutdown system and method.
This patent application is currently assigned to HONEYWELL INTERNATIONAL, INC.. Invention is credited to Jim E. DeLaloye.
Application Number | 20090078508 11/858738 |
Document ID | / |
Family ID | 39580217 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090078508 |
Kind Code |
A1 |
DeLaloye; Jim E. |
March 26, 2009 |
ELECTRIC MOTOR DRIVEN LUBRICATION SUPPLY SYSTEM SHUTDOWN SYSTEM AND
METHOD
Abstract
A system and method for controlling lubricant displacement from
a lubrication system and a rotating machine includes supplying a
gaseous fluid to the lubrication supply system to displace the
lubricant. The gaseous fluid is preferentially directed through a
first section of the lubrication supply system and to the rotating
machine, and is at least inhibited from flowing through a second
section of the lubrication supply system. As a result, the gaseous
fluid displaces the lubricant in the rotating machine and in the
first section of the lubrication supply system, while the second
section of the lubrication supply system remains at least
substantially full of lubricant.
Inventors: |
DeLaloye; Jim E.; (Mesa,
AZ) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
101 COLUMBIA ROAD, P O BOX 2245
MORRISTOWN
NJ
07962-2245
US
|
Assignee: |
HONEYWELL INTERNATIONAL,
INC.
Morristown
NJ
|
Family ID: |
39580217 |
Appl. No.: |
11/858738 |
Filed: |
September 20, 2007 |
Current U.S.
Class: |
184/6.11 |
Current CPC
Class: |
F01D 25/20 20130101 |
Class at
Publication: |
184/6.11 |
International
Class: |
F01D 25/18 20060101
F01D025/18 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] This invention was made with Government support under
Contract No. N00019-02-C-3002, awarded by the U.S. Navy. The
Government has certain rights in this invention.
Claims
1. An aircraft lubrication supply system, comprising: a motor
coupled to be selectively energized from a power bus and operable,
upon being energized, to rotate at a rotational speed and supply a
drive force; a pump having at least a fluid inlet and a fluid
outlet, the pump coupled to receive the drive force from the motor
and configured, in response thereto, to draw fluid into the fluid
inlet from either a lubricant source or a gaseous fluid source, and
to discharge the fluid via the fluid outlet; a fluid supply line
coupled to the fluid outlet and configured to supply the fluid
discharged from the fluid outlet to a rotating machine; a fluid
bypass line having an inlet and an outlet, the fluid bypass line
inlet coupled to the fluid supply line at a first location, the
fluid bypass line outlet coupled to the fluid supply line at a
second location that is downstream of the first location; a bypass
control valve disposed between the fluid bypass line inlet and the
fluid bypass line outlet, the bypass control valve operable to
control fluid flow at least through the fluid bypass line; and a
controller configured to couple to the power bus and to receive a
machine de-lube signal, the machine de-lube signal indicating that
the rotating machine is being de-lubricated, the controller
operable, upon receipt of the machine de-lube signal, to: (i)
controllably energize the motor from the power bus to thereby
displace at least a substantial volume of lubricant in the fluid
supply line and the rotating machine with fluid from the gaseous
fluid source, and (ii) cause the bypass control valve to move to a
position that results in the fluid bypass line remaining at least
substantially full of lubricant when the at least substantial
volume of lubricant is displaced from the fluid supply line and the
rotating machine.
2. The system of claim 1, wherein the bypass control valve is
disposed in the supply line between the first location and the
second location.
3. The system of claim 1, wherein the bypass control valve is
disposed in the fluid bypass line between the bypass inlet and the
fluid bypass line outlet.
4. The system of claim 1, wherein the bypass control valve is
responsive to fluid temperature to thereby control fluid flow at
least through the fluid bypass line.
5. The system of claim 1, further comprising: a heat exchanger
coupled to receive fluid flowing in the fluid bypass line and a
second fluid flowing in a second fluid system at a flow rate, the
heat exchanger configured to allow heat transfer between the fluid
flowing in the bypass line and the second fluid.
6. The system of claim 5, wherein the controller, upon receipt of
the machine de-lube signal, causes the flow rate of the second
fluid to the heat exchanger to vary.
7. The system of claim 6, wherein the controller, upon receipt of
the machine de-lube signal, causes the flow rate of the second
fluid to the heat exchanger to increase.
8. The system of claim 1, further comprising: a de-lube control
valve in fluid communication with the pump fluid inlet, the de-lube
control valve movable between at least a first position, in which
the pump fluid inlet is in fluid communication with the gaseous
fluid source, and a second position, in which the pump fluid inlet
is not in fluid communication with the gaseous fluid source.
9. The system of claim 8, wherein the de-lube control valve is
coupled to receive one or more de-lube valve control signals and is
operable, in response thereto, to move to either the first or the
second position.
10. The system of claim 9, wherein the controller is further
operable, in response to the de-lube signal, to supply a valve
control signal that causes the de-lube control valve to move to the
second position.
11. An aircraft lubrication supply system, comprising: a motor
coupled to be selectively energized from a power bus and operable,
upon being energized, to rotate at a rotational speed and supply a
drive force; a pump having at least a fluid inlet and a fluid
outlet, the pump coupled to receive the drive force from the motor
and configured, in response thereto, to draw fluid into the fluid
inlet from either a lubricant source or a gaseous fluid source, and
to discharge the fluid via the fluid outlet; a fluid supply line
coupled to the fluid outlet and configured to supply the fluid
discharged from the fluid outlet to a rotating machine; a fluid
bypass line having an inlet and an outlet, the fluid bypass line
inlet coupled to the fluid supply line at a first location, the
fluid bypass line outlet coupled to the fluid supply line at a
second location that is downstream of the first location; a bypass
control valve disposed in the fluid supply line between the first
location and the second location, the bypass control valve
responsive to fluid temperature to control fluid flow through the
fluid bypass line; and a controller configured to couple to the
power bus and to receive a machine de-lube signal, the machine
de-lube signal indicating that the rotating machine is being
de-lubricated, the controller operable, upon receipt of the machine
de-lube signal, to: (i) controllably energize the motor from the
power bus to thereby displace at least a substantial volume of
lubricant in the fluid supply line and the rotating machine with
fluid from the gaseous fluid source, and (ii) cause the bypass
control valve to move to a position that results in the fluid
bypass line remaining at least substantially full of lubricant when
the at least substantial volume of lubricant is displaced from the
fluid supply line and the rotating machine.
12. The system of claim 11, further comprising: a heat exchanger
coupled to receive fluid flowing in the fluid bypass line and a
second fluid flowing in a second fluid system at a flow rate, the
heat exchanger configured to allow heat transfer between the fluid
flowing in the bypass line and the second fluid.
13. The system of claim 12, wherein the controller, upon receipt of
the machine de-lube signal, causes the flow rate of the second
fluid to the heat exchanger to vary.
14. The system of claim 6, wherein the controller, upon receipt of
the machine de-lube signal, causes the flow rate of the second
fluid to the heat exchanger to increase.
15. The system of claim 1, further comprising: a de-lube control
valve in fluid communication with the pump fluid inlet, the de-lube
control valve movable between at least a first position, in which
the pump fluid inlet is in fluid communication with the gaseous
fluid source, and a second position, in which the pump fluid inlet
is not in fluid communication with the gaseous fluid source.
16. A method of removing lubricant from a lubrication supply system
and a rotating machine supplied with lubricant by the lubrication
supply system, the method comprising the steps of: supplying a
gaseous fluid to the lubrication supply system to displace the
lubricant; preferentially directing the gaseous fluid through a
first section of the lubrication supply system and to the rotating
machine, and at least inhibiting the gaseous fluid from flowing
through a second section of the lubrication supply system, whereby
the gaseous fluid displaces the lubricant in the rotating machine
and in the first section of the lubrication supply system, and the
second section of the lubrication supply system remains at least
substantially full of lubricant.
17. The method of claim 16, wherein the lubrication supply system
includes a control valve that, based on its position, selectively
at least inhibits fluid flow through the second section of the
lubrication supply system, and wherein the method further
comprises: positioning the control valve to a position that at
least inhibits fluid flow through the second section of the
lubrication supply system.
18. The method of claim 16, wherein: the control valve is disposed
in the first section of the lubrication supply system; and the step
of position the control valve comprises positioning the control
valve to an open position.
19. The method of claim 16, wherein the control valve is disposed
in the second section of the lubrication supply system; and the
step of position the control valve comprises positioning the
control valve to a closed position.
20. The method of claim 16, further comprising: disposing a heat
exchanger in the second section of the lubrication supply system;
flowing fluid in the second section of the lubrication system and a
second fluid from a second fluid system through the heat exchanger;
and increasing the flow of the second fluid through the heat
exchanger.
Description
TECHNICAL FIELD
[0002] The present invention relates to rotating machine
lubrication and, more particularly, to a system and method for
controlling lubricant removal from the rotating machine and the
machine lubrication supply system during shutdown of the
machine.
BACKGROUND
[0003] Many aircraft gas turbine engines are supplied with
lubricant from a pump driven lubrication supply system. In
particular, the lubrication supply pump, which may be part of a
pump assembly having a plurality of supply pumps on a common,
engine-driven or electric motor driven shaft, draws lubricant from
a lubricant reservoir, and increases the pressure of the lubricant.
The lubricant is then delivered, via an appropriate piping circuit,
to the engine. The lubricant is directed, via appropriate flow
circuits within the engine, to the various components that may need
lubrication, and is collected in one or more recovery sumps in the
engine. One or more of the pump assembly pumps then draws the
lubricant that collects in the recovery sumps and returns the
lubricant back to the reservoir.
[0004] When an aircraft gas turbine engine is shutdown, the
lubricant is typically removed and returned to the reservoir to
reduce the viscous drag due to residual lubricant on rolling and
sliding lubricated surfaces during a subsequent startup. In many
instances this is accomplished by actuating a valve that, when
appropriately positioned, allows the supply pumps to draw air,
rather than lubricant, into the system. The supply pumps direct the
air into the supply system and engine, displacing the lubricant
therefrom, and directing the displaced lubricant back to the
lubricant reservoir.
[0005] Although the above-described systems and methods are
generally safe, reliable, and robust, theses systems and methods do
suffer certain drawbacks. For example, during a subsequent cold
engine and lubrication system startup, after the lubricant has been
removed from the lubrication system and engine, the lubrication
system and engine are first refilled with lubricant before
lubricant pressure rises sufficiently to force lubricant into some
engine components. Because lubricant is removed from the entire
lubrication system during the engine shutdown sequence, the
subsequent startup can use an undesired amount of power and take an
undesired amount of time to raise lubricant pressure sufficiently
high.
[0006] Hence, there is a need for lubricant supply system and
method that can remove lubricant from a rotating machine during
shutdown of the machine and supply system, while decreasing the
amount of power and time needed to raise lubricant pressure during
a subsequent startup of the supply system and machine. The present
invention addresses at least this need.
BRIEF SUMMARY
[0007] In one embodiment, and by way of example only, an aircraft
lubrication supply system includes a motor, a pump, a fluid supply
line, a fluid bypass line, and a controller. The motor is coupled
to be selectively energized from a power bus and is operable, upon
being energized, to rotate at a rotational speed and supply a drive
force. The pump has at least a fluid inlet and a fluid outlet, is
coupled to receive the drive force from the motor and is
configured, in response thereto, to draw fluid into the fluid inlet
from either a lubricant source or a gaseous fluid source, and to
discharge the fluid via the fluid outlet. The fluid supply line is
coupled to the fluid outlet and is configured to supply the fluid
discharged from the fluid outlet to a rotating machine. The fluid
bypass line has an inlet and an outlet. The fluid bypass line inlet
is coupled to the fluid supply line at a first location, and the
fluid bypass line outlet is coupled to the fluid supply line at a
second location that is downstream of the first location. The
bypass control valve is disposed between the fluid bypass line
inlet and the fluid bypass line outlet, and is operable to control
fluid flow at least through the fluid bypass line. The controller
is configured to couple to the power bus and to receive a machine
de-lube signal that indicates the rotating machine is being
de-lubricated. The controller is operable, upon receipt of the
machine de-lube signal, to controllably energize the motor from the
power bus to thereby displace at least a substantial volume of
lubricant in the fluid supply line and the rotating machine with
fluid from the gaseous fluid source, and to cause the bypass
control valve to move to a position that results in the fluid
bypass line remaining at least substantially full of lubricant when
the at least substantial volume of lubricant is displaced from the
fluid supply line and the rotating machine.
[0008] In another exemplary embodiment, a method of removing
lubricant from a lubrication supply system and a rotating machine
supplied with lubricant by the lubrication supply system includes
supplying a gaseous fluid to the lubrication supply system to
displace the lubricant. The gaseous fluid is preferentially
directed through a first section of the lubrication supply system
and to the rotating machine, and is at least inhibited from flowing
through a second section of the lubrication supply system. As a
result, the gaseous fluid displaces the lubricant in the rotating
machine and in the first section of the lubrication supply system,
while the second section of the lubrication supply system remains
at least substantially full of lubricant.
[0009] Other independent features and advantages of the preferred
lubrication supply system and method will become apparent from the
following detailed description, taken in conjunction with the
accompanying drawings which illustrate, by way of example, the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1, which is the sole FIGURE, is a schematic diagram of
an aircraft lubrication supply system according to an exemplary
embodiment of the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0011] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or its
application and uses. Furthermore, there is no intention to be
bound by any theory presented in the preceding background or the
following detailed description. In this regard, although the system
is depicted and described as supplying lubricant to a turbomachine,
it will be appreciated that the invention is not so limited, and
that the system and method described herein may be used to supply
lubricant to any one of numerous airframe mounted rotating
machines.
[0012] The following detailed description is merely exemplary in
nature and is not intended to limit the invention or its
application and uses. Furthermore, there is no intention to be
bound by any theory presented in the preceding background or the
following detailed description. In this regard, although the system
is depicted and described as supplying lubricant to a turbomachine,
it will be appreciated that the invention is not so limited, and
that the system and method described herein may be used to supply
lubricant to any one of numerous airframe mounted rotating
machines.
[0013] With reference now to FIG. 1, a schematic diagram of an
exemplary aircraft lubrication supply system 100 is depicted, and
includes a reservoir 102, a pump assembly 104, a motor 106, and a
controller 108. The reservoir 102 is used to store a supply of
lubricant 112 such as, for example, oil or other suitable hydraulic
fluid. A level sensor 114 and a temperature sensor 116 are
installed within, or on, the reservoir 102. The level sensor 114
senses the level of lubricant in the reservoir 102 and supplies a
level signal representative of the sensed level to the controller
108. The temperature sensor 116 senses the temperature of the
lubricant in the reservoir 102 and supplies a temperature signal
representative of the sensed temperature to the controller 108. It
will be appreciated that the level sensor 114 and the temperature
sensor 116 may be implemented using any one of numerous types of
level and temperature sensors, respectively, that are known now or
that may be developed in the future.
[0014] The pump assembly 104, at least in n the depicted
embodiment, includes a plurality of supply pumps 118 and a
plurality of return pumps 122. The supply pumps 118 each include a
fluid inlet 117 and a fluid outlet 119. The supply pumps 118, when
driven, draw fluid from one of two fluid sources, and discharge the
fluid, at an increased pressure, into a fluid supply conduit 124.
The fluid supply conduit 124, among other potential functions,
supplies the lubricant to one or more rotating machines. Although
one or more various types of machines could be supplied with the
lubricant, in the depicted embodiment the lubricant is supplied to
a rotating turbomachine. It will be appreciated that each of the
pumps 118, 122 that comprise the pump assembly 104 could be
implemented as any one of numerous types of centrifugal or positive
displacement type pumps, but in the preferred embodiment each pump
118, 122 is implemented as a positive displacement pump.
[0015] The two fluid sources from which the supply pumps 118 may
draw fluid include the reservoir 102 and a gaseous fluid source
126. The gaseous fluid source 126 may be configured as any one of
numerous sources of gaseous fluid, but in the depicted embodiment
it is configured as an air source. Preferably, the surrounding
environment acts as a suitable air source. If not, however, a
dedicated source of a suitable gas may be used. The specific source
from whence the supply pumps 118 draw fluid may be controlled by,
for example, a de-lube control valve 128. It will be appreciated
that the de-lube control valve 128 may be implemented using any one
of numerous types of valves to. In the depicted embodiment,
however, the de-lube control valve 128 is implemented as a
solenoid-operated valve.
[0016] As FIG. 1 also depicts, a lubricant filter 132 may also be
disposed within the lubricant supply conduit 124. The lubricant
filter 132 removes any particulate or other debris that may be
present in lubricant before it is supplied to the rotating machine.
A filter bypass valve 134, and appropriate bypass piping 136, are
disposed in parallel with the lubricant filter 132. The bypass
valve 134 is configured such that it is normally in a closed
position, and moves to the open position when a predetermined
differential pressure exists across it. Thus, if the lubricant
filter 132 becomes clogged and generates a sufficiently high
differential pressure, the bypass valve 134 will open to ensure a
sufficient flow of lubricant to the rotating machine is
maintained.
[0017] The lubricant supply conduit 132 also includes a pair of
pressure sensors, a filter inlet pressure sensor 138 and a filter
outlet pressure sensor 142. The pressure sensors 138, 142 are each
operable to sense lubricant pressure and to supply a pressure
signal representative of the sensed pressure to the controller 108.
As the assigned nomenclature connotes, the filter inlet pressure
sensor 138 senses lubricant pressure at the inlet to the lubricant
filter 132, and the filter outlet pressure sensor 142 senses
lubricant pressure at the outlet of the lubricant filter 132. It
will be appreciated that the depicted configuration is merely
exemplary of a particular embodiment, and that the system 100 could
be implemented with more or less than this number of pressure
sensors. For example, the system 100 could be implemented with only
the filter inlet pressure sensor 138 or only the filter outlet
pressure sensor 142, with a plurality of filter inlet pressures
sensors 138 and filter outlet pressure sensors 142, or with no
pressure sensors.
[0018] The temperature of the lubricant that is supplied to the
rotating machine is controlled, at least partially, via a fluid
bypass line 144 and a bypass control valve 146. The fluid bypass
line 144 includes an inlet 148 and an outlet 152. The fluid bypass
line inlet 148 is coupled to the fluid supply line 124 at a first
location, and the fluid bypass line outlet 152 is coupled to the
fluid supply line 124 at a second location downstream of the first
location. A heat exchanger 154 is disposed in the fluid bypass line
144. Fluid in the bypass line 144 and fluid from a second fluid
system 175 flow into and through the heat exchanger 154. In the
heat exchanger 154, heat is transferred between the two fluids.
During normal system 100 operation, heat is typically transferred
from the fluid (e.g., lubricant) in the fluid bypass line 144 to
the fluid from the second fluid system 175, thereby cooling the
fluid in the fluid bypass line 144. The cooled fluid then flows
back into the fluid supply line 124. The amount of fluid (if any)
that flows into and through the fluid bypass line 144 is controlled
via the bypass control valve 146, embodiments of which will now be
briefly described.
[0019] The bypass control valve 146 is disposed in the fluid supply
line 124 between the fluid bypass line inlet 148 and the fluid
bypass line outlet 152. The bypass control valve 146 is operable to
control fluid flow at least through the fluid bypass line 144. More
specifically, in the depicted embodiment, the bypass control valve
146 is movable between a closed position and an open position. When
the bypass control valve 146 is in the closed position, all of the
fluid discharged from the supply pumps 118 will flow into and
through the fluid bypass line 144. Conversely, when the bypass
control valve 146 is in the open position, most (if not all) of the
fluid discharged from the supply pumps 118 will flow through the
bypass control valve 146, and only a portion (if any) of the fluid
will flow into and through the fluid bypass line 144.
[0020] From the above discussion, it may thus be appreciated that
during normal system operations the bypass control valve 146 is
preferably positioned to regulate the temperature of the lubricant
supplied to the rotating machine. That is, if the lubricant
discharged from the supply pumps 118 is below a predetermined
temperature, then the bypass control valve 146 will be open and
only a portion (if any) of the discharged lubricant discharged will
flow into and through the fluid bypass line 144. If, however, the
lubricant discharged from the supply pumps 118 reaches or exceeds a
predetermined set temperature, then the bypass control valve 146
will close and all of the fluid discharged from the supply pumps
118 will flow into and through the fluid bypass line 144, and be
cooled in the heat exchanger 154.
[0021] Before proceeding further it is noted that the bypass
control valve 146 may be variously disposed and variously
configured. For example, and as is depicted in phantom in FIG. 1,
rather than being disposed in the supply line 124, the bypass
control valve 146 could be disposed in the fluid bypass line 144.
Moreover, the bypass control valve 146 could be implemented using
any one of numerous suitable devices, and be configured to move
between the closed and open positions based on various sensed
temperatures. For example, in the depicted embodiment the bypass
control valve 146 is implemented using a thermally actuated valve,
such as a eutectic-based actuator operated valve, that moves a
valve element between the closed and open position based on the
temperature of the actuator. With this type of valve, the actuator
temperature varies with fluid temperature at the outlet of the
bypass control valve 146 and, based on this temperature, controls
the position of the valve element. In other embodiments, the fluid
temperature at the inlet of the bypass control valve 146 could be
used. In addition, a fluid temperature sensor could be included to
sense fluid temperature at one or more locations in the fluid
supply line 124 and the sensed temperature could be used to control
an electric, hydraulic, or pneumatic actuator, or various other
actuator types, to move the bypass control valve 146 between the
closed and open positions.
[0022] No matter the specific configuration of the bypass control
valve 146, it is noted that the lubricant that is ultimately
supplied to the rotating machine flows to various components within
the machine and is collected in one or more sumps in the rotating
machine. The lubricant that is collected in the rotating machine
sumps is then returned to the reservoir 102 for reuse. To do so, a
plurality of the above-mentioned return pumps 122 draws used
lubricant from the rotating machine sumps and discharges the used
lubricant back into the reservoir 102 for reuse. It will be
appreciated that the configuration of the pump assembly 104
described herein is merely exemplary, and that the pump assembly
104 could be implemented using any one of numerous other
configurations. For example, the pump assembly 104 could be
implemented with a single supply pump 118 and a single return pump
122, or with just one or more supply pumps 118. No matter how many
supply or return pumps 118, 122 are used to implement the pump
assembly 104, it is seen that each pump 118, 122 is mounted on a
common pump assembly shaft 148 and is driven via a drive force
supplied from the motor 106.
[0023] The motor 106 is selectively energized from a power bus 115
and, when energized, rotates at a speed controlled by the
controller 108 to thereby supply the drive force to the pump
assembly 104. In the depicted embodiment the motor 106 is directly
coupled to the pump shaft 148 and thus rotates the pump shaft 148
(and thus the pumps 118, 122) at the motor speed. It will be
appreciated, however, that the motor 106, if needed or desired,
could be coupled to the pump shaft 148 via one or more gear
assemblies, which could be configured to either step up or step
down the motor speed. It will additionally be appreciated that the
motor 106 could be implemented as any one of numerous types of AC
or DC motors, but in a particular preferred embodiment the motor
106 is implemented as a brushless DC motor.
[0024] As noted above, the motor 106 is selectively energized from
the power bus 115 under the control of the controller 108. The
controller 108 implements control logic via, for example, a central
processing unit 152. The control logic that the controller 108
implements during operation of the rotating machine may differ from
the control logic implemented during a shutdown sequence of the
rotating machine. For example, during operation of the rotating
machine the control logic may implement a predefined schedule of
lubricant supply pressure as a function of various conditions. More
specifically, the controller 108 may receive signals representative
of various parameters. In response to these signals, the control
logic in the controller 108 may determine the scheduled lubricant
supply pressure based on these parameters, and control the motor
106 to rotate at least the supply pumps 118 at a speed that will
supply lubricant from the reservoir 102 at the scheduled lubricant
supply pressure. Conversely, during the shutdown sequence, the
control logic may control the rotational speed of the motor 106 in
accordance with a schedule that will displace at least a
substantial volume of the lubricant in the rotating machine with
air from the gaseous fluid source 126. Although the controller 108
is depicted using a single function block, it is noted that the
controller 108 may be implemented as a single device or as two or
more separate devices. For example, the controller 108 may
implement the functions of both a motor controller and an engine
(or other rotating machine) controller, or the controller 108 may
be implemented separately, as a motor control unit and an engine
control unit.
[0025] Regardless of the specific physical implementation of the
controller 108, and regardless of the specific control logic that
is implemented in the controller 108, when the shutdown sequence
for the rotating machine is initiated, the system 100 is configured
to de-lube the rotating machine. In the depicted embodiment, when
the shutdown sequence is initiated, a valve control signal is
additionally supplied to the de-lube control valve 128 that causes
the de-lube control valve 128 to move to a position that fluidly
communicates the supply pump inlets 117 with the gaseous fluid
source 126. It will be appreciated that this valve control signal
may be supplied from the controller 108 or from another device.
Preferably, however, the valve control signal is supplied from the
controller 108. When the shutdown sequence is initiated, a de-lube
signal indicating that the rotating machine is being de-lubricated
is additionally supplied to the controller 108. The de-lube signal
may be generated within the controller 108 or it may be supplied to
the controller 108 from another device.
[0026] No matter the specific source of the de-lube signal, the
controller 108, in response to the de-lube signal, controllably
energizes the motor 106 from the power bus 115. Because the supply
pump inlets 117 are in fluid communication with the gaseous fluid
source 126, air is discharged from the supply pumps 118 into the
supply line 124. As alluded to above, the control logic implemented
by the controller 108 during the shutdown sequence controls the
rotational speed of the motor 106 in accordance with a schedule
that will displace at least a substantial volume of the lubricant
in the rotating machine with air from the gaseous fluid source
126.
[0027] In addition to the above, the controller 108 is also
responsive to the de-lube signal to cause the bypass control valve
146 to move to a position that results in the fluid bypass line 144
remaining at least substantially full of lubricant when the
lubricant is displaced from the fluid supply line 124 and the
rotating machine. The manner in which the controller 108 implements
this functionality may vary, but in the depicted embodiment the
controller 108 supplies one or more signals that results in the
bypass control valve 146 moving to the open position. With the
bypass control valve 146 in the open position, the air being
discharged by the pump will preferentially flow through the fluid
supply line 124 and into and through the rotating machine, rather
than through the fluid bypass line 144. This will result in the
lubricant being displaced from the fluid supply line 124 and the
rotating machine, yet the fluid bypass line 144 will remain full,
or at least substantially full, of lubricant.
[0028] As was just noted, the controller 108 may cause the bypass
control valve 146 to open in accordance with any one of numerous
implementations. In one particular embodiment, the controller 108
supplies one or more signals that directly or indirectly results in
an increased flow rate of the fluid from the second fluid system
175 through the heat exchanger 154. Because the flow rate of this
fluid through the heat exchanger 154 increases, the amount of heat
transfer from the lubricant to the fluid also increases, thereby
cooling the lubricant in the fluid bypass line 144. The increase in
flow rate of the fluid from the second fluid system 175 through the
heat exchanger 154 is sufficient to maintain lubricant temperature
at the outlet of the bypass control valve 146 at or below the
temperature at which the bypass control valve 146 will open.
[0029] It will be appreciated that in other embodiments, such as
when the bypass control valve 146 is disposed in the fluid bypass
line 144, the controller 108 will supply one or more signals that
directly or indirectly cause the bypass control valve 146 to remain
closed. It will additionally be appreciated that for those
embodiments in which the bypass control valve 146 is implemented
with an electric, hydraulic, or pneumatic actuator, the controller
could supply suitable signals directly to the actuator that
appropriately position the bypass control valve 146 to either
prevent or inhibit air flow through the fluid bypass line 144
during the de-lubrication portion of the machine shutdown
sequence.
[0030] The above-described process results in a portion of the
lubrication supply system 100 remaining full, or at least
substantially full, of lubricant following the shutdown of the
rotating machine. Hence, the lubricant fill volume during a
subsequent start sequence of the rotating machine will be reduced
relative to a system that is fully purged of its lubricant, and the
lubricant pressure in the system 100 will rise relatively quicker.
As a result, the electrical power drawn by the motor 106 during the
start sequence is significantly reduced relative to a system that
was fully purged of its lubricant.
[0031] While the invention has been described with reference to a
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt to a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the appended
claims.
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