U.S. patent application number 13/866573 was filed with the patent office on 2013-11-07 for system and method for a compressor.
The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to NEIL W. BURKELL, MILAN KARUNARATNE, RICHARD C. PEOPLES, DAVID E. PETERSON, JASON M. STRODE, BRET DWAYNE WORDEN.
Application Number | 20130294937 13/866573 |
Document ID | / |
Family ID | 48326433 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130294937 |
Kind Code |
A1 |
WORDEN; BRET DWAYNE ; et
al. |
November 7, 2013 |
SYSTEM AND METHOD FOR A COMPRESSOR
Abstract
Systems and methods of the invention relate to diagnosing a
compressor. A method may include monitoring a crankcase pressure of
a compressor, analyzing the monitored crankcase pressure, and
identifying a condition of the compressor based on the analysis of
the monitored crankcase pressure. A system is also disclosed
including an engine, a compressor operatively connected to the
engine, and a controller that is operable to identify a condition
of the compressor.
Inventors: |
WORDEN; BRET DWAYNE; (ERIE,
PA) ; PEOPLES; RICHARD C.; (GROVE CITY, PA) ;
PETERSON; DAVID E.; (LAWRENCE PARK, PA) ; STRODE;
JASON M.; (LAWRENCE PARK, PA) ; BURKELL; NEIL W.;
(LAWRENCE PARK, PA) ; KARUNARATNE; MILAN;
(LAWRENCE PARK, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
SCHENECTADY |
NY |
US |
|
|
Family ID: |
48326433 |
Appl. No.: |
13/866573 |
Filed: |
April 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61636192 |
Apr 20, 2012 |
|
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|
Current U.S.
Class: |
417/53 ;
417/63 |
Current CPC
Class: |
F04B 51/00 20130101;
G01M 3/2876 20130101; F04B 49/10 20130101; F04B 2205/063 20130101;
F15B 19/005 20130101; F16K 37/0091 20130101; F04B 49/022 20130101;
F04B 49/065 20130101; F04B 41/02 20130101; F04B 25/00 20130101;
F04B 49/02 20130101; F04B 23/02 20130101; F04B 2201/0605
20130101 |
Class at
Publication: |
417/53 ;
417/63 |
International
Class: |
F04B 49/00 20060101
F04B049/00 |
Claims
1. A method for a compressor, comprising: monitoring a crankcase
pressure of a compressor; analyzing the monitored crankcase
pressure; and identifying a condition of the compressor based on
the analysis of the monitored crankcase pressure.
2. The method of claim 1, wherein analyzing the monitored crankcase
pressure comprises: calculating an average of the crankcase
pressure over a time period; and comparing the average crankcase
pressure over the time period to a nominal crankcase average
pressure.
3. The method of claim 2, wherein the condition of the compressor
is identified based on a difference between the calculated
crankcase average pressure and the nominal crankcase average
pressure.
4. The method of claim 2, further comprising identifying the
nominal crankcase average pressure from at least one of ambient air
temperature or ambient air pressure.
5. The method of claim 2, further comprising identifying the
nominal crankcase average pressure from at least one of compressor
speed, reservoir pressure, or oil temperature.
6. The method of claim 1, wherein analyzing the monitored crankcase
pressure comprises identifying frequency content of the monitored
crankcase pressure at one or more known frequencies.
7. The method of claim 6, further comprising identifying the one or
more known frequencies based on a rate at which the compressor is
operated.
8. The method of claim 1, wherein analyzing the monitored crankcase
pressure comprises correlating the monitored crankcase pressure
with an indication of the position of a piston of the compressor
during a time period in which the piston is operated.
9. The method of claim 8, wherein identifying the condition of the
compressor further comprises identifying a condition of a cylinder
of the compressor based on a correlation of the monitored crankcase
pressure and an indication of the position of the piston in the
cylinder of the compressor.
10. The method of claim 1, wherein identifying the condition of the
compressor comprises at least one of the following: identifying a
piston blow-by condition of at least one cylinder of the compressor
based on the analysis of the monitored crankcase pressure; or
identifying a crankcase breather valve failure based on the
analysis of the monitored crankcase pressure.
11. The method of claim 1, wherein the crankcase pressure is
monitored while a piston is cycled within a cylinder of the
compressor in at least one of an unloaded condition or in a loaded
condition.
12. The method of claim 1, wherein: monitoring the crankcase
pressure of the compressor comprises: monitoring the crankcase
pressure during a first time period during which a piston is cycled
within a cylinder of the compressor in an unloaded; and monitoring
the crankcase pressure of the compressor during a second time
period during which the piston is cycled within the cylinder of the
compressor in a loaded condition; and the condition of the
compressor is identified based on the analysis of the monitored
crankcase pressure from the first time period and the second time
period.
13. The method of claim 1, further comprising generating a signal
in response to identifying the condition of the compressor based on
the analysis of the monitored crankcase pressure.
14. The method of claim 13, further comprising notifying personnel
with the signal, the signal comprising one or more of an audio
alarm, a visual alarm, a text message, an email, an instant
message, or a phone call.
15. The method of claim 1, further comprising reducing a duty cycle
of the compressor in response to identifying the condition of the
compressor.
16. A controller operable in association with a compressor, wherein
the controller is configured to: receive a signal corresponding to
a monitored crankcase pressure within a crankcase of the
compressor; analyze the monitored crankcase pressure; and identify
a condition of the compressor based on the analysis of the
monitored crankcase pressure.
17. The controller of claim 16, wherein the condition of the
compressor is at least one of the following: a piston blow-by
condition of at least one cylinder of the compressor; or a
crankcase breather valve failure.
18. The controller of claim 16, wherein for the analysis of the
monitored crankcase pressure, the controller is configured to:
calculate an average of the crankcase pressure over a time period;
and compare the average crankcase pressure over the time period to
a nominal crankcase average pressure.
19. The controller of claim 16, wherein the controller is further
configured to communicate with one or more crankcase pressure
sensors and receive the signal corresponding to the monitored
crankcase pressure from the one or more crankcase pressure
sensors.
20. A system, comprising: an engine; a compressor operatively
connected to the engine, wherein the compressor includes a
crankcase having a crankcase pressure sensor; and a controller
configured to: receive a signal corresponding to a monitored
crankcase pressure within the crankcase of the compressor from the
crankcase pressure sensor; analyze the monitored crankcase
pressure; and identify a condition of the compressor based on the
analysis of the monitored crankcase pressure.
21. The system of claim 20, wherein the condition of the compressor
is at least one of the following: a piston blow-by condition of at
least one cylinder of the compressor; or a crankcase breather valve
failure.
22. The system of claim 20, wherein the controller is further
configured to communicate with a crankshaft position sensor to
identify a position of a piston in a cylinder of the compressor,
and wherein the controller is configured to analyze the monitored
crankcase pressure based at least in part on the position of the
piston.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/636,192, filed Apr. 20, 2012, and entitled
"SYSTEM AND METHOD FOR A COMPRESSOR." The entirety of the
aforementioned application is incorporated herein by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] Embodiments of the subject matter disclosed herein relate to
compressor diagnostics.
[0004] 2. Discussion Of Art
[0005] Compressors compress gas, such as air. Compressors may be
driven by electric motors, and may be air cooled. Some compressors
include three cylinders with two stages. For example, a compressor
can have two low pressure cylinders which deliver an intermediate
pressure air supply to a single high pressure cylinder for further
compression for final delivery to an air reservoir. Compressor and
compressor components are subject to various failure modes, which
increase difficulties in maintaining a healthy compressor.
[0006] It may be desirable to have a system and method that differs
from those systems and methods that are currently available.
BRIEF DESCRIPTION
[0007] In an embodiment, a method (e.g., a method for controlling
and/or operating a compressor) is provided that includes the steps
of monitoring a crankcase pressure of a compressor; analyzing the
monitored crankcase pressure; and identifying a condition of the
compressor based on the analysis of the monitored crankcase
pressure. (The method may be carried out automatically or otherwise
by a controller.)
[0008] Another embodiment relates to a controller that is operable
in association with a compressor (e.g., the controller may receive
data from and/or about the compressor and control the compressor or
other systems based on the data). The controller is configured to
receive a signal corresponding to a monitored pressure within a
crankcase of the compressor, and to analyze the monitored crankcase
pressure. The controller can further be configured to identify a
condition of the compressor based on the analysis of the monitored
crankcase pressure.
[0009] In an embodiment, a system comprises a compressor
operatively connected to an engine, wherein the compressor includes
a crankcase having a crankcase pressure sensor. The system further
comprises a controller that is configured to receive a signal
corresponding to a monitored pressure within the crankcase of the
compressor from the crankcase pressure sensor. The controller is
further configured to analyze the monitored crankcase pressure and
to identify a condition of the compressor based on the analysis of
the monitored crankcase pressure.
[0010] In an embodiment, a compressor system is provided that
includes means for monitoring a crankcase pressure of a compressor
and means for analyzing the monitored crankcase pressure. The
compressor system further includes means for identifying a
condition of the compressor based on the analysis of the monitored
crankcase pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Reference is made to the accompanying drawings in which
particular embodiments and further benefits of the invention are
illustrated as described in more detail in the description below,
in which:
[0012] FIG. 1 is an illustration of an embodiment of a vehicle
system with a compressor;
[0013] FIG. 2 is an illustration of an embodiment of system that
includes a compressor;
[0014] FIG. 3 is a graph depicting a measured crankcase pressure
for a compressor;
[0015] FIG. 4 is a graph depicting a measured crankcase pressure
for a compressor;
[0016] FIG. 5 is an illustration of an embodiment of a system that
includes a compressor;
[0017] FIG. 6 is a graph depicting a measured crankcase pressure
for a compressor; and
[0018] FIG. 7 is a flow chart of an embodiment of a method for
identifying a condition of a compressor based upon a measured
crankcase pressure.
DETAILED DESCRIPTION
[0019] Embodiments of the subject matter disclosed herein relate to
systems and methods that facilitate identifying a leak condition or
other condition within a compressor and, in particular, identifying
a leak condition by monitoring a crankcase pressure. A controller
can be configured to identify a compressor condition based upon the
monitored crankcase pressure. Moreover, a crankcase pressure sensor
(e.g., also referred to more generally as a detection component)
can be configured to monitor crankcase pressure for the compressor,
for purposes of detecting a change (e.g., a fluctuation, increase,
decrease, among others) in the pressure. Based upon a detected
change in the monitored crankcase pressure, the controller can be
configured to determine a condition of the compressor. In an
embodiment, the controller can be further configured to communicate
an alert related to the detected change in the crankcase pressure.
The alert can be a signal (e.g., diagnostic code, audio, text,
visual, haptic, among others) that indicates a change in the
monitored pressure of the crankcase of the compressor. This alert
can be utilized to provide maintenance on the compressor or a
portion thereof. In an embodiment, the controller can be configured
to schedule a maintenance operation based upon the detected change
in crankcase pressure and/or the communicated alert in order to
perform preventative maintenance. Still further, the controller can
be configured to automatically or otherwise control the compressor
based on and/or responsive to monitored air pressure.
[0020] With reference to the drawings, like reference numerals
designate identical or corresponding parts throughout the several
views. However, the inclusion of like elements in different views
does not mean a given embodiment necessarily includes such elements
or that all embodiments of the invention include such elements.
[0021] The term "component" as used herein can be defined as a
portion of hardware, a portion of software, or a combination
thereof. A portion of hardware can include at least a processor and
a portion of memory, wherein the memory includes an instruction to
execute. The term "vehicle" as used herein can be defined as any
asset that is a mobile machine that transports at least one of a
person, people, or a cargo, or that is configured to be portable
from one location to another. For instance, a vehicle can be, but
is not limited to being, a locomotive or other rail vehicle, an
intermodal container, a marine vessel, a mining equipment, a
stationary portable power generation equipment, an industrial
equipment, a construction equipment, and the like. The term
"loaded" as used herein can be defined as a compressor system mode
where air is being compressed into the reservoir. The term "loaded
start" as used herein can be defined as a compressor system mode in
a loaded condition during a starting phase of the compressor. The
term "unloaded" as used herein can be defined as a compressor
system mode where air is not being compressed into the
reservoir.
[0022] A compressor compresses gas, such as air. In some
embodiments, the compressed gas is supplied to operate pneumatic or
other equipment powered by compressed gas. A compressor may be used
for mobile applications, such as vehicles. By way of example,
vehicles utilizing compressors include locomotives, on-highway
vehicles, off-highway vehicles, mining equipment, and marine
vessels. In other embodiments, a compressor may be used for
stationary applications, such as in manufacturing or industrial
applications requiring compressed air for pneumatic equipment among
other uses. The compressor depicted in the below figures is one
which utilizes spring return inlet and discharge valves for each
cylinder, wherein the movement of these valves is caused by the
differential pressure across each cylinder as opposed to a
mechanical coupling to the compressor crank shaft. The subject
invention can be applicable to machines with either type of valve
(e.g., spring return valves, mechanical coupled valves, among
others) and the spring return valve is depicted solely for example
and not to be limiting on the subject innovation.
[0023] The components of a compressor may degrade over time
resulting in performance reductions and/or eventual failure of a
compressor. In vehicle applications, for example, a compressor
failure may produce a road failure resulting in substantial costs
to the vehicle owner or operator. In this context, a road failure
includes a vehicle, such as a locomotive, becoming inoperative when
deployed in service as a result of the failure or degradation of a
compressor system that prevents operation or requires shutting down
the vehicle until repairs can be made. Prior to a total failure,
the detection of degraded components or other deterioration of the
compressor may be used to identify incipient faults or other
conditions indicative of deterioration. In response to detecting
such conditions, remedial action may be taken to mitigate the risk
of compressor failure and associated costs.
[0024] The systems and methods presently disclosed can also be used
to diagnose and/or prognose problems in a compressor prior to total
compressor failure. If deterioration or degradation of the
compressor is detected in the system, action can be taken to reduce
progression of the problem and/or further identify the developing
problem. In this manner, customers realize a cost savings by
prognosing compressor problems in initial stages to reduce the
damage to compressor components and avoid compressor failure and
unplanned shutdowns. Moreover, secondary damage to other compressor
components (e.g., pistons, valves, liners, and the like) or damage
to equipment that relies upon the availability of the compressed
gas from the compressor may be avoided if compressor problems are
detected and addressed at an early stage.
[0025] FIG. 1 illustrates a block diagram of an embodiment of a
vehicle system 100. The vehicle system 100 is depicted as a rail
vehicle 106 (e.g., a locomotive) configured to run on a rail 102
via a plurality of wheels 108. The rail vehicle includes a
compressor system with a compressor 110. In an embodiment, the
compressor is a reciprocating compressor that delivers air at high
pressure. In another embodiment, the compressor is a reciprocating
compressor with a bi-directional drive system that drives a piston
in a forward direction and the reverse direction. In an embodiment,
the compressor receives air from an ambient air intake 114. The air
is then compressed to a pressure greater than the ambient pressure
and the compressed air is stored in reservoir 180, which is
monitored by a reservoir pressure sensor 185. In one embodiment,
the compressor is a two-stage compressor (such as illustrated in
FIG. 2) in which ambient air is compressed in a first stage to a
first pressure level and delivered to a second stage, which further
compresses the air to a second pressure level that is higher than
the first pressure level. The compressed air at the second pressure
level is stored in a reservoir. The compressed air may then be
provided to one or more pneumatic devices as needed. In other
embodiments, the compressor 110 may be a single stage or
multi-stage compressor.
[0026] The compressor includes a crankcase 160. The crankcase is an
enclosure for a crankshaft (not shown in FIG. 1) connected to
cylinders (not shown in FIG. 1) of the compressor. A motor 104
(e.g., electric motor) is employed to rotate the crankshaft to
drive the pistons within the cylinders. In another embodiment, the
crankshaft may be coupled to a drive shaft of an engine or other
power source configured to rotate the crankshaft of the compressor.
In each embodiment, the crankshaft may be lubricated with
compressor oil that is pumped by an oil pump (not shown) and
sprayed onto the crankshaft. The crankshaft is mechanically coupled
to a plurality of pistons via respective connecting rods. The
pistons are drawn and pushed within their respective cylinders as
the crankshaft is rotated to compress a gas in one or more
stages.
[0027] The rail vehicle further includes a controller 130 for
controlling various components related to the vehicle system. In an
embodiment, the controller is a computerized control system with a
processor 132 and a memory 134. The memory may be computer readable
storage media, and may include volatile and/or non-volatile memory
storage. In an embodiment, the controller includes multiple control
units and the control system may be distributed among each of the
control units. In yet another embodiment, a plurality of
controllers may cooperate as a single controller interfacing with
multiple compressors distributed across a plurality of vehicles.
Among other features, the controller may include instructions for
enabling on-board monitoring and control of vehicle operation.
Stationary applications may also include a controller for managing
the operation of one or more compressors and related equipment or
machinery.
[0028] In an embodiment, the controller receives signals from one
or more sensors 150 to monitor operating parameters and operating
conditions, and correspondingly adjust actuators 152 to control
operation of the rail vehicle and the compressor. In various
embodiments, the controller receives signals from one or more
sensors corresponding to compressor speed, compressor load, boost
pressure, exhaust pressure, ambient pressure, exhaust temperature,
or other parameters relating to the operation of the compressor or
surrounding system. In another embodiment, the controller receives
a signal from a crankcase pressure sensor 170 that corresponds to
the pressure within the crankcase. In yet another embodiment, the
controller receives a signal from a crankshaft position sensor 172
that indicates a position of the crankshaft. The position of the
crankshaft may be identified by the angular displacement of the
crankshaft relative to a known location such that the controller is
able to identify the position of each piston within its respective
cylinder based upon the position of the crankshaft. In some
embodiments, the controller controls the vehicle system by sending
commands to various components. On a locomotive, for example, such
components may include traction motors, alternators, cylinder
valves, and throttle controls among others. The controller may be
connected to the sensors and actuators through wires that may be
bundled together into one or more wiring harnesses to reduce space
in vehicle system devoted to wiring and to protect the signal wires
from abrasion and vibration. In other embodiments, the controller
communicates over a wired or wireless network that may allow for
the addition of components without dedicated wiring.
[0029] The controller may include onboard electronic diagnostics
for recording operational characteristics of the compressor.
Operational characteristics may include measurements from sensors
associated with the compressor or other components of the system.
Such operational characteristics may be stored in a database in
memory. In one embodiment, current operational characteristics may
be compared to past operational characteristics to identify trends
of compressor performance.
[0030] The controller may include onboard electronic diagnostics
for identifying and recording potential degradation and failures of
components of vehicle system. For example, when a potentially
degraded component is identified, a diagnostic code may be stored
in memory. In one embodiment, a unique diagnostic code may
correspond to each type of degradation that may be identified by
the controller. For example, a first diagnostic code may indicate a
malfunctioning exhaust valve of a cylinder, a second diagnostic
code may indicate a malfunctioning intake valve of a cylinder, a
third diagnostic code may indicate deterioration of a piston or
cylinder resulting in a blow-by condition. Additional diagnostic
codes may be defined to indicate other deteriorations or failure
modes. In yet other embodiments, diagnostic codes may be generated
dynamically to provide information about a detected problem that
does not correspond to a predetermined diagnostic code. In some
embodiments, the controller modifies the output of charged air from
the compressor, such as by reducing the duty cycle of the
compressor, based on parameters such as the condition or
availability of other compressor systems (such as on adjacent
locomotive engines), environmental conditions, and overall
pneumatic supply demand.
[0031] The controller may be further linked to display 140, such as
a diagnostic interface display, providing a user interface to the
operating crew and/or a maintenance crew. The controller may
control the compressor, in response to operator input via user
input controls 142, by sending a command to correspondingly adjust
various compressor actuators. Non-limiting examples of user input
controls may include a throttle control, a braking control, a
keyboard, and a power switch. Further, operational characteristics
of the compressor, such as diagnostic codes corresponding to
degraded components, may be reported via display to the operator
and/or the maintenance crew.
[0032] The vehicle system may include a communications system 144
linked to the controller. In one embodiment, communications system
may include a radio and an antenna for transmitting and receiving
voice and data messages. For example, data communications may be
between vehicle system and a control center of a railroad, another
locomotive, a satellite, and/or a wayside device, such as a
railroad switch. For example, the controller may estimate
geographic coordinates of a vehicle system using signals from a GPS
receiver. As another example, the controller may transmit
operational characteristics of the compressor to the control center
via a message transmitted from communications system. In one
embodiment, a message may be transmitted to the command center by
communications system when a degraded component of the compressor
is detected and the vehicle system may be scheduled for
maintenance.
[0033] As discussed above, the term "loaded" refers to a compressor
mode where air is being compressed into the reservoir. The
compressor depicted is one which utilizes spring return inlet and
discharge valves for each cylinder in which the movement of these
valves is caused by the differential pressure across them as
opposed to a mechanical coupling to the compressor crank shaft. The
subject disclosure may be applicable to machines with either type
of valve, but the spring return type will be illustrated here for
the sake of brevity.
[0034] The controller can be configured to adjust at least one of
the following: an operation of the compressor; a scheduled
maintenance for the compressor; a maintenance for the compressor; a
service for the compressor; a diagnostic code of the compressor; an
alert for the compressor; among others. In an embodiment, the
controller can be configured to adjust the compressor based upon a
detection of a change in pressure for the crankcase. In a more
particular embodiment, the controller can be configured to adjust
the compressor based upon a monitored change in pressure in
combination with a position of a piston of the compressor.
[0035] The compressor 110 can include a detection component 128
that can be configured to detect at least one of a pattern, a
signature, a level, among others related to a crankcase pressure
measured, wherein such detection is indicative of a leak condition
for the compressor. In particular, the leak condition can relate to
crankcase breather valve or blow-by condition (discussed in more
detail below). The detection component and/or the pressure sensor
(e.g., pressure sensor 170) can be employed with the compressor to
collect pressure data that is indicative of a leak condition. In an
embodiment, the controller can be configured to adjust the
compressor based upon the detection component and/or the pressure
sensor.
[0036] The detection component can be a stand-alone component (as
depicted), incorporated into the controller component, or a
combination thereof. The controller component can be a stand-alone
component (as depicted), incorporated into the detection component,
or a combination thereof. In another embodiment, the detection
component and/or the pressure sensor can be a stand-alone component
(as depicted), incorporated into the controller component, or a
combination thereof.
[0037] FIG. 2 illustrates a detailed view of the compressor set
forth in FIG. 1 above. The compressor includes three cylinders 210,
220, 230. Each cylinder contains a piston 218, 228, 238 that is
coupled to a crankshaft 250 via connecting rods 240, 242, 244. The
crankshaft is driven by the motor to cyclically pull the respective
pistons to a Bottom-Dead-Center (BDC) and push the pistons to a
Top-Dead-Center (TDC) to output charged air, which is delivered to
the reservoir via air lines 280, 282, 284, 286. In this embodiment,
the compressor is divided into two stages: a low pressure stage and
a high pressure stage to produce charged air in a stepwise
approach. The low pressure stage compresses air to a first pressure
level which is further compressed by the high pressure stage to a
second pressure level. In this example, the low pressure stage
includes cylinders 220, 230 and the high pressure stage includes
cylinder 210.
[0038] In operation, air from the ambient air intake is first drawn
into the low pressure cylinders via intake valves 222, 232, which
open and close within intake ports 223, 233. The ambient air is
drawn in as the low pressure cylinders are pulled towards BDC and
the intake valves 222, 232 separate from intake ports 223, 233 to
allow air to enter each cylinder 220, 230. Once the pistons reach
BDC, the intake valves 222, 232 close the intake ports 223, 233 to
contain air within each cylinder. Subsequently, pistons 228, 238
are pushed toward TDC, thereby compressing the ambient air
initially drawn into the cylinders. Once the cylinders have
compressed the ambient air to a first pressure level, exhaust
valves 224, 234 within exhaust ports 225, 235 are opened to release
the low pressure air into low pressure lines 280, 282.
[0039] The air compressed to a first pressure level is routed to an
intermediate stage reservoir 260. The intermediate stage reservoir
260 received air from one stage of a multistage compressor and
provides the compressed air to a subsequent stage of a multistage
compressor. In an embodiment, the intermediate stage reservoir 260
is a tank or other volume connected between successive stages by
air lines. In other embodiments, the air lines, such as low
pressure lines 280, 282 provide sufficient volume to function as an
intermediate stage reservoir without the need for a tank or other
structure.
[0040] In an embodiment, the compressor system also includes an
intercooler 264 that removes the heat of compression through a
substantially constant pressure cooling process. One or more
intercoolers may be provided along with one or more intercooler
controllers 262. In some embodiments, the intercooler 264 is
integrated with the intermediate stage reservoir 260. A decrease in
the temperature of the compressed air increases the air density
allowing a greater mass to be drawn into the high pressure stage
increasing the efficiency of the compressor. The operation of the
intercooler is controlled by the intercooler controller 262 to
manage the cooling operation. In an embodiment, the intercooler
controller 262 employs a thermostatic control through mechanical
means such as via thermal expansion of metal. In a multistage
compressor system having more than two stages, an intercooler may
be provided at each intermediate stage.
[0041] The air at a first pressure level (e.g., low pressure air)
is exhausted from the intercooler into low pressure air line 284
and subsequently drawn into the high pressure cylinder 210. More
particularly, as piston 218 is pulled toward BDC, the intake valve
212 opens, thereby allowing the low pressure air to be drawn into
the cylinder 210 via intake port 213. Once the piston 218 reaches
BDC, the intake valve 212 closes to seal the low pressure air
within the cylinder 210. The piston is then pushed upward thereby
compressing the low pressure air into high pressure air. High
pressure air is air at a second pressure level greater than the
first pressure level, however the amount of compression will vary
based upon the requirements of the application. As compression
increases, the exhaust valve 214 is opened to allow the high
pressure air to exhaust into high pressure line 286 via exhaust
port 215. An aftercooler 270 cools the high pressure air to
facilitate a greater density to be delivered to the reservoir via
high pressure air line 288.
[0042] The above process is repeated cyclically as the crankshaft
250 rotates to provide high pressure air to the reservoir 180,
which is monitored by the reservoir pressure sensor 185. Once the
reservoir reaches a particular pressure level (e.g., 140 psi), the
compressor operation is discontinued.
[0043] In some embodiments, the compressor includes one or more
valves configured to vent compressed air from intermediate stages
of the compressor system. The unloader valves and/or relief valves
may be operated after compressor operations are discontinued, or
may be operated during compressor operations to relieve pressure in
the compressor system. In an embodiment, an unloader valve 268 is
provided in the intermediate stage reservoir 260 and configured to
vent the low pressure compressed air from the intermediate stage
reservoir, low pressure air lines 280, 282 and intercooler 264.
Venting compressed air reduces stress on system components during
periods when the compressor is not in use and may extend the life
of the system. In another embodiment, the unloader valve 268
operates as a relief valve to limit the buildup of pressure in the
intermediate stage reservoir 260. In yet another embodiment, intake
valves 222, 232 operate as unloader valves for the cylinders 220,
230 allowing compressed air in the cylinders to vent back to the
ambient air intake 114. In another embodiment, the system 200 can
include relief valves such as breather valve 174, a relieve valve
on the intercooler 264 (shown in FIG. 4), a relieve valve for air
line 286, a rapid unloader valve on the intercooler 264 (shown in
FIG. 4)
[0044] A compressor, such as the compressor illustrated in FIG. 2,
operates to charge the reservoir 180 with compressed air or other
gas. Once the compressor charges the reservoir to a determined
pressure value the compressor operation is discontinued. In some
embodiments, when compressor operations are discontinued, one or
more unloader valves are opened to vent intermediate stages of the
compressor to the atmosphere. The intake valves of the cylinders as
well as unloader valves of the intermediate stage reservoirs may
all operate as unloader valves to vent the cylinders of the
compressor to the atmosphere. Once the unloader valves are actuated
and the cylinders and intermediate stages of the compressor have
been vented to the atmosphere the pressure within the reservoir is
expected to remain constant as previously discussed.
[0045] The compressor 110 can include additional features and/or
components that are not illustrated in FIGS. 1 and 2. For instance,
the system may include a Control Mag Valve (CMV), a
Thermostatically Controlled Intercooler System (TCIS) bypass, a
rapid unloader valve, an unloader valve for cylinder 230, an
unloader valve for cylinder 220, a relief valve(s), among
others.
[0046] The crankshaft can include a first end opposite a second end
in which the first end is coupled to one or more connecting rods
for each respective cylinder. The crankshaft, cylinders, and
pistons are illustrated in BDC position based upon the location of
the first end. BDC position is a location of the first end at
approximately negative ninety degrees (-90 degrees) or 270 degrees.
A TDC position is a location of the first end at approximately
ninety degrees (90 degrees) or -270 degrees.
[0047] As discussed above, the controller can be configured to
employ an adjustment to the compressor based upon at least one of a
detected change of pressure in the crankcase or a detected change
of pressure in the crankcase correlated with a position of a
piston. In embodiment, the pressure sensor can monitor a pressure
for the crankcase with or without a cycling of a piston. Upon
detection of a change in the pressure of the crankcase, the
controller can implement an adjustment to the compressor and/or
communicate an alert based on the detected change.
[0048] Referring now to FIGS. 3-6, an embodiment of a method and/or
employment of a system for a compressor is illustrated. In an
embodiment, a method for a compressor includes monitoring a
crankcase pressure of a compressor, analyzing the monitored
crankcase pressure, and identifying a condition of the compressor
based on the analysis of the monitored crankcase pressure. When a
reciprocating compressor is operating, such as the compressor 110
shown in FIG. 2, the crankshaft 250 rotates causing the pistons
218, 228, 238 to move within their respective cylinders. As the
pistons move through each revolution, the effective volume of the
crankcase 160 changes.
[0049] For ease of illustration, a crankcase pressure 350 of a
single stage compressor having only one cylinder, such as cylinder
210, is illustrated in graph 300 of FIG. 3. As the piston rises on
a compression stroke the effective volume of the crankcase
increases (e.g., due to the volume of the piston leaving the
crankcase) resulting in a drop in crankcase pressure as measured by
a crankcase pressure sensor, such as crankcase pressure sensor 170.
The crankcase pressure 350 falls until the piston reaches top dead
center at which point the crankcase pressure reaches a minimum as
shown by a trough 352. As the piston moves through a suction stroke
the effective volume of the crankcase is reduced resulting in an
increase in crankcase pressure. The crankcase pressure 350 rises
until the piston reaches bottom dead center at which point the
crankcase pressure reaches a peak 354. As illustrated in FIG. 3,
crankcase pressure rises and falls corresponding to the position of
the piston within the cylinder with a period 362 corresponding to
one revolution of the piston. In a multistage compressor, such as a
compressor having two or more cylinders, the movement of each
piston affects the crankcase pressure in a similar manner. In the
compressor illustrated in FIG. 2, each of the three pistons 218,
228, 238 would produce similar periodic pressure variations that
would be offset from each other depending upon the configuration of
the crankshaft. The corresponding crankcase pressure would
therefore reflect multiple peaks and troughs correlated to the
positions of one, two or more pistons of the compressor. In
multi-stage compressor, the crankcase pressure may be correlated
with an indication of the position of one or more of the pistons to
identify the effect that each piston has on the crankcase pressure.
Using the correlation, a condition of one of the plurality of
cylinders of the compressor may be determined
[0050] As shown in graph 300 of FIG. 3, in a healthy compressor
system the crankcase pressure 350 is typically maintained below
atmospheric pressure, which is indicated as "0". In various
embodiments, the compressor includes a crankcase breather valve,
such as breather valve 174 in FIG. 2, which regulates crankcase
pressure by permitting air to exit the crankcase when crankcase
pressure rises and limiting air entering the crankcase when
crankcase pressure falls. In this manner, excessive pressure within
the crankcase is avoided so as to improve the efficiency of the
compressor system. As a result, the average crankcase pressure
during operation of the compressor system is maintained in the
desired range.
[0051] In one embodiment, analyzing the monitored crankcase
pressure includes calculating an average of the crankcase pressure
over a time period and comparing the average crankcase pressure to
a nominal crankcase average pressure. The condition of the
compressor may then be determined (e.g., identified) based on the
difference between the calculated crankcase average pressure and
the nominal crankcase average pressure. In an embodiment, the
nominal crankcase average pressure is the expected average pressure
based upon the design of the compressor and crankcase. The nominal
crankcase average pressure may be determined from empirical tests
to establish a baseline when the compressor is new or otherwise
known to be operating correctly. The baseline may be stored in
memory and compared to the actual crankcase average pressure
periodically to monitor compressor operations. In yet another
embodiment, the nominal crankcase average pressure is calculated
based upon environmental or operating conditions. For example, in
some designs the crankcase pressure may vary based on ambient air
temperature or ambient air pressure. The nominal crankcase average
pressure may thus be adjusted to account for such environmental
conditions. In other embodiments, one or more of the compressor
operating speed, the reservoir pressure or the compressor oil
temperature are correlated to the nominal or expected crankcase
average compressor. In yet other embodiments, the nominal crankcase
pressure is a predetermined limit which if exceeded requires
compressor operation to be discontinued. The nominal crankcase
average pressure may therefore be determined from at least one or
more of these or other environmental or operating parameters of the
compressor.
[0052] In a healthy compressor system, the crankcase average
pressure and correlation of the crankcase pressure to the position
of the piston may remain substantially constant as illustrated in
graph 300 of FIG. 3. The failure or degradation of the breather
valve however may interfere with the proper regulation of crankcase
pressure. If the breaker valve becomes clogged, air is not released
as crankcase pressure rises resulting in a shift in the measured
crankcase pressure, such as illustrated in graph 400 of FIG. 4. As
shown, the periodic peaks 360 and troughs 358 correlated with
piston movement are still detectable in a measured crankcase
pressure 356 (also referred to as crankcase pressure 356). The
crankcase average pressure however rises as the breather valve is
unable to vent the excess pressure within the crankcase. In this
manner, a crankcase breather valve failure is identified by the
increased average pressure, and appropriate maintenance or repair
operations may be scheduled. Over time, the increased crankcase
average pressure may result in damage to the seals and other
components of the compressor system, and if unchecked could render
the compressor system inoperative. Increased crankcase pressure may
also reduce the efficiency of the compressor system by pushing
against each piston as the piston is pulled through its suction
stroke increasing the load on the motor 104 or other power source
driving the crankshaft 250.
[0053] In other embodiments, a method for a compressor that
includes monitoring the crankcase pressure is used to identify
other compressor failure modes. In one embodiment, a condition of
one of a plurality of cylinders is identified based on the
correlation of the monitored crankcase pressure and the indication
of the position of the piston in the cylinder of a reciprocating
compressor. During operation, air is compressed within the cylinder
as the piston travels through a compression stroke to fill the
reservoir 180 with compressed air. In order to maintain efficient
operation, the volume of the cylinder in which compression occurs
is substantially sealed, such as with a lining or seal may be used
to limit leakage of air as the piston travels within the
cylinder.
[0054] Referring now to system 500 of FIG. 5, the high pressure
cylinder 210 of FIG. 2 is illustrated during a compression stroke.
During at least a portion of the compression stroke of the piston
218, the intake valve 212 is closed sealing the intake port 213,
and the exhaust valve 214 is closed sealing the exhaust port 215.
With the intake and exhaust ports sealed, the internal volume of
the cylinder 210 is expected to be substantially sealed such that
the air within the cylinder can be compressed. As a result of wear
between the piston 218 and a cylinder inner wall 290 or other
degradation in the lining or seals used to maintain the closed
volume, air may leak between the piston 218 and the cylinder inner
wall 290 into the crankcase 160 as illustrated by arrows 370. Wear
of the piston or cylinder wall may result from a variety of
problems, such as misalignment of the piston or operating without
sufficient lubricating oil or at excessive oil temperatures. In
addition, seals or cylinder linings may degrade as a result of
excess crankcase pressure, such as may be caused by the failure of
a breather valve as previously discussed. Regardless of the
underlying cause, a piston blow-by condition develops when air
escapes from the cylinder 210 passed the piston 218 and into the
crankcase 160 (as illustrated by arrows 370).
[0055] The flow of air into the crankcase resulting from a piston
blow-by condition affects the crankcase pressure measured by the
crankcase pressure sensor 170. By way of illustration, graph 600 of
FIG. 6 illustrates a healthy crankcase pressure 372 analogous to
that illustrated in graph 300 of FIG. 3. When a cylinder has been
degraded, the crankcase pressure may develop a blow-by indication
374. In one embodiment, the blow-by indication 374 is an increase
in measured crankcase pressure during the compression stroke of a
piston. Using crankshaft position sensor 172, the position of each
piston may be determined such that the compression stroke of each
position is identified. By correlating the identified blow-by
condition 374 with the compression stroke of a given piston, a
blow-by condition of a given cylinder is identified. The
identification of a specific cylinder in which the blow-by
condition is occurring facilitates repairs and improves the
efficiency of maintenance operations.
[0056] In addition to identifying the existence of a blow-by
condition, the severity of the blow-by condition may be assessed.
As illustrated in graph 600 of FIG. 6, a blow-by condition may
present as an increase in crankcase pressure during a compression
stroke. In other embodiments where the blow-by condition is less
severe, the blow-by indication may be a reduction in the decrease
of crankcase pressure during a compression stroke. Stated another
way, a reduction in the difference between the peaks 376 and
troughs 378 of the measured crankcase pressure may indicate a
blow-by condition even if the crankcase pressure does not rise
during the compression stroke.
[0057] The illustrations of monitored crankcase pressure in graphs
300, 400, and 600 in FIGS. 3-4, and 6 respectively, demonstrate the
effects of a single cylinder. In compressor systems having two or
more cylinders, each cylinder produces a similar effect on
crankcase pressure such that the resulting crankcase pressure
reflects the combination of those effects. In another embodiment,
the monitored crankcase pressure is analyzed by identifying the
frequency content of the monitored crankcase pressure at one or
more known frequencies. The known frequencies are determined based
on the rate at which the compressor is operated. As noted above,
the monitored crankcase pressure is expected to rise and fall as
the piston cycles within the cylinder. The monitored crankcase
pressure thus includes a periodic variation that corresponds to a
once-per-revolution signature associated with the movement of the
piston. As shown in graph 600 of FIG. 6, a piston blow-by condition
may produce an additional peak 374 (also referred to as a blow-by
condition). The blow-by condition is therefore identifiable in a
frequency analysis based upon the rate at which the compressor is
operated. In one embodiment, the blow-by condition may result in a
detectable change in the once-per-revolution signature. In other
embodiments, the blow-by condition may result in a detectable
twice-per-revolution signature. A range of frequency components
related to the compressor operating speed may also be generated as
the crankcase pressure is affected by one or more pistons, one or
more blow-by conditions, breather valve failures, or other effects
during operation of the compressor. In this manner, a frequency
analysis of the monitored crankcase pressure is used to determine
(e.g., identify) the condition of the compressor. The frequency
analysis may be used in addition or as an alternative to time
domain analysis of the monitored crankcase pressure. To further
assist in identifying faults, crankcase pressure is monitored under
different operating conditions, such as at different reservoir
pressure levels, and when the pistons are cycled under loaded and
unloaded conditions. In this manner, the methods for a compressor
presently disclosed provide advanced detection of faults and
facilitate troubleshooting and repair by identifying the nature of
the failure and the likely components at fault.
[0058] In yet another embodiment, a controller is provided to
determine a condition of a compressor. The controller is configured
to receive a signal corresponding to a monitored pressure within a
crankcase of a compressor. In an embodiment, the controller is
configured to communicate with one or more crankcase pressure
sensors 170 and receive the signal corresponding to the monitored
pressure from the one or more crankcase pressure sensors. The
controller is also configured to analyze the monitored crankcase
pressure and determine a condition of the compressor based on the
analysis of the monitored crankcase pressure. In one embodiment,
the controller performs a frequency analysis and identifies
frequency components in the monitored crankcase pressure based upon
the rate at which the compressor is operated.
[0059] In another embodiment, the controller correlates the
monitored crankcase pressure with an indication of a position of a
piston in a cylinder of the compressor. The controller may
communicate with the crankshaft position sensor 172 to determine
the position of the piston in the cylinder. In an embodiment, the
controller is integral with a vehicle system, such as controller
130. In yet another embodiment, the controller is provided with a
test kit used for maintenance and repair or diagnostic operations.
In this manner, the controller may be further configured to actuate
the compressor in either a loaded or unloaded condition while
monitoring crankcase pressure. In embodiments, the controller is
able to identify a blow-by condition of at least one cylinder of
the compressor and identity a crankcase breather valve failure by
analyzing the measured crankcase pressure as described above. The
controller may include a processor and may be configured to
calculate an average of the crankcase pressure over a time period,
and compare the average crankcase pressure over the time period to
a nominal crankcase average pressure. In some embodiments, the time
period is determined by the operator, however in other embodiments,
the time period is determined by the controller based on operating
conditions of the compressor. In some applications, the measured
crankcase pressure will also be influenced by vibrations and noise
from related system components. By averaging the measured crankcase
pressure over a time period, such influences may be reduced
providing a more accurate assessment of crankcase pressure.
[0060] When a fault is detected, such as a blow-by condition or a
breather valve failure, a variety of steps may be taken to reduce
further degradation of the compressor system. In one embodiment, a
signal is generated in response to determining a condition of the
compressor based on the analysis of the monitored crankcase
pressure. The generated signal may indicate a severity level of the
condition, such as the severity of a blow-by condition as indicated
by the rise in crankcase pressure during a compression stroke of a
piston. In an embodiment, in response to the signal, the duty cycle
of the compressor is reduced in order to reduce further degradation
of the compressor until repairs can be made. The duty cycle may be
reduced by a fixed amount, such as by 25%, 50% or more, or may be
reduced in proportion to the severity of the identified failure. If
the leak condition is severe, power to the compressor may be
disconnected such that the compressor ceases operating until
appropriate repairs have been effected. In another embodiment,
personnel are notified by an audio alarm, a visual alarm, a text
message, an email, an instant message, a phone call, or other
method appropriate for the operating environment. In a system
having multiple compressors, in response to a detected leak on one
compressor the operation of the other compressors may be adjusted
to compensate for the reduced performance of one compressor
allowing the system to remain functional until repairs can be
scheduled.
[0061] In various other embodiments, the aspects of the systems and
methods previously described may also be employed individually or
in combination to diagnose the condition of a compressor. In one
embodiment, a method for diagnosing a compressor includes operating
a compressor in an unloaded condition by cycling the pistons within
their respective cylinders, monitoring at least the reservoir
pressure and the crankcase pressure, and determining a condition of
the compressor based on an analysis of both the monitored reservoir
pressure and crankcase pressure. In another embodiment, a method
for diagnosing a compressor includes operating a multi-stage
compressor to charge a reservoir with compressed air, monitoring at
least a crankcase pressure and an intermediate stage pressure, and
determining a condition of the compressor based on an analysis of
both the monitored crankcase pressure and the monitored
intermediate stage pressure. In yet another embodiment, a method
for diagnosing a compressor includes monitoring signals from at
least two of a primary reservoir pressure sensor, an intermediate
reservoir pressure sensor, a crankcase pressure sensor, and a
crankshaft position sensor, and correlating the monitored signals
to identify a failure condition of the compressor. In yet another
embodiment, a method of diagnosing a compressor includes actuating
an unloader valve, monitoring at least a reservoir pressure sensor
and a crankshaft position sensor, and identifying a leak condition
of a valve disposed between a cylinder and a reservoir of a
compressor. By way of example and not limitation, the subject
disclosure can be utilized alone or in combination with a system
and/or method disclosed in U.S. Provisional Application Ser. No.
61/636,192, filed Apr. 20, 2012, and entitled "SYSTEM AND METHOD
FOR A COMPRESSOR" in which the entirety of the aforementioned
application is incorporated herein by reference.
[0062] The methods and systems disclosed herein may be applied to a
reciprocating compressor having one or more compressor stages, such
as the compressor illustrated in FIG. 2. In other embodiments, the
methods and systems may be applied to other types of compressors.
For example, the compressor may be a diaphragm or membrane
compressor in which the compression is produced by movement of a
flexible membrane. The compressor may also be a hermetically sealed
or semi-hermetically sealed compressor. In addition, the compressor
types may include centrifugal compressors, diagonal or mixed flow
compressors, axial flow compressors, rotary screw compressors,
rotary vane compressors, and scroll compressors, among others.
[0063] The methods presently disclosed may also include generating
a signal corresponding to the failure condition and alerting an
operator or other personnel so that remedial action may be taken.
Each of these systems and methods described above may also be
implemented on a vehicle system such as the rail vehicle 106
described above. In still yet other embodiments, a test kit is
provided that includes a controller having a memory and a processor
configured to perform the methods described above.
[0064] In each of the embodiments presently disclosed, component
fault data may be recorded. In one embodiment, component fault data
may be stored in a database including historical compressor data.
For example, the database may be stored in memory 134 of controller
130. As another example, the database may be stored at a site
remote from rail vehicle 106. For example, historical compressor
data may be encapsulated in a message and transmitted with
communications system 144. In this manner, a command center may
monitor the health of the compressor in real-time. For example, the
command center may perform steps to diagnose the condition of the
compressor using the compressor data transmitted with
communications system 144. For example, the command center may
receive compressor data including cylinder pressure data from rail
vehicle 106, reservoir pressure, intermediate stage pressure,
crankcase pressure, displacement of one or more pistons, and/or
movement of the crankshaft to diagnose potential degradation of the
compressor. Further, the command center may schedule maintenance
and deploy healthy locomotives and maintenance crews in a manner to
optimize capital investment. Historical compressor data may be
further used to evaluate the health of the compressor before and
after compressor service, compressor modifications, and compressor
component change-outs.
[0065] If a leak or other fault condition exists, further
diagnostics and response may be performed. For example, a potential
faulty valve condition can be reported to notify appropriate
personnel. In an embodiment, reporting is initiated with a signal
output to indicate that a fault condition exists. The report is
presented via display 140 or a message transmitted with
communications system 144, as examples. Once notified, the operator
may adjust operation of rail vehicle 106 to reduce the potential of
further degradation of the compressor.
[0066] In one embodiment, a message indicating a potential fault is
transmitted with communications system 144 to a command center.
Further, the severity of the potential fault may be reported. For
example, diagnosing a fault based on the above described methods
may allow a fault to be detected earlier than when the fault is
diagnosed with previously available means. In some applications,
the compressor is permitted to continue operating when a potential
fault is diagnosed in the early stages of degradation. In other
applications, the compressor is stopped or maintenance may be
promptly scheduled, such as when the potential fault is diagnosed
as severe. In this manner the cost of secondary damage to the
compressor can be avoided by early and accurate detection.
[0067] The severity of the potential fault may be determined based
upon an analysis of one or more parameters from one or more
diagnostic methods. For example, it may be more desirable to switch
off the compressor than to have a degraded cylinder fail in a
manner that may cause additional damage to the compressor. In one
embodiment, a threshold value or one or more monitored parameters
may be determined that indicates continued operation of the
compressor is undesirable because the potential fault is severe. As
one example, the potential fault may be judged as severe if the
leakage of an exhaust valve exceeds a predetermined threshold.
[0068] In some embodiments, a request to schedule service is sent,
such as by a message sent via communications system 144. Further,
by sending the potential fault condition and the severity of the
potential fault, down-time of rail vehicle 106 may be reduced. For
example, service may be deferred on rail vehicle 106 when the
potential fault is of low severity. Down-time may be further
reduced by derating power of the compressor, such as by adjusting a
compressor operating parameter based on the diagnosed
condition.
[0069] In yet other embodiments, backup or redundant systems may be
available. In an example, backup systems can be evaluated to
determine if adequate substitute resources exist to replace the
compromised compressor. In some instances, a pre-ordered list of
backup systems is used to prioritize the use of backup systems,
such as other compressors configured to supply compressed air to
pneumatic devices on a plurality of rail vehicles. Various backup
systems may be employed including stopping the faulty compressor
and receiving charged air from another source. In one example, the
other source is a compressor that is disposed on an adjacent
locomotive engine. In another example, the other source is a
redundant compressor on the same locomotive that is used for this
purpose. The backup procedure can be designed to minimize negative
system-wide consequences to operation of the locomotive. This is
especially true for mission critical systems.
[0070] The aforementioned systems, components, (e.g., controller,
detection component, pressure sensor, among others), and the like
have been described with respect to interaction between several
components and/or elements. It should be appreciated that such
devices and elements can include those elements or sub-elements
specified therein, some of the specified elements or sub-elements,
and/or additional elements. Further yet, one or more elements
and/or sub-elements may be combined into a single component to
provide aggregate functionality. The elements may also interact
with one or more other elements not specifically described
herein.
[0071] In view of the exemplary devices and elements described
supra, methodologies that may be implemented in accordance with the
disclosed subject matter will be better appreciated with reference
to the flow chart of FIG. 7. The methodologies are shown and
described as a series of blocks, the claimed subject matter is not
limited by the order of the blocks, as some blocks may occur in
different orders and/or concurrently with other blocks from what is
depicted and described herein. Moreover, not all illustrated blocks
may be required to implement the methods described hereinafter. The
methodologies can be implemented by a component or a portion of a
component that includes at least a processor, a memory, and an
instruction stored on the memory for the processor to execute.
[0072] FIG. 7 illustrates a flow chart of a method 700 for
identifying a condition of a compressor based upon a measured
crankcase pressure. At reference numeral 702, a crankcase pressure
of a compressor can be monitored. At reference numeral 704, the
monitored crankcase pressure can be analyzed. At reference numeral
706, a condition of the compressor can be identified based on the
analysis of the monitored crankcase pressure.
[0073] In an embodiment, a method for a compressor is provided that
includes monitoring a crankcase pressure of a compressor; analyzing
the monitored crankcase pressure; and determining a condition of
the compressor based on the analysis of the monitored crankcase
pressure. In embodiment, the method can include analyzing the
monitored crankcase pressure by calculating an average of the
crankcase pressure over a time period; and comparing the average
crankcase pressure over the time period to a nominal crankcase
average pressure. In an embodiment, the method includes determining
a condition of the compressor based on the difference between the
calculated crankcase average pressure and the nominal crankcase
average pressure. In an embodiment, the method includes determining
the nominal crankcase average pressure from at least one of ambient
air temperature and ambient air pressure. In an embodiment, the
method includes determining the nominal crankcase average pressure
from at least one of compressor speed, reservoir pressure, and oil
temperature.
[0074] In an embodiment, the method includes analyzing the
monitored crankcase pressure by identifying frequency content of
the monitored crankcase pressure at one or more known frequencies.
In an embodiment, the method includes determining the one or more
known frequencies based on a rate at which the compressor is
operated. In an embodiment, the method includes analyzing the
monitored crankcase pressure by correlating the monitored crankcase
pressure with an indication of the position of one or more pistons
of the compressor during a time period in which the one or more
pistons are operated. In an embodiment, the method includes
determining a condition of the compressor by identifying a
condition of one of a plurality of cylinders of the compressor
based on a correlation of the monitored crankcase pressure and an
indication of the position of the piston in the cylinder of the
compressor.
[0075] In an embodiment, the method includes determining a
condition of the compressor by identifying a piston blow-by
condition of at least one cylinder of the compressor based on the
analysis of the monitored crankcase pressure. In an embodiment, the
method includes determining a condition of the compressor by
identifying a crankcase breather valve failure based on the
analysis of the monitored crankcase pressure. In an embodiment, the
method includes monitoring the crankcase pressure of a compressor
while a piston is cycled within a cylinder of the compressor in an
unloaded condition. In an embodiment, the method includes
monitoring the crankcase pressure of the compressor while a piston
is cycled within a cylinder of the compressor in a loaded
condition.
[0076] In an embodiment, the method includes monitoring the
crankcase pressure of the compressor during a first time period
during which a piston is cycled within a cylinder of the compressor
in an unloaded; monitoring the crankcase pressure of the compressor
during second time period during which the piston is cycled within
the cylinder of the compressor in a loaded condition; and
determining a condition of the compressor based on the analysis of
the monitored crankcase pressure from the first time period and the
second time period.
[0077] In an embodiment, the method includes generating a signal in
response to determining a condition of the compressor based on the
analysis of the monitored crankcase pressure. In an embodiment, the
method includes reducing a duty cycle of the compressor in response
to determining a condition of the compressor based on the analysis
of the monitored crankcase pressure. In an embodiment, the method
includes notifying personnel via one or more of an audio alarm, a
visual alarm, a text message, an email, an instant message, or a
phone call in response to determining a condition of the compressor
based on the analysis of the monitored crankcase pressure.
[0078] In an embodiment, a controller that is operable to determine
a condition of a compressor is provided in which the controller is
configured to receive a signal corresponding to a monitored
pressure within a crankcase of the compressor; analyze the
monitored crankcase pressure; and identify a condition of the
compressor based on the analysis of the monitored crankcase
pressure. In an embodiment, the condition of the compressor is a
piston blow-by condition of at least one cylinder of the
compressor. In an embodiment, the condition of the compressor is a
crankcase breather valve failure. In an embodiment, the controller
is further configured to calculate an average of the crankcase
pressure over a time period; and compare the average crankcase
pressure over the time period to a nominal crankcase average
pressure. In an embodiment, the controller is further configured to
communicate with one or more crankcase pressure sensors and receive
the signal corresponding to the monitored pressure from the one or
more crankcase pressure sensors.
[0079] In embodiments, a system is disclosed. The system includes
an engine; a compressor operatively connected to the engine,
wherein the compressor includes a crankcase having a crankcase
pressure sensor; a controller that is operable to determine a
condition of the compressor, wherein the controller is configured
to receive a signal corresponding to a monitored pressure within
the crankcase of the compressor from the crankcase pressure sensor,
analyze the monitored crankcase pressure; and determine a condition
of the compressor based on the analysis of the monitored crankcase
pressure.
[0080] In embodiments, a compressor system is disclosed that
includes means for means for monitoring a crankcase pressure of a
compressor (for example, a crankcase pressure of a compressor can
be monitored by the pressure sensor 170, the sensor 172, the
detection component 128, among others); means for analyzing the
monitored crankcase pressure (for example, the analysis of the
monitored crankcase pressure can be provided by the controller 130,
the detection component 128, among others); and means for
determining a condition of the compressor based on the analysis of
the monitored crankcase pressure (for example, the condition of the
compressor can be determined by the controller 130).
[0081] In an embodiment, a compressor can be provided that includes
a sensor configured to measure pressure in a crankcase of a
compressor and means for determining the position of a piston in a
cylinder of the compressor, wherein the piston is operably
connected to a crankshaft in the crankcase of the compressor. In
the embodiment, the compressor can further include means for
determining a condition of the compressor based on a correlation of
the monitored crankcase pressure and an indication of a position of
a piston in a cylinder of the compressor. Furthermore, the means
for determining the position of a piston in a cylinder of the
compressor can include a crankshaft position sensor.
[0082] As used herein, the terms "high pressure" and "low pressure"
are relative to one another, that is, a high pressure is higher
than a low pressure, and a low pressure is lower than a high
pressure. In an air compressor, low pressure may refer to a
pressure that is higher than atmospheric pressure, but that is
lower than another, higher pressure in the compressor. For example,
air at atmospheric pressure may be compressed to a first, low
pressure (which is still higher than atmospheric pressure), and
further compressed, from the first, low pressure, to a second, high
pressure that is higher than the low pressure. An example of a high
pressure in a rail vehicle context is 140 psi (965 kPa).
[0083] In the specification and claims, reference will be made to a
number of terms that have the following meanings. The singular
forms "a", "an" and "the" include plural referents unless the
context clearly dictates otherwise. Approximating language, as used
herein throughout the specification and claims, may be applied to
modify a quantitative representation that could permissibly vary
without resulting in a change in the basic function to which it is
related. Accordingly, a value modified by a term such as "about" is
not to be limited to the precise value specified. In some
instances, the approximating language may correspond to the
precision of an instrument for measuring the value. Moreover,
unless specifically stated otherwise, a use of the terms "first,"
"second," etc., do not denote an order or importance, but rather
the terms "first," "second," etc., are used to distinguish one
element from another.
[0084] As used herein, the terms "may" and "may be" indicate a
possibility of an occurrence within a set of circumstances; a
possession of a specified property, characteristic or function;
and/or qualify another verb by expressing one or more of an
ability, capability, or possibility associated with the qualified
verb. Accordingly, usage of "may" and "may be" indicates that a
modified term is apparently appropriate, capable, or suitable for
an indicated capacity, function, or usage, while taking into
account that in some circumstances the modified term may sometimes
not be appropriate, capable, or suitable. For example, in some
circumstances an event or capacity can be expected, while in other
circumstances the event or capacity cannot occur--this distinction
is captured by the terms "may" and "may be."
[0085] This written description uses examples to disclose the
invention, including the best mode, and also to enable one of
ordinary skill in the art to practice the invention, including
making and using a devices or systems and performing incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to one of
ordinary skill in the art. Such other examples are intended to be
within the scope of the claims if they have structural elements
that do not differentiate from the literal language of the claims,
or if they include equivalent structural elements with
insubstantial differences from the literal language of the
claims.
* * * * *