U.S. patent application number 15/796124 was filed with the patent office on 2019-05-02 for system and method of valve wear detection.
The applicant listed for this patent is General Electric Company. Invention is credited to Chandan Kumar, Pavan Chakravarthy Nandigama, Amit Shrivastava.
Application Number | 20190128203 15/796124 |
Document ID | / |
Family ID | 63965531 |
Filed Date | 2019-05-02 |
United States Patent
Application |
20190128203 |
Kind Code |
A1 |
Shrivastava; Amit ; et
al. |
May 2, 2019 |
SYSTEM AND METHOD OF VALVE WEAR DETECTION
Abstract
A system includes a reciprocating engine having a piston
disposed in a cylinder, an intake valve, an exhaust valve, and an
exhaust flow path downstream of the exhaust valve. The system also
includes a first sensor configured to obtain a first feedback
indicative of an exhaust gas parameter in the exhaust flow path.
The system also includes a controller configured to identify a
valve wear condition of at least one of the intake valve or the
exhaust valve at least partially based on the first feedback from
the first sensor.
Inventors: |
Shrivastava; Amit;
(Bangalore, IN) ; Kumar; Chandan; (Hyderabad,
IN) ; Nandigama; Pavan Chakravarthy; (Bangalore,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
63965531 |
Appl. No.: |
15/796124 |
Filed: |
October 27, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01L 3/00 20130101; F02D
2041/228 20130101; F01L 2800/11 20130101; F02D 41/2451 20130101;
Y02T 10/40 20130101; F02D 41/1459 20130101; F02D 2041/224 20130101;
F02D 41/1446 20130101; F02D 41/1454 20130101; F02D 41/22 20130101;
F02D 41/1448 20130101; F02D 41/221 20130101 |
International
Class: |
F02D 41/22 20060101
F02D041/22; F02D 41/24 20060101 F02D041/24 |
Claims
1. A system, comprising: a reciprocating engine having a piston
disposed in a cylinder, an intake valve, an exhaust valve, and an
exhaust flow path downstream of the exhaust valve; a first sensor
configured to obtain a first feedback indicative of an exhaust gas
parameter in the exhaust flow path; and a controller configured to
identify a valve wear condition of at least one of the intake valve
or the exhaust valve at least partially based on the first feedback
from the first sensor, wherein the controller is configured to
correlate the valve wear condition specifically to one valve of the
intake valve or the exhaust valve.
2. The system of claim 1, wherein the exhaust gas parameter
comprises an exhaust gas composition.
3. The system of claim 2, wherein the first sensor comprises an
oxygen sensor, a fuel sensor, or a combination thereof.
4. The system of claim 2, comprising a second sensor configured to
obtain a second feedback indicative of an exhaust temperature in
the exhaust flow path, wherein the controller is configured to
identify the valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor and the second feedback from the
second sensor.
5. The system of claim 4, comprising a third sensor configured to
obtain a third feedback indicative of an exhaust pressure in the
exhaust flow path, wherein the controller is configured to identify
the valve wear condition of at least one of the intake valve or the
exhaust valve at least partially based on the first feedback from
the first sensor, the second feedback from the second sensor, and
the third feedback from the third sensor.
6. The system of claim 1, comprising one or more additional sensors
configured to obtain additional feedback indicative of an exhaust
temperature, an exhaust pressure, a crank angle, a valve movement
of the intake valve or the exhaust valve, or any combination
thereof, wherein the controller is configured to identify the valve
wear condition of at least one of the intake valve or the exhaust
valve at least partially based on the first feedback from the first
sensor and the additional feedback from the one or more additional
sensors.
7. The system of claim 1, wherein the controller is configured to
compare the first feedback against one or more threshold values to
help identify the valve wear condition of at least one of the
intake valve or the exhaust valve.
8. The system of claim 1, wherein the controller is configured to
identify a specific piston-cylinder assembly among a plurality of
piston-cylinder assemblies having the valve wear condition of at
least one of the intake valve or the exhaust valve.
9. (canceled)
10. The system of claim 1, wherein the controller is configured to
generate an alert, an alarm, a control signal to the reciprocating
engine, a maintenance request or schedule, or any combination
thereof, in response to identification of the valve wear
condition.
11. The system of claim 1, wherein the first sensor is coupled to
an exhaust manifold having the exhaust flow path.
12. A non-transitory computer readable medium comprising executable
instructions that, when executed, cause a processor to: obtain,
from a first sensor, a first feedback indicative of an exhaust gas
parameter in an exhaust flow path downstream from an exhaust valve
of a reciprocating engine, wherein the reciprocating engine has a
piston disposed in a cylinder, an intake valve, and the exhaust
valve; identify a valve wear condition of at least one of the
intake valve or the exhaust valve at least partially based on the
first feedback from the first sensor, wherein the exhaust gas
parameter comprises an exhaust gas composition, wherein the exhaust
gas composition comprises an oxygen content, a fuel content, or a
combination thereof; obtain, from a second sensor, a second
feedback indicative of an exhaust temperature in the exhaust flow
path; identify the valve wear condition of at least one of the
intake valve or the exhaust valve at least partially based on the
first feedback from the first sensor and the second feedback from
the second sensor; obtain, from a third sensor, a third feedback
indicative of an exhaust pressure in the exhaust flow path; and
identify the valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor, the second feedback from the second
sensor, and the third feedback from the third sensor.
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. The non-transitory computer readable medium of claim 12,
wherein the executable instructions, when executed, cause the
processor to: obtain, from one or more additional sensors, an
additional feedback indicative of an exhaust temperature, an
exhaust pressure, a crank angle, a valve movement of the intake
valve or the exhaust valve, or any combination thereof; and
identify the valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor and the additional feedback from the
one or more additional sensors.
18. A method, comprising: obtaining, from a first sensor, a first
feedback indicative of an exhaust gas parameter in an exhaust flow
path downstream from an exhaust valve of a reciprocating engine,
wherein the reciprocating engine has a piston disposed in a
cylinder, an intake valve, and the exhaust valve; identifying a
valve wear condition of at least one of the intake valve or the
exhaust valve at least partially based on the first feedback from
the first sensor, wherein the exhaust gas parameter comprises an
exhaust gas composition, wherein the exhaust gas composition
comprises an oxygen content, a fuel content, or a combination
thereof; obtaining, from a second sensor, a second feedback
indicative of an exhaust temperature in the exhaust flow path;
identifying the valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor and the second feedback from the
second sensor; obtaining, from a third sensor, a third feedback
indicative of an exhaust pressure in the exhaust flow path; and
identifying the valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor, the second feedback from the second
sensor, and the third feedback from the third sensor.
19. (canceled)
20. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to combustion
engines and, more specifically, to a system and method for
detecting operating events and conditions of a reciprocating
combustion engine using one or more sensors.
[0002] Combustion engines typically combust a carbonaceous fuel,
such as natural gas, gasoline, diesel, and the like, and use the
corresponding expansion of high temperature and pressure gases to
apply a force to certain components of the engine, e.g., piston
disposed in a cylinder, to move the components over a distance.
Each cylinder may include one or more valves that open and close
correlative with combustion of the carbonaceous fuel. For example,
an intake valve may direct an oxidizer such as air into the
cylinder. The air then mixes with fuel and combusts to generate hot
combustion gases, which may then be directed to exit the cylinder
via an exhaust valve. The timing of opening and closing the valves
may affect engine performance, longevity of parts, exhaust
emissions, and other engine parameters. Unfortunately, improper
timing may negatively impact the foregoing engine parameters.
BRIEF DESCRIPTION OF THE INVENTION
[0003] Certain embodiments commensurate in scope with the
originally claimed invention are summarized below. These
embodiments are not intended to limit the scope of the claimed
invention, but rather these embodiments are intended only to
provide a brief summary of possible forms of the invention. Indeed,
the invention may encompass a variety of forms that may be similar
to or different from the embodiments set forth below.
[0004] In a first embodiment, a system includes a reciprocating
engine having a piston disposed in a cylinder, an intake valve, an
exhaust valve, and an exhaust flow path downstream of the exhaust
valve. The system also includes a first sensor configured to obtain
a first feedback indicative of an exhaust gas parameter in the
exhaust flow path. The system also includes a controller configured
to identify a valve wear condition of at least one of the intake
valve or the exhaust valve at least partially based on the first
feedback from the first sensor.
[0005] In a second embodiment, an apparatus a non-transitory
computer readable medium includes executable instructions that,
when executed, cause a processor to obtain, from a first sensor, a
first feedback indicative of an exhaust gas parameter in an exhaust
flow path downstream from an exhaust valve of a reciprocating
engine. The reciprocating engine has a piston disposed in a
cylinder, an intake valve, and the exhaust valve. The executable
instructions that, when executed, also cause the process to
identify a valve wear condition of at least one of the intake valve
or the exhaust valve at least partially based on the first feedback
from the first sensor.
[0006] In a third embodiment, a method includes obtaining, from a
first sensor, a first feedback indicative of an exhaust gas
parameter in an exhaust flow path downstream from an exhaust valve
of a reciprocating engine. The reciprocating engine has a piston
disposed in a cylinder, an intake valve, and the exhaust valve. The
method also includes identifying a valve wear condition of at least
one of the intake valve or the exhaust valve at least partially
based on the first feedback from the first sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0008] FIG. 1 is a block diagram of an embodiment of an engine
driven power generation system;
[0009] FIG. 2 is a schematic cross-sectional view of an embodiment
of a piston -cylinder assembly of a reciprocating combustion
engine;
[0010] FIG. 3 is a block diagram of an embodiment of an engine
driven power assembly having multiple piston-cylinder
assemblies;
[0011] FIG. 4 is an embodiment of a graphical output of an oxygen
sensor over a time period;
[0012] FIG. 5 is an embodiment of a graphical output of a pressure
sensor over a time period;
[0013] FIG. 6 is an embodiment of a graphical output of a
temperature sensor over a time period;
[0014] FIG. 7 is an embodiment of a graphical output of a
crankshaft sensor over a time period;
[0015] FIG. 8 is an embodiment of a flow chart for a method of
detecting valve wear using one or more sensors;
[0016] FIG. 9 is an embodiment of a flow chart for logic for
determining the possibility of a valve wear scenario; and
[0017] FIG. 10 is an embodiment of a graphical output of a pressure
sensor over a period of time.
DETAILED DESCRIPTION OF THE INVENTION
[0018] One or more specific embodiments of the present invention
will be described below. In an effort to provide a concise
description of these embodiments, all features of an actual
implementation may not be described in the specification. It should
be appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0019] When introducing elements of various embodiments of the
present invention, the articles "a," "an," "the," and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising," "including," and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0020] Embodiments of the present disclosure include a system and
method for evaluating operational parameters of an engine (e.g., a
reciprocating combustion engine) to determine the possibility of
wear to intake and/or exhaust valves. For example, an electronic
controller may be utilized to evaluate signals from various sensors
positioned throughout the engine against a set of baseline values
and/or threshold values. The sensors may obtain feedback indicative
of residual oxidant (e.g., oxygen), unburn fuel, or a combination
thereof, in the combustion gases (e.g., exhaust gas). The sensors
may obtain feedback indicative of gas composition of the combustion
gases. The sensors also may obtain feedback indicative of
temperature and/or pressure in each combustion chamber (e.g.,
inside cylinder above piston), in an engine intake manifold, an
engine exhaust manifold, or any combination thereof. By determining
whether or not the signals fall outside of the threshold values,
changes in the operational conditions of the engine may be
identified. As a result, further operational parameters may be
identified to determine the likelihood that valve wear is
occurring. In certain embodiments, operational changes may be
indicative of valve wear, thereby enabling the electronic
controller to change operational conditions of the engine, send
stop signals (e.g., engine shutdown), schedule maintenance or
repair, or alert the operator of potential valve wear.
[0021] Turning to the drawings, FIG. 1 illustrates a block diagram
of an embodiment of a portion of an engine driven power generation
system 10. As described in detail below, the system 10 includes an
engine 12 (e.g., a reciprocating internal combustion engine) having
one or more combustion chambers 14 (e.g., 1, 2, 3, 4, 5, 6, 7, 8,
10, 12, 14, 16, 18, 20, or more combustion chambers 14). An air
supply 16 is configured to provide a pressurized oxidant 18, such
as air, oxygen, oxygen-enriched air, oxygen-reduced air, or any
combination thereof, to each combustion chamber 14. The combustion
chamber 14 is also configured to receive a fuel 20 (e.g., a liquid
and/or gaseous fuel) from a fuel supply 22, and a fuel-air mixture
ignites and combusts within each combustion chamber 14. The hot
pressurized combustion gases exert pressure onto a piston 24
adjacent to each combustion chamber 14. The pressure drives the
piston 24 to reciprocate within a cylinder 28 (e.g., an engine
cylinder). Moreover, the reciprocating movement of the piston 24
drives a shaft 30 to rotate. Further, the shaft 30 may be coupled
to a load 32, which is powered via rotation of the shaft 30. For
example, the load 32 may be any suitable device that may generate
power via the rotational output of the system 10, such as an
electrical generator. Additionally, although the following
discussion refers to air as the oxidant 18, any suitable oxidant
may be used with the disclosed embodiments. Similarly, the fuel 20
may be any suitable gaseous fuel, such as natural gas, associated
petroleum gas, propane, biogas, sewage gas, landfill gas, coal mine
gas, for example.
[0022] The system 10 disclosed herein may be adapted for use in
stationary applications (e.g., in industrial power generating
engines) or in mobile applications (e.g., in cars or aircraft). The
engine 12 may be a two-stroke engine, three-stroke engine,
four-stroke engine, five-stroke engine, or six-stroke engine. The
engine 12 may also include any number of combustion chambers 14,
pistons 24, and associated cylinders 28 (e.g., 1-24). For example,
in certain embodiments, the system 10 may include a large-scale
industrial reciprocating engine having 4, 6, 8, 10, 16, 24 or more
pistons 20 reciprocating in cylinders 28. In some such cases, the
cylinders 28 and/or the pistons 20 may have a diameter of between
approximately 13.5-34 centimeters (cm). In some embodiments, the
cylinders 28 and/or the pistons 20 may have a diameter of between
approximately 10-40 cm, 15-25 cm, or about 15 cm. The system 10 may
generate power ranging from 10 kW to 10 MW. In some embodiments,
the engine 12 may operate at less than approximately 1800
revolutions per minute (RPM). In some embodiments, the engine 10
may operate at less than approximately 2000 RPM, 1900 RPM, 1700
RPM, 1600 RPM, 1500 RPM, 1400 RPM, 1300 RPM, 1200 RPM, 1000 RPM,
900 RPM, or 750 RPM. In some embodiments, the engine 12 may operate
between approximately 750-2000 RPM, 900-1800 RPM, or 1000-1600 RPM.
In some embodiments, the engine 10 may operate at approximately
1800 RPM, 1500 RPM, 1200 RPM, 1000 RPM, or 900 RPM. Exemplary
engines 12 may include General Electric Company's Jenbacher Engines
(e.g., Jenbacher Type 2, Type 3, Type 4, Type 6 or J920 FleXtra) or
Waukesha Engines (e.g., Waukesha VGF, VHP, APG, 275GL), for
example.
[0023] The driven power generation system 10 may include one or
more sensors 34 suitable for detecting one or more parameters of
the engine 12. For example, the sensors 34 may include gas
composition sensors (e.g., oxygen sensors and/or fuel sensors),
knock sensors, temperature sensors, pressure sensors, or the like.
As used herein, the oxygen sensor may refer to the sensor 34
configured to detect a quantity of oxygen in a gaseous flow (e.g.,
a total quantity of oxygen or a percentage of oxygen in the flow).
Moreover, the fuel sensor may refer to the sensor 34 configured to
detect a quality of fuel in a gaseous flow (e.g., residual unburn
fuel). As used herein, the knock sensor may refer to the sensor 34
configured to sense sounds or vibrations caused by the engine 12,
such as sound or vibration due to detonation, pre-ignition, and or
pinging. In the illustrated embodiment, the sensor 34 is shown
communicatively coupled to an engine controller 36 (e.g., engine
control unit (ECU), an electronic controller). During operations,
signals from the sensor 34 are communicated to the ECU 36 to
monitor at least one parameter of the engine 12. For example, the
ECU 36 may be configured to monitor residual/unused oxygen and/or
residual/unburn fuel in an exhaust after the fuel 20 is combusted
within the cylinder 28 to determine whether the amount of residual
oxygen or residual fuel is within predefined limits. The ECU 36 may
then adjust certain engine parameters to bring the oxygen content
within the predefined limits, send a signal to an operator, or a
combination thereof. In the illustrated embodiment, the ECU 36 may
be a controller, which includes a memory 38 and a processor 40. The
memory 38 may include a mass storage device, a FLASH memory device,
removable memory, or any other non -transitory computer-readable
medium (e.g., not only a signal). Additionally and/or
alternatively, the instructions may be stored in an additional
suitable article of manufacture that includes at least one
tangible, non-transitory computer-readable medium that at least
collectively stores these instructions or routines in a manner
similar to the memory 38 as described above.
[0024] FIG. 2 is a side cross-sectional view of an embodiment of a
piston-cylinder assembly 50 having the piston 24 disposed within
the cylinder 28 of the reciprocating engine 10. The cylinder 26 has
an inner annular wall 52 defining a cylindrical cavity 54 (e.g.,
bore, annular bore). The piston 24 may be defined by an axial axis
or direction 56, a radial axis or direction 58, and a
circumferential axis or direction 60. The piston 24 includes a top
portion 62 (e.g., a top land). The top portion 62 generally blocks
the fuel 20 and the air 18, or a fuel-air mixture, from escaping
from the combustion chamber 14 during reciprocating motion of the
piston 24.
[0025] As shown, the piston 24 is coupled to a crankshaft 64 via a
connecting rod 66 and a pin 68. The crankshaft 64 translates the
reciprocating linear motion of the piston 24 into a rotating
motion. As the piston 24 moves, the crankshaft 64 rotates to power
the load 32 (shown in FIG. 1), as discussed above. As shown, the
combustion chamber 14 is positioned adjacent to the top land 62 of
the piston 24. A fuel injector 70 provides the fuel 20 to the
combustion chamber 14, and an intake valve 72 controls the delivery
of air 18 to the combustion chamber 14. An exhaust valve 74
controls discharge of exhaust from the engine 12. However, it
should be understood that any suitable elements and/or techniques
for providing fuel 20 and air 18 to the combustion chamber 14
and/or for discharging exhaust may be utilized, and in some
embodiments, no fuel injection is used. In operation, combustion of
the fuel 20 with the air 18 in the combustion chamber 14 cause the
piston 24 to move in a reciprocating manner (e.g., back and forth)
in the axial direction 56 within the cavity 54 of the cylinder
28.
[0026] During operations, when the piston 24 is at the highest
point in the cylinder 28 it is in a position called top dead center
(TDC). When the piston 24 is at its lowest point in the cylinder
28, it is in a position called bottom dead center (BDC). As the
piston 24 moves from top to bottom or from bottom to top, the
crankshaft 64 rotates one half of a revolution. Each movement of
the piston 24 from top to bottom or from bottom to top is called a
stroke, and engine 12 embodiments may include two-stroke engines,
three-stroke engines, four-stroke engines, five-stroke engine,
six-stroke engines, or more.
[0027] During engine 12 operations, a sequence including an intake
process, a compression process, a power process, and an exhaust
process occurs. The intake process enables a combustible mixture,
such as fuel and air, to be pulled into the cylinder 28, thus the
intake valve 72 is open and the exhaust valve 74 is closed. The
compression process compresses the combustible mixture into a
smaller space, so both the intake valve 72 and the exhaust valve 74
are closed. The power process ignites the compressed fuel-air
mixture, which may include a spark ignition through a spark plug
system, and/or a compression ignition through compression heat. The
resulting pressure from combustion then forces the piston 24 to
BDC. The exhaust process returns the piston 24 to TDC while keeping
the exhaust valve 74 open. The exhaust process thus expels the
spent fuel-air mixture through the exhaust valve 74. It is to be
noted that more than one intake valve 72 and exhaust valve 74 may
be used per cylinder 28.
[0028] In the illustrated embodiment, various sensors 34 are
distributed throughout the system 10 to monitor one or more
parameters of the piston-cylinder assembly 50 during operation. For
example, a crankshaft sensor 80 is positioned proximate the
crankshaft 64 to sense the position and/or rotational speed of the
crankshaft 64. Accordingly, a crank angle or crank timing
information may be derived from the sensor feedback via the ECU 36.
That is, when monitoring combustion engines, timing is expressed in
terms of crankshaft 64 angle. For example, a full cycle of a four
stroke engine 12 may be measured as a 720.degree. cycle. As will be
described below, monitoring the lift of the intake valve 72 and/or
the exhaust valve 74 relative to the crank angle may be utilized to
detect wear on the intake valve 72 and/or the exhaust valve 74. As
used herein, wear refers to deformation, erosion, corrosion, or the
like to a valve body that may hinder and/or block full opening or
closure of the valve.
[0029] Moreover, a knock sensor 82 is positioned is positioned
proximate the combustion chamber 24 to sense vibration,
acceleration, sound, and/or movement. For example, the knock sensor
82 may be a Piezo-electric accelerometer, a microelectromechanical
system (MEMS) sensor, a Hall effect sensor, a magnetostrictive
sensor, and/or any other sensor designed to sense vibration,
acceleration, sound, noise, and/or movement. In some embodiments,
knock sensor 82 may not be a knock sensor in the traditional sense,
but the knock sensor 82 may include any sensor that may sense
vibration, pressure, acceleration, deflection, or movement, and may
not be used to detect engine "knock." Because of the percussive
nature of the engine 12, the knock sensor 82 may be capable of
detecting signatures even when mounted on the exterior of the
cylinder 28. As used herein, signatures refer to at least one set
of data indicative of a noise event (e.g., opening/closing of a
valve) corresponding to the valves 72, 74. However, the knock
sensor 82 may be disposed at various locations in or about the
cylinder 28. Additionally, in some embodiments, a single knock
sensor 82 may be shared, for example, with one or more adjacent
cylinders 28. In some embodiments, each cylinder 28 may include one
or more knock sensors 82.
[0030] In the illustrated embodiment, an intake manifold 84
includes a pressure sensor 86 and a temperature sensor 88. The
pressure sensor 86 is configured to monitor the pressure in the
intake manifold 84 as the intake valve 72 opens and closes to
enable the oxidant 18 to enter the combustion chamber 14. As will
be described below, by monitoring the pressure of the intake
manifold 84 over operation of the engine 12, a decrease in pressure
may be indicative of wear to the intake valve 72, thereby enabling
oxidant 18 to continuously leak into and/or out of the combustion
chamber 14 during operation. Moreover, the intake manifold 84
includes the temperature sensor 88 to monitor the temperature of
the intake manifold 84 during operation of the engine 12 to
evaluate intake valve 72 wear. In certain embodiments, each
cylinder 28 may include individual pressure and temperature sensors
86, 88 at the piston assemblies 50. However, in some embodiments,
adjacent cylinders 28 may share the pressure and/or temperature
sensors 86, 88.
[0031] Furthermore, an exhaust manifold 90 may include one or more
of the pressure and temperature sensors 86, 88. As described above,
the exhaust manifold 90 receives hot combustion gases from the
combustion chamber 14. For example, as the piston 24 returns to
TDC, the exhaust gases may enter the exhaust manifold 90 as the
exhaust valve 74 is in the open position. As will be described
below, wear in the exhaust valve 74 may be represented by higher
exhaust manifold pressures or lower exhaust manifold temperatures.
Moreover, in certain embodiments, individual sensors 34 (e.g.,
pressure and temperature sensors 86, 88) may be positioned at the
exhaust of each piston-cylinder assembly 50. Furthermore, in some
embodiments, different piston-cylinder assemblies 50 from a
plurality of piston-cylinder assemblies 50 may be evaluated based
on timing (e.g., firing order) while the feedback is evaluated to
determine which piston-cylinder assemblies 50 may have valve
wear.
[0032] Additionally, in the illustrated embodiment, the exhaust
manifold 90 includes an oxygen sensor 92 (e.g., a lambda sensor).
As described above, the oxygen sensor 92 is configured to measure
an amount of residual unused oxygen present in the exhaust manifold
90 (i.e., oxygen not used in the combustion reaction). In certain
embodiments, the oxygen sensor may determine a percentage of oxygen
in the exhaust flow. By determining the percentage of oxygen in the
exhaust manifold 90, the valve wear of the exhaust valve 74 may be
determined by the ECU 36. For example, a higher oxygen content in
the exhaust manifold 90 may be indicative of non-combusted oxygen
leaking from the combustion chamber 14, around the exhaust valves,
and into the exhaust manifold 90. As a result, the oxygen sensor 92
may be utilized to monitor leakage into the exhaust manifold 90, in
the cylinder 28, and/or other associated piping or equipment. In
certain embodiments, the oxygen sensor 92 monitors a threshold
amount to determine whether additional data analysis is performed.
For example, a predetermined percentage of oxygen may be present in
the exhaust manifold 90 before additional analysis of other
operational parameters of the engine 12 is conducted.
[0033] In the illustrated embodiment, the sensors 34 (e.g.,
crankshaft sensor 80, knock sensor 82, pressure sensor 86,
temperature sensor 90, and/or oxygen sensor 92) are communicatively
coupled to the ECU 36. That is, the ECU 36 may receive one or more
signals from the sensors 34 indicative of the operational
parameters of the engine 12. The ECU 36 may evaluate the signal via
the processor 40 with values stored on the memory 38. For example,
the ECU 36 may compare the percentage of oxygen and/or fuel in the
exhaust manifold 90 to a predetermined limit, or compare the
pressure and/or temperature in the intake manifold 84 with a
threshold set of values, or compare the pressure and/or temperature
in the exhaust manifold 90 with a threshold set of values.
[0034] FIG. 3 is a schematic diagram of the engine driven power
system 10 having an exhaust system 100 configured to recover
exhaust gas from the exhaust manifold 90 for utilization during
operation of the system 10. For example, as described above, the
engine 12 may include a plurality of piston assemblies 50
configured to drive motion of the crankshaft 64 to provide power to
the load 32. In the illustrated embodiment, the engine 12 includes
six piston assemblies 50. However, in some embodiments, the engine
12 may include any suitable number of piston assemblies (e.g., 1,
2, 3, 4, 8, 10, 12, etc.). As described above, the fuel 20 from the
fuel supply 22 is configured to enter the fuel injectors 70, while
the oxidant 18 enters the intake manifold 84 for later combination
and combustion within the combustion chamber 14. Thereafter, the
exhaust gases may exit the combustion chamber 14 and enter the
exhaust manifold 90. In the illustrated embodiment, the exhaust
gases are directed toward a turbocharger 102. In the illustrated
embodiment, the exhaust gases may enter a turbine side 104, while
the oxidant 18 enters a compressor side 106. In the illustrated
embodiment, exhaust from the turbine side 104 may enter an exhaust
treatment system 108. The exhaust treatment system 108 may be
configured to remove selected impurities or particulates from the
exhaust to enable recirculation through the system 10. For example,
the exhaust treatment system 108 may include filters, absorption
beds, adsorption beds, or the like. In certain embodiments, the
exhaust treatment system 108 may direct the processed exhaust to an
exhaust gas recovery unit 110 to be combined with the fuel 20 and
oxidant 18 in a mixer 112. Thereafter, the combination may be
directed to the compressor side 106 and transported toward the
engine 12 for reuse within the system 10.
[0035] As described above, sensors 34 may be positioned at numerous
locations throughout the system 10 to measure one or more
parameters of operation. For example, the exhaust manifolds 90 may
include the pressure sensor 86, temperature sensor 88, residual
fuel sensor, and/or the oxygen sensor 92. In the illustrated
embodiment, each piston-cylinder assembly 50 includes an individual
pressure, temperature, and oxygen sensor 86, 88, 92. However, in
certain embodiments, the exhaust manifold 90 may include pressure,
temperatures, and oxygen sensors 86, 88, 92 to measure the overall
operational parameters within the exhaust manifold 90 as a whole,
instead of individually at each piston-cylinder assembly 50.
Moreover, in the illustrated embodiment, both the overall exhaust
manifold 90 and each individual piston-cylinder assembly 50 may
include pressure, temperature, residual fuel sensor, and oxygen
sensors 86, 88, 92. Additionally, as shown, the sensors 34 may be
distributed on the exhaust lines (e.g., exhaust pipes, exhaust
conduits, etc.) directing the exhaust from the exhaust manifold 90
to the turbocharger 102, on the intake manifold 84, or other areas
throughout the system 10. Moreover, the sensors 34 may be
communicatively coupled to the ECU 36 to enable continuous
operation and/or adjustment of the operating parameters of the
system 10.
[0036] As described above, monitoring the operational parameters of
the system 10 may enable operators to detect valve wear in the
piston assemblies 50 while the engine 12 is operational. In certain
embodiments, the ECU 36 may be configured to receive signals from
the sensors 34 indicative of operational parameters of the system
10. Moreover, the processor 40 may be configured to continuously
monitor the signals during operation of the system 10. Furthermore,
the memory 38 may include predetermined values, or ranges of
valves, associated with the operational parameters. For example,
the memory 38 may include a threshold value (e.g., upper value,
lower value, predetermined range) of the exhaust manifold pressure,
the exhaust manifold temperature, the exhaust manifold oxygen
content, and/or the exhaust manifold fuel content. As will be
described below, one or a combination of the parameters (e.g.,
pressure, temperature, oxygen, fuel content) may be utilized to
detect valve wear. The processor 40 may evaluate the signal
indicative of the exhaust manifold pressure, the exhaust manifold
temperature, the exhaust manifold oxygen content, and/or the
exhaust manifold fuel content, over a time interval. In embodiments
in which the value of the signal is outside of the threshold value
for the time interval, the processor 40 may be configured to
trigger an alarm or indication indicative of the parameter being
outside of the predetermined range.
[0037] FIG. 4 is an embodiment of a graph monitoring the oxygen
content (e.g., lambda value) of the exhaust manifold 90. However,
as described above, in certain embodiments the oxygen content of
the individual cylinders 28 may be monitored separately. In the
illustrated embodiment, the vertical axis 120 represents the oxygen
content and the horizontal axis 122 represents time. As shown, the
oxygen content in the exhaust manifold 90 is monitored over a
period of time to determine whether changes in the oxygen content
are indicative of valve wear. For example, a line 124 represents a
no-wear scenario in which neither the intake valve 72 nor the
exhaust valve 74 has appreciable wear. As used herein, appreciable
wear refers to a state of valve wear in which performance of the
engine 12 is not changed or hindered due to the wear on the intake
or exhaust valves 72, 74. Moreover, a line 126 represents an intake
valve wear scenario, a line 128 represents an exhaust valve wear
scenario, and a line 130 represents both an intake and exhaust
valve wear scenario. As will be described below, by monitoring
changes in the oxygen content during operation of the system 10
over the entire time period and/or specified time intervals, valve
wear may be identified while the engine 12 is operational.
Moreover, in some embodiments, timing is also evaluated (e.g.,
firing order for a plurality of piston-cylinder assemblies 50). As
a result, if the ECU 36 determines the possibility of valve wear is
increased, the ECU 36 may also evaluate the timing to determine
which piston-cylinder assembly 50 of the plurality of
piston-cylinder assemblies 50 may have valve wear.
[0038] In the illustrated embodiment, the line 124 is substantially
constant over a time period 132. That is, the value of the oxygen
content does not significantly change over the time period 132. In
certain embodiments, a threshold value 134 may be utilized to
determine whether the intake valve 72 and/or the exhaust valve 74
has wear. For example, the threshold value 134 may be approximately
20% higher than a baseline value 136. However, in some embodiments,
the threshold value 134 may be 5, 10, 15, 20, 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 100, 125, 150, or 200 percent higher than
the baseline value 136, or any suitable percentage higher than the
baseline value 136. Additionally, in some embodiments, the
threshold value 134 may be approximately 20% lower than a baseline
value 136. However, in some embodiments, the threshold value 134
may be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75,
100, 125, 150, or 200 percent lower than the baseline value 136, or
any suitable percentage lower than the baseline value 136.
Moreover, in some embodiments, the threshold value 134 may be
predetermined based on experimental conditions. By comparing the
oxygen content over different time intervals 138, the ECU 36 may
determine whether the intake valve 72 and/or the exhaust valve 74
is experiencing wear. Moreover, evaluating the timing (e.g., firing
order) may enable the ECU 36 to determine which piston-cylinder
assembly 50 of a plurality of piston -cylinder assemblies 50 has
valve wear.
[0039] As described above, the line 124 may represent the no-wear
scenario in which both the intake valve 72 and the exhaust valve 74
are sealing at the intervals, thereby blocking excess,
non-combusted oxygen from entering the exhaust manifold 90. In the
illustrated embodiment, oxygen content over the time period 132
represented by the line 124 may be approximately equal to the
baseline value 136. As will be appreciated, the baseline value 136
may be determined by experimental operations of the engine 12,
normal operations of the engine 12 or a group of engines (e.g., new
engines), computer modeling, calculations, user inputs, or the
like. As shown, the oxygen content corresponding to the value of
the line 124 may be evaluated over the time intervals 138a, 138b,
138c, 138d. In the illustrated embodiment, the oxygen content
corresponding to the value of the line 124 does not increase higher
(e.g., have a value larger) than the threshold value 134. As a
result, the ECU 36 may determine that the potential for appreciable
valve wear is low for the line 124.
[0040] Additionally, as described above, the line 126 may represent
the intake valve wear scenario. That is, wear (e.g., corrosion,
erosion, deformation, etc.) to the intake valve 72 may facilitate
oxidant 18 leakage into the combustion chamber 14, thereby creating
an air-to-fuel (A/F) ratio that is leaner (e.g., higher) than the
normal operating conditions. As a result, performance of the engine
12 may drop and/or unused oxygen may enter the exhaust manifold 90.
In the illustrated embodiment, the ECU 36 monitors the oxygen
content corresponding to the line 126 across the time period 132.
As shown, during the time interval 138d, the oxygen content
corresponding to the line 126 is greater than the threshold value
134. That is, the amount of unused oxygen is at a level indicative
of valve wear. Accordingly, the ECU 36 may determine the
possibility of wear to the intake valve 72 is increased.
[0041] In the illustrated embodiment, the line 128 represents the
exhaust valve wear scenario. During the exhaust valve wear
scenario, wear to the exhaust valve 72 may facilitate oxidant 18
leakage into the exhaust manifold 90. For example, as oxidant
enters the combustion chamber 14 from the intake manifold 84, a
fluid pathway between the combustion chamber 14 and the exhaust
manifold 90 may not be sealed (e.g., because of wear to exhaust
valve 74), thereby enabling the oxidant 18 to enter the exhaust
manifold 90 before combustion in the combustion chamber 14. As
shown, by monitoring the oxygen content corresponding to the line
128 over the time period 132, the oxygen content may be detected as
larger than the threshold value 134 during the time interval 138b,
and remain larger than the threshold value 134 throughout the time
intervals 138c, 138d. As a result, the ECU 36 may determine the
possibility of valve wear is increased.
[0042] Moreover, the line 130 may represent both the intake and
exhaust valve wear scenario. As described above, in certain
embodiments, wear may be present on both the intake valve 72 and
the exhaust valve 74. In the illustrated embodiment, the oxygen
content corresponding to the line 130 is larger than the threshold
value 134 during the time interval 138d. Accordingly, the possibly
of wear may be increased. In certain embodiments, the value of
oxygen content may be utilized to determine the type of wear
present. For example, the exhaust valve wear scenario may
correspond to a higher oxygen content than the intake valve wear
scenario and/or both the intake and exhaust valve wear scenario.
Moreover, in some embodiments, monitoring of the oxygen content may
continue for a predetermined time interval 138 after detection
above the threshold value 134 is detected. For example, the oxygen
content may exceed the threshold value 134 by 1, 2, 3, 4, 5, 6, 7,
or any suitable number of time intervals (e.g., one stroke, two
strokes, three strokes, or any suitable number of strokes), because
the ECU 36 determines the possibly of valve wear is increased. As a
result, intermittent increases in oxygen content in the exhaust
manifold 90 may not be registered as valve wear, thereby decreasing
the possibility of false positive identifications of valve
wear.
[0043] As described above, oxygen content in the exhaust manifold
90 may be utilized to determine the possibility of valve wear to
the intake valve 72 and the exhaust valve 74. However, in certain
embodiments, the increase in oxygen content due to valve wear may
be small. Accordingly, other operational parameters may also be
utilized to determine the possibility of valve wear or to
distinguish between intake and exhaust valve 72, 74 wear. To that
end, FIG. 5 is an embodiment of a graph monitoring the pressure of
the exhaust manifold 90. However, as described above, in certain
embodiments the pressure of the individual cylinders 28 may be
monitored separately. As described above, the lines 124, 126, 128,
and 130 may represent different wear scenarios associated with the
engine 12. For example, in the illustrated embodiment, the line 124
corresponds to the no-wear scenario in which the pressure of the
exhaust manifold 90 is substantially equal to the baseline value
136. In certain embodiments, the baseline value 136 may be
determined by experimental operations of the engine 12, normal
operations of the engine 12 or a group of engines (e.g., new
engines), computer modeling, calculations, user inputs, or the
like. As described above, the threshold value 134 may be utilized
to determine whether the intake valve 72 and/or the exhaust valve
74 has wear. In certain embodiments, the threshold value 134 is a
predetermined value. However, in some embodiments, the threshold
value 134 may be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65,
70, 75, 100, 125, 150, or 200 percent lower than the baseline value
133, or any suitable percentage lower than the baseline value 134.
Moreover, in some embodiments, the threshold value 134 may be 1.5,
2, 2.3, 3, or any suitable factor greater than the baseline value
136. Accordingly, valve wear may be monitored by evaluating the
pressure in the exhaust manifold 90 in comparison to the baseline
value 136.
[0044] In the illustrated embodiment, similar element numbers are
used to define the threshold and baseline values 134, 136, but may
be applicable to oxygen content, temperature, and pressure. In the
illustrated embodiment, the line 126 represents the pressure in the
exhaust manifold 90 during the intake valve wear scenario over the
time period 132. As shown, the pressure value represented by line
126 is less than the baseline value 136 across the time intervals
138a, 138b, 138c, 138d. For example, a reduction of combustion
charge within the cylinder 28 may indicate intake valve wear and,
as a result, reduce the pressure of the exhaust manifold 90. In the
illustrated embodiment, the line 126 is not above the threshold
value 134. However, as mentioned above, in certain embodiments the
ECU 36 may monitor a range (e.g., a threshold above and a threshold
below) while evaluating the wear of the intake and/or exhaust
valves 72, 74. For example, the ECU 36 may monitor a range of
approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
20, 30, 40 percent plus or minus the threshold value 134 and/or
baseline value 136, or any other suitable range, to define upper
and lower values which may be indicative of valve wear.
Accordingly, the ECU 36 may monitor the pressure of the exhaust
manifold 90 to evaluate valve wear, while the pressure of the
exhaust manifold 90 is lower than the threshold value 134 and the
baseline value 136.
[0045] In the illustrated embodiment, the line 128 represents the
pressure in the exhaust manifold 90 during the exhaust valve wear
scenario over the time period 132. As shown, the value of the
pressure represented by the line 128 is greater than threshold
value 134 in the time intervals 138c, 138d. Accordingly, the ECU 36
may output a signal indicative of exhaust valve wear, because of
the increased pressure measurement in the exhaust manifold 90
(e.g., based on a trend of the exhaust manifold 90 pressure at
different combustion intervals). For example, the pressure may
increase in the exhaust manifold 90 during the exhaust valve wear
scenario, because leakage may occur during the combustion phase of
the piston stroke, thereby increasing the pressure in the exhaust
manifold 90.
[0046] As shown in FIG. 5, the line 130 represents the pressure in
the exhaust manifold 90 during the intake and exhaust valve wear
scenario. That is, in embodiments where both the intake valve 72
and the exhaust valve 74 experience wear, the value of the pressure
represented by the line 130 may be greater than the threshold value
134 (e.g., due to incomplete combustion, due to leakage, etc.). As
a result, the ECU 36 may output a signal indicative of valve wear.
Moreover, evaluating the timing (e.g., firing order) may enable the
ECU 36 to determine which piston-cylinder assembly 50 of a
plurality of piston-cylinder assemblies 50 has valve wear. However,
as will be described below, further evaluation may be undertaken to
determine whether the valve wear is due to intake valve wear,
exhaust valve wear, or a combination of both.
[0047] FIG. 6 is an embodiment of a graph monitoring the
temperature of the exhaust manifold 90. However, as described
above, in certain embodiments the temperature of the individual
cylinders 28 may be monitored separately. In the illustrated
embodiment, similar element numbers are used to define the
threshold and baseline values 134, 136, but may be applicable to
oxygen content, temperature, and pressure. In the illustrated
embodiment, the line 124 represents the no-wear scenario and is
substantially equal to the baseline value 136. Accordingly, the ECU
36 may evaluate the signal and determine that the possibility of
wear of the intake and/or exhaust valves 72, 74 is low.
[0048] In the illustrated embodiment, the line 126 represents the
intake valve wear scenario, in which the temperature of the exhaust
manifold 90 is lower than the baseline value 136. As shown in the
illustrated embodiment, the temperature represented by the line 126
is less than the threshold value 134. For example, intake valve 72
wear may lead to less charge in the combustion chamber 14,
resulting in reduced effective compression ratios and lower outlet
temperatures. In certain embodiments, the threshold value 134 may
be determined by experimental operations of the engine 12, normal
operations of the engine 12 or a group of engines (e.g., new
engines), computer modeling, calculations, user inputs, or the
like. However, as described above, in some embodiments the
threshold value 134 may be a percentage of the baseline value 136.
For example, the threshold value 134 may be plus or minus 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 percent, or any suitable
percentage of the threshold value 134. As a result, the threshold
value 134 may be adjusted for different engines, different
operating conditions (e.g., ambient air temperatures, fuel types,
oxidant types), or the like. Because the line 126 is less than the
threshold value 134 throughout the time intervals 138c, 138d, the
ECU 36 may determine that the possibility of valve wear is
increased.
[0049] Additionally, the line 128 represents the exhaust valve wear
scenario, in which the temperature of the exhaust manifold 90 is
lower than the baseline value 136, but not lower than the threshold
value 134. Accordingly, in the illustrated embodiment, the ECU 36
may evaluate the temperature of the exhaust manifold 90 and
determine that the possibility of valve wear to the exhaust valve
74 is low based on line 128. However, in some embodiments, the
threshold value 134 may be set such that small reductions in the
temperature of the exhaust manifold 90 may trigger a signal from
the ECU 36. Moreover, in certain embodiments, a combination of
indicators (e.g., from pressure and temperature, from oxygen and
temperature, from oxygen and pressure, etc.) may be indicative of
valve wear, as opposed to one indicator (e.g., only oxygen, only
pressure, only temperature).
[0050] In the illustrated embodiment, the line 130 represents the
intake and exhaust valve wear scenario, in which the temperature
represented by the line 130 is lower than the threshold value 134.
Accordingly, the ECU 36 may determine that the possibility of valve
wear is increased because the temperature represented by the line
130 is lower than the threshold value 134 during the time intervals
138c, 138d. In this manner, the ECU 36 may output a signal
indicative of valve wear. Moreover, evaluating the timing (e.g.,
firing order) may enable the ECU 36 to determine which
piston-cylinder assembly 50 of a plurality of piston-cylinder
assemblies 50 has valve wear.
[0051] FIG. 7 is an embodiment of a graph monitoring a lift 150 of
the intake and exhaust valves 72, 74 relative to a crank angle 152.
In the illustrated embodiment, the vertical axis 120 is
representative of the lift 150. As used herein, the lift 150 refers
to the movement of the intake and/or exhaust valves 72, 74 away
from seats to enable injection into and expulsion from the
combustion chamber 14. Additionally, the horizontal axis 122 is
representative of the crank angle 152. As described above, the
crank angle describes the angle of rotation of the crankshaft 64 as
the piston 24 moves between TDC and BDC. In the illustrated
embodiment, a line 154 is representative of a no exhaust valve wear
scenario, in which the exhaust valve 74 does not have appreciable
wear. In other words, the exhaust valve 74 is configured to open to
enable the hot exhaust to exit the combustion chamber 14 and enter
the exhaust manifold 90 without experiencing appreciable leakage.
As shown, a line 156 is representative of a no intake valve wear
scenario, in which the intake valve 72 does not have appreciable
wear. The intake valve 72 is configured to open (e.g., increase the
value of the lift) after the exhaust valve 74 shuts (e.g., decrease
the value of the lift) to enable injection of the oxidant 18 and
the fuel 20 into the combustion chamber 14. As shown, a crossing
point 158 indicates an intentional overlap between the opening of
the intake valve 72 and the closure of the exhaust valve 74. The
area under the line 154 and the line 156 at the crossing point 158
may be referred to as the no-wear overlap 160. As will be described
above, monitoring the crossing point 158 and/or the no-wear overlap
160 may be utilized to determine the possibility of wear to the
intake and/or exhaust valves 72, 74.
[0052] In the illustrated embodiment, a line 162 is representative
of an exhaust valve wear scenario. That is, the exhaust valve 72
may experience corrosion, erosion, deformation, or the like which
may block or hinder opening and closing of the valve. For example,
erosion to the exhaust valve 72 may block a tight seal between the
exhaust valve 72 and a seat. Moreover, in some embodiments, wear to
a spring of the exhaust valve 72 may hinder opening and closing. As
shown, the line 162 indicates valve closure (e.g., lift is
approximately equal to zero) later (e.g., at a larger crank angle)
than the line 154 representing the no exhaust valve wear scenario.
As a result, the exhaust valve 72 remains open longer, which may
enable oxidant 18 to enter the exhaust manifold 90 directly from
the intake manifold 84 without reacting within the combustion
chamber 14. Furthermore, a line 164 is representative of an intake
valve wear scenario. As shown, the line 164 indicates valve opening
at an earlier crank angle 152 than the intake valve 72 of line 156
As a result, a second crossing point 166 is higher (e.g., has a
larger lift value) than the crossing point 158. Accordingly, the
overlap 168 is larger than the overlap 160, thereby forming a
longer duration in which both the intake valve 72 and the exhaust
valve 74 are open during each stroke. Because the overlaps 160, 168
may be indicative of valve wear, the ECU 36 may monitor the
overlaps 160, 168 (e.g., via the crankshaft sensor 80, via position
sensors, via displacement sensors) as indicators of valve wear.
[0053] FIG. 8 is a flow chart of an embodiment of a
computer-implemented method 180 for monitoring the possibility of
wear to the intake and exhaust valves 72, 74. In the illustrated
embodiment, the oxygen content of the exhaust manifold 90 is
monitored by the ECU 36 over the time interval 138 (block 182). For
example, the oxygen sensor 92 positioned in the exhaust manifold 90
(or positioned at an exhaust outlet of each piston-cylinder
assembly 50) may send a first signal to the ECU 36 indicative of
the oxygen content (e.g., amount of oxygen) in the exhaust manifold
90. Moreover, as described above, the time interval 138 may be a
portion of the time period 132 or the entire time period 132. By
monitoring the oxygen content over the time interval 138, the ECU
36 may distinguish between potential valve wear and temporary
upsets and/or spikes. In certain embodiments, the ECU 36 determines
whether the oxygen content in the exhaust manifold 90 is within a
range (block 184). For example, the range may include one or more
threshold values 134 (e.g., an upper threshold and/or a lower
threshold). The ECU 36 may monitor the first signal from the oxygen
sensor 92 over the time interval 138. In embodiments in which the
oxygen content is within the range, the ECU 36 may continue to
monitor the oxygen content (186). However, in embodiments in which
the oxygen content is outside of the range defined by the threshold
values 134, the ECU 36 may proceed with further evaluation of the
operating parameters of the system 10 (188). In certain
embodiments, the evaluation of the oxygen content of the exhaust
manifold 90 and/or the oxygen content at each outlet of the
piston-cylinder assembly 50 may compare the measured oxygen level
against a threshold and/or triggering value. For example, the
method 180 may proceed only if the oxygen content it outside of the
range. However, in some embodiments, the oxygen content may be at
least one operating parameter evaluated by the ECU 36 to determine
whether the inlet and/or exhaust valves 72, 74 are worn. Moreover,
in certain embodiments, the oxygen content may not be monitored or
utilized to detect valve wear.
[0054] The pressure of the exhaust manifold 90 is monitored by the
ECU 36 (e.g., via a signal from the pressure sensor 86) over the
time interval 138 (block 190). As described above, in certain
embodiments, the pressure of the entire exhaust manifold 90 may be
monitored by the pressure sensor 86. However, in some embodiments,
individual pressure values for each piston-cylinder assembly 50 may
be monitored by pressure sensors 86 and output to the ECU 36 (e.g.,
via a signal). Thereafter, the pressure of the exhaust manifold 90
or individual piston-cylinder assemblies 50 may be evaluated by the
ECU 36 to determine whether the pressure is within a range (block
192). For example, the ECU 36 may evaluate whether the pressure is
above or below the thresholds 134. In certain embodiments, pressure
values below a lower threshold may be indicative of intake valve
wear, as shown in FIG. 5. However, in some embodiments, pressure
values above an upper threshold may be indicative of exhaust valve
wear, as shown in FIG. 5. It is appreciated that different engine
types, operating conditions, and the like may include a variety of
pressure indicators to determine whether the intake and/or exhaust
valves 72, 74 are worn. While the pressure value from the pressure
sensor 86 is within the range, the ECU 36 may continue monitoring
parameters of the system 10 (194). However, in embodiments where
the value from the pressure sensor 86 is outside of the range, the
ECU 36 may proceed to monitor additional parameters of the system
10 (196).
[0055] In the illustrated embodiment, the ECU 36 monitors the
temperature of the exhaust manifold 90 (block 198) for the time
interval 138. For example, the ECU 36 may receive a temperature
signal from the temperature sensor 88 positioned on/within the
exhaust manifold 90. However, in some embodiments, one or more
temperature sensors 88 may be positioned at the respective outlets
of the piston assemblies 50. Additionally, in the illustrated
embodiment, the ECU 36 determines whether the temperature signal is
within a range (block 200). For example, the range may include
upper and/or lower thresholds 134. In embodiments where the
temperature is outside of the range (e.g., above the upper
threshold or below the lower threshold), the ECU 36 may send a
fourth signal indicative of the possibility of valve wear (block
202). For example, the signal may be an alert to inform the
operator of the possibility of valve wear. In some embodiments, the
signal may send an alert to schedule maintenance or to shut down
the system 10. Moreover, in some embodiments, the signal may alert
the operator to adjust operating parameters of the engine 12 to
avoid shutting down the engine 12. However, in embodiments where
the temperature signal is within the range, the ECU 36 may continue
to monitor the oxygen content of the exhaust manifold 90 (204).
[0056] FIG. 9 is a flow chart of an embodiment of
computer-implemented logic 210 that may be utilized by the ECU 36
to determine the type of wear present in the engine 12. It is
appreciated that the flow chart is an embodiment of the logic 210
utilized for the wear conditions presented in the graphs of FIGS.
4-6 and may be different for other types of engines or operating
conditions. In the illustrated embodiment, the ECU 36 monitors the
oxygen content of the exhaust manifold 90 via the oxygen sensor 92
(operator 212). The ECU 36 may continue to monitor the oxygen
content while the oxygen sensor 92 returns a value that is
approximately equal to the baseline value 136 (214). Moreover, the
ECU 36 may continue to monitor the oxygen content while the oxygen
sensor 92 returns a value that is less than the baseline value 136
(216). However, while the oxygen sensor 92 returns a value that is
more than the baseline value 136 (line 218), the ECU 36 may monitor
the pressure of the exhaust manifold 90 via the pressure sensor 86
(operator 220). In other words, in the illustrated embodiment,
detection of the oxygen content being higher than the baseline
value 136 may be a trigger event to continue monitoring additional
operational parameters of the engine 12.
[0057] In the illustrated embodiment, the ECU 36 may evaluate the
value of the pressure in the exhaust manifold 90, and the compare
the value to the baseline value 136 and/or the threshold value(s)
134. In embodiments where the value is less than the baseline value
136 and/or the threshold value 134 (line 222), the ECU 36 may
proceed to evaluate the temperature of the exhaust manifold 90 via
the temperature sensor 88 (operator 224). Additionally, in
embodiments where the pressure is greater than the baseline value
136 and/or the threshold value 134 (line 226), the ECU 36 may
proceed to evaluate the temperature (operator 228). Furthermore, in
embodiments where the value of the pressure is approximately equal
to the baseline value 136 and/or within the threshold(s) 134, the
ECU 36 may continue to monitor the oxygen content of the exhaust
manifold 90 via the oxygen sensor 92 (line 230). In this manner,
the pressure of the exhaust manifold 90 may serve as a further
triggering event to continue monitoring additional operational
parameters of the engine 12.
[0058] As mentioned above, in certain embodiments the ECU 36 may
determine that the pressure of the exhaust manifold 90 is lower
than the baseline value 136 and/or the threshold value 134 (line
222). As the ECU 36 monitors the temperature of the exhaust
manifold 90 (operator 224), the ECU 36 may determine that the
temperature is lower than the baseline value 136 and/or the
threshold value 134 (line 232). As a result, the ECU 36 may
determine that the possibility of the inlet valve wear scenario is
increased (block 234). Moreover, the ECU 36 may determine that the
temperature is approximately equal to the baseline value 136 and
continue to monitor the oxygen content (line 236). However, in some
embodiments, the ECU 36 may determine that the pressure of the
exhaust manifold 90 is higher than the baseline value 136 and/or
the threshold value 134 (line 226). As a result, the ECU 36
monitors the temperature of the exhaust manifold 90 (operator 228).
In certain embodiments, the ECU 36 may determine that the
temperature is lower than the baseline value 136 (line 238). As a
result, the ECU 36 may determine that the possibility of the
exhaust vale wear scenario is increased (block 240). Furthermore,
in certain embodiments, the ECU 36 may determine the temperature is
lower than the threshold value 134 (line 242). Accordingly, the ECU
36 may determine that the possibility of both the intake and
exhaust valve wear scenario is increased (block 244). Furthermore,
in some embodiments, the ECU 36 may determine that the temperature
is approximately equal to the baseline value 136 and continue to
monitor the oxygen content (line 246).
[0059] As described in detail above, continuous monitoring of
various operational parameters of the engine 12 may be utilized to
determine the possibility of valve wear. For example, in certain
embodiments, the ECU 36 may evaluate signals from various sensors
34 (e.g., the oxygen sensor 92, the pressure sensor 86, the
temperature sensor 88, etc.). The ECU 36 may evaluate threshold
values 134 to determine whether or not the operational parameters
are within normal operating ranges. In certain embodiments, a
triggering event of one of the operational parameters may
facilitate further evaluation of the operational parameters of the
engine 12 to detect valve wear. For example, detection of a higher
than normal oxygen content may be the triggering event to further
evaluate the pressure and temperature of the exhaust manifold 90.
Accordingly, analysis of the operational parameters may be utilized
to predict the possibility of valve wear, thereby enabling the
operators to schedule shut downs or planned maintenance
activities.
[0060] By detecting the various operational parameters of the
engine 12, the ECU 36 may identify valve wear in the piston
cylinder assemblies 50. For example, identification of an increased
oxygen content in the exhaust manifold 90, a reduced pressure in
the exhaust manifold 90, and a reduced temperature in the exhaust
manifold 90 may be indicative of intake valve wear. Additionally,
identification of an increased oxygen content in the exhaust
manifold 90, an increased pressure in the exhaust manifold 90, and
a reduced temperature in the exhaust manifold 90 may be indicative
of exhaust valve wear. Furthermore, identification of an increased
oxygen content in the exhaust manifold 90, an increased pressure in
the exhaust manifold 90, and a greatly reduced temperature in the
exhaust manifold 90 may be indicative of both intake and exhaust
valve wear. Accordingly, the ECU 36 may identify and alert the
operator which valve of the piston cylinder assemblies 50 may
experience wear.
[0061] Turning now to FIG. 10, the figure depicts an embodiment of
a graphical output or graph 300 of a pressure sensor over a period
of time. More specifically, the graph 300 includes curves 302, 304,
306, and 308 plotted over an x-axis 310 representative of crank
angle (or time) and a y-axis 312 representative of pressure. In the
depicted embodiment, the ECU 36 may monitor for pressure pulses.
That is, one or more of the peaks in the curves 302, 304, 306, and
308, such as the peaks 314, may be representative of an exhaust
pressure pulse that may be indicative of a problematic cylinder
facing valve wear. Accordingly, when a pulse or pulses 314 is
detected, the ECU 36 may derive that valve wear may occur at a
given cylinder. Further, in certain embodiments the valve that
caused the pressure pulse 314 may be identified by the crank angle
of the pulse 314, by location of the knock sensor, or via a
combination thereof.
[0062] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
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