U.S. patent application number 16/788102 was filed with the patent office on 2020-08-13 for knock sensor systems and methods for valve recession conditions.
The applicant listed for this patent is AI ALPINE US BIDCO INC. Invention is credited to Stephan Laiminger, James Richard Zurlo.
Application Number | 20200256275 16/788102 |
Document ID | 20200256275 / US20200256275 |
Family ID | 1000004786429 |
Filed Date | 2020-08-13 |
Patent Application | download [pdf] |
United States Patent
Application |
20200256275 |
Kind Code |
A1 |
Zurlo; James Richard ; et
al. |
August 13, 2020 |
KNOCK SENSOR SYSTEMS AND METHODS FOR VALVE RECESSION CONDITIONS
Abstract
In one embodiment, a method is provided. The method includes
receiving a signal representative of an engine vibration
transmitted via a knock sensor, wherein the knock sensor is
disposed in an engine. The method additionally includes deriving a
valve wear measurement during operation of the engine based on the
signal. The method further includes communicating the valve wear
measure.
Inventors: |
Zurlo; James Richard;
(Wilmington, DE) ; Laiminger; Stephan;
(Kirchbichl, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AI ALPINE US BIDCO INC |
Wilmington |
DE |
US |
|
|
Family ID: |
1000004786429 |
Appl. No.: |
16/788102 |
Filed: |
February 11, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15877363 |
Jan 22, 2018 |
10557434 |
|
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16788102 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01L 23/221 20130101;
F02D 41/2422 20130101; F01L 2800/17 20130101; F02D 35/027 20130101;
F01L 1/22 20130101; F02D 2200/025 20130101; G01M 15/06 20130101;
F02D 41/22 20130101; G07C 5/0825 20130101; F02D 41/009 20130101;
G01M 15/05 20130101; F01L 2820/04 20130101 |
International
Class: |
F02D 41/22 20060101
F02D041/22; G01L 23/22 20060101 G01L023/22; G01M 15/05 20060101
G01M015/05; G01M 15/06 20060101 G01M015/06; F01L 1/22 20060101
F01L001/22; F02D 41/24 20060101 F02D041/24; G07C 5/08 20060101
G07C005/08 |
Claims
1. A method, comprising: receiving a signal representative of an
engine vibration transmitted via a knock sensor, wherein the knock
sensor is disposed in an engine; deriving a valve wear measurement
during operation of the engine based on the signal; and
communicating the valve wear measurement.
2. The method of claim 1, wherein deriving the valve wear
measurement comprises deriving an exhaust valve lift
measurement.
3. The method of claim 2, wherein deriving the exhaust valve lift
measurement comprises deriving an exhaust valve closing angle based
on the signal and then converting the exhaust valve closing angle
into the exhaust valve lift measurement.
4. The method of claim 1, wherein deriving the valve wear
measurement comprises using at least one row of a lookup table
based on the signal.
5. The method of claim 1, wherein deriving a valve wear measurement
during operation of the engine based on the signal comprises
applying a signal baseline to the signal.
6. The method of claim 5, wherein the signal baseline comprises a
valve adjustment baseline, a new valve installation baseline, a new
valve seat installation baseline, or a combination thereof.
7. The method of claim 1, wherein deriving a valve wear measurement
during operation of the engine based on the signal comprises
applying a crank angle measurement.
8. The method of claim 1, wherein deriving the valve wear
measurement comprises capturing a second signal via a second knock
sensor, wherein the second signal is representative of an intake
valve closing and wherein the first signal is representative of an
exhaust valve closing.
9. The method of claim 1, comprising adjusting a valve lash based
when the valve wear measurement exceeds a range.
10. A system, comprising: an engine control system comprising a
processor configured to: receive a signal representative of an
engine vibration transmitted via a knock sensor, wherein the knock
sensor is disposed in an engine; derive a valve wear measurement
during operation of the engine based on the signal; and communicate
the valve wear measurement.
11. The system of claim 10, wherein the processor is configured to
derive the valve wear measurement by deriving an exhaust valve lift
measurement.
12. The system of claim 11, wherein deriving the exhaust valve lift
measurement comprises deriving an exhaust valve closing angle based
on the signal and then converting the exhaust valve closing angle
into the exhaust valve lift measurement.
13. The system of claim 11, wherein the processor is configured to
derive the valve wear measurement by using at least one row of a
lookup table based on the signal.
14. The system of claim 11, wherein the processor is configured to
derive the valve wear measurement by applying a signal baseline to
the signal.
15. A tangible, non-transitory computer readable medium storing
code configured to cause a processor to: receive a signal
representative of an engine vibration transmitted via a knock
sensor, wherein the knock sensor is disposed in an engine; derive a
valve wear measurement during operation of the engine based on the
signal; and communicate the valve wear measurement.
16. The tangible, non-transitory computer readable medium of claim
15, wherein causing the processor to derive the valve wear
measurement comprises causing the processor to derive an exhaust
valve lift measurement.
17. The tangible, non-transitory computer readable medium of claim
16, wherein causing the processor to derive the exhaust valve lift
measurement comprises causing the processor to derive an exhaust
valve closing angle based on the signal and then to convert the
exhaust valve closing angle into the exhaust valve lift
measurement.
18. The tangible, non-transitory computer readable medium of claim
15, wherein the code is configured to cause the processor to derive
the valve wear measurement by using at least one row of a lookup
table based on the signal.
19. The tangible, non-transitory computer readable medium of claim
15, wherein the code is configured to cause the processor to derive
the valve wear measurement by applying a signal baseline to the
signal.
20. The tangible, non-transitory computer readable medium of claim
19, wherein the baseline comprises a valve closing angle.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/877,363, entitled "KNOCK SENSOR SYSTEMS AND
METHODS FOR VALVE RECESSION CONDITIONS" and filed on Jan. 22, 2018,
which are hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The subject matter disclosed herein relates to systems and
methods for valve recession conditions, and more specifically, to
knock sensor systems and method applied to valve recession
conditions.
[0003] Combustion engines will 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 move 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, which is then mixed with fuel and combusted. Combustion
fluids, e.g., hot gases, may then be directed to exit the cylinder
via an exhaust valve. Accordingly, the carbonaceous fuel is
transformed into mechanical motion, useful in driving a load. For
example, the load may be a generator that produces electric power.
As the valves (e.g., valve seats) wear, valve clearance may be
reduced and valve recession may occur. It would be beneficial to
improve detection of valve recession and wear.
BRIEF DESCRIPTION
[0004] 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.
[0005] In a first embodiment, a method is provided. The method
includes receiving a signal representative of an engine vibration
transmitted via a knock sensor, wherein the knock sensor is
disposed in an engine. The method additionally includes deriving a
valve wear measurement during operation of the engine based on the
signal. The method further includes communicating the valve wear
measure.
[0006] In a second embodiment, a system includes an engine control
system comprising a processor configured to receive a signal
representative of an engine vibration transmitted via a knock
sensor, wherein the knock sensor is disposed in an engine. The
processor is further configured to derive a valve wear measurement
during operation of the engine based on the signal. The processor
is additionally configured to communicate the valve wear
measurement.
[0007] In a third embodiment, a tangible, non-transitory computer
readable medium storing code is provided. The code is configured to
cause a processor to receive a signal representative of an engine
vibration transmitted via a knock sensor, wherein the knock sensor
is disposed in an engine. The code is additionally configured to
derive a valve wear measurement during operation of the engine
based on the signal, and to communicate the valve wear
measurement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] 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:
[0009] FIG. 1 is a block diagram of an embodiment of an engine
driven power generation system in accordance with aspects of the
present disclosure;
[0010] FIG. 2 is a side cross-sectional view of an embodiment of a
piston assembly in accordance with aspects of the present
disclosure;
[0011] FIG. 3 is an embodiment of an engine noise plot of data
measured by the knock sensor shown in FIG. 2 in accordance with
aspects of the present disclosure;
[0012] FIG. 4 is an embodiment of a combustion signature and a
valve signature plotted over a first complete intake, compression,
combustion and exhaust cycle in accordance with aspects of the
present disclosure;
[0013] FIG. 5 is a flow chart of an embodiment of a process
suitable for analyzing a vibration data and applying a lookup
table;
[0014] FIG. 6 is a graph illustrating an embodiment of various
valve closing angles graphed at various operating engine hours;
and
[0015] FIG. 7 is a graph showing an embodiment of various crank
degrees (e.g., valve closing degrees) for convertion into valve
lift measurements.
DETAILED DESCRIPTION
[0016] 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.
[0017] 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.
[0018] The techniques described herein include the use of one or
more knock sensor systems and methods that may detect a dynamic
response of a various gas engine components during engine
operations to derive conditions related to the components and
component conditions, including valve recession. For example, knock
sensors signals related to a variety of engine components may be
detected, including cylinder head components (e.g., cylinder head
and gaskets), cylinder block components (e.g., cylinder block,
cylinder sleeves), valves train components (e.g., valves, valve
seats, valve stems), camshaft and drive components (e.g., camshaft,
cam lobes, timing belts/chains, tensioners), piston components
(e.g., pistons, piston rings, connection rods), crankshaft assembly
components (e.g., crankshaft, engine bearings, flywheels), gear
train components (e.g., gearbox, gears, output shaft), and so
on.
[0019] The knock sensor signals detected may then be compared, for
example, by using a "look up" table to determine certain engine
conditions that may have cause the knock sensor signals, including
changes in valve geometry. Indeed, rather than applying techniques
to separate knock from other noise data present in knock sensor
signals, the techniques described herein embrace the "spurious"
data and apply the data to determine a variety of engine
conditions. By having a look up table of the engine's key
components related to, for example, crank angle degree, the
engine's components can be indexed with respect to temporal windows
related to crank angle degree to cross-check and estimate what key
component and component condition is likely causing the noise. For
example, as valve wear, the knock sensor signal may change, and the
change may be used to derive a valve recession measurement.
Accordingly, a more proactive engine maintenance and repair process
may be provided.
[0020] 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). Though
FIG. 1 shows a combustion engine 12, it should be understood that
any reciprocating device may be used. 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 cause a piston 24 adjacent to each combustion
chamber 14 to move linearly within a cylinder 26 and convert
pressure exerted by the gases into a rotating motion, which causes
a shaft 28 to rotate. Further, the shaft 28 may be coupled to a
load 30, which is powered via rotation of the shaft 28. For
example, the load 30 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.
[0021] 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 26 (e.g., 1-24). For example,
in certain embodiments, the system 10 may include a large-scale
industrial reciprocating engine 12 having 4, 6, 8, 10, 16, 24 or
more pistons 24 reciprocating in cylinders 26. In some such cases,
the cylinders 26 and/or the pistons 24 may have a diameter of
between approximately 13.5-34 centimeters (cm). In some
embodiments, the cylinders 26 and/or the pistons 24 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 12 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 12
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.
[0022] The driven power generation system 10 may include one or
more knock sensors 32 suitable for detecting engine "knock" and/or
other run characteristics of the engine 12. The knock sensor 32 may
be any sensor configured to sense vibration caused by the engine
12, such as vibration due to detonation, pre-ignition, and or
pinging. The knock sensor 32 is shown communicatively coupled to a
controller (e.g., a reciprocating device controller), engine
control unit (ECU) 34. During operations, signals from the knock
sensors 32 are communicated to the ECU 34 to determine if knocking
conditions (e.g., pinging), or other behaviors exist. The ECU 34
may then adjust certain engine 12 parameters to ameliorate or avoid
the undesirable conditions. For example, the ECU 34 may adjust
ignition timing and/or adjust boost pressure to avoid knocking. As
further described herein, the knock sensors 32 may additionally
detect other vibrations beyond knocking. It is to be noted that the
same signal may be used for both analysis of knocking as well as
for analysis of other conditions, such as valve recession.
[0023] More specifically, the one or more knock sensors 32 may be
used to detect a variety of signals and to correlate the signals
based on crank angle degrees, noise signatures, or a combination
thereof. For example, rather than filtering out "noise" in a signal
so that the signal only detects knock, the knock sensor's 32 signal
used to detect nock may also be analyzed in its entirety to
determine certain engine conditions, including valve recession. In
one embodiment, the signal may be analyzed by using a look table
described in more detail below, to determine if the noise detected
is correlative to a certain crank angle or timing. If so, then the
condition that caused the noise may be narrowed down to a small set
or a single condition (e.g., a specific valve geometry or valve
geometry range). Additionally or alternatively, a noise signature
analysis may be performed, and the noise signature of the detected
noise, in combination with the look up table, may narrow down the
condition set even further.
[0024] FIG. 2 is a side cross-sectional view of an embodiment of a
piston assembly 36 having a piston 24 disposed within a cylinder 26
(e.g., an engine cylinder) of the reciprocating engine 12. The
cylinder 26 has an inner annular wall 38 defining a cylindrical
cavity 40 (e.g., bore). The piston 24 may be defined by an axial
axis or direction 42, a radial axis or direction 44, and a
circumferential axis or direction 46. The piston 24 includes a top
portion 48 (e.g., a top land). The top portion 48 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 attached to a crankshaft 50 via a
connecting rod 52 and a pin 54. Also shown is a counterweight 55 of
the crankshaft 50 useful in balancing a weight of a crank throw.
The crankshaft 50 translates the reciprocating linear motion of the
piston 24 into a rotating motion. As the piston 24 moves, the
crankshaft 50 rotates to power the load 30 (shown in FIG. 1), as
discussed above. As shown, the combustion chamber 14 is positioned
adjacent to the top land 48 of the piston 24. A fuel injector 56
provides the fuel 20 to the combustion chamber 14, and an intake
valve 58 controls the delivery of air 18 to the combustion chamber
14. An exhaust valve 60 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
42 within the cavity 40 of the cylinder 26.
[0026] During operations, when the piston 24 is at the highest
point in the cylinder 26 it is in a position called top dead center
(TDC). When the piston 24 is at its lowest point in the cylinder
26, 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 50 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 typically occurs. The intake process enables a combustible
mixture, such as fuel and air, to be pulled into the cylinder 26,
thus the intake valve 58 is open and the exhaust valve 60 is
closed. The compression process compresses the combustible mixture
into a smaller space, so both the intake valve 58 and the exhaust
valve 60 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 typically returns
the piston 24 to TDC while keeping the exhaust valve 60 open. The
exhaust process thus expels the spent fuel-air mixture through the
exhaust valve 60. It is to be noted that more than one intake valve
58 and exhaust valve 60 may be used per cylinder 26.
[0028] The engine 12 may also include a crankshaft sensor 62, one
or more knock sensors 32, and the engine control unit (ECU) 34,
which includes a processor 64 and memory 66 (e.g., non-transitory
computer readable medium). The crankshaft sensor 62 senses the
position and/or rotational speed of the crankshaft 50. Accordingly,
a crank angle or crank timing information may be derived. That is,
when monitoring combustion engines, timing is frequently expressed
in terms of crankshaft 50 angle. For example, a full cycle of a
four stroke engine 12 may be measured as a 720.degree. cycle. The
one or more knock sensors 32 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, and/or movement. In other
embodiments, sensor 32 may not be a knock sensor in the traditional
sense, but any sensor that may sense vibration, pressure,
acceleration, deflection, or movement.
[0029] Because of the percussive nature of the engine 12, the knock
sensor 32 may be capable of detecting engine vibrations and/or
certain "signatures" related to a variety of engine conditions even
when mounted on the exterior of the cylinder 26. The one or more
knock sensors 32 may be disposed at many different locations on the
engine 12. For example, in FIG. 2, one knock sensors 32 is shown on
the head of the cylinder 26. In other embodiments, one or more
knock sensors 32 may be used on the side of the cylinder 26.
Additionally, in some embodiments, a single knock sensor 32 may be
shared, for example, with one or more adjacent cylinders 26. In
other embodiments, each cylinder 26 may include one or more knock
sensors 32 on either or both sides of a cylinder 26. The crankshaft
sensor 62 and the knock sensor 32 are shown in electronic
communication with the engine control unit (ECU) 34. The ECU 34
includes a processor 64 and a memory 66. The memory 66 may store
non-transitory code or computer instructions that may be executed
by the processor 64. The ECU 34 monitors and controls and operation
of the engine 12, for example, by adjusting spark timing, valve 58,
60 timing, adjusting the delivery of fuel and oxidant (e.g., air),
and so on.
[0030] Knock sensors 32 are used to detect engine knock. Engine
knock is the premature combustion of fuel outside the envelope of
normal combustion. In some cases, the ECU 34 may attempt to reduce
or avoid engine knock when it occurs by adjusting the operating
parameters of the engine. For example, the ECU 34 may adjust the
air/fuel mix, ignition timing, boost pressure, etc. in an effort to
reduce or avoid engine knock. However, knock sensors may also be
used to detect other vibrations in an engine unrelated to engine
knock. More specifically, the same knock sensor signal may be
processed both to detect knock as well as to detect other
conditions, including valve recession conditions. In valve
recession, the valve 60 or a valve seat (e.g., valve seat ring) 67
may experience wear and valve clearance or "lash" may be reduced,
causing unwanted escape of combustion gases which may cause further
wear to the valve 60 and/or to valve seat 67. Valve recession or
valve wear may be derived as described below.
[0031] FIG. 3 is an embodiment of a raw engine noise plot 68
derived (e.g., by the ECU 34) of noise data measured by a single
knock sensor 32 mounted on a single cylinder 26 in which x-axis 70
is time and the y-axis 72 is raw noise amplitude. In the depicted
embodiment, an amplitude curve 74 of the knock sensor 32 signal is
shown. That is, the raw signal 74 includes amplitude measurements
of vibration data (e.g., noise, sound data) sensed via the knock
sensor 32 and plotted against time. It should be understood that
this is merely a plot 68 of a sample data set, and not intended to
limit plots generated by the ECU 34. It should also be understood
that plot 68 is of a signature from one knock sensor 32 mounted to
one cylinder 26. In other embodiments there may be multiple
signatures from multiple knock sensors mounted to multiple
cylinders, e.g., mating cylinders. The raw signal 74 may then be
further processed, as described in more detail below, including via
the use of a look up table and/or signature analysis.
[0032] With respect to signature analysis, as shown in FIG. 4,
signals can be filtered into a combustion signature 76 and a valve
signature 78. Events can then be derived from the signatures and
the timing of those events checked via look up table(s). Once data
from the one or more knock sensors 32 is collected, one or more
filters may be applied to the data to derive a combustion signature
76 (i.e., noise attributable to combustion events) and a valve
signature 78 (i.e., noise attributable to valve 58, 60 movement).
The combustion signature 76 and valve signature 78 may be derived
by applying filters, fast Fourier transforms (FFT), or applying
other digital signal processing (DSP) techniques to the sampled
data. For example, the ECU 34 may derive the combustion signature
76 by applying a low pass filter at 1200 Hz or a band pass filter
from 0.5 Hz to 1200 Hz. The valve signature may be derived using a
band pass filter from 12 kHz to 18 kHz. FIG. 4 is an embodiment of
a sample plot 82 of a combustion signature 76 and a valve signature
78 over a first complete intake, compression, and combustion and
exhaust cycle. The x-axis 84 is shown as time in seconds, but may
also be shown as crank angle. The y-axis 86 on the left corresponds
to the valve signature 78, and the y-axis 88 on the right
corresponds to the combustion signature 76. Each of the y-axes 86,
88 represents the amplitude of the corresponding noise signature
76, 78. Depending upon the measurement technique and the preference
of the user, the units may be dB, volts, or some other unit). Note
that the scales of the y-axes 86, 88 may be different because the
amplitudes of the two signatures 76, 78 are likely to be different.
FIG. 4 is illustrative of data that may be undergoing data
processing, for example, via a process described in more detail
with respect to the figures below. The data for FIG. 4 may include
data transmitted via the knock sensor 32 and the crank angle sensor
62 once the ECU 34 has derived a combustion signature 76 and a
valve signature 78 from the data using digital signal processing
(DSP) techniques. Furthermore, for the sake of clarity, only a
single combustion signature and a single valve signature are shown
in FIG. 4. It should be understood, however, that the same or
similar processing may be performed on more than one knock sensor
32 mounted to more than one cylinder.
[0033] The combustion signature 76 includes significant combustion
events, such as peak firing pressure (PFP) of both the measured
cylinder 26, and a mating cylinder 80 (i.e., the cylinder in the
engine that is 360 degrees out of phase with the measured cylinder
26). The valve signature 78 includes the closing of the intake
valve 58 and exhaust valve 60. Some combustion events, such as PFP
(of both the measured cylinder 26 and the mating cylinder 80), may
appear in both the combustion signature 76 and the valve signature
78. FIG. 4 shows slightly more than one complete combustion cycle,
or 720 degrees of rotation (two complete revolutions) at the
crankshaft 50. Each cycle includes intake, compression, combustion,
and exhaust.
[0034] In one example, the signatures 76, 78, and/or the raw signal
74 may be processed to determine if any abnormal conditions exist.
In one embodiment, the signatures 76, 78, and/or the raw signal 74
may be compared to a baseline, and the comparison used to determine
that sufficient differences exist such that a condition affecting
engine performance is occurring. In certain embodiments, the
baseline may be signals representative of the engine 12 operating
with valve 60 and/or valve seat 67 with no wear (e.g., new valves
and valve seats). Then, as wear occurs, deviations from the
baseline may be detected and used to determine valve 60 and/or
valve seat 67 wear, such as recession measurements. For example, as
wear occurs, a valve 60 closing angle may change. For example, the
crank angle of the crank 50 may shift slightly, resulting in a new
valve closing angle. The valve 60 closing angle may be
representative of a recession or lash measure. That is, deviations
from a baseline valve closing angle may be converted into a
recession measurement in, for example, millimeters. In one example,
a table may be used, where deviations, e.g., in degrees, may be
converted to recession in millimeters, inches, etc. In other
examples, equation(s) (e.g., geometric equations) may be used to
convert from closing angles to recession measurements.
[0035] Indeed, the comparison between the signatures 76, 78, and/or
the raw signal 74 and the baseline may include a crank angle degree
or timing comparison. That, is differences between the signatures
76, 78, and/or the raw signal 74 and the baseline may be
ascertained by comparison based on when in the engine combustion
cycle the signatures 76, 78, and/or the raw signal 74 was captured,
which may be correlative with the position or crank angle of the
crank 50. The baseline may be derived by observing normal
operations of the engine 12 over the course of multiple combustion
cycles.
[0036] In another embodiment, the determination that an abnormal
condition of some sort exists may be made by other techniques, such
as lubricant analysis, emissions analysis, wear debris detection,
and the like. Regardless of the techniques used to determine that
some sort of abnormality is occurring, including baselining the
signatures 76, 78, and/or the raw signal 74, the techniques
described herein may additionally or alternatively aid in
determining what component or components may be involved. More
specifically, the techniques described herein may apply a look up
table to determine component(s) of the engine 12 involved in the
current condition, such as the valve 60 and/or the valve seat 67
wear.
[0037] In one embodiment, the look up table for a twelve-cylinder
embodiment of the engine 12 may include a first Knock sensor window
"open", followed by one or more position columns. The position
columns may include cam position (degrees), crank position
(degrees), #1 Right Cylinder Piston Position (inches from TDC), #1
Right Cylinder Counterweight Position Angle from Highest Point
where Highest point=0 degrees, #6 Left Cylinder Piston Position
(inches from TDC), #6 Left Cylinder Counterweight Position Angle
from Highest Point where Highest point=0 degrees, #5 Right Cylinder
Piston Position (inches from TDC), #5 Right Cylinder Counterweight
Position Angle from Highest Point where Highest point=0 degrees, #2
Left Cylinder Piston Position (inches from TDC), #2 Left Cylinder
Counterweight Position Angle from Highest Point where Highest
point=0 degrees, #3 Right Cylinder Piston Position (inches from
TDC), #3 Right Cylinder Counterweight Position Angle from Highest
Point where Highest point=0 degrees, #4 Left Cylinder Piston
Position (inches from TDC), and #4 Left Cylinder Counterweight
Position Angle from Highest Point where Highest point=0
degrees.
[0038] The Knock sensor window "open" column may refer to a time
window (e.g., time range) or crank angle window (e.g., angle range)
at which a particular sensor 32 is more suited to derive engine 12
conditions, based on the one or more position columns. For example,
the knock sensor 32 disposed in the #1 right cylinder 26 may be
more suitable at a window or range when the camshaft position
(e.g., crank position (degrees) column) is between 0 and 15
degrees. Likewise, the remainder columns crank position (degrees),
#1 Right Cylinder Piston Position (inches from TDC), #1 Right
Cylinder Counterweight Position Angle from Highest Point where
Highest point=0 degrees, #6 Left Cylinder Piston Position (inches
from TDC), #6 Left Cylinder Counterweight Position Angle from
Highest Point where Highest point=0 degrees, #5 Right Cylinder
Piston Position (inches from TDC), #5 Right Cylinder Counterweight
Position Angle from Highest Point where Highest point=0 degrees, #2
Left Cylinder Piston Position (inches from TDC), #2 Left Cylinder
Counterweight Position Angle from Highest Point where Highest
point=0 degrees, #3 Right Cylinder Piston Position (inches from
TDC), #3 Right Cylinder Counterweight Position Angle from Highest
Point where Highest point=0 degrees, #4 Left Cylinder Piston
Position (inches from TDC), and #4 Left Cylinder Counterweight
Position Angle from Highest Point where Highest point=0 degrees may
include data related to when a particular knock sensor 32 (e.g., #1
right, #1 left, #2 right, #2 left, #3 right, #3 left, #4 right, #4
left, #5 right, #5 left, #6 right, #6 left) is more effective at
certain positions.
[0039] The look up table may be created, for example, to correlate
noise received via the knock sensors 32 and corresponding position
columns, with one or more engine 12 conditions, such as conditions
affecting cylinder 26 head components (e.g., cylinder head and
gaskets), cylinder 26 block components (e.g., cylinder block,
cylinder sleeves), valve 58, 60 train components (e.g., valves,
valve seats, valve stems), camshaft 50 and drive components (e.g.,
camshaft, cam lobes, timing belts/chains, tensioners), piston 24
components (e.g., pistons, piston rings, connection rods),
crankshaft 50 assembly components (e.g., crankshaft, engine
bearings, flywheels), gear train components (e.g., gearbox, gears,
output shaft), and so on. In one embodiment, the crankshaft sensor
62 may aid in the correlation, for example, by additionally
providing for crankshaft 50 position data (e.g., crank position
(degrees) column). By correlating which of a particular knock
sensor 32 (e.g., #1 right, #1 left, #2 right, #2 left, #3 right, #3
left, #4 right, #4 left, #5 right, #5 left, #6 right, and/or #6
left knock sensor 32, where the number and position corresponds to
a cylinder 32 number and position of, for example, the 12 cylinder
embodiment of the engine 12), and when the knock sensor 32 detected
the unusual or unexpected noise, the techniques described herein
may provide for an estimate of which component is likely causing
the unexpected noise.
[0040] In certain embodiments, the estimate is an estimated
recession measure. For example, various rows in the look up table
would contain deviations from a baseline (e.g., baseline with new
valve 60, seat 67) representative of various valve closing angles.
In one embodiment, more than one look up table may be used, each
table correlating noise to a specific component, set of components,
engine condition, set of engine conditions, or a combination
thereof. In another embodiment, the set of engine 12 conditions
correlative to the position columns and the Knock sensor window
"open" column may be stored as additional Condition columns in the
lookup table(s). Accordingly, the techniques described herein may
enable a real time detection of engine 12 conditions through, for
example, existing knock sensors 32, which may result in proactive
engine maintenance and repair processes.
[0041] FIG. 5 is a flow chart depicting a process 150 suitable for
analyzing vibration data via the knock sensors 32 and lookup
table(s). The process 150 may be implemented as computer code or
instructions executable via the processor 64 and stored in the
memory 66. In the depicted embodiment, the process 150 may create
(block 152) one or more lookup tables 154. As mentioned above, the
look up table(s) 154 may be created to correlate noise received via
the knock sensors 32 and corresponding position columns, with one
or more engine 12 conditions, such as conditions affecting cylinder
26 head components (e.g., cylinder head and gaskets), cylinder 26
block components (e.g., cylinder block, cylinder sleeves), valve
58, 60 train components (e.g., valves, valve seats, valve stems),
camshaft 50 and drive components (e.g., camshaft, cam lobes, timing
belts/chains, tensioners), piston 24 components (e.g., pistons,
piston rings, connection rods), crankshaft 50 assembly components
(e.g., crankshaft, engine bearings, flywheels), gear train
components (e.g., gearbox, gears, output shaft), and so on.
[0042] In one embodiment of a twelve-cylinder engine 12, the lookup
table(s) 154 may include a Knock sensor window "open" column
followed by one or more position columns. The position columns may
include: cam position (degrees), crank position (degrees), #1 Right
Cylinder Piston Position (inches from TDC), #1 Right Cylinder
Counterweight Position Angle from Highest Point where Highest
point=0 degrees, #6 Left Cylinder Piston Position (inches from
TDC), #6 Left Cylinder Counterweight Position Angle from Highest
Point where Highest point=0 degrees, #5 Right Cylinder Piston
Position (inches from TDC), #5 Right Cylinder Counterweight
Position Angle from Highest Point where Highest point=0 degrees, #2
Left Cylinder Piston Position (inches from TDC), #2 Left Cylinder
Counterweight Position Angle from Highest Point where Highest
point=0 degrees, #3 Right Cylinder Piston Position (inches from
TDC), #3 Right Cylinder Counterweight Position Angle from Highest
Point where Highest point=0 degrees, #4 Left Cylinder Piston
Position (inches from TDC), and #4 Left Cylinder Counterweight
Position Angle from Highest Point where Highest point=0.
[0043] Each row of the lookup table(s) 154 may include a specific
knock sensor 32 (e.g., #1 right, #1 left, #2 right, #2 left, #3
right, #3 left, #4 right, #4 left, #5 right, #5 left, #6 right,
and/or #6 left sensor 32) in the Knock sensor window "open" column
and corresponding position values for the position columns. In one
embodiment, a test bed engine 12 may be instrumented and used to
create the lookup table(s) 154. For example, noise related to the
one or more engine 12 conditions listed above may be captured and
analyzed, and the columns of the lookup table(s) 154 associated
with the noise. In use, the knock sensor(s) 32 may sense (block
156) engine noise during engine 12 operations. Certain noises, such
as unusual noises, may be found, for example, by using the
baselining and/or signature techniques described above, or by other
techniques. The noises may then be correlated by applying (block
158) the lookup table(s) 154. For example, the relevant knock
sensor(s) 32 that detect the noise and/or the signals from the
crankshaft sensor 62 may be used to derive values for the position
columns of the table(s) 154. Based on the noise detected and/or the
position of certain components (e.g., derived by using the position
columns of the lookup table(s) 154), certain engine conditions may
be derived (block 160). As mentioned earlier, a derived condition
may be a variation from a baseline closing angle. That is, if the
baseline closing angle is a number, like 386 degrees, then knock
sensor 32 signals may be received, correlated to an engine
condition (e.g., correlated to be a signal representative of
deviation from valve closing baseline), and the look table(s) 154
may then be used to determine the deviation. For example,
recognition software may be trained to recognize the knock sensor
signal as being a valve closing event signal deviating from a
baseline (e.g., valve closing baseline) based on crank angle and
then the recognition software may "point" to a row corresponding to
the deviation in the look up table(s) 154, which may include the
degrees of deviation in valve closing and/or a valve recession
measurement.
[0044] For example, based on cam position (degrees), crank position
(degrees), #1 Right Cylinder Piston Position (inches from TDC), #1
Right Cylinder Counterweight Position Angle from Highest Point
where Highest point=0 degrees, #6 Left Cylinder Piston Position
(inches from TDC), #6 Left Cylinder Counterweight Position Angle
from Highest Point where Highest point=0 degrees, #5 Right Cylinder
Piston Position (inches from TDC), #5 Right Cylinder Counterweight
Position Angle from Highest Point where Highest point=0 degrees, #2
Left Cylinder Piston Position (inches from TDC), #2 Left Cylinder
Counterweight Position Angle from Highest Point where Highest
point=0 degrees, #3 Right Cylinder Piston Position (inches from
TDC), #3 Right Cylinder Counterweight Position Angle from Highest
Point where Highest point=0 degrees, #4 Left Cylinder Piston
Position (inches from TDC), and/or #4 Left Cylinder Counterweight
Position Angle from Highest Point where Highest point=0, it may be
possible to more easily narrow down (or fully derive) (block 160)
that the noise captured by the knock sensor(s) 32 is due to a
certain engine condition (e.g., valve closing event or deviation
from a baseline valve closing angle), or subset of engine
conditions.
[0045] The process 150 may then communicate (block 162) the derived
engine 12 conditions. For example, the process 150 may display the
one or more engine 12 conditions (e.g., valve recession
measurement) in a display communicatively coupled to the ECU 34,
set an error code (e.g., controller area network [CAN] code,
on-board diagnostics II [OBD-II] code), set an alarm or an alert,
and so on. By correlating noise via lookup table(s) 154, the
techniques described herein may enhance engine operations and
maintenance processes.
[0046] FIG. 6 is a graph 200 illustrating an embodiment of various
valve 60 closing angles shown in axis 202 graphed at various
operating engine hours shown in an axis 204. In the depicted
embodiment, at zero operating hours, a baseline 206 having 386
degrees of valve 60 closing angle is depicted. The baseline 206 may
be representative of an adjustment (e.g., valve lash adjustment)
and/or installation of new valve seats and/or new valves. As the
engine 12 operates, wear cause closing angle changes until at time
T1 the closing angle may now be at 374 degrees. The systems and
methods described herein may have a range of valve closing angles
and corresponding recession values at which a valve lash adjustment
may be recommended. Likewise a new valve ring and/or a new valve
may be recommended. Accordingly, the graph shows a point 208 after
valve adjustment and/or new valve seat installation and/or new
valve installation.
[0047] Subsequent points in the graph show changes in valve closing
angles after more operating hours. That is, operating hours after
T1 show changes in valve closing angles which again may be due to
wear. At certain points, such as point 210, alarms/alerts, and so
on, may be provided to the engine 12 operator, to ask the operator
to once again perform a valve lash adjustment (or install new valve
seats and/or new valves). It is to be understood that the degree
values show in axis 202 are for example only, and other values may
be used depending on the type of engine 12 being used. The graph
200 may also be provided to engine 12 operators via a vehicle
display, a log, printed media, and so on.
[0048] The graph 200 may be dynamically derived via the techniques
described herein. That is, a running tally may be kept of operating
hours for the engine 12, and after the passage of a certain time
(e.g., minute, 5 minutes, 15 minutes, 30 minutes, 1 hour) the ECU
34 may then derive a valve closing angle, for example via block 160
above. According, a valve closing angle may be correlated to a
given operating time for the engine 12. As mentioned earlier, valve
closing angles may be converted into other measures such as valve
lift. Turning now to FIG. 7, the figure is a graph 300 showing an
embodiment of various crank degrees (e.g., valve closing degrees)
in axis 302 being converted into valve lift points in axis 304,
where valve lift is representative of valve recession measurement.
In the depicted example, given an certain crank angle (e.g., 374
degrees), the graph 300 may then provide a corresponding valve lift
measure (e.g., 0.237 mm). It is to be understood that the values in
axis 302 and 304 are for example only.
[0049] By first deriving valve closing angles and then providing
for corresponding valve lift measurements, the techniques described
herein may enable improved engine 12 maintenance and increase life.
For example, a range of valve lift may be set, and if a derived
valve lift value is outside the range then the engine 12 operator
may be notified. The engine 12 may then be maintained in a
condition-based maintenance (CBM) mode, as opposed to on a schedule
mode. The schedule mode may result in, for example, valve
adjustments that performed unnecessarily too many times or not as
often as the actual valve recession would call for.
[0050] Technical effects of the invention include detecting engine
vibrations via certain sensors, such as knock sensors. Certain
lookup table(s) may be created, suitable for associating one or
more knock sensor "windows" with one or more conditions of certain
engine components. The vibrations are correlated, via the one or
more lookup tables and/or crankshaft sensor data, and certain
engine conditions may be detected. The engine conditions include
valve wear, valve seat wear, and the like, which may be converted
into certain measurements, such as valve recession
measurements.
[0051] 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.
* * * * *