U.S. patent application number 13/973016 was filed with the patent office on 2014-12-18 for system and method for determining effectiveness of a friction modifier along a route segment.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is General Electric Company. Invention is credited to Ajith Kuttannair Kumar, Joseph Forrest Noffsinger.
Application Number | 20140371959 13/973016 |
Document ID | / |
Family ID | 50972472 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140371959 |
Kind Code |
A1 |
Kumar; Ajith Kuttannair ; et
al. |
December 18, 2014 |
SYSTEM AND METHOD FOR DETERMINING EFFECTIVENESS OF A FRICTION
MODIFIER ALONG A ROUTE SEGMENT
Abstract
A method including obtaining creep measurements and
tractive/braking measurements from at least one vehicle system at
different locations along a route segment while the at least one
vehicle system moves through the route segment. The method also
includes calculating tribology characteristics of the route segment
at the different locations. The tribology characteristics are based
on the creep measurements and the tractive/braking measurements
from the at least one vehicle system. The tribology characteristics
are indicative of a friction coefficient of the route segment at
the different locations. The method also includes determining an
effectiveness of a friction modifier applied to the route segment
based on the tribology characteristics.
Inventors: |
Kumar; Ajith Kuttannair;
(Erie, PA) ; Noffsinger; Joseph Forrest; (Grain
Valley, MO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
50972472 |
Appl. No.: |
13/973016 |
Filed: |
August 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61834395 |
Jun 12, 2013 |
|
|
|
Current U.S.
Class: |
701/20 ; 701/1;
701/70 |
Current CPC
Class: |
B60T 13/665 20130101;
B61C 15/14 20130101; B60T 17/228 20130101; B61K 9/08 20130101; B60T
2210/12 20130101; Y02T 30/10 20130101; Y02T 30/00 20130101; B60T
8/172 20130101 |
Class at
Publication: |
701/20 ; 701/1;
701/70 |
International
Class: |
B61K 9/08 20060101
B61K009/08 |
Claims
1. A method comprising: obtaining creep measurements and
tractive/braking measurements from at least one vehicle system at
different locations along a route segment while the at least one
vehicle system moves through the route segment; calculating
tribology characteristics of the route segment at the different
locations, the tribology characteristics being based on the creep
measurements and the tractive/braking measurements from the at
least one vehicle system, wherein the tribology characteristics are
indicative of a friction coefficient of the route segment at the
different locations; and determining an effectiveness of a friction
modifier applied to the route segment based on the tribology
characteristics.
2. The method of claim 1, wherein obtaining the creep measurements
and the tractive/breaking measurements includes obtaining a series
of the creep measurements and the tractive/breaking measurements
throughout the route segment of the at least one vehicle
system.
3. The method of claim 1, wherein the route segment is at least two
kilometers long and wherein the creep measurements and the
tractive/breaking measurements are obtained, on average, at least
once every 50 meters for the route segment.
4. The method of claim 1, wherein obtaining the creep measurements
and the tractive/braking measurements from the at least one vehicle
system includes obtaining the creep measurements and the
tractive/braking measurements in response to a tractive effort of a
first wheelset being increased by a designated amount and a
tractive effort of a second wheelset being decreased by the
designated amount thereby maintaining a total tractive effort of
the at least one vehicle system.
5. The method of claim 1, wherein obtaining the creep measurements
and the tractive/braking measurements from the at least one vehicle
system includes the tractive/braking measurements being
representative of maximum tractive efforts at the different
locations.
6. The method of claim 1, wherein the at least one vehicle system
operates in accordance with an operating plan, the operating plan
including predetermined instructions for one or more
propulsion-generating vehicles of the at least one vehicle system
to provide at least one of a designated tractive effort or a
designated braking effort.
7. The method of claim 1, wherein the at least one vehicle system
includes at least one locomotive and wherein a plurality of the
creep measurements and a plurality of the tractive/braking
measurements are obtained from the at least one locomotive.
8. The method of claim 1, further comprising obtaining creep
measurements and tractive/braking measurements from at least one
other separate vehicle system while the at least one other separate
vehicle system moves through the route segment, wherein calculating
the tribology characteristics of the route segment includes using
the creep measurements and the tractive/braking measurements from
the at least one other separate vehicle system.
9. The method of claim 1, wherein obtaining the creep measurements
and the tractive/braking measurements includes obtaining the creep
measurements and the tractive/braking measurements at an off-board
monitoring system, the at least one vehicle system being a
plurality of separate vehicle systems that travel along the route
segment.
10. The method of claim 1, wherein the tribology characteristic is
an adhesion coefficient or is based on or indicative of the
adhesion coefficient.
11. A system comprising: a receiver configured to receive creep
measurements and tractive/braking measurements from at least one
vehicle system at different locations along a route segment while
the at least one vehicle system moves through the route segment; a
calculation module configured to calculate tribology
characteristics of the route segment at the different locations,
the tribology characteristics being based on the creep measurements
and the tractive/braking measurements from the at least one vehicle
system, wherein the tribology characteristics are indicative of a
friction coefficient of the route segment at the different
locations; and an analysis module configured to determine an
effectiveness of a friction modifier applied to the route segment
based on the tribology characteristics at the different
locations.
12. The system of claim 11, wherein the analysis module is
configured to compare the tribology characteristics at the
different locations to expected tribology characteristics at the
different locations.
13. The system of claim 11, wherein the analysis module is
configured to identify one or more regions of the route segment
that having an amount of the friction modifier that is below a
first designated threshold and identify one or more regions of the
route segment having an amount of the friction modifier that is
above a second designated threshold.
14. The system of claim 11, wherein the receiver is configured to
receive compensating data relating to route conditions and the
analysis module is configured to determine the effectiveness of the
friction modifier using the compensating data to compensate for the
route conditions.
15. The system claim 11, wherein the receiver is configured to
receive a series of the creep measurements and the
tractive/breaking measurements throughout the route segment from
the at least one vehicle system.
16. The system of claim 11, wherein the route segment is at least
two kilometers long and wherein the creep measurements and the
tractive/breaking measurements are obtained, on average, at least
once every 50 meters for the route segment.
17. A system comprising: a vehicle-control module configured to
control tractive and braking operations of a vehicle system; a
measurement module configured to obtain creep measurements and
tractive/braking measurements of the vehicle system at different
locations along a route segment while the vehicle system moves
through the route segment; and a transmitter configured to
communicate the creep measurements and the tractive/braking
measurements from the vehicle system; wherein the vehicle-control
module is configured to increase the tractive effort of a first
wheelset by a designated amount and decrease the tractive effort of
a second wheelset by the designated amount thereby maintaining a
total tractive effort of the vehicle system, the measurement module
configured to obtain the creep measurements and the
tractive/braking measurements when the first and second wheelsets
operate at increased and decreased tractive efforts,
respectively.
18. The system of claim 17, wherein the measurement module is
configured to obtain the creep measurements and the
tractive/braking measurements of the vehicle system when the
vehicle system is operating at a designated throttle setting, the
tractive/braking measurements being representative of maximum
tractive efforts at the different locations.
19. The system of claim 17, wherein the vehicle-control module is
configured to control the vehicle system in accordance with an
operating plan, the operating plan including predetermined
instructions for one or more propulsion-generating vehicles of the
vehicle system to provide at least one of a designated tractive
effort or a designated braking effort.
20. The system of claim 17, wherein the vehicle system includes a
plurality of locomotives, the calculation module configured to
obtain the creep measurements and the tractive/braking measurements
from the plurality of locomotives.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S.
Provisional Patent Application No. 61/834,395, filed on Jun. 12,
2013, which is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] Embodiments of the subject matter described herein relate to
systems and methods of determining a condition of a route that is
traversed by a vehicle system.
[0003] The ability of a vehicle system to provide tractive efforts
for propelling the vehicle system along a route is dependent upon
the friction between a propulsion-generating component (e.g.,
wheel) and a surface of the route. Monitoring and controlling this
friction may lead to the reduction in operating costs. For example,
routes for rail vehicle systems (e.g., locomotives, tram lines,
monorails, subways, mining equipment, and the like) typically
include tracks (e.g., rails) that are traversed by the vehicle
systems. In many cases, the forces applied by such rail vehicle
systems provide a significant amount of stress and wear on the
rails of the tracks and certain components of the rail vehicle
systems. Railroad owners often monitor rail conditions to ensure
that the locomotives can operate efficiently. For instance, it is
often desirable that the coefficients of friction (COFs) (or other
friction metrics) of the rails are within a designated range to (a)
reduce wearing of the rails and wearing of the wheels of the
locomotives and/or (b) to obtain a desired adhesion between the
rails and the wheels. To this end, railroads may apply a lubricant
to the rails to reduce the COF. Reducing the COF may not only
reduce the wear on rails and wheels, but may also lead to fuel
savings. In other cases, railroads may desire a greater adhesion
and, thus, apply a substance that increases the adhesion between
the wheels and rails.
[0004] To monitor the COF or other friction metric, railroads may
test a number of points along the rails with a tribometer. For
example, once a month (or other frequency) a railroad may take a
series of measurements along a segment of the track, such as a
curve of the track. The segment of the track may extend for a
substantial distance, such as a half mile or mile. The measurements
are often taken manually in which an inspector walks along the
track with the tribometer riding the rail.
[0005] This conventional measurement process, however, can be
cumbersome and can take a substantial amount of time. On some
occasions, the process can even disrupt rail traffic. Furthermore,
railroads are often responsible for overseeing thousands of miles
of tracks and may have hundreds of route segments that are
frequently tested. Hundreds of instruments may be necessary to
sufficiently monitor these route segments. Such instruments may, at
times, become faulty or have an undetected measurement bias that
leads to incorrect data. Accordingly, the costs of monitoring the
rails can be large and difficult to manage.
BRIEF DESCRIPTION
[0006] In an embodiment, a method is provided that includes
obtaining creep measurements and tractive/braking measurements from
at least one vehicle system at different locations along a route
segment while the at least one vehicle system moves through the
route segment. The method also includes calculating tribology
characteristics of the route segment at the different locations.
The tribology characteristics are based on the creep measurements
and the tractive/braking measurements from the at least one vehicle
system. The tribology characteristics are indicative of a friction
coefficient of the route segment at the different locations. The
method also includes determining an effectiveness of a friction
modifier applied to the route segment based on the tribology
characteristics.
[0007] In another embodiment, a system (e.g., monitoring system) is
provided that includes a receiver configured to receive creep
measurements and tractive/braking measurements from at least one
vehicle system at different locations along a route segment while
the at least one vehicle system moves through the route segment.
The system also includes a calculation module configured to
calculate tribology characteristics of the route segment at the
different locations. The tribology characteristics are based on the
creep measurements and the tractive/braking measurements from the
at least one vehicle system. The tribology characteristics are
indicative of a friction coefficient of the route segment at the
different locations. The system also includes an analysis module
configured to determine an effectiveness of a friction modifier
applied to the route segment based on the tribology characteristics
at the different locations.
[0008] In another aspect, a system (e.g., control system of a
vehicle system) is provided that includes a vehicle-control module
configured to control tractive and braking operations of a vehicle
system. The system also includes a measurement module configured to
obtain creep measurements and tractive/braking measurements of the
vehicle system at different locations along a route segment while
the vehicle system moves through the route segment. The system also
includes a transmitter configured to communicate the creep
measurements and the tractive/braking measurements from the vehicle
system. The vehicle-control module is configured to increase the
tractive effort of a first wheelset by a designated amount and
decrease the tractive effort of a second wheelset by the designated
amount thereby maintaining a total tractive effort of the vehicle
system. The measurement module is configured to obtain the creep
measurements and the tractive/braking measurements when the first
and second wheelsets operate at increased and decreased tractive
efforts, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic diagram of an embodiment of a vehicle
system traversing a track.
[0010] FIG. 2 is a schematic diagram of two propulsion-generating
vehicles that are linked to each other in accordance with an
embodiment.
[0011] FIG. 3 is a flowchart illustrating a method in accordance
with an embodiment.
[0012] FIG. 4 illustrates a graph with representative
traction-creep curves.
[0013] FIG. 5 illustrates a graph including representative curves
that demonstrate a relationship between calculated tribology
characteristics and locations within a route segment.
DETAILED DESCRIPTION
[0014] Embodiments of the inventive subject matter described herein
include methods and systems for monitoring one or more tribology
characteristics of a route that is traversed by a vehicle system.
Tribology is a branch of engineering that relates to the friction,
wear, and/or lubrication between surfaces, such as the two surfaces
that define the wheel-rail interface. Tribology may be used to
describe an effectiveness of a friction modifier that has been
applied to the route. For example, after a friction modifier has
been applied to a region-of-interest of a route, vehicle systems
traversing the route spread the friction modifier along surfaces of
the route. It may be desirable to know (a) whether the friction
modifier has spread beyond the region-of-interest and/or (b)
whether the friction modifier remaining within the
region-of-interest is sufficient to achieve the target effect. As
such, embodiments may obtain and/or analyze tribology data to
determine the effectiveness of the friction modifier along the
designated segment of the route. In one specific example,
embodiments may obtain and/or analyze tribology data to determine
the effectiveness of a friction modifier along a designated segment
of a track that is traveled along by rail vehicle systems (e.g.,
locomotives). Tribology data provides information regarding
friction along the route. The tribology data may include, for
example, coefficients of friction COFs (or friction coefficients),
adhesion coefficients, or other friction metrics at different
locations along the route.
[0015] A vehicle system includes at least one propulsion-generating
vehicle that generates vehicle tractive efforts (TEs) for
propelling the vehicle system. The propulsion-generating vehicle
may also generate vehicle braking efforts (BEs) for slowing or
stopping the vehicle system. A vehicle system may include multiple
propulsion-generating vehicles. In such instances, the multiple
propulsion-generating vehicles may be arranged to form a single
vehicle consist or a plurality of vehicle consists. In some
embodiments, the propulsion-generating vehicles of a single vehicle
consist are configured to communicate with each other to coordinate
vehicle TEs and/or vehicle BEs. Vehicle systems may also include
multiple vehicle consists. In some cases, the vehicle consists may
communicate with one another.
[0016] While the description herein refers to rail vehicles,
locomotives, tracks, and the like, not all embodiments are so
limited. The inventive subject matter described herein may be used
in connection with one or more other vehicles and routes, such as
automobiles traveling along roads. Accordingly, in some instances,
the terms rail vehicle and track (or rails) may be substituted with
more general terms of vehicle and route.
[0017] As used herein, a "vehicle TE" refers to the tractive effort
provided by a single propulsion-generating vehicle (e.g.,
locomotive). An "axle TE" refers to the tractive effort provided by
a single wheelset or axle of a propulsion-generating vehicle. In
some cases, a propulsion-generating vehicle may have individually
controllable wheelsets. For example, the traction motors on a
single locomotive may be selectively controlled such that it is
possible to provide different tractive and/or braking efforts among
the wheelsets of the locomotive. A first wheelset may provide 30
klbs (about 13,600 kg) of TE and a second wheelset may provide 10
klbs of TE (about 4,500 kg). Thus, the axle TEs of the first and
second wheelsets are 30 klbs (about 13,600 kg) and 10 klbs (about
4,500 kg), respectively. A "system TE" refers to the total tractive
effort provided by a vehicle system, which may include plural
propulsion-generating vehicles or only one propulsion-generating
vehicle. Thus, for cases in which the vehicle system has only a
single propulsion-generating vehicle, the system TE is equal to a
vehicle TE.
[0018] A route segment is a portion of the route that includes a
region-of-interest and, optionally, one or more baseline portions
extending from the region-of-interest. The route segment may be
referred to as a "track segment" for embodiments that include rail
vehicle systems (e.g., locomotives). The region-of-interest may
have had a friction modifier directly applied to the rails within
the region-of-interest. As such, the region-of-interest may also be
referred to as a surface-modified portion of the route.
Non-limiting examples of regions-of-interest include curves,
heavily trafficked segments, or segments that have been affected by
environmental conditions (e.g., snowfall, leaves, mud, and the
like). In some cases, it may be suspected that the friction
modifier has spread beyond the region-of-interest and into the
baseline portion(s).
[0019] The region-of-interest may be the entire route segment or
only a portion of the route segment. A precise length or dimension
of the route segment may be determined before analyzing the
tribology data or only after analyzing the tribology data. For
example, although it may be known before analysis that the friction
modifier was directly applied between mile post 214 and mile post
215, it may not be known an extent of spreading beyond the mile
post 214 and beyond the mile post 215. Accordingly, only after
analyzing the data may it be determined that the route segment
extends between, for example, the mile post 213 and the mile post
216.
[0020] Embodiments described herein may obtain creep measurements
and tractive/braking measurements as a vehicle system is traveling
along a route segment. A creep measurement may be based on an
amount of slippage of one or more wheels during operation of the
vehicle system. Maximum tractive or braking effort may be obtained
if each wheel of the propulsion-generating vehicle is rotating at
such an angular velocity that its actual peripheral speed is
slightly higher (for traction) or slightly lower (for braking) than
the true vehicle speed, which may be referred to as the "ground
speed" or "track speed" of the propulsion-generating vehicle. The
difference between wheel speed and track speed may be referred to
as "slip speed." There is a relatively low limit value of slip
speed at which a peak tractive effort or braking effort is
realized. This value, which may be referred to as a "maximum creep
speed" or "optimum creep," is a variable that depends on track
speed and rail conditions. Provided that the maximum creep speed is
not exceeded, slip speed is normal and the propulsion-generating
vehicle will operate in a stable microslip or creep mode. If
wheel-to-rail adhesion is reduced or lost, however, some or all of
the wheels may slip excessively. In other words, wheels may slip
when the actual slip speed is greater than the maximum creep speed.
This may cause a wheel slip condition. A wheel slip condition that
occurs during a tractive operation may include one or more spinning
wheels. A wheel slip condition that occurs during a braking
operation may include one or more sliding or skidding wheels.
[0021] Creep measurements may also be referred to as or
characterized as wheel slip, wheel creep, slip speed. In some
embodiments, creep measurements can be expressed as a percentage of
the current speed (e.g., ground speed, track speed) or a value
above/below the current speed. In some embodiments, a creep
measurement is obtained, at least in part, by calculating a
difference between a ground speed (e.g., speed at which the
propulsion-generating vehicle or the vehicle system is traveling)
and a wheel speed (e.g., angular velocity of the wheel). Creep
measurements may be acquired in other manners. For example, creep
measurements may be detected by an abrupt change in the traction
motor current or an abrupt change in the revolutions per minute
(rpms) of the traction motor or axle. Another manner of detecting
creep measurements may include using a rotary sensor on the
traction motor or drive axle. Other manners of obtaining creep
measurements may be used.
[0022] The creep measurement and the tractive/braking operation may
be acquired at approximately the same time such that useful
tribology data may be obtained regarding a designated portion or
point along the track. For instance, the measurements may be
acquired simultaneously, concurrently, or immediately after each
other. In some embodiments, one creep measurement is correlated or
associated with one tractive/braking measurement. In other
embodiments, however, multiple creep measurements may be correlated
or associated with one tractive/braking measurement or one creep
measurement may be correlated or associated with multiple
tractive/braking measurements. As an example, first, second, and
third tractive measurements may be obtained at 30 meters, 60
meters, and 90 meters, respectively, but only one creep measurement
may be obtained between 30 and 90 meters. In such instances, the
single creep measurement may be paired with each of the first,
second, and third tractive measurements when the tribology data is
analyzed.
[0023] In some cases, an average of the multiple measurements
(e.g., creep and/or tractive/braking) may be calculated and the
averaged measurement may be communicated. In some cases, one or
more measurements may be specific to an axle or wheelset while
other measurements are associated with a propulsion-generating
vehicle as a whole. For example, the creep measurement may be
associated with a locomotive, but the tractive/braking measurement
may be related to a specific wheelset of the locomotive or
vice-versa. Creep and tractive/braking measurements that are
associated with each other may also be associated with a specific
region of the track. By way of example, a region along the track
(e.g., 0.25 km to 0.28 km) may be associated with a
calculated/detected creep measurement and associated with a
calculated/detected TE measurement.
[0024] Tractive/braking measurements (which may also be referred to
as "at least one of tractive and braking measurements") include
measurements that are based on or indicative of tractive effort (or
horsepower) and measurements that are based on or indicative of
braking efforts. Tractive/braking measurements may be obtained by
monitoring or detecting motor characteristics, such as motor
current, motor RPMs, motor torque, and motor power. In some cases,
tractive/braking measurements may be acquired by monitoring or
detecting inter-vehicle forces (e.g., using a coupling hook between
locomotive and load) or measuring a vehicle speed. TE may be
characterized as an amount of force that the motive power must
produce to move a train without slipping the wheels. TE may be
detected by sensors and/or may be calculated by acquiring other
measurements. TE may be calculated by multiplying an adhesion
coefficient with an appropriate weight parameter (e.g., weight of
the locomotive, weight per axle, and the like). More specifically,
a maximum TE value may be directly proportional to weight and
adhesion. TE may also be calculated by dividing horsepower by
speed. Braking measurements may be acquired in a similar manner as
acquiring TE measurements.
[0025] As described herein, embodiments may use the creep
measurements and tractive/braking measurements to determine a
tribology characteristic that is then used to determine an
effectiveness of a friction modifier (e.g., lubrication, sand, or
other substance, and air). The tribology characteristic may be an
adhesion coefficient, a COF, or the like. A friction modifier may
increase or decrease friction. For example, lubrication may reduce
the COF or adhesion coefficient whereas sand may increase the COF.
In some cases, the tribology characteristic may be calculated after
attempting to remove at least some of the friction modifier by
blowing with air or wiping with another surface.
[0026] In some embodiments, the measurements are acquired during
normal operation of the vehicle system. For example, the
measurements may be acquired without deviating from an operating
plan or without deviating from inputs or instructions from an
operator (e.g., engineer). An operating plan, which may also be
referred to as a trip plan or mission plan, may include
instructions for controlling the propulsion-generating vehicles to
provide designated TEs and/or designated BEs for predetermined
portions of a trip. The instructions may be expressed as a function
of time and/or distance of a trip along a route. The vehicle system
may be autonomously controlled according to the operating plan or
the instructions of the operating plan may be presented to an
operator of the vehicle system so that the operator can manually
control the vehicle system according to the operating plan (also
referred to as a "coaching mode"). The operating plans may be based
on trip profiles, which may include, among other things,
information about a geography of the route. The operating plans may
also be based on operating information of the vehicle system, such
as the size, weight, tractive effort, power output, weight
distribution, and the like, of the vehicle system.
[0027] As used herein, a "vehicle system" may include a single
propulsion-generating vehicle or multiple propulsion-generating
vehicles. For those embodiments that include multiple
propulsion-generating vehicles, the multiple propulsion-generating
vehicles may be arranged into a single vehicle consist or a
plurality of vehicle consists. As one specific example, a train may
include first, second, and third locomotive consists, wherein each
of the locomotive consists includes two locomotives.
[0028] At least one technical effect of embodiments described
herein may include a more efficient use of a friction modifier. For
example, embodiments may identify different locations and/or
different amounts of the friction modifier to apply to the rails.
Another technical effect may include a more efficient use of
vehicle systems. With more tribology data and with tribology data
that is more current than data obtained through conventional
methods, the vehicle systems may be operated in a more efficient
manner.
[0029] FIG. 1 is a schematic diagram of a vehicle system 100 formed
in accordance with an embodiment. In the illustrated embodiment,
the vehicle system 100 is a rail vehicle system. As shown, the
vehicle system 100 is traveling along a portion of a route or track
102. While only one vehicle system 100 is shown in FIG. 1, it is
understood that several vehicle systems may traverse the track 102.
The vehicle system 100 includes a plurality of discrete vehicles.
As used herein, "discrete" vehicles are separate and distinct
vehicles that are capable of being removably coupled to and part of
a larger vehicle system. The vehicle system 100 may be a rail
vehicle system that includes at least one propulsion-generating
vehicle (e.g., locomotive) and, optionally, at least one
non-powered vehicle (e.g., rail car or passenger car) that are
linked to one another.
[0030] In the illustrated embodiment, the vehicle system 100
includes propulsion-generating vehicles 104 and 105 and non-powered
vehicles 106 and 107 that are mechanically linked to one another
and are configured to travel as a group along the track 102. The
terms "powered" or "propulsion-generating" refer to the capability
of a vehicle to propel itself and not whether the vehicle receives
or generates energy for one or more other purposes. For example,
the non-powered vehicles 106, 107 may receive electric current to
power one or more loads disposed onboard the non-powered vehicles
106, 107 (e.g., air conditioning, lighting, etc.).
[0031] In FIG. 1, the propulsion-generating vehicle 104 may be
considered a principal or lead vehicle of a vehicle consist 110,
and the propulsion-generating vehicle 105 may be considered a
remote vehicle of the vehicle consist 110. A propulsion-generating
vehicle that controls one or more other propulsion-generating
vehicles may be referred to as "principal" or "lead"
propulsion-generating vehicle, and propulsion-generating vehicles
that are controlled by another propulsion-generating vehicle may be
referred to as "remote" propulsion-generating vehicles. The
plurality of propulsion-generating vehicles 104, 105 in the single
vehicle consist 110 are configured to operate as a single moving
apparatus. For example, the multiple propulsion-generating vehicles
104, 105 may coordinate TEs and/or BEs to propel the vehicle system
100 along the track 102. The propulsion-generating vehicles 104,
105 may also coordinate the acquisition of creep and/or
tractive/braking measurements as described herein.
[0032] A vehicle system may be or include a single vehicle consist
or include a plurality of vehicle consists that are directly or
indirectly coupled to another. For example, the vehicle system 100
includes a second vehicle consist 111 that is coupled to the
vehicle consist 110. When a vehicle system includes multiple
vehicle consists, the vehicle consists may be referred to as
sub-consists. If the vehicle system includes multiple vehicle
consists, the vehicle consists may be configured to operate as a
single moving apparatus. For example, the multiple vehicle
sub-consists may be controlled by a master computing system that
coordinates tractive and/or braking efforts among the sub-consists
to control operation of the vehicle system as a whole. The master
control system may also include instructions for acquiring creep
and/or tractive/braking measurements as described herein.
[0033] In some embodiments, the vehicle system 100 has a
distributed power system or is capable of operating in different
modes. In a distributed power system, different
propulsion-generating vehicles (or different vehicle consists) are
capable of being controlled by a common control system, which may
be on a principal vehicle. For example, a single vehicle system may
include first and second propulsion-generating vehicles. A common
control system for the vehicle system may instruct the first and
second propulsion-generating vehicles in a manner that coordinates
TEs and/or BEs of the vehicle system. More specifically, the common
control system may communicate signals to the first and second
propulsion-generating vehicles that include operating instructions.
The common control system, however, may communicate different
instructions to each of the propulsion-generating vehicles. For
example, the first propulsion-generating vehicle may be instructed
to operate at a high notch (or throttle) setting. At the same time,
the second propulsion-generating vehicle may be instructed to
operate at a lower notch setting or to apply brakes to the
propulsion-generating vehicle. The common control system may be
part of a single vehicle, may be distributed among the vehicles, or
may be a remote system that controls the vehicle system
wirelessly.
[0034] Likewise, a common control system may instruct multiple
vehicle consists. As one specific example, a vehicle system may
include a leading vehicle consist and a trailing vehicle consist.
As this vehicle system is traversing a mountain, the leading
vehicle consist may crest the mountain top and travel on the
downward slope of the mountain. At this time, the common control
system may instruct the leading vehicle consist to cease tractive
efforts and commence braking. The trailing vehicle consist,
however, may not have passed the mountaintop and may still be
climbing the mountain. If so, the common control system may
instruct the trailing vehicle consist to maintain tractive efforts.
By operating the leading and trailing vehicle consists in a
different manner, tensile forces at the mechanical couplers that
connect adjacent vehicles may be reduced. Accordingly, different
propulsion-generating vehicles or different vehicle consists of a
single vehicle system may operate asynchronously or independent
from each other. This may also be referred to as operating
according to an asynchronous mode, independent mode, or decoupled
mode.
[0035] It is noted that the embodiment of FIG. 1 is provided for
illustrative purposes only, and other arrangements, orientations,
and/or numbers of propulsion-generating vehicles and/or non-powered
vehicles may be used in other embodiments. In some embodiments, the
propulsion-generating vehicle 104 may control the operations of
other propulsion-generating vehicles, such as the
propulsion-generating vehicle 105. In other embodiments, a
propulsion-generating vehicle other than the propulsion-generating
vehicle 104 may act to control the operations of one or more other
propulsion-generating vehicles. For example, the
propulsion-generating vehicle 105 may control operations of the
propulsion-generating vehicle 104. In some cases, the principal
vehicle that controls the vehicle system 100 is the leading vehicle
(e.g., first vehicle) that controls operation of other vehicles. In
other cases, the principal vehicle may follow or trail other
propulsion-generating vehicles while traveling.
[0036] FIG. 1 also shows two route segments A and B along the track
102. As shown, the vehicle system 100 is traveling along the route
segment A in a left-to-right direction along the page. Each of the
route segments A and B may have a different track condition. The
track condition may be, at least in part, based on the friction
between a surface of the track and a surface of the vehicle system
that directly engages the surface of the track, such as the surface
of a wheel. The track condition may also be based on a contour
(e.g., grade or curvature) of the track. With respect to FIG. 1,
the route segment A represents a portion of the track 102 that has
a substantially straight and even route contour.
[0037] Route segment B illustrates a route segment that includes a
region-of-interest 124, which is a curve in FIG. 1. In other
embodiments, the region-of-interest may include other track
contours and/or tracks with various types of rail conditions. In
particular embodiments, the region-of-interest is a portion of a
track that has had a friction modifier applied to the rails. The
friction modifier may be applied to effectively increase or
decrease the COF or adhesion coefficient. Lubricants may be used to
decrease the COR or adhesion coefficient. Non-limiting examples of
friction modifiers that may be used to increase the COR or adhesion
coefficient include sand (e.g., sandite), composition sticks (e.g.,
Kelsan HPF sticks), suspensions of colloidal silica particles,
ethyl caprylate, tertiary butylamine solution, sodium metasilicate,
or a mixture of any of the above.
[0038] As described herein, entities may desire to know whether the
friction modifier is effective within the localized region in which
it was applied and whether the friction modifier has undesirably
spread into other portions of the route segment. Accordingly,
embodiments described herein may acquire a number of measurements
to analyze the effectiveness of the friction modifier. The
measurements may be creep measurements, tractive/braking
measurements, and other measurements that facilitate the analysis.
In addition to the region-of-interest 124, measurements may also be
acquired within baseline portions 122 and 126 of the route 102. Due
to the travel direction of the vehicle system 100, the baseline
portion 122 is the leading baseline portion and the baseline
portion 126 is the trailing baseline portion. In the illustrated
embodiment, each of the baseline portions 122 and 126 are
substantially straight relative to the region-of-interest 124. In
other embodiments, however, the baseline portions 122, 126 and the
region-of-interest 124 may have various contours relative to each
other. In some embodiments, the region-of-interest 124 is also
substantially straight and even.
[0039] Also shown in FIG. 1, the vehicle system 100 may communicate
with an off-board system 116 (e.g., monitoring system) that can be
disposed off-board (e.g., outside) of the vehicle system 100. For
example, the system 116 may be disposed at a central dispatch
office for a railroad company. The system 116 can generate and
communicate various operating plans and/or communicate information
regarding track conditions. The system 116 may also include one or
more modules for receiving and analyzing the measurements acquired
by the vehicle system 100. The system 116 can include a wireless
antenna 118 (and associated transceiving equipment), such as a
radio frequency (RF) or cellular antenna, that wirelessly transmits
signals to the vehicle system 100. The vehicle system 100 may also
include a wireless antenna 120 (and associated transceiving
equipment).
[0040] Although the following is described with reference to an
off-board monitoring system, it is understood that the system 116
and/or one or more of the modules 130, 132, 134 may be disposed
onboard the vehicle system 100. In such embodiments, the vehicle
system 100 may calculate tribology characteristics and determine an
effectiveness of the friction modifier.
[0041] Returning to FIG. 1, the system 116 may include a receiver
130 that is configured to receive creep measurements and
tractive/braking measurements from one or more vehicle systems that
were obtained as the one or more vehicle systems moved through the
route segment B. The creep measurements and the tractive/braking
measurements that were acquired may be associated with different
locations along the route segment B. The receiver 130 may include
or be operably coupled to the wireless antenna 118. The receiver
130 may also include other electronic devices or components for
receiving data. The receiver 130 may receive data wirelessly and/or
through hard wires, such as telecommunication lines. The receiver
130 may be configured to process the signals that represent the
creep measurements and the tractive/braking measurements in order
to render the measurements more suitable for analysis.
[0042] The system 116 also includes a calculation module 132 that
is configured to calculate tribology characteristics of the track
102. In particular, the calculation module 132 may calculate
tribology characteristics of the route segment B at the different
locations along the route segment B. The tribology characteristics
may be based on the creep measurements and the tractive/braking
measurements that were acquired from the one or more vehicle
systems. A tribology characteristic that corresponds to a
designated location along the track 102 may be based on or
determined by the friction that exists between the surfaces of the
wheel and the surfaces of the rails at the designated location. The
tribology characteristics calculated herein may provide some
information as to the amount of friction that exists between the
surfaces.
[0043] The system 116 may also include an analysis module 134 that
is configured to determine an effectiveness of the friction
modifier applied to the route segment B. The effectiveness may be
based on the calculated tribology characteristics at the different
locations along the route segment B. The different locations may be
a series of locations (e.g., successive locations). The
effectiveness is based on the tribology characteristics (e.g.,
COFs, adhesion coefficients, or other friction metrics) of the
route segment B that were calculated by the calculation module 132.
In some embodiments, the analysis module 134 may compare the
tribology characteristics at the different locations to expected
tribology characteristics of the different locations. For example,
a railroad may expect that the adhesion coefficients at different
locations will not exceed certain values. Moreover, if the friction
modifier was improperly applied, was spread by vehicle systems, was
exposed to harsh environmental conditions, and the like, the
adhesion coefficients may be affected.
[0044] In some embodiments, the analysis module 134 may calculate a
spread or distribution function of the friction modifier. The
spread function may represent a relationship between track location
and tribology characteristic value. For example, the tribology
characteristic may be an adhesion coefficient value. One example of
a range of adhesion coefficient values may be about 0.20 to about
0.60. FIG. 5 illustrates three different spread functions. From the
spread function, one or more portions of the route segment that has
an improper amount of friction modifier (e.g., too much or too
little) can be identified. More specifically, the spread function
may indicate one or more portions of the route segment that have an
insufficient amount or an excessive amount of the friction
modifier. In some embodiments, the analysis module 134 is
configured to identify one or more regions of the route segment
having an amount of the friction modifier that is below a first
designated threshold (e.g., desired minimum or baseline amount of
the friction modifier) and/or one or more regions above a second
designated threshold (e.g., a desired maximum or limit amount of
the friction modifier). In between the first and second designated
thresholds may be a designated range for an amount of the friction
modifier. The designated range may be configured (e.g., by a
railroad) to (a) reduce wearing of the rails and wearing of the
wheels of the locomotives and/or (b) to obtain a desired adhesion
between the rails and the wheels.
[0045] In some embodiments, the analysis module 134 may use
compensating data that relates to effectiveness of the friction
modifier. More specifically, the values of the tribology
characteristics may be determined or modified, in part, by various
compensating factors. Compensating data may include, for example, a
weight or load of the propulsion-generating vehicle or the vehicle
system, speed of the vehicle system, environmental data (such as
weather conditions, e.g., rain, snow, temperature), and/or external
rail conditions, such as leaves or other debris on the route.
Various formulas may be used by the calculation and analysis
modules to determine the effectiveness of the friction
modifier.
[0046] By way of one example, a number of vehicle systems may
travel along a designated track segment in a single day. Over an
extended period of time (e.g., days, weeks, months) weather
conditions may change such that precipitation (e.g., ice, snow)
develops on the surfaces of the track segment or debris (e.g.,
leaves, mud) is somehow provided on the surfaces of the track
segments. For days with increased precipitation or increased
debris, the tribology characteristics calculated by each of the
vehicle systems that travel along the track segment may be less
than the values of the tribology characteristics calculated by the
vehicle systems that travel along the track segment when
precipitation and debris are not present (e.g., warm days without
rain or wind). Thus, when determining effectiveness of a friction
modifier, embodiments may compensate or account for such changing
weather conditions.
[0047] FIG. 2 is a schematic diagram of a rail vehicle system 200
that includes a plurality of propulsion-generating vehicles 202,
204. The rail vehicle system 200 may be similar or identical to the
vehicle system 100 (FIG. 1). The propulsion-generating vehicles
202, 204 may constitute or be part of a vehicle consist that may or
may not be coupled with other vehicle consist(s) (not shown) in the
rail vehicle system 200. In FIG. 2, the propulsion-generating
vehicle 202 is a principal or lead propulsion-generating vehicle
and the propulsion-generating vehicle 204 is a remote
propulsion-generating vehicle that is controlled by the
propulsion-generating vehicle 202. To this end, the
propulsion-generating vehicle 202 includes a control system 206
that is configured to control operation of the
propulsion-generating vehicle 202 and, optionally,
propulsion-generating vehicle 204. In other embodiments, the
propulsion-generating vehicle 204 may be the principal vehicle and
may include a control system that is configured to control
operation of the propulsion-generating vehicle 202. Alternatively,
the control system 206 may be distributed between the
propulsion-generating vehicles 202, 204. For embodiments that
include multiple vehicle consists, the control system 206 may be
configured to control operation of other vehicle consists.
[0048] The control system 206 may have a plurality of modules
including a vehicle-control module 210 and a measurement module
212. The control system 206 and the modules 210 and 212 are
configured to communicate signals to and receive signals from
different components, assemblies, and sub-systems for controlling
operation of the rail vehicle system 200. The control system 206
may be or include one or more controllers, processors, or other
logic-based devices that perform operations based on one or more
sets of instructions (e.g., software). In some cases, the different
modules of the control system 206 are part of the same logic-based
device or, alternatively, are distributed within multiple
logic-based devices. The instructions on which the control system
206 operates may be stored on a tangible and non-transitory (e.g.,
not a transient signal) computer readable storage medium, such as a
memory. The memory may include one or more computer hard drives,
flash drives, RAM, ROM, EEPROM, and the like. Alternatively, one or
more of the sets of instructions that direct operations of the
control system 206 may be hard-wired into the logic of the control
system 206, such as by being hard-wired logic formed in the
hardware of the control system 206.
[0049] The vehicle-control and measurement modules 210, 212 are
shown as being included in or as being part of a common structure
of the control system 206. The modules 210, 212, however, are not
required to be part of the same structure and may instead be
separated from other portions of the control system 206 and/or each
other. In some embodiments, one or more of the modules may be
located off-board the propulsion-generating vehicle 202.
[0050] The vehicle-control module 210 is configured to control
tractive and/or braking operations of the propulsion-generating
vehicle 202. To this end, the vehicle-control module 210 is
configured to communicate with a propulsion system 220 and a
braking system (not shown). The vehicle-control module 210 may
instruct (e.g., communicate signals to one or more components of
the propulsion system 220) to increase or decrease power, tractive
effort, etc. For example, the instructions may be in accordance
with one or more operating plans that designate tractive operations
(e.g., notch or throttle settings) and braking operations to be
implemented by the rail vehicle system 200. The operating plan may
include instructions for controlling tractive and/or braking
efforts of a vehicle system for only a portion of the route or for
the entire route. The instructions may be expressed as a function
of time and/or distance of a trip along the track. In an
embodiment, the vehicle-control module 210 may autonomously control
operations of the propulsion-generating vehicle 202 according to
the operating plan.
[0051] The propulsion system 220 can include a variable speed prime
mover or engine 224 that is mechanically coupled to a rotor of a
dynamo electric machine. In the illustrated embodiment, the dynamo
electric machine is an alternator 226 and, in particular, a 3-phase
alternating current (AC) synchronous alternator. The 3-phase
voltages generated by the alternator 226 are supplied to input
terminals of a power rectifier bridge 228. The rectifier bridge 228
may transform or modify the AC power from the alternator 226 into
direct current (DC) power. The power rectifier bridge 228 has
output terminals that supply the DC power to a DC link or bus 230.
Although the propulsion system 220 is described as being an AC-type
propulsion system that is powered by diesel, it is understood that
embodiments set forth herein may also be implemented with DC-type
propulsion systems and/or propulsion systems that are at least
partially powered by electricity (e.g., batteries, catenary system,
and the like).
[0052] As shown, the DC link 230 is electrically connected to
inverters 232, 234. The inverters 232, 234 are configured to
convert (e.g., invert) the DC power into AC power at a designated
frequency for powering traction motors 241-244. The inverters 232,
234 may employ high power gate turn-off devices which switch in and
out of conduction in response to gating signals from the control
system 206 (or the vehicle-control module 210) so as to invert the
DC voltage on the DC link 230 to a controlled frequency AC
voltage.
[0053] Although not shown, the DC link 230 may also be electrically
coupled to other components, such as a conditioning device and/or
an auxiliary sub-system. The conditioning device may be configured
to filter out unwanted frequencies and/or regulate the current of
the DC link 230. The auxiliary sub-system may be operably coupled
to one or more non-tractive components (e.g., compressors, fans or
blowers, onboard air conditioners, radiators).
[0054] The motors 241, 242 are electrically connected to and
powered by the inverter 232, and the motors 243, 244 are
electrically connected to and powered by the inverter 234. The
motors 241, 242 are electrically parallel to each other, and the
motors 243, 244 are electrically parallel to each other. In some
embodiments, the motors 241-244 are adjustable speed AC traction
motors. Also shown, the motors 241-244 are operably coupled to
axles 251-254, respectively, that are each coupled to wheels
271-274. The motors 241-244, the axles 251-254, and the wheels
271-274 may constitute respective axle wheelsets 261-264. For
example, the motor 241, the axle 251, and a pair of wheels 271 may
constitute the wheelset 261, which is configured to generate a TE
for propelling the propulsion-generating vehicle 202 and, hence,
the rail vehicle system 200. Each of the axle wheelsets 261-264 may
be selectively controlled by the vehicle-control module 210 and the
control system 206 to provide a designated TE (e.g., axle TE). More
specifically, the axle wheelsets 261-264 of the
propulsion-generating vehicle 202 may be selectively controlled to
provide different axle TEs.
[0055] Although not shown, the propulsion-generating vehicle 204
may have a similar or identical propulsion system as the propulsion
system 220. In some embodiments, the propulsion system of the
propulsion-generating vehicle 204 (not shown) may be controlled by
the control system 206. The propulsion-generating vehicles 202, 204
may be communicatively coupled to each other through a
communication cable 265. The cable 265 may include, for example, an
Ethernet over multiple units (eMU) cable. The cable 265 may enable
the propulsion-generating vehicles 202, 204 to communicate with
each other regarding various operations of the rail vehicle system
200. It is noted, however, that embodiments may utilize other
methods of communicating, such as other wired systems, wired
distributed power (DP) links, wireless communication (e.g., radio
communication), and the like.
[0056] In the illustrated embodiment, the propulsion-generating
vehicles 202, 204 are adjacent to each other and directly connected
by a mechanical coupler 266. The mechanical coupler 266 may allow
some tolerance or slack such that the propulsion-generating
vehicles 202, 204 are permitted to move a limited distance toward
each other or away from each other. In alternative embodiments, the
propulsion-generating vehicles 202, 204 are not adjacent to each
other. Instead, the propulsion-generating vehicles 202, 204 may be
indirectly coupled to one another via other vehicles, which may be
propulsion-generating or non-powered vehicles. For example, the
propulsion-generating vehicle 202 may lead the rail vehicle system
200 as shown in FIG. 2 and the propulsion-generating vehicle 204
may be located at a position that is about 2/3 a length of the rail
vehicle system 200 away from the propulsion-generating vehicle
204.
[0057] The propulsion-generating vehicles 202, 204 of FIG. 2 are
only particular examples of locomotives that may be used with
embodiments set forth herein. It is understand that various
modifications may be made to the rail vehicle system 200 and that
other types of locomotives may be used. For example, it may be
desirable to provide an inverter for each motor or to couple
additional motors to a single inverter. As such, it is understood
that the inventive subject matter described herein is not limited
to 4-axle systems and is equally applicable to other systems, for
example, such as 6-axle locomotives with six inverters each
connected for powering a respective one of six traction motors each
connected to respective ones of the six axles.
[0058] The rail vehicle system 200 travels along a route 208, such
as a track having one or more rails. Each of the
propulsion-generating vehicles 202, 204 facilitates driving the
rail vehicle system 200 using the wheelsets of the respective
vehicle. For example, the traction motors 241-244 deliver torque to
the wheels 271-274, which exert tangential force (e.g., tractive
effort) along the route 208, thereby propelling the rail vehicle
system 200 along the route 208. The TE developed at each wheel of
the propulsion-generating vehicle 202 is proportional to a normal
force 280 acting on the respective wheel. The axle TE of a single
axle wheelset is approximately equal to the friction coefficient
multiplied by the normal force 280 acting on the respective
wheelset. The total TE provided by the propulsion-generating
vehicle 202 is the sum of each of the axle TEs.
[0059] For a dynamic braking mode, the traction motors 241-244 are
reconfigured (via power switching devices (not shown)) so that the
fraction motors 241-244 operate as generators. So configured, the
traction motors 241-244 generate electric energy which has the
effect of slowing the propulsion-generating vehicle 202. In some
cases, energy generated in a dynamic braking mode may be
transferred to resistance grids (not shown) that are coupled to the
propulsion-generating vehicle 202. The dynamic braking energy may
be converted to heat and dissipated from the propulsion-generating
vehicle 202 through the grids. In other embodiments, the dynamic
braking energy may be stored (e.g., batteries) by the
propulsion-generating vehicle 202.
[0060] Also shown in FIG. 2, the rail vehicle system 200 may
include a number of detection devices 291-295. The detection
devices 293, 294 of the control system 206 may be incorporated with
the inverters 232, 234, respectively, but the detection devices
293, 294 may have other locations in other embodiments.
Alternatively, each of the motors 241-244 may include a respective
detection device. The detection devices 293, 294 are configured to
monitor one or more operating conditions that have a direct
relation to TE, BE, and/or creep. More specifically, data obtained
regarding the operating conditions may be used to calculate at
least one of a creep measurement, a tractive measurement, or a
braking measurement. In some embodiments, the detection devices
293, 294 are configured to detect a motor characteristic, such as
motor current, motor RPMs, motor torque, and motor power. The data
can be communicated to the measurement module 212.
[0061] The detection devices 291, 292 may obtain data from the
wheelsets 261-264 that have a direct relation to TE, BE, and/or
creep. Such data may be used to calculate at least one of the creep
measurement, the tractive measurement, or the braking measurement
described herein. For example, the detection devices 291, 292 may
be configured to detect at least one of rotation speed, torque,
torsional vibrations, vehicle speed (e.g., ground speed), wheel
strain, axle strain, dog-bone strain, or motor speed. The data can
be communicated to the measurement module 212.
[0062] In the illustrated embodiment, the detection devices 291,
292 are rotation-speed and vehicle-speed sensors, respectively. The
detection devices 291 may communicate data (e.g., in the form of
signals) that is representative of a rotational speed of a
corresponding wheelset. For example, the detection devices 291 may
measure how fast a wheel, axle, or motor shaft of the corresponding
wheelset is rotating. In particular embodiments, the detection
devices 291 detect a voltage or current signal of the electrical
power supplied to the respective motor that is representative of
the wheel speed. The detection devices 292 communicate data that is
representative of how fast the propulsion-generating vehicle 202 is
moving along the route 208. By way of example, the detection
devices 292 may include a radar system (e.g., Doppler radar gun or
other type of radar system) or a Global Positioning System (GPS)
system that is used to obtain the data representative of the speed
at which the propulsion-generating vehicle 202 moves along the
route 208. Other vehicle speed sensors may be used as well. The
data representative of the wheel speed and the vehicle speed can be
communicated to the measurement module 212.
[0063] As another example, the detection devices 291-294 may
monitor or obtain data relating to wheel creep to improve or
optimize the wheel creep during operation of the rail vehicle
system 200. More specifically, a designated tractive effort or
braking effort may be obtained if each of the wheelsets 261-264 of
the propulsion-generating vehicle 202 is rotating at such an
angular velocity that its actual peripheral speed (e.g., wheel
speed) is slightly higher (in case of motoring) or slightly lower
(in case of braking) than the actual speed of the vehicle. The
difference between the linear speed at which the vehicle is
traveling (referred to as vehicle speed) and the wheel speed is
referred to as wheel creep. There is usually a relatively low limit
on the value of wheel creep at which peak tractive effort or
braking effort is realized.
[0064] This value, commonly known as optimum creep, is a variable
that depends on the vehicle speed and the surface conditions of the
rail vehicle system 200 and the route 208. The optimum creep
correlates to a peak value of an applicable wheel-rail
adhesion-creep curve. Operation of any or all wheelsets away from
the optimum creep, such as too large of a creep value, may cause a
reduction or loss of wheel-to-surface adhesion. If the
wheel-to-surface adhesion is reduced or lost, some or all the
vehicle wheels may slip excessively. This is often undesirable as
slippage can cause accelerated wheel wear, rail damage, high
mechanical stresses in the drive components of the propulsion
system, and an undesirable decrease of tractive (or braking)
effort.
[0065] The detection device 295 may be operably connected to the
mechanical coupler 266 and configured to detect stresses or forces
sustained at the mechanical coupler 266. In some embodiments, the
data obtained by the detection device 295 may be used to calculate
the measurements used to determine the tribology
characteristics.
[0066] The measurement module 212 is configured to obtain data
relating to the creep measurements and tractive/braking
measurements of the rail vehicle system 200. The data may be
acquired at different locations along a route segment as the
vehicle system moves through the route segment. The data that may
be used to calculate the creep measurements and/or the
tractive/braking measurements is communicated to the measurement
module 212 from the detection devices 291-295. In some embodiments,
the measurement module 212 calculates the measurements that are
transmitted from the rail vehicle system 200 to the system 116. In
other embodiments, the measurements are calculated by the detection
devices 291-295.
[0067] In some embodiments, the measurement module 212 may analyze
the measurements and/or data to determine that the data is
sufficient or trustworthy. The measurement module 212 may package
the measurement or data in predetermined format so that a
monitoring system (e.g., system 116) may recognize the
measurements. The measurement module 212 may execute preliminary
processing steps. For example, the measurement module 212 may
obtain data from the detection devices 291-295 and calculate the
measurements that will be used to determine the effectiveness of
the friction modifier. More specifically, the measurement module
212 may calculate one or more creep measurements based on the data
obtained by one or more of the detection devices 291-295. The
measurement module 212 may also calculate one or more tractive
measurements or one or more braking measurements based on the data
obtained by one or more of the detection devices 291-295.
[0068] In some embodiments, the measurement module 212 may
communicate the measurements or data relating to the measurements
to a transmitter 296. The transmitter 296 is configured to
communicate the creep measurements and the tractive/braking
measurements from the rail vehicle system 200 to, for example, the
system 116. In other embodiments, the rail vehicle system 200 may
calculate the tribology characteristics from the measurements and
determine an effectiveness of the friction modifier. For example,
the rail vehicle system 200 may have a calculation module and an
analysis module that is similar or identical to the calculation and
analysis modules 132, 134.
[0069] FIG. 3 is a flow chart illustrating a method 300 in
accordance with an embodiment. The method 300, for example, may
employ structures or aspects of various embodiments (e.g., systems
and/or methods) discussed herein. In various embodiments, certain
steps (or operations) may be omitted or added, certain steps may be
combined, certain steps may be performed simultaneously, certain
steps may be performed concurrently, certain steps may be split
into multiple steps, certain steps may be performed in a different
order, or certain steps or series of steps may be re-performed in
an iterative fashion. The method 300 (or certain steps thereof) may
be implemented by one or more algorithms that are executed by
logic-based devices to control hardware (e.g., propulsion system,
measurement module, analysis module) to perform designated
operations as described herein.
[0070] The method 300 may include obtaining (at 302) creep
measurements and tractive/braking measurements at different
locations along a route segment. The creep measurements and the
tractive/braking measurements may be measurements as described
above. The creep measurements and the tractive/braking measurements
or the data that is used to calculate the creep measurements and
the tractive/braking measurements may be obtained during a tractive
operation (e.g., while the vehicle system or propulsion-generating
vehicle is motoring), during a braking operation, or when the
vehicle system or propulsion-generating vehicle is idling (e.g.,
coasting).
[0071] In some embodiments, obtaining (at 302) includes only
obtaining measurements of a single vehicle system. In other
embodiments, obtaining (at 302) includes obtaining measurements
from a plurality of vehicle systems. For example, each vehicle
system that traverses the route segment and is capable of obtaining
the creep and tractive/braking measurements may communicate the
measurements to, for example, an offboard monitoring system.
[0072] Obtaining (at 302) may include obtaining measurements
continuously, at a periodic rate, or at an aperiodic rate. For
example, an aperiodic rate may include obtaining fewer measurements
when the vehicle system is outside of the region-of-interest (e.g.,
in the leading or trailing baseline portions of the route segment).
An aperiodic rate may include obtaining incrementally more and more
measurements as the rail vehicle system approaches (e.g., becomes
nearer to) the region-of-interest. In some embodiments,
measurements may be continuously obtained when the vehicle system
is within the region-of-interest. In other embodiments,
measurements may be continuously obtained when the vehicle system
is within the region-of-interest and outside the region-of-interest
along the route segment.
[0073] In some embodiments, the route segment is at least a
kilometer (or equivalent in miles) or at least two kilometers (or
equivalent in miles). In some embodiments, the route segment is at
least one mile (or equivalent in kilometers) or at least two miles
(or equivalent in kilometers). In some embodiments, the creep
measurements and the tractive/breaking measurements are obtained,
on average, at least once every 100 meters, at least once every 50
meters, or, more specifically, at least once every 10 meters along
the route segment. In some embodiments, a total number of
measurements obtained and used by the analysis module is at least
100 measurements or, more specifically, at least 1000 measurements.
The 100 or 1000 measurements may be from a single vehicle system or
from multiple vehicle systems.
[0074] In some embodiments, obtaining (at 302) includes instructing
the propulsion system of the propulsion-generating vehicle to
operate in a designated manner. For example, if the
propulsion-generating vehicle includes multiple wheelsets,
obtaining (at 302) may include increasing the tractive effort of a
first wheelset by a designated amount and decreasing the tractive
effort of a second wheelset by the designated amount thereby
maintaining a total tractive effort of the corresponding vehicle
system. By increasing the tractive effort of the first wheelset, a
clearer measurement of the tribology characteristic may be
acquired. More specifically, increasing the tractive effort may
induce greater slippage (e.g., a greater creep measurement) at the
first wheelset that may correspond to a higher confidence in the
tribology characteristic. Furthermore, by not changing the total
tractive effort of the vehicle system, the measurements can be
obtained automatically without substantially disrupting or
deviating from the operating plan or from the operator's
instructions.
[0075] Alternatively or additionally, obtaining (at 302) may
include operating the corresponding vehicle system at a designated
throttle setting. In some instances, the throttle setting may
correspond to a maximum tractive effort. When a maximum tractive
effort is sought by the vehicle system, the vehicle system may
continue to increase tractive effort until the optimum creep point
is determined. More specifically, the tractive/braking measurements
that are obtained when the throttle setting requires a maximum
tractive effort may be representative of the optimum creep point.
The optimum creep point may be used to determine the tribology
characteristic.
[0076] In other embodiments, obtaining (at 302) may include
operating the corresponding vehicle system at a designated throttle
setting in which the throttle setting requires less than maximum
tractive efforts. Nonetheless, creep measurements may be obtained
and associated with the applied tractive effort (or braking
effort). Such instances may be particularly suitable when an
initial slope of a traction-creep curve is being formed.
[0077] Accordingly, creep measurements may be acquired at any time
when tractive efforts are being provided or when braking efforts
are being supplied. In addition, creep measurements may be acquired
when the propulsion-generating vehicle is moving but with the
engine effectively idling. As described above, different wheelsets
may provide different efforts such that the total change in effort
(braking effort or tractive effort) is substantially zero. When the
efforts of a single wheelset are changed, creep measurements may be
acquired. Thus, numerous data points may be obtained that may be
used to acquire information of the friction modifier. For example,
the data points may be used to form a traction-creep curve.
[0078] FIG. 4 provides a graph 330 that include traction-creep
curves 331-333. Each of the traction-creep curves 331-333
represents a tractive effort versus creep relationship that is
based on data points acquired at different locations along the same
route segment. The y-axis corresponds to increasing tractive
effort, and the x-axis corresponds to increasing creep. It should
be noted that similar curves (or relationships) may be shown for
other tractive/horsepower characteristics and creep. For example,
under some circumstances, an adhesion coefficient may exhibit a
similar relationship with creep. As shown, each curve exhibits a
slightly different relationship between tractive effort and creep.
This may be due to the amount of friction modifier at the location
of the route segment. Each of the curves 331-333 has an optimum
creep 341-343, respectively, and has a traction-creep slope
351-353, respectively. The optimum creeps 341-343 and/or the
traction-creep slopes 351-353 may be used to calculate a tribology
characteristic.
[0079] Returning to FIG. 3, the method 300 may also include
communicating (at 304) the creep and tractive/braking measurements
and receiving (at 306) the creep and tractive/braking measurements.
The measurements may be received by a system (e.g., monitoring
system, such as the system 116). In other embodiments, the
measurements may not be communicated externally and, instead, may
be communicated to an onboard system that is configured to
calculate tribology characteristics and, optionally, determine an
effectiveness of a friction modifier based on the tribology
characteristics.
[0080] The method 300 also includes obtaining (at 308) compensating
data that relates to or may have an effect on the creep or
tractive/braking measurements. The tribology characteristics may be
a function of various changing factors. For example, the tribology
characteristics may be based on weight of the propulsion-generating
vehicle or the vehicle system, speed of the vehicle system, and
predetermined limits of the vehicle system. Such compensating data
may be communicated by the vehicle system to the monitoring system.
Other compensating data may include environmental data, such as
weather conditions (e.g., rain, snow, temperature) and external
rail conditions, such as leaves on the track.
[0081] The method 300 also includes calculating (at 310) tribology
characteristics of the route segment at different locations. In
particular embodiments, the tribology characteristic is indicative
of or based on a COF at the track location or an adhesion
coefficient at the track location. As described herein, COFs and
adhesion coefficients may be directly affected by the application
of friction modifiers. Various formulas may be used to calculate
the tribology characteristics.
[0082] The method 300 may also include determining (at 312) an
effectiveness of the friction modifier that was applied to the
route segment (e.g., the region-of-interest in the route segment).
Determining (at 312) may include determining a function (e.g.,
graph or relationship curve or formula) that indicates tribology
characteristics as a function of location. FIG. 5 shows a graph 360
including three separate curves 361-363 illustrating such
relationships between tribology characteristics and location. The
friction modifier applied in this instance was lubrication
configured to reduce adhesion. A region-of-interest 365 along the
track is indicated, and a suitable range 366 of the tribology
characteristic (e.g., adhesion coefficient) is shown for the
region-of-interest 365. More specifically, it is desired that the
tribology characteristics be within the suitable range 366 for the
entire region-of-interest 365. As shown, the curve 361 corresponds
to the route segment in which an insufficient or inadequate amount
of lubrication exists for portions of the region-of-interest 365.
More specifically, the tribology characteristics are relatively
high and not within the suitable range 366 for portions of the
region-of-interest 365. The curve 363 corresponds to the route
segment in which an excessive amount of lubrication exists. As
shown, the tribology characteristics are relatively low and never
exceed the suitable range 366 even outside of the
region-of-interest 365. More specifically, the lubrication has
spread beyond the region-of-interest and may be preventing vehicle
systems from obtaining a maximum tractive effort. The curve 362
corresponds to the route segment having a suitable amount of
lubrication.
[0083] In some embodiments, determining (at 312) the effectiveness
of the friction modifier may include identifying one or more
portions of the route segment that have an inadequate amount of
friction modifier or have an excessive amount of friction modifier.
For example, the tribology characteristics for the different
portions of the route segments may be compared to a first
designated threshold (e.g., desired minimum or baseline amount)
and/or to a second designated threshold (e.g., a desired maximum or
limit amount). In some embodiments, determining (at 312) the
effectiveness of the friction modifier may include comparing the
tribology characteristics to expected tribology characteristics.
For example, either of curves 361 and 363 may be compared to the
curve 362.
[0084] The method may also include generating (at 314) a
friction-management plan based on the effectiveness of the friction
modifier. The friction-management plan may include instructions for
applying friction modifier to the route segment. The friction
modifier may be applied by passenger or freight vehicle systems,
such as those that obtain the measurements, or by systems or
devices that are specifically configured to apply the friction
modifier. The instructions in the friction-management plan may
include increasing an amount of the friction modifier at designated
points along the route segment and/or decreasing an amount of the
friction modifier at designated points along the track. Increasing
may be accomplished by more frequent applications and/or more
friction modifier being applied at each application. Decreasing may
be accomplished by fewer applications and/or less friction modifier
being applied at each application. The friction-management plan may
also recommend using a different friction modifier.
[0085] As used herein, the terms "system" and "module" include a
hardware and/or software system that operates to perform one or
more functions. For example, a module or system may include a
computer processor, controller, or other logic-based device that
performs operations based on instructions stored on a tangible and
non-transitory computer readable storage medium, such as a computer
memory. Alternatively, a module or system may include a hard-wired
device that performs operations based on hard-wired logic of the
device. The modules shown in the attached figures may represent the
hardware that operates based on software or hardwired instructions,
the software that directs hardware to perform the operations, or a
combination thereof.
[0086] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
or "an embodiment" of the presently described inventive subject
matter are not intended to be interpreted as excluding the
existence of additional embodiments that also incorporate the
recited features. Moreover, unless explicitly stated to the
contrary, embodiments "comprising," "comprises," "including,"
"includes," "having," or "has" an element or a plurality of
elements having a particular property may include additional such
elements not having that property.
[0087] In an embodiment, a method is provided that includes
obtaining creep measurements and tractive/braking measurements from
at least one vehicle system at different locations along a route
segment while the at least one vehicle system moves through the
route segment. The method also includes calculating tribology
characteristics of the route segment at the different locations.
The tribology characteristics are based on the creep measurements
and the tractive/braking measurements from the at least one vehicle
system. The tribology characteristics are indicative of a friction
coefficient of the route segment at the different locations. The
method also includes determining an effectiveness of a friction
modifier applied to the route segment based on the tribology
characteristics.
[0088] In one aspect, obtaining the creep measurements and the
tractive/breaking measurements may include obtaining a series of
the creep measurements and the tractive/breaking measurements
throughout the route segment from each of the vehicle systems.
Optionally, the route segment may be at least a half-kilometer long
or at least one kilometer long or, more particularly, at least two
kilometers long. Optionally, the creep measurements and the
tractive/breaking measurements may be obtained, on average, at
least once every 100 meters of the route segment. In some
embodiments, the creep measurements and the tractive/breaking
measurements may be obtained, on average, at least once every 50
meters of the route segment. In more particular embodiments, the
creep measurements and the tractive/breaking measurements may be
obtained, on average, at least once every 10 meters of the route
segment.
[0089] In another aspect, obtaining the creep measurements and the
tractive/braking measurements from the at least one vehicle system
includes obtaining the creep measurements and the tractive/braking
measurements in response to a tractive effort of a first wheelset
being increased by a designated amount and a tractive effort of a
second wheelset being decreased by the designated amount thereby
maintaining a total tractive effort of the at least one vehicle
system.
[0090] In another aspect, obtaining the creep measurements and the
tractive/braking measurements from the at least one vehicle system
includes the tractive/braking measurements being representative of
maximum tractive efforts at the different locations.
[0091] In another aspect, the at least one vehicle system operates
in accordance with an operating plan. The operating plan includes
predetermined instructions for one or more propulsion-generating
vehicles of the at least one vehicle system to provide at least one
of a designated tractive effort or a designated braking effort.
[0092] In another aspect, the at least one vehicle system includes
at least one locomotive in which a plurality of the creep
measurements and a plurality of the tractive/braking measurements
are obtained from the at least one locomotive.
[0093] In another aspect, the method also includes obtaining creep
measurements and tractive/braking measurements from at least one
other separate vehicle system while the at least one other separate
vehicle system moves through the route segment. Calculating the
tribology characteristic of the route segment includes using the
creep measurements and the tractive/braking measurements from the
at least one other separate vehicle system.
[0094] In another aspect, obtaining the creep measurements and the
tractive/braking measurements includes obtaining the creep
measurements and the tractive/braking measurements at an off-board
(e.g., remotely located site) monitoring system. The at least one
vehicle system may be a plurality of separate vehicle systems that
travel along the route segment.
[0095] In another aspect, the tribology characteristic is an
adhesion coefficient or is based on or indicative of the adhesion
coefficient.
[0096] In another embodiment, a system (e.g., monitoring system) is
provided that includes a receiver configured to receive creep
measurements and tractive/braking measurements from at least one
vehicle system at different locations along a route segment while
the at least one vehicle system moves through the route segment.
The system also includes a calculation module configured to
calculate tribology characteristics of the route segment at the
different locations. The tribology characteristics are based on the
creep measurements and the tractive/braking measurements from the
at least one vehicle system. The tribology characteristics are
indicative of a friction coefficient of the route segment at the
different locations. The system also includes an analysis module
configured to determine an effectiveness of a friction modifier
applied to the route segment based on the tribology characteristics
at the different locations.
[0097] In one aspect, the analysis module is configured to compare
the tribology characteristics at the different locations to
expected tribology characteristics at the different locations.
[0098] In another aspect, the analysis module is configured to
identify one or more regions of the route segment that having an
amount of the friction modifier that is below a first designated
threshold and identify one or more regions of the route segment
having an amount of the friction modifier that is above a second
designated threshold.
[0099] In another aspect, the receiver is configured to receive
compensating data relating to route conditions and the analysis
module is configured to determine the effectiveness of the friction
modifier using the compensating data to compensate for the route
conditions.
[0100] In another aspect, the receiver is configured to receive a
series of the creep measurements and the tractive/breaking
measurements throughout the route segment from the at least one
vehicle system.
[0101] In another aspect, the route segment is at least two
kilometers long and wherein the creep measurements and the
tractive/breaking measurements are obtained, on average, at least
once every 50 meters for the route segment.
[0102] In another aspect, a system (e.g., control system of a
vehicle system) is provided that includes a vehicle-control module
configured to control tractive and braking operations of a vehicle
system. The system also includes a measurement module configured to
obtain creep measurements and tractive/braking measurements of the
vehicle system at different locations along a route segment while
the vehicle system moves through the route segment. The system also
includes a transmitter configured to communicate the creep
measurements and the tractive/braking measurements from the vehicle
system. The vehicle-control module is configured to increase the
tractive effort of a first wheelset by a designated amount and
decrease the tractive effort of a second wheelset by the designated
amount thereby maintaining a total tractive effort of the vehicle
system. The measurement module is configured to obtain the creep
measurements and the tractive/braking measurements when the first
and second wheelsets operate at increased and decreased tractive
efforts, respectively.
[0103] In one aspect, the measurement module is configured to
obtain the creep measurements and the tractive/braking measurements
of the vehicle system when the vehicle system is operating at a
designated throttle setting. The tractive/braking measurements may
be representative of maximum tractive efforts at the different
locations.
[0104] In another aspect, the vehicle-control module is configured
to control the vehicle system in accordance with an operating plan.
The operating plan includes predetermined instructions for one or
more propulsion-generating vehicles of the vehicle system to
provide at least one of a designated tractive effort or a
designated braking effort.
[0105] In another aspect, the vehicle system includes a
locomotive.
[0106] In another aspect, the vehicle system includes a plurality
of locomotives. The calculation module is configured to obtain the
creep measurements and the tractive/braking measurements from the
plurality of locomotives.
[0107] In another aspect, the vehicle system includes a train that
transports at least one of freight or passengers.
[0108] In another aspect, at least some of the vehicle systems may
include plural locomotives. Each of the locomotives may obtain a
plurality of the creep measurements and a plurality of the
tractive/braking measurements.
[0109] In another aspect, the vehicle systems may include trains
that transport at least one of freight or passengers.
[0110] In an embodiment, a system is provided that includes a
receiver configured to receive creep measurements and
tractive/braking measurements from multiple vehicle systems at
different locations along a route segment while the vehicle systems
move through the route segment. The system may also include a
calculation module that is configured to calculate a tribology
characteristic of the route segment at the different locations. The
tribology characteristic is based on the creep measurements and the
tractive/braking measurements from the vehicle systems, wherein the
tribology characteristic is indicative of a friction coefficient of
the route segment at the respective location. The system may also
include an analysis module that is configured to determine an
effectiveness of a friction modifier applied to the route segment
based on the tribology characteristic.
[0111] In another aspect, the route segment is at least a
half-kilometer long or at least one kilometer long or, more
particularly, at least two kilometers long. Optionally, a number of
the creep measurements and the tractive/breaking measurements may
correlate to, on average, at least once every 100 meters of the
route segment, at least once every 50 meters of the route segment,
or at least once every 10 meters of the route segment.
[0112] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the inventive subject matter without departing from its scope.
While the dimensions and types of materials described herein are
intended to define the parameters of the inventive subject matter,
they are by no means limiting and are exemplary embodiments. Many
other embodiments will be apparent to one of ordinary skill in the
art upon reviewing the above description. The scope of the
inventive subject matter should, therefore, be determined with
reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled. In the appended
claims, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Moreover, in the following claims, the terms "first,"
"second," and "third," etc. are used merely as labels, and are not
intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112, sixth paragraph, unless and until
such claim limitations expressly use the phrase "means for"
followed by a statement of function void of further structure.
[0113] This written description uses examples to disclose several
embodiments of the inventive subject matter, and also to enable one
of ordinary skill in the art to practice the embodiments of
inventive subject matter, including making and using any devices or
systems and performing any incorporated methods. The patentable
scope of the inventive subject matter is defined by the claims, and
may include other examples that occur to one of ordinary skill in
the art. Such other examples are intended to be within the scope of
the claims if they have structural elements that do not differ from
the literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal
languages of the claims.
[0114] The foregoing description of certain embodiments of the
present inventive subject matter will be better understood when
read in conjunction with the appended drawings. To the extent that
the figures illustrate diagrams of the functional blocks of various
embodiments, the functional blocks are not necessarily indicative
of the division between hardware circuitry. Thus, for example, one
or more of the functional blocks (for example, controllers or
memories) may be implemented in a single piece of hardware (for
example, a general purpose signal processor, microcontroller,
random access memory, hard disk, and the like). Similarly, the
programs may be stand-alone programs, may be incorporated as
subroutines in an operating system, may be functions in an
installed software package, and the like. The various embodiments
are not limited to the arrangements and instrumentality shown in
the drawings.
* * * * *