Abstract:
A system ( 10 ) for ensuring the quality of lubricating oil in an engine of a locomotive without the need for specialized diagnostic and fluid handling systems on the locomotive. A test portion ( 28 ) of lubricating oil is removed from the engine and is analyzed at an oil analysis center ( 26 ) to determine an oil quality parameter ( 32 ). The oil quality parameter is used as an input to a calculator ( 34 ) to determine a quantity of oil ( 36 ) that must be replaced by fresh oil during a current maintenance outage in order to ensure that the engine oil quality will remain acceptable throughout a forthcoming operating period. In this manner, a complete change-out of the lubricating oil may be delayed or avoided. The oil replacement decision and quantity is communicated to a service center ( 18 ) via a communications link such as the Internet ( 40 ) prior to the arrival of the locomotive at the service center. The used oil may be removed from the engine using a portable transfer device and mixed with fuel in a fuel storage tank for subsequent refueling of other locomotives.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims benefit of the Feb. 5, 2002, filing date of U.S. provisional application No. 60/354,658. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to the field of lubricating oil management systems for the internal combustion engine of a vehicle.  
         BACKGROUND OF THE INVENTION  
         [0003]    An internal combustion engine relies upon a lubricating fluid, typically natural or synthetic oil, to reduce friction between moving parts and to remove heat from critical components of the engine. It is well known that the desirable properties of such fluids will degrade with continued operation of the engine, due to chemical changes in the fluid itself as well as the accumulation of contaminants that cannot be successfully filtered out of the fluid.  
           [0004]    Many schemes are used to maintain the quality of lubrication in the internal combustion engine of a vehicle. Lubricating oil may be removed and replaced after a predetermined time period, after a predetermined number of operating hours, or after a predetermined number of miles of travel of the vehicle. Such schemes are necessarily conservative to avoid engine damage during worst-case operating conditions, such as high temperature, high speed, high altitude, and dusty environment operation. Such predetermined interval schemes result in unnecessarily frequent oil changes for most normal operating situations.  
           [0005]    U.S. Pat. No. 5,749,339 describes a system for automatically replacing a portion of the lubricating oil in an internal combustion engine of a vehicle at a rate influenced by the fuel consumption of the engine. The removed portion of the oil is consumed in the engine by mixing it with the fuel supply for the engine, and fresh oil is added from an on-board supply. U.S. Pat. No. 5,964,318 describes a similar on-board lubricating oil quality management system that controls the amount of oil removed and replaced in response to a continually sensed oil quality parameter. The on-board sensors may be used to determine oil temperature, pressure, dielectric or viscosity values. An on-board controller receives the sensor signal as an input, and it automatically controls an on-board valve for regulating the amount of oil removed from and added to the engine. The controller may also be programmed to consider variables such as the number of starts, run time or distance and fuel usage. Such onboard systems are useful for extending the time period between oil changes for an engine; however, they require expensive on-board diagnostic and fluid systems.  
           [0006]    It is common practice in the railroad industry to perform a laboratory oil analysis on a test sample of lubricating oil from a locomotive diesel engine, and to base an oil change/no-change decision on the results of the oil analysis. The oil analysis performed on the test sample is generally more thorough than the type of onboard measurements described in the prior art &#39;318 patent. If the as-measured quality of the lubricating oil is determined to be below a predetermined threshold, the locomotive is scheduled for a complete engine oil change. The quality parameters may include pentane insolubles, viscosity, and total base number (TBN). The quality parameter(s) set point levels used to make this decision are selected to ensure that the oil quality will not drop to an unacceptable level at any time before the next scheduled service outage for the locomotive, typically ninety (90) days hence. Accordingly, it is often necessary to change lubricating oil that is still performing adequately in order to avoid the possibility that it will fall below a quality threshold during the next engine-operating period.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0007]    A method for maintaining the quality of lubricant in the engine of a mobile vehicle is described herein as including: planning operation of a mobile vehicle for a number of operating periods separated by a respective number of maintenance periods; removing a test portion of lubricant from an engine of the mobile vehicle during a first of the maintenance periods; determining at least one quality parameter associated with the test portion of lubricant; using the at least one quality parameter to determine a replacement quantity of lubricant that must be removed from the engine and replaced with fresh lubricant in order to maintain a desired engine lubricant quality parameter in the engine until a second of the maintenance periods; and removing the replacement quantity of lubricant from the engine and replacing it with fresh lubricant. The method may further include: removing the test portion of lubricant from the engine at a first maintenance location; delivering the test portion of lubricant to an analysis location remote from the first maintenance location; and communicating the replacement quantity to one of the first maintenance location and a second maintenance location for performing the steps of removing the replacement quantity of lubricant and replacing it with fresh lubricant. A global information network may be used during the step of communicating. The method may include transferring the replacement quantity of lubricant from the engine to a fuel tank of a mobile vehicle. The method may further include transferring the replacement quantity of lubricant from the engine to a storage apparatus to create a mixture of fuel and replaced lubricant; and transferring at least a portion of the mixture of fuel and replaced lubricant to the fuel tank.  
           [0008]    A system for maintaining the quality of lubricant in an engine of a mobile vehicle during a period of operation between successive service outages is described herein as including: a lubricant analysis device for determining at least one quality parameter associated with a test portion of lubricant removed from an engine of a mobile vehicle; and a calculator responsive to the at least one quality parameter for determining a replacement quantity of lubricant to be removed from the engine and replaced with fresh lubricant sufficient to maintain a desired engine lubricant quality parameter in the engine during a next period of operation of the engine until a next service outage. The lubricant analysis device and the calculator may be connected to an information network for communicating the at least one quality parameter and the replacement quantity of lubricant. The system may further include a service location where the mobile vehicle will have the replacement quantity of lubricant removed and replaced with fresh lubricant, the service location connected to the information network for receiving the replacement quantity of lubricant. The lubricant analysis device may be a hand-held permittivity sensor. The system may further include a tank for receiving the replacement quantity of lubricant and for receiving fuel to create a mixture used to fuel an engine.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawings in which:  
         [0010]    [0010]FIG. 1 illustrates a system for maintaining the quality of lubricant in an engine of a vehicle. The system includes, among other elements, an oil analysis center, a vehicle service center, and a diagnostic center, all interconnected by a global information network.  
         [0011]    [0011]FIG. 2 illustrates a fuel/oil management system as may be located at a fuel pad or service center. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    [0012]FIG. 1 illustrates one embodiment of a system  10  for maintaining the quality of lubricant in an engine of a vehicle during a period of operation between successive service outages. The engine may be a diesel internal combustion engine of a locomotive (not shown) operating on a rail system  12 . The rail system  12  includes a plurality of fueling locations, such as fuel pads  14 ,  16  and a number of service locations, such as service centers  18 ,  20 . A fuel pad  16  may be co-located and associated with a service center  18 . The operation of locomotives and trains of rail vehicles along the rail system  12  may be controlled from a railroad control center  22 . A diagnostic center  24  may be associated with the rail system  12  and the railroad control center  22  for performing a variety of technical and economic diagnostic functions designed to improve the operating efficiency of the rail system  12 . One such diagnostic center  24  operated by the assignee of the present invention is located in Erie, Pa.  
         [0013]    The system  10  also includes an oil analysis center  26  where a test portion  28  of lubricating oil from a locomotive may be taken for a complete chemical and physical analysis. The oil analysis center  26  may be located at any convenient location, preferably at a location that can service a large number of clients in an economical fashion. The oil analysis center  26  may be located at one of the fuel pads  14 ,  16 , at one of the service centers  18 ,  20 , at the diagnostic center  24 , at the railroad control center  22 , or most likely at an independent location. The oil analysis center  26  may contain a complete line of analysis equipment  30  as may be known now or may become known in the art, for example, a kinematic viscometer for measuring viscosity; atomic absorption and inductively coupled plasma (ICP) instruments for detecting metals indicative of engine/bearing wear; potentiometric titration instruments for TBN and TAN; filtration or centrifuge techniques for measuring pentane insolubles; thermal gravimetric analysis (TGA) for soot/carbon measurements; and infrared spectroscopy for measuring soot, TBN and TAN. The chemical and physical properties of the test portion  28  of lubricating oil are determined at the oil analysis center  26 , and at least one oil quality parameter  32  is determined. The quality parameter  32  may be, for example, the same parameter that is used in the prior art as the basis for the known oil change/no-change decision, e.g. pentane insolubles, TBN and viscosity. The at least one oil quality parameter  32  is communicated to a calculator  34  typically associated with the diagnostic center  24 . The calculator  34  is responsive to the oil quality parameter(s)  32  and is used for determining a replacement quantity of lubricant  36  to be removed from the engine and replaced with fresh lubricant that is sufficient to maintain one or more desired engine lubricant quality parameters in the engine during the next period of operation of the engine until the next service outage. The calculator  34  may be as simple as a look-up table or graph, or it may be a computer-implemented sequence of calculations embodied in a software program, such as a mechanistic or empirical process model that takes into account specific features of the lubricant, the engine (age, duty cycle, etc.), the locomotive design, the rail system  12 , the season of operation, etc. For example, a conservatively high rate of deterioration of a quality parameter verses hours of operation may be developed from past experience with an engine. The calculator  34  may include a curve of the quality parameter verses hours of operation, together with a mechanism for locating the present quality parameter value on the curve, and for predicting remaining hours of operation until the quality parameter drops below a predetermined minimum value. If the quality of the lubricant is then predicted to remain acceptable during the entire following operating period, the calculator  34  will indicate that no lubricant will have to be replaced during the present service outage. If, however, it is projected that the quality of the lubricant will fall below the predetermined minimum value during the forthcoming operating period, a specific replacement quantity of lubricant  36  is calculated. The calculator may include equations for determining the amount of lubricant that must be removed and replaced by fresh lubricant in order to return the quality parameter to a sufficiently high value so that its predicted degradation during the following usage period will not result in a valued below the predetermined minimum value. The calculator  34  for implementing such steps may be a personal computer, hand-held calculator or other type of available hardware for implementing such process steps. By replacing only a predetermined quantity of the existing lubricant from the engine with fresh lubricant during the present outage, the quality of the lubricant in the engine will be improved to a point wherein it will remain acceptable during the entire forthcoming operating period. In this manner, a complete change of the lubricating oil may be delayed or eliminated, thereby reducing the total consumption of lubricant by the engine and lowering the overall cost and environmental impact of operation of the locomotive. This process may be repeated for each successive scheduled maintenance outage for the locomotive in order to ensure that the lubricating oil quality will remain acceptable for the respective following operating period. At some point, a decision may be made to change the entire quantity of lubricating oil in the engine, but such a complete change-out will likely be delayed as a result of the use of the system  10  and method described above.  
         [0014]    The communication of the quality parameter  32  and/or replacement quantity  36  between the various elements of the system  10  may be by a direct link  38 , such as U.S. mail or facsimile transmission, or it may be accomplished via connections to a global information network, such as the World Wide Web of the Internet  40 . The use of the Internet  40  provides all of the interested parties with convenient access to such information. For example, if the oil test portion  28  is extracted at a fuel pad  14  shortly prior to a scheduled maintenance outage for the locomotive, the decision to replace a portion of the lubricating oil and the work order to accomplish such replacement may be communicated to a down-rail service center  18  where the locomotive will be serviced in advance of the locomotive arriving at the service center  18 . Advance access to such information will allow the operations of the service center  18  to be optimized. Because lubricant will likely be lost from the engine through a variety of pathways, the fresh lubricant added to the engine will be an amount equal to the greater of the replacement quantity  36  and a quantity necessary to fill the engine to a desired level. From an oil quality perspective, as long as a quantity of fresh oil is added to the engine in a quantity at least equal to the removal quantity  36 , the assumptions regarding the ongoing quality of the oil during the next operating interval will be satisfied.  
         [0015]    Used lubricant may be removed from the locomotive with a portable transfer device. The lubricant removed from the locomotive  42  may be transferred to the fuel tank of the locomotive, to the fuel tank of another locomotive, to a used-oil storage tank on a locomotive, to a used-oil storage tank associated with a fuel pad  16 , or to a fuel storage tank associated with a fuel pad  16  for later consumption by a vehicle engine. FIG. 2 illustrates one embodiment of such a fuel/oil management center  50  servicing two locomotives  52 ,  54 . Each locomotive  52 ,  54  may include a used oil storage tank  56 ,  58  in addition to the typical fuel tank  60 ,  62 . The fuel/oil management center  50  also includes storage tanks for used oil storage  64 , fuel storage  66  without oil, and fuel/oil mixture storage  68 . The removed lubricant  42  is used to create a mixture of fuel and removed lubricant that may be used to refuel a vehicle. Such mixture may be made on-board a locomotive  52 ,  54  or at the fuel pad/service center location  70 . The fuel/oil management center  50  includes appropriate mechanical and electrical systems for pumping, metering and control, automatic shutoff, and volume adjustment in the various storage tanks. Such systems may include a computerized inventory control system for tracking the quantity of used oil, the concentration of oil and oil contaminants in the fuel/oil mixture, the volumes available in various storage locations, etc. The system  50  may also include communication links  72  such as the Internet, telephone or facsimile transmission for conveying information that may be useful to other similar locations on the rail system, for communicating with various fuel and oil suppliers, and/or for communicating with the locomotives  52 ,  54  during operation. The control of such resources should include precautions not to exceed a predetermined concentration of lubricant in the fuel supply in order to avoid exceeding emissions limits.  
         [0016]    The analysis equipment  30  may be located at a central oil analysis center  26 , or alternatively, may be located proximate the location where the test portion  28  of oil is removed from the engine. In one embodiment, a hand-held sensor would be used, for example to measure a permittivity and temperature of the removed lubricant. Permittivity is an indicator of the quantity of contaminates entrained in a lubricant, and therefore, it is an indicator of the fitness of the lubricant for continued service. The temperature-compensated permittivity value would be used with a trending analysis to determine the replacement quantity  36 . A trending analysis with a mechanistic or empirical model could be performed on the calculator  34  at the diagnostic center  24 , with communication of the permittivity value being transmitted electronically, such as via the Internet  40 , between the hand-held measurement equipment  30  and the diagnostic center  24 . The replacement quantity  36  resulting from the trending analysis may also be communicated to service personnel electronically.  
         [0017]    While off-board oil analysis equipment  30  may be the most practical with today&#39;s generation of electronic equipment, future systems may beneficially utilize at least some on-board sensing capability. For example, the hand-held permittivity sensor described above as being used off-board to obtain a permittivity measurement on the test portion  28  may alternatively be used on-board while the vehicle is being operated. Other economically practical on-board lubricant quality sensing systems may be identified for a particular application. The permittivity value or other measured oil quality parameter may then be transmitted electronically from the vehicle via any known communication system to the diagnostic center calculator  34 . The lubricant removal or change decision may thus be made and communicated to an appropriate service center  18  prior to the arrival of the vehicle.  
         [0018]    While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.