Patent Application
20130131912
This invention relates in general to methods for evaluating the condition of a lubricating material, such as oil, in a vehicle engine. In particular, this invention relates to an improved method for estimating when such a lubricating material should be changed.
Virtually all types of engines (such as internal combustion, diesel, and the like) use one or more lubricating materials, such as oil, to provide lubrication between engaging mechanical components that slide or otherwise move relative to one another. The use of such lubricating materials reduces the amount of friction that occurs between these engaging and sliding components, thereby minimizing the generation of undesirable heat and wear. It is well known that the ability of most lubricating materials to perform this function degrades as a result of use. As a result, replacing old lubricating material with new lubricating material too infrequently can result in damage to the engine. However, it is also known that replacing the lubricating material too frequently is undesirably wasteful.
Many engine manufacturers simply recommend that the lubricating material in the engine be replaced at predetermined fixed intervals of either distance traveled by the vehicle or amount of time of usage of the engine. For example, some engine manufacturers recommend that the lubricating material in the engine be replaced after a fixed amount of distance of travel by the vehicle, such as 7,500 miles. In other instances, engine manufacturers recommend that the lubricating material in the engine be replaced after a fixed amount of time of engine operation, such as 200 hours for example. In both instances, it is known to generate an audible and/or visual alarm to alert an operator of a vehicle when either or both of these fixed intervals has been reached.
Although these fixed interval types of systems have functioned satisfactorily, the fixed intervals that are used therein merely represent estimates that are based upon predetermined assumptions of operation of the vehicle. Consequently, if the vehicle is operated differently from those predetermined assumptions, then the fixed interval types of systems can estimate replacement of the lubricating material at less than optimal occasions (both sooner and later) than is desirable in light of the actual operating conditions of the engine. For example, it is known that an engine experiences relatively harsh operating conditions when operated at relatively extreme speeds (such as when the vehicle is either idling or driven at racing speeds), while an engine experiences relatively mild operating conditions when operated at relatively moderate speeds (such as when the vehicle is driven at moderate speeds). Thus, if the vehicle is idling or driven at racing speeds for an extended period of time (more than that assumed by a fixed interval type of system), it would be desirable to replace the lubricating material sooner than the predetermined time interval of 200 hours of engine operation. Conversely, if the vehicle is driven at moderate speeds for an extended period of time (again, more than that assumed by a fixed interval type of system), it would be desirable to replace the lubricating material later than the predetermined distance interval of 7,500 miles.
Additionally, the assumed correlation between amount of distance of traveled by the vehicle and the condition of the lubricating material used in the engine is even more tenuous in the context of hybrid vehicles, which are becoming increasingly popular. In such hybrid vehicles, the actual amount of use of the engine can vary widely depending upon how the hybrid vehicle is operated. For example, when driven for relatively small distances and time durations, the hybrid vehicle may be propelled primarily or exclusively by a battery-driven motor. In those situations, the engine may not used much (or at all) in relation to the amount of distance of traveled by the vehicle. However, when driven for relatively large distances and time durations, the hybrid vehicle may not be propelled much (or at all) by the battery-driven motor. Thus, the engine may be used quite a bit in relation to the amount of distance of traveled by the vehicle.
To address some of the shortcomings of fixed interval types of systems, it is also known to replace the lubricating material when any one of a plurality of engine operating parameters is reached. Such engine operating parameters can include, for example, a predetermined amount of fuel in the oil or a predetermined amount of soot in the oil. Each of these engine operating parameters can be detected by a conventional sensor and fed to a controller. In response thereto, the controller can generate an audible and/or visual alarm to an operator of a vehicle when either one (or both) of these engine operating parameters has been reached. Unfortunately, known systems that are responsive to engine operating parameters such as this are typically also responsive to either one of the above-described fixed intervals and, therefore, still suffer from the same shortcomings as described above. Thus, it would be desirable to provide an improved method for estimating when a lubricating material should be changed in response to the amount of actual usage of the engine.
This invention relates to an improved method for estimating when a lubricating material should be changed in response to the amount of actual usage of the engine. Initially, a quantity of use of an engine and a time of use of the engine are measured. A useful life indication of a lubricating fluid in the engine is generated based upon a first relationship between the quantity of use of an engine and the time of use of the engine when an operating characteristic is at or below a predetermined amount, such as the average speed of a vehicle containing the engine. The useful life indication of the lubricating fluid in the engine is generated based upon a second relationship between the quantity of use of an engine and the time of use of the engine when the operating characteristic is above the predetermined amount.
Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
Referring now to the drawings, there is illustrated in
A system reset component 11 is provided that can send signals over respective lines 20a, 20b, 20c, and 20d to reset each of the four triggers 12, 14, 16, and 18 after an oil change has been performed. The four triggers 12, 14, 16, and 18 operate in a parallel fashion, independently of one another, such that any one or more of the triggers 12, 14, 16, and 18 can send its signal over the associated lines 12′, 14′, 16′, and 18′ to a maximum engine oil life signal collector 22. When the maximum engine oil life signal collector 22 receives a signal over any one or more of the lines 12′, 14′, 16′, and 18′ from any one of the triggers 12, 14, 16, and 18, it generates a change oil message 24 to alert an operator of the vehicle that an oil change should be performed.
Referring now to
The signals generated from the distance traveled trigger 32 and the operating time trigger 34 are fed respectively over the lines 32′ and 34′ to an operating model 50. In a manner that is described in detail below, the operating model 50 selectively generates a composite trigger signal on a line 50′ to a maximum engine oil life signal collector 42. The signals generated from the fuel-in-oil trigger 36 and the soot-in-oil trigger 38 are fed over the respective lines 36′ and 38′ to the maximum engine oil life signal collector 42. When the maximum engine oil life signal collector 42 receives either the composite trigger signal over the line 50′ from the operating model 50 or one of the signals over the lines 36′ or 38′ from either of the fuel-in-oil or the soot-in-oil triggers 36 and 38, it generates a change oil message 44 to alert an operator of the vehicle that an oil change is due to be performed.
If desired, each of the triggers 36, 38, and 50 may be configured to send two signals over the lines 36′, 38′, and 50′, respectively, to the maximum engine oil life signal collector 42. A first signal can be generated by any of the triggers 36, 38, or 50 when it reaches a value that is equivalent to 95% of a predetermined actual maximum oil life. When one of these first signals is sent, the maximum engine oil life signal collector 42 can send a signal over a line 44 to activate a first vehicle operator message 45 indicating that an oil change will soon be needed. A second signal can be generated by any of the triggers 36, 38, or 50 when it reaches a value that is equivalent to 100% of the predetermined actual maximum oil life. When one of these second signals is sent, the maximum engine oil life signal collector 42 can send a signal over a line 48 to activate a second vehicle operator message 49 indicating that an oil change is currently needed.
The operating model 50 is designed to represent the vehicle usage in a manner that is more closely relevant to the actual condition of the lubricating material used in the engine 6. For example, a vehicle operating mainly in the city, with greater than normal stop-and-go and idling, will experience engine oil deterioration at a different rate than a vehicle operating mainly at highway speeds, and a hybrid vehicle engine will experience engine oil deterioration at an even further different rate. The operating model 50 of this invention simply and efficiently accounts for these differing operating conditions to estimate when such a lubricating material should be changed.
In a preferred embodiment, the operating model 50 calculates an average speed of a vehicle containing the engine 6 when the engine 6 is operated. This average engine speed is used as an operating characteristic that will determine when the operating model 50 will generate its composite trigger signal on the line 50′ to the maximum engine oil life signal collector 42. Using this calculated average speed operating characteristic, a selection of two or more relationships (such as are indicated at 52 and 54 in
The first illustrated relationship 52 is average vehicle speed (which can be expressed in terms of miles per hour on the horizontal axis) vs. engine on time (which can be expressed in terms of hours of running time on the left vertical axis). In this example, when the average vehicle speed is at or below six miles per hour, the first illustrated relationship 52 shows the trigger point of the operating model 50 varying from 200 hours to 800 hours of engine running time, regardless of actual vehicle mileage. The second illustrated relationship 54 is average vehicle speed (which can be expressed in terms of miles per hour on the horizontal axis) vs. oil change distance interval (which can be expressed in terms of miles on the right vertical axis). In this example, when the average vehicle speed is greater than six miles per hour, the second illustrated relationship 54 shows the trigger point of the operating model 50 varying from 5,000 to 10,000 vehicle miles, regardless of engine running time. Although the two illustrated relationships 52 and 54 are different, it is possible that they may produce the same outcome on occasion, such as would occur at point 56 in
In hybrid vehicles, the time of engine use determined by the timer 35 used in the system 30 is limited to that of the engine 6 itself (which is typically an internal combustion engine). Because of the hybrid nature of the vehicle, the total vehicle mileage (or even mileage accumulated only when the engine is running) may not accurately represent the quantity of use of the engine 6. This is because the engine 6 may be contributing varying amounts of torque or power at any speed, depending on the torque or power contribution of the electrical operation of the hybrid vehicle. Therefore, a representation of the quantity of engine use can be represented by engine torque, which in turn can be represented by fuel usage. Engine speed (measured in revolutions per minute) can also accurately represent the quantity of engine use in hybrid vehicles, as will be apparent to those skilled in the art.
This invention improves upon previously known methods of evaluating internal combustion engine lubrication oil by employing a vehicle operating model instead of just predetermined triggers. This invention uses the relationship between engine running time and engine vehicle distance traveled to create variable trigger points. Alternatively, engine speed or the number of combustion ignitions can be used instead of vehicle distance traveled to indicate the amount of engine use. This invention utilizes multiple relationships for estimating oil condition and recommending oil change intervals.
In summary, it can be seen that this invention can indicate trigger points above and below that of prior known systems depending upon one or more operating conditions of the vehicle. This will provide a more accurate and reliable estimation of oil life for optimized oil change intervals to insure that the engine runs with high quality oil for reliability and engine durability, and at the same time reduces oil waste.
While this invention has been described in reference to the illustrated embodiment, various modifications thereto will occur to those skilled in the art. In this regard, it will be understood that systems incorporating such modifications may fall within the scope of this invention, which is defined by the appended claims.
