Internal combustion engine oils, used as lubricants, lose their initial qualities after extended use and are thus no longer effective. Prolonged use causes the oil to degrade and lose its effectiveness due to an accumulation of combustion-generated solid debris and chemicals, accumulation of frictionally-generated metallic particles and a resulting drop in viscosity.
Due to this degradation over time, engine oils must be changed periodically. The frequency of these changes depends upon the usage patterns of the engine-driven equipment. For example, the oil in a homeowner's lawnmower engine may only need to be changed once per season. On the other hand, a commercial lawnmower engine may need to have its oil changed many times during a given season due to almost daily use of the equipment. These frequent oil changes lead to increased downtime of the equipment and increased costs to the users. The size of the sump in the engine may be increased to allow for a greater oil capacity (and hence greater oil life), but such an increase in size is not practical for many lawn and garden applications.
Accordingly, it would be advantageous to have an internal combustion engine with a supplemental oil reservoir capable of recirculating oil at given time intervals. This supplemental oil reservoir enables increased life of the oil in the system and therefore increased intervals between oil changes.
An embodiment relates to an oil recirculation system including an engine lubricated by a flow of oil through the engine, a supplemental oil tank arranged to contain a quantity of oil, an oil inlet conduit arranged to fluidly connect the supplemental oil tank and the engine, an oil outlet conduit arranged to fluidly connect the supplemental oil tank and the engine, a first pump operable to pump oil from the supplemental oil tank to the engine through the oil outlet conduit; and a second pump operable to pump oil from the engine to the supplemental oil tank through the oil inlet conduit. wherein the oil inlet conduit is coupled to the supplemental oil tank at a location above where the oil outlet conduit is coupled to the supplemental oil tank.
Another embodiment relates to a ride-on mower including an engine lubricated by a flow of oil through the engine, a supplemental oil tank arranged to contain a quantity of oil, a seat arranged to define a forward and a rearward direction of the ride-on mower, wherein the engine and the supplemental oil tank are located rearward of the seat, an oil inlet conduit arranged to fluidly connect the supplemental oil tank and the engine, an oil outlet conduit arranged to fluidly connect the supplemental oil tank and the engine, a first pump operable to pump oil from the supplemental oil tank to the engine through the oil outlet conduit, and a second pump operable to pump oil from the engine to the supplemental oil tank through the oil inlet conduit, wherein the oil inlet conduit is coupled to the supplemental oil tank at a location above where the oil outlet conduit is coupled to the supplemental oil tank.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
Referring to
Fluidly coupled to engine 102 and sump 105 is a supplemental oil tank 104. Supplemental oil tank 104 is isolated from engine 102 and fluidly coupled to sump 105 via both an oil inlet conduit 110 and an oil outlet conduit 112. The locations of oil inlet conduit 110 and oil outlet conduit 112 are not limited to that which is shown in
Oil inlet conduit 110 enables oil contained in reservoir 115 of supplemental oil tank 104 to be selectively and intermittently exchanged with the oil within sump 105 of engine 102. Prior to or concurrent with the exchange of oil from reservoir 115 to sump 105, some or all of the oil within sump 105 is pumped or otherwise drained from sump 105 via oil outlet conduit 112. For example, a pump 114 may be used to draw the oil out of sump 105 and into supplemental oil tank 104. This recently “used” oil from sump 105 is then mixed with a greater amount of supplemental oil within reservoir 115. A certain amount of supplemental oil from reservoir 115 is then added to sump 105 via oil inlet conduit 110. This supplemental oil may be added either via a gravity feed or via another pump 90 placed in-line with oil inlet conduit 110. A float system 118 may be configured to limit the amount of oil added to sump 105 by cutting off the flow of oil from reservoir 115 to sump 105 once the oil in sump 105 reaches a predetermined level. Additionally, while not shown, a vent line could be included between supplemental oil tank 104 and sump 105 such that the pressure levels within tank 104 and sump 105 are maintained substantially equal to one another.
Using the above-described oil exchange system, the intervals between required oil changes for engine 102 can be substantially increased. Also, because the supplemental oil tank 104 and engine 102 are fluidly isolated from one another during operation of engine 102, there are no substantial alterations or limitations to engine 102. The system is not susceptible to tilting, etc., as may be the case if the system were to be fluidly coupled and in communication during certain points of engine operation.
Referring to
Another inlet/outlet fitting 416 of pump 410 is fluidly coupled to an engine sump 418 via a sump conduit 420. Within sump 418 and connected to sump conduit 420 is a bent tube 422. Bent tube 422 may be inserted into sump 418 through the existing oil drain plug 424 of the engine and is sized and angled such that its open end is positioned near the center of the oil volume, which is typically near the centerline (or crankshaft) of a vertical shaft engine. This positioning of the bent tube 422 reduces the effects that tilting or angling of the engine will have on the oil level 426 relative to the tube.
In operation, a controller (not shown) onboard the bottle holder 402 or elsewhere on the machine detects whether or not the engine is running. If the engine has not been running for a predetermined period of time (e.g., 5 seconds to 5 minutes), a signal is sent to pump 410 via communication lines 432 to begin the oil exchange process. This process comprises pumping oil from oil bottle 404 for a predetermined period of time (e.g. 1-15 seconds) to transfer a quantity of oil from oil bottle 404 to sump 418 (e.g., 4-20 fl. oz.). After this predetermined period of time has lapsed, the controller then sends a signal to pump 410 to reverse operation and pump oil out of sump 418 of the engine for another predetermined period of time (e.g., 5-30 seconds). The pump 410 will typically run longer when it is pumping oil out of sump 418 than when it is pumping oil into sump 418 to ensure that the engine oil is maintained within sump 418 at the correct level (i.e., approximately the level of the opening on bent tube 422) such that predominantly air is being pumped out of pump 410. Pump 410 is preferably an electric motor-powered gear pump that is able to self-prime, pump air, and easily reverse pumping direction. However, other pump designs may also be used. Alternatively, the controller may determine that the oil level in sump 418 is sufficient by detecting that the current draw of pump 410 has reached a predetermined low threshold amount, signifying that pump 410 is sucking air rather than oil and thus it is safe to turn pump 410 off. The controller could also be configured to allow for a predetermined wait period between pumping oil into sump 418 and pumping oil out of sump 418 so as to allow time for the oil to mix. In this way, a single set of input/output lines can be used between oil bottle 404 and sump 418, oil can be interchanged after engine operation, and the user can be assured that sump 418 maintains the correct oil level after each oil exchange operation. In an alternative construction, a single line extends between the supplemental oil tank and engine. The line would then branch into two separate lines within the engine with one line arranged to draw oil from the engine sump and the second line arranged to add oil to the engine sump. Check valves could be positioned in each line to assure the proper flow in each line.
As an alternative to the process described above, it is also contemplated that the oil exchange process could be activated when an engine's ignition key is detected to be in the “off” position. Likewise, the process could be activated when the ignition key is detected to be in the “on” position, or the fill cycle could be activated when the key is in the “off” position and the drain cycle activated when the key is in the “on” position. Another alternative is for there to be a user-actuated switch to allow the operator to determine when they would like the oil exchange process to be activated.
Turning to
Additionally, the configuration shown in
To replace the drained oil, the tank and sump could each be filled conventionally through respective oil fill openings. Alternately, the engine alone is filled with a sufficient quantity of oil to refill both the engine and oil tank to proper predetermined levels. The pump is then operated in reverse to pump any excess engine oil to the oil tank, thereby leaving the engine at the proper full level. Alternately, oil could be added only to the supplemental tank and the pump operated to return the engine to the proper oil level, either in one timed add/drain pumping process or several smaller add/drain cycles. Pump current draw could also be used to detect when the engine has been filled properly, by detecting the timing and/or order of high and low current draw associated with pumping oil and air respectively.
Controller programming and an additional LCD display with user interface buttons could provide step-by-step instructions to guide the user through the oil change drain and/or refill process and activate the pump when appropriate. The display could also show the oil life percent remaining, hours of operation, when the system has completed a refresh cycle, and other useful user updates. Various methods of establishing oil life percentage are possible. A simple “time only” system may be the simplest, but time at load or speed and other oil element detectors could also be used. A sophisticated electromechanical valve system and controller could also be added to help automate the drain process.
Referring now to
Supplemental oil tank 602 may be formed of metal, plastic, or any other suitable material. Additionally, the capacity of supplemental oil tank 602 (e.g., 2 gallons) is preferably larger than the capacity of the engine sump. Supplemental oil tank 602 comprises an easily-accessible oil fill cap 603 capable of being removed such that a user can fill supplemental oil tank 603 with engine oil. In the present embodiment, supplemental oil tank 602 is mounted via one or more tank brackets 604 to a transmission fluid cooling structure 606. In some zero-turn radius mowers, transmission fluid cooling structures are mounted above an engine and are configured to accept transmission fluid from one or more hydrostatic transmissions that are used to drive the wheels of the mower. As the fluid flows through the cooling structure, it is cooled and then returned to the hydrostatic transmission. In the present embodiment, because cooling structure 606 is mounted above engine 609, it makes an ideal mounting point for supplemental oil tank 602. However, it is to be understood that supplemental oil tank 602 may be mounted elsewhere on the mower and may be used with mowers that do not utilize a transmission fluid cooling structure.
System 600 further comprises a vent tube 608 which extends from the interior of supplemental oil tank 602 to the crankcase of engine 609. More specifically, vent tube 608 runs from a point near oil fill cap 603 to the engine crankcase so as to maintain a pressure in oil tank 602 equal to or nearly equal to the pressure within the running engine's crankcase. This configuration prevents large pressure differentials between the tank and the engine which may lead to unwanted supplemental oil delivery or extraction via siphoning effects, etc.
Running from the bottom portion of supplemental oil tank 602 is a first oil hose 611, as shown in
First oil hose 611 runs from tank 602 to an inlet of an anti-siphon chamber 618, where a second oil hose 612 is coupled to the outlet of anti-siphon chamber 618. Anti-siphon chamber 618 is configured to prevent oil from being unintentionally siphoned from tank 602 to the sump of engine 609. To achieve this, anti-siphon chamber 618 is designed to have a larger diameter than the diameter of first oil hose 611 and second oil hose 612 and is mounted on the mower or other device at a point higher than the level of oil within tank 602. In addition, the volume of the anti-siphon chamber 618 that is disposed above the oil level in the supplemental oil tank 602 should be larger (e.g., 1.2-2 times larger) than the internal system volume of the various hoses and other fluid containing devices between the anti-siphon chamber 618 and the engine sump 602. The anti-siphon chamber 618 has a 180 degree bend at a top portion such that the chamber 618 is located near the uppermost section of the oil path between tank 602 and engine 609. At least a portion of anti-siphon chamber 618 is mounted above the oil level, even when tank 602 is tipped to an extreme operating angle (e.g., 30 degrees). Alternatively, the chamber 618 may have straight or other angled fittings that position it high within the hose path. As anti-siphon chamber 618 is higher than the oil level within tank 602, the oil's natural tendency to maintain the same level throughout the system (i.e., in both the tank and the hoses) does not cause the oil to flow out of chamber 618 when the flow of oil is not desired. Additionally, the angle of the mower (and subsequently tank 602) does not cause oil to flow out of chamber 618 when not desired due to the fact that chamber 618 is mounted at this height.
An electric pump 610 is coupled in-line with second oil hose 612 and is operational to both pump oil from supplemental oil tank 602 to the sump of engine 609 and, conversely, to pump oil from the sump to supplemental oil tank 602. Electric pump 610 is preferably a gear pump but may be any appropriate fluid pump. For example, electric pump 610 could also be a positive displacement pump. A coupling 614 is placed in the oil drain port of engine 609 to fluidly couple oil hose 612 to a sump tube assembly 616 that is inside the sump of engine 609. Sump tube assembly 616 preferable extends upward and into the sump of engine 609 such that its outlet is near the center of the sump and is a predetermined distance (e.g. several inches) above the base of the sump. This location of the outlet of sump tube assembly 616 prevents variations in oil level due to the angle of engine 609 when oil is being added to or removed from the sump. Additionally, in this embodiment, the outlet of sump tube assembly 616 preferably sprays the oil laterally away from sump tube assembly 616 such that the oil added to the sump is better mixed with oil already within the sump, thereby preventing this “new” oil from easily being pumped out of the sump during the oil exchange process.
Referring still to
In the present exemplary embodiment, control module 620 detects when the engine has been shut down for a predetermined period of time (e.g., 6-10 seconds). If that period of time has elapsed without the engine being restarted, control module 620 instructs pump 610 to begin pumping oil from supplemental oil tank 602 into the sump of engine 609 via oil hose 612 for another, second, predetermined period of time. When this second predetermined period of time has elapsed, the system waits for a third predetermined period of time to allow the oil within the sump to mix and settle, and then control module 620 instructs pump 610 to reverse and pump oil out of the sump and into the supplemental oil tank 602 via the same oil hose 612 for a fourth predetermined period of time, wherein the fourth predetermined period of time is longer than the second predetermined period of time. In an alternative embodiment, the fourth period of time may be equal to the second period of time. With this configuration, an oil exchange process that allows for extended intervals between general engine service tasks is possible. In another alternative embodiment, control module 620 may include electronics configured to sense the angle of supplemental oil tank 602 and engine 609 and to prevent pump 610 from cycling when the angle is equal to or greater than a predetermined amount. This configuration reduces the potential for under-filling or overfilling the sump of engine 609 due to the angle of the system. The system may further comprise an extended-performance oil filter 624, which allows for these extended intervals.
It should be noted that the movement of oil from the supplemental tank to the engine sump and from the engine sump to the supplemental tank occurs in conjunction. Thus, the order in which the oil is moved is not critical so long as movements in both directions occurs, thereby assuring that the desired level of oil within the oil sump is maintained.
The system described herein is described in use with a lawn mower. However, the system could be employed with virtually any system that includes an oil-lubricated engine and more particularly an oil-lubricated internal combustion engine. For example, stand-by generators (residential and commercial) as well as remote power generators (e.g., cell towers, remote pumping stations, etc.) often employ an oil-lubricated engine and would benefit from use of the system described herein. As such, the invention should not be limited to only lawn mower applications.
Although the present disclosure has been described with reference to example embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the defined subject matter. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. Because the technology of the present disclosure is relatively complex, not all changes in technology are foreseeable. The present disclosure described with reference to the example embodiments and set forth in the following definitions is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the definitions reciting a single particular element also encompass a plurality of such particular elements.
Various features and advantages of the invention are set forth in the following claims.
This application is a continuation of U.S. application Ser. No. 14/453,048 filed Aug. 6, 2014, which claims priority to U.S. Provisional Application No. 61/894,156 filed Oct. 22, 2013, and U.S. Provisional Application No. 61/862,133 filed Aug. 5, 2013, all of which are incorporated herein by reference in their entireties.
Number | Date | Country | |
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61862133 | Aug 2013 | US | |
61894156 | Oct 2013 | US |
Number | Date | Country | |
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Parent | 14453048 | Aug 2014 | US |
Child | 17123854 | US |