Patent Application
20160333752
The invention relates to a wet oil sump for an engine, in particular for an engine for marine application (or “marine engine”). It also relates to an engine, for example a marine engine, incorporating a sump of the invention.
Oil is used to lubricate the moving parts of an internal combustion engine, and this oil drains towards the bottom of the engine and collects in a reservoir, known as a “sump” (or as an “oil pan” in some countries such as the USA) which is provided at the bottom of the engine. In a “wet” sump an oil feed pipe is provided in the sump having an inlet disposed a short distance above the base of the sump, and oil is then pumped back up to the moving parts of the engine via the oil feed pipe by means of an oil pump provided on the engine. (In an alternative arrangement known as a “dry” sump oil is scavenged from the sump and is held in a separate reservoir, and is pumped to the moving parts of the engine from the reservoir.)
There is increasing interest in the use of un-manned vessels for monitoring a particular location, such as an oil well, a geological fault, exploratory work, surveying or military applications. These vessels may stay on station, follow a predetermined survey area or pattern, or be remotely operated for as long as possible with minimal servicing. However, there are various technical problems associated with such unmanned vessels, particular in the case of unmanned marine vessels.
Unmanned marine vessels may be surface vessels or sub-surface vessels, and so they are subject to wave action while they are in operation at their desired location or surveying an area, and can be subject to extreme pitch and/or roll, or even capsizing, in very bad seas. (As used herein, “pitch” is when a vessel rocks or oscillates about a lateral axis so that the bow of the vessel rises or falls with respect to the stern of the vessel, whereas “roll” is when a vessel rocks or oscillates about its longitudinal axis so that one side of the vessel rises or falls with respect to the other side of the vessel.) It is known to arrange for an engine of a marine vessel to cut out if the pitch or roll of the vessel exceeds a certain angle, in order to reduce the risk of water entering the engine if the vessel pitches or rolls heavily or capsizes. However, if a vessel having an engine with a wet sump pitches or rolls heavily or capsizes, oil can drain from the sump thereby substantially or completely emptying the sump of oil.
This means that, when the vessel rights itself, there can be a delay in re-starting the engine if the rolling of the boat has caused the sump to empty of oil since it is necessary to wait for oil to drain back into the sump so that the level of oil in the sump reaches the inlet of the oil feed pipe. Alternatively there is the risk of damage to the engine if the engine is restarted before the level of oil in the sump reaches the inlet of the oil feed pipe, since the engine would not be correctly lubricated.
A first aspect of the invention provides an engine, comprising: an engine superstructure; and an oil sump for collecting oil from the engine superstructure; wherein at a least a first baffle extending generally horizontally and a second baffle extending generally vertically are provided in the oil sump to reduce displacement of oil contained in the sump as the orientation of the engine varies.
The terms “horizontally” and “vertically” as used herein relate to the engine in its intended orientation, in which the oil sump is located generally vertically below the engine block.
Providing a horizontal baffle in the sump means that oil is retained within the sump even if the engine nearly or completely turns over, and providing the vertical baffle in the sump means that oil is contained within the sump even if the engine, for example, rolls from side to side or pitches from end to end. When the invention is applied to an engine which is arranged to cut out if the pitch or roll exceeds a certain angle, it is possible to reduce the time taken to restart the engine after the engine returns to its normal orientation—oil is retained in the sump by the baffles, and it is not necessary to wait for oil that was lost from the sump when the engine rolled to return to the sump.
A third baffle extending generally vertically may be provided in the oil sump, the third baffle being generally crossed with the second baffle. Providing two vertical baffles, crossed with one another, in the sump means that oil is contained within the sump if the engine rolls from side to side and if the engine pitches from end to end.
An external perimeter of the first baffle may substantially correspond to the internal cross-section of the oil sump, at least one aperture being provided in the first baffle. This prevents, or minimises, leakage of oil between the first baffle and the interior wall of the oil sump, while oil draining from the engine superstructure can pass through the aperture(s) in the baffle into the sump.
At least a portion of the upper surface of the first baffle may inclined downwardly towards the at least one aperture.
A downwardly extending wall may be provided on a lower surface of the first baffle, the wall enclosing the circumference of the at least one aperture. If the vehicle in which the engine is mounted should overturn, or nearly overturn, oil in the sump may leak out of the sump through the aperture(s) in the horizontal baffle—and providing the wall on the lower surface of the horizontal baffle can reduce this leakage.
The second baffle may extend from a first internal face of the sump to an opposite internal face of the oil sump, and the third baffle may extend from a second internal face of the oil sump to an opposite internal face of the oil sump.
The oil sump may comprise a sump base portion and a sump extension portion disposed between the sump base portion and the engine superstructure. Providing the extension portion increases the volume of the sump, and this increases the time that the engine can operate without requiring the oil in the sump to be changed or refilled.
The engine may be a marine engine.
A second aspect of the invention provides a vehicle comprising an engine of the first aspect.
The vehicle may comprise a marine vessel. It may comprise an unmanned marine vessel. It may comprise a remotely-operated marine vessel.
A further aspect of the invention provides a sump for an engine of the first aspect.
Preferred features of the present invention will now be described by way of illustrative example with reference to the accompanying figures, in which:
The engine further comprises a sump 4 mounted on the opposite face of the base plate 3 to the engine superstructure such that, in the intended orientation of the engine, the sump 4 is below the engine superstructure 2. Oil used to lubricate moving parts of the engine superstructure 2 drains towards the bottom of the engine, and collects in the sump 4.
In principle, the present invention could be incorporated in an engine at manufacture. However, supply of engines for use in remotely operated vessels is a relatively small market, and in many cases it is therefore not worthwhile for an engine manufacturer to design and manufacture an engine that is adapted for this specific application. It is therefore likely that, in the majority of cases, the invention will be implemented by modifying an engine that has been manufactured to a conventional engine design—and the invention will therefore be described with reference to an engine that has been modified after manufacture to incorporate the principles of the invention.
The sump is provided with an oil pick-up 9 that, as shown in
It will be understood that correct operation of the engine requires that the oil inlet 10 is below the level of oil in the sump 4—if the inlet is not immersed in the oil held in the sump, oil will not be removed from the sump via the inlet 10 and conduit 11, and the engine will not be lubricated correctly. In many applications of an engine, it is straightforward to ensure that the sump contains sufficient oil for the oil level to cover the inlet 10. However, where the engine is to be used in applications where the orientation of the engine may vary significantly—such as marine applications, for example—it may not be straightforward to ensure a continuous supply of oil to the engine superstructure. Where an engine is mounted in a boat, for example, if the boat rolls or pitches in rough seas, oil held in the sump will be displaced within the sump relative to the inlet 10 and, if the vessel rolls or pitches by a sufficient amount, the oil in the sump may be displaced so much that the inlet 10 is no longer immersed in the oil held in the sump.
A further problem occurs with vessels that are designed with a “self-righting” capability, so as to automatically right themselves after a capsize, such as rescue vessels, manned or unmanned. If such a vessel should capsize the oil will drain out of the sump into the engine superstructure 2, and this will cause a delay in restarting the engine once the vessel has righted itself—after the vessel has righted itself it will be necessary to wait for oil to drain back into the sump before it is safe for the engine to be re-started. This delay in re-starting the engine is undesirable, and potentially dangerous.
Accordingly, the present invention provides one or more vertical baffles 7 and one or more horizontal baffles 8 in the sump to reduce the displacement of oil in the sump that occurs if the vessel rolls or pitches, or even completely overturns and ensure, to the greatest extent possible, that the inlet 10 remains below the oil level even if the vessel in which the engine 1 is mounted should roll or pitch significantly.
It should be understood that the terms “horizontal” and “vertical” in “horizontal baffle” and “vertical baffle” indicate that the baffles extends generally horizontally and generally vertically, respectively, when the engine is in its normal orientation as shown in
The horizontal baffle 8 of
The horizontal baffle 8 of
The horizontal baffle 8 has an exterior perimeter that, as closely as possible, matches the interior profile of the sump extension 5, to prevent, or at least minimise, leakage of oil between the edge of the horizontal baffle and the sump extension 5.
The horizontal baffle(s) can be secured to the sump extension by any suitable technique. As an example, the horizontal baffle may be provided with upturned edge portions 15a-15d that are provided with apertures 21 that, when the horizontal baffle is correctly positioned, align with threaded apertures 22 in the interior wall of the sump extension to allow the horizontal baffle to be secured in position by bolts 28 or other suitable fasteners.
As shown in
In the example of
The baffle plates 16-18 making up the vertical baffle may be arranged to have any desired arrangement, subject to the constraint that the baffle plates must leave a space free to accommodate the oil pick-up 9. In the embodiment of
As noted it is expected that, in the majority of cases, the present invention will be implemented by modifying an engine that has been manufactured as a conventional engine. Where it is required to modify a conventional engine to implement the present invention, the principal steps required would be as follows:
The original sump and oil-pick-up are removed from the engine, and the sump extension 5 is provided. This increases the oil-holding capacity of the sump, and thus extends the length of time that the engine can operate without requiring the lubricating oil to be re-filled/replaced. The sump extension 5 is preferably configured such that it may be fastened to the base plate 3 using the fastenings provided in the base plate for attachment of the original sump, and/or (where the original sump forms the lower sump portion 6 of the modified engine) so that the original sump can be fastened to the sump extension using the fastenings provided on the original sump.
The oil pick-up is assembled from the inlet 10, conduit 11 and extension conduit 12. In one example the inlet 10 and conduit 11 are components of the original engine that are re-used, and this is preferable as it reduces the number of new components needed. It is necessary to extend the length of the oil pick-up 9 by an amount approximately equal to the length of the sump extension, to maintain the inlet 10 in substantially the same position relative to the bottom of the sump—if this were not done the benefit of increasing the volume of the sump by providing the sump extension would be lost. The extension conduit 12 is therefore provided to increase the length of the oil pick-up 9. In this example the conduit 11 terminates in a mounting block 11a that, in the original engine, is used to secure the conduit to the engine baseplate—and in the modified engine the mounting block 11a may be used to secure the conduit and the extension conduit 12 to the engine baseplate, as shown in
The assembled oil pick-up, formed in this example by the inlet 10, the conduit 11, the mounting block 11a and the extension conduit 12, is then mounted in position on the sump extension. In one example the extension conduit 12 is provided with a threaded recess 27, which is used to secure the extension conduit to the sump extension 5 using a fastener 31 such as a bolt.
The vertical baffle 7 is then placed in the sump extension 5, and is secured to the sump extension.
The horizontal baffle is then placed in the sump extension, such that the extension conduit of the oil pick-up passes through the cut-out 14 in the horizontal baffle, and the horizontal baffle is secured to the sump extension.
The conduit 11 is preferably secured to the vertical baffle by a clamp 30, shown in
The sump extension 5 may then be positioned on the engine baseplate 3, and is held temporarily in position. As shown in
The oil pickup assembly is preferably fastened to the engine baseplate as well as to the sump extension. In one advantageous example the extension conduit is provide with through-holes that extend along its length, and that align with the existing fastening holes for the oil conduit in the engine baseplate. The oil pick-up may then be lengthened simply by, after unfastening the mounting block 11a from the engine baseplate, positioning the extension conduit 12 between the engine baseplate and the mounting block 11 a and fastening the mounting block 11a to the engine baseplate using bolts that pass through the through-holes 32 in the extension conduit, thereby also securing the extension conduit 12 in place. This requires no modification to the engine baseplate or to the mounting block, and simply requires the use of new bolts that are longer than the original bolts by approximately the length of the extension conduit.
The lower sump portion 6 (which, as noted, may be the original sump of the engine) is then fastened to the engine. In one advantageous example the sump extension is provide with through-holes that extend along its length, and that align with the existing fastening holes for the sump in the engine baseplate. The lower sump portion (which as noted may be the original sump) is secured to the baseplate of the engine by fasteners (eg bolts) that pass through holes in the flange of the lower sump portion 6, pass through corresponding through-holes of the sump extension 5, and are inserted into the fastening holes for the sump provided in the engine base plate. This requires no modification to the engine baseplate or to the original sump (where this is re-used as the lower sump portion 6), and simply requires the use of new bolts that are longer than the original bolts by approximately the length of the sump extension.
It should be noted that when an engine is modified to increase the time that it can run without maintenance visits, it may be desired to make modifications to the engine superstructure 2 as well as to increase the sump capacity and install the horizontal and vertical baffles of the present invention. The modifications to the engine structure are, however, unrelated to the modifications to the sump, and will therefore not be described further.
An engine of the present invention may be used in a vehicle such as for example, a marine vessel, and may provide particular advantage when used in an unmanned marine vessel. (It should be understood that the term “marine vessel” as used herein is not limited to a sea-going vessel, but also encompasses vessels intended for operation on fresh water.)
The invention has been described above with reference to some examples for illustrative purposes, but the invention is not limited to the examples described above. For example, although the arrangement of baffles shown in the figures is just an example of one possible arrangement, and many other arrangements could be used and still reduce the tendency of oil drain from the sump if the vessel in which the engine is mounted pitches or rolls heavily.
As one example, although the figures shown just one horizontal baffle it would be possible to provide two, or even more, horizontal baffles at different levels in the sump extension or lower sump portion. Preferably each horizontal baffle would extend over generally the entire width and breadth of the sump cross-section and be similar to the present baffle—and in particular would be provided with one or more drainage apertures 13. The spacing between adjacent horizontal baffles would be determined by the number of horizontal baffles, and by the overall depth of the sump extension and lower sump. Use of two or more horizontal baffles would further reduce the flow of oil from the sump when the oil is subjected to movement due to the pitch and/or roll of the vessel in which the engine is mounted. In addition, the apertures in different horizontal baffles could be offset from one another, to further obstruct the flow of oil from the sump if the vessel in which the engine is mounted overturns, or nearly overturns.
As a further example, more vertical baffles than shown in the figures could be provided, and this also would further reduce the flow of oil from the sump if the vessel in which the engine is mounted pitches and/or rolls.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1508403.1 | May 2015 | GB | national |
