DE102018213724A1 - OIL PAN, COMBUSTION ENGINE, VEHICLE AND METHOD - Google Patents

Abstract

An oil pan (103), an internal combustion engine (102), a vehicle (101) and a method are disclosed. The oil pan (103) comprises a container (202) defining a volume (205) for receiving oil (401), the volume (205) having a primary volume (206) for receiving an oil outlet (209), a secondary volume (207 ) and an intermediate volume (208). A first wall (211) separates the primary volume (206) from the intermediate volume (208). The first wall (211) includes a first flow restrictor (214) configured to allow restricted oil flow from the intermediate volume (208) to the primary volume (206). A second wall (212) including a second flow restrictor (216) is arranged to separate the secondary volume (207) from the intermediate volume (208). A refill assembly (219) is configured to direct recirculated oil to the secondary volume (207) and allow overflow of excess recirculated oil into the intermediate volume (208). A first overflow device (217) is positioned to allow overflow of recirculated oil into the primary volume (206).

Description

TECHNICAL AREA

The present disclosure relates to an oil pan, an internal combustion engine, a vehicle, and a method. In particular, but not exclusively, it relates to an oil pan, an internal combustion engine, a vehicle and a method in a vehicle such. B. a road vehicle.

Aspects of the invention relate to an oil pan, an internal combustion engine, a vehicle and a method.

STATE OF THE ART

Oil from an internal combustion engine is repeatedly circulated from a trough to parts of the engine to provide lubrication, among other things. A relatively small amount of oil (for example, 1 liter) could be used to provide the required lubrication, but a larger amount (e.g., 5 liters) is generally used to allow venting of the oil, provide chemical resistance, and allow cooling when the engine is hot.

It takes a relatively long time (typically for 5 liters 30 minutes) to heat all the oil due to heat losses to the engine block as well as surrounding structures and air. A problem with such a long period of time is that the viscosity of the oil is relatively high while it is cold, and therefore the efficiency of the engine is reduced as the oil heats up.

The present invention aims to remedy this problem.

BRIEF SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide an oil pan, an internal combustion engine, a vehicle, and a method according to the appended claims.

According to one aspect of the invention, there is provided an oil pan comprising: a container defining a volume for receiving oil, the volume comprising a primary volume, a secondary volume, and an intermediate volume; a first wall separating the primary volume from the intermediate volume, the first wall including first flow restricting means configured to allow a restricted flow of oil from the intermediate volume to the primary volume; a second wall including a second flow restrictor arranged to separate the secondary volume from the intermediate volume; a first overflow device positioned to allow a first overflow of oil into the primary volume; and a refill assembly configured to direct recirculated oil to the secondary volume and allow overflow of excess recirculated oil into the intermediate volume.

For an internal combustion engine incorporating such an oil pan, this offers the advantage that during an initial period after engine start, only a portion of the oil in the pan is used to lubricate the engine and that oil is heated relatively quickly. This leads to a relatively rapid decrease in the viscosity of the oil and increased efficiency of the engine.

In some embodiments, the first overflow device includes a first overflow wall to allow the first overflow of oil from the intermediate volume via the first overflow wall into the primary volume.

In some embodiments, the refill assembly includes: a second overflow device positioned to allow overflow of excess recycled oil into the intermediate volume; and a first cover wall positioned over the secondary volume, the first cover wall having an outer surface configured to allow the flow of oil falling on the outer surface toward the intermediate volume via the second overflow device. This has the advantage that oil that falls to the secondary volume can be used to fill the intermediate volume and, if the intermediate volume is full, to allow the oil to overflow into the primary volume.

In some embodiments, the first cover wall defines a refill opening to allow oil to flow from the outer surface into the secondary volume. This offers the advantage of a simple arrangement to allow oil falling on the first top wall to be used to fill the secondary volume.

In some embodiments, the second overflow device includes a second overflow wall to allow excess recycled oil to flow into the intermediate volume via the second overflow wall.

In some embodiments, the first overflow device is configured to allow the first overflow of oil when oil within the intermediate volume is above a first level; the refill assembly is configured to overflow excess oil returned to the intermediate volume when the oil within the secondary volume is above a second altitude; wherein the first oil level is equal to the second oil level. This offers the advantage that the oil pressures on each of the sides of the second flow restrictor are equal when the oil flows over the first overflow device and the second overflow device, and therefore there is no oil flow through the second flow restrictor.

In some embodiments, the first flow restriction device comprises: a flap door configured to move from a closed position to an open position at or above a threshold temperature; and / or a screen cloth.

The word "screen mesh" as used in this document refers to a layer of material that defines an array of holes. For example, a mesh fabric may comprise a network of wires or filaments, such as e.g. Polymer fibers, or it may be a substantially continuous layer of material in which an array of holes has been formed, for example in a molding process.

In some embodiments, the first flow restricting device includes a flapper door configured to move from a closed position to an open position at or above a threshold temperature. This provides the advantage of increased flow through the first flow restrictor at a temperature determined by the trapdoor.

In some embodiments, the first flow restriction device comprises a mesh screen. This offers the advantage of a simple and compact design without a moving part, such. B. a door is needed.

In some embodiments, the second flow restricting device comprises: a flap door configured to move from a closed position to an open position at or above a threshold temperature; and / or a screen cloth.

In some embodiments, the second flow restriction device comprises a mesh screen. This offers the advantage of a simple and compact design without a moving part, such. B. a door is needed.

In some embodiments, the oil pan includes a cover extending over a first portion of the intermediate volume and positioned to allow excess oil from the refill assembly to fall onto the cover; and the cover defines at least one hole to allow entry of oil into the first portion of the intermediate volume. This offers the advantage that there is less mixing of hot oil flowing into the intermediate volume via the second overflow device with cold oil arranged below the cover.

In some embodiments, the at least one hole in the cover is dimensioned to provide a first resistance to oil flow at a first threshold temperature; the first flow restrictor of the first wall is dimensioned to provide a second resistance to the oil flow at the first threshold temperature; wherein the second resistance is less than the first resistance. This offers the advantage that the oil level in the intermediate volume drops at the first threshold temperature, which causes oil to flow through the second flow restricting device into the intermediate volume.

In some embodiments, the oil pan comprises a second top wall positioned over the primary volume, the second top wall being arranged to direct oil falling on the second top wall to the first top wall. This has the advantage that all the oil that falls back into the tub from an internal combustion engine can be used to replenish the secondary volume. Therefore, the secondary volume replenishes faster after the engine starts and oil that overflows into the primary volume heats up faster.

In some embodiments, the first top wall includes a trough and the refill opening extends through a tube extending from the trough. This offers the advantage that when the secondary volume is full, hot oil flowing past the refill opening of the intermediate volume exerts less of an effect on the cold standing oil in the secondary volume.

In some embodiments, the secondary volume includes a deflector configured to direct recirculated oil entering the secondary volume away from the second flow restrictor of the second wall. This offers the advantage that cold oil adjacent to the second flow restrictor is less disturbed by the oil entering the secondary volume.

In some embodiments, the first wall surrounds the primary volume and the second wall surrounds the intermediate volume and the first wall.

In some embodiments: the container comprises an outer wall and a plurality of Baffles configured to direct the flow of oil within the container, the plurality of baffles defining a receiving chamber for receiving an oil outlet and a plurality of outer chambers surrounding the receiving chamber.

In some embodiments, at least a portion of each one of the plurality of baffles extends from a corresponding first position adjacent the outer wall to a corresponding second position adjacent the receiving chamber. This offers the advantage that the plurality of baffles allows the flow of oil to the receiving chamber and prevents unwanted splash around of oil within the tub. It also allows air exchange from one room to another within an engine to cause airflows through the receiving chamber that can be used to separate oil droplets from the air.

In some embodiments, the plurality of baffles extend from the second positions about the receiving chamber in the same direction of rotation. This has the advantage that the baffles cause air and oil entering the receiving chamber to be circulated within the receiving chamber to prevent further squirting and assist in the separation of air and oil.

In some embodiments, the plurality of baffles include a first plurality of baffles and a second plurality of baffles, and at least a portion of each one of the plurality of baffles extends around the receiving chamber to provide walls for the receiving chamber. This has the advantage that the baffles cause the oil, which is circulated within the receiving chamber, to be retained within the receiving chamber to prevent further squirting and assist in the separation of air and oil. The second plurality of baffles may also be configured to cause air and oil entering the receiving chamber to flow in the same direction of rotation within the receiving chamber. For example, each one of the second plurality of baffles may be provided with the same direction of rotation to effect the rotational flow within the receiving chamber.

In some embodiments, each one of the second plurality of baffles is different than each one of the first plurality of baffles; and the second plurality of baffles form a ring of laminations surrounding the receiving chamber.

In some embodiments, where the plurality of baffles includes a first plurality of baffles and a second plurality of baffles, the first wall and the second wall intersect each one of the first plurality of baffles.

According to another aspect of the invention, there is provided an internal combustion engine comprising the oil pan of any one of the preceding paragraphs and engine oil.

In some embodiments, at temperatures of the engine oil, the first flow restrictor is configured below a threshold temperature to permit restricted flow of oil at a first flow rate, and the at least one hole defined by the cover is configured to allow an oil flow rate into the first section of the intermediate volume. which is equal to the first flow rate. This offers the advantage that the oil level in the intermediate volume can be kept at the same level as the level in the secondary volume in order to prevent oil leakage through the second flow-limiting device.

In some embodiments, the at least one hole in the cover is configured at temperatures of the engine oil above the threshold temperature to limit an oil flow rate in the first portion of the intermediate volume to a second flow rate, and the first flow restriction is configured to allow an oil flow rate is higher than the second flow rate. This has the advantage that when the oil has reached the threshold temperature, the oil in the intermediate volume may decrease and escape of oil from the secondary volume may be possible. In this way, all the oil can be used when the oil has reached a sufficiently high temperature.

According to another aspect of the invention, there is provided a vehicle comprising an internal combustion engine according to any one of the preceding paragraphs.

According to yet another aspect of the invention, there is provided a method of circulating oil through a trough of an internal combustion engine, wherein the trough comprises a first wall separating a primary volume from an intermediate volume and a second wall separating a secondary volume from the intermediate volume; the method comprising: pumping oil through the primary volume of the tub; Allowing the flow of oil returned from the engine to the secondary volume of the pan; depending on whether the secondary volume is full, Allowing overflow of the recirculated oil into an intermediate volume of the tub to fill the intermediate volume; and allowing overflow of oil into the primary volume, wherein: a rate of oil leakage through the first wall is dependent on the temperature of the oil adjacent the first wall; a rate of oil leakage through the second wall is dependent on the difference in fluid pressure across the second wall; and the method comprises, at temperatures of the oil adjacent the first wall, below a threshold temperature to allow oil to flow into the intermediate volume at a rate that maintains a volume of oil in the intermediate volume sufficient to allow the oil to exit through the second wall to prevent.

This offers the advantage that the second wall can be provided with flow means to allow oil to flow through the wall so that oil within the secondary volume can be used to lubricate the engine but to reach the threshold temperature Outflow through the flow device is prevented by the amount of oil in the intermediate volume is maintained.

In some embodiments, at temperatures above the threshold temperature, the method includes restricting the oil flow rate to the intermediate volume to a restricted flow rate that is lower than the exit rate through the first wall to cause the amount of oil in the intermediate volume to decrease, causing oil exits through the second wall in the intermediate volume. This provides a method that all the oil in the tub can be used when the temperature returned to the tub from the engine has reached a required level.

In some embodiments, the first wall includes a mesh and a viscosity of the oil below the threshold temperature maintains the escape of oil through the mesh at a rate that is below the restricted flow rate.

In some embodiments, the first wall includes a trap door, and the method includes opening the trapdoor by causing the temperature of the oil adjacent the trapdoor to rise above the threshold temperature.

In some embodiments, the second wall includes a mesh to allow it to exit through the second wall in response to a pressure differential across the second wall.

According to yet another aspect of the invention, there is provided an oil pan comprising: a container defining a volume for receiving oil, the volume including a primary volume, a secondary volume, and an intermediate volume; an oil outlet located within the primary volume; a first wall separating the primary volume from the intermediate volume, the first wall including a first flow restrictor configured to allow a restricted flow of oil from the intermediate volume to the primary volume, the first flow restrictor including a first flap door configured to to move from a closed position to an open position at or above a threshold temperature, and / or a screen cloth; a first overflow wall positioned to allow a first overflow of oil from the intermediate volume to the primary volume; a second wall separating the secondary volume from the intermediate volume, the second wall including a second flow restrictor configured to allow restricted flow of oil from the secondary volume to the intermediate volume, the second flow restrictor including a second flap door configured to expand to move from a closed position to an open position at or above a second threshold temperature, and / or a second screen cloth; a refill assembly configured to allow returned oil to keep the secondary volume filled with oil and allow overflow of excess recirculated oil into the intermediate volume.

In yet another aspect of the invention, there is provided an oil pan comprising: a container defining a volume for receiving oil, the volume including a primary volume for receiving an oil outlet, a secondary volume, and an intermediate volume; a first wall separating the primary volume from the intermediate volume, the first wall including first flow restricting means configured to allow a restricted flow of oil from the intermediate volume to the primary volume; a second wall separating the secondary volume from the intermediate volume, the second wall including second flow restricting means configured to allow restricted flow of oil from the secondary volume to the intermediate volume; a refill assembly configured to maintain the secondary volume filled with oil and to allow excess recycled oil to flow into the intermediate volume; and a first overflow device configured to allow overflow of returned oil into the primary volume.

The oil pan can for an internal combustion engine of a vehicle, such. As a road vehicle to be determined.

It is expressly intended, within the scope of this application, that the various aspects, embodiments, examples and alternatives presented in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular, their individual features, be independent of each other or in any combination. This means that all embodiments and / or features of any embodiment can be combined in any manner and / or in any combination, provided that these features are not incompatible. The Applicant reserves the right to change any original claim or submission of any new claim, including the right to change any originally filed claim to depend on and / or integrate any feature of any other claim although it has not been claimed in this way before.

list of figures

• 1 ein Fahrzeug, das einen Verbrennungsmotor umfasst, der eine Ölwanne aufweist, der die vorliegende Erfindung verkörpert;
• 2 eine Draufsicht auf die Ölwanne;
• 3 eine Querschnittsansicht der Ölwanne;
• 4 einen gleichen Ölstand in jedem der drei Volumina der Wanne;
• 5 die Wanne kurz nach dem Motorstart, wenn sich ein Sekundärvolumen und ein Zwischenvolumen mit Öl gefüllt haben;
• 6 die Wanne, wenn sich das Öl im Zwischenvolumen erwärmt hat und die Ölstände im Zwischenvolumen und Sekundärvolumen zu sinken begonnen haben;
• 7 eine perspektivische Ansicht einer alternativen Ölwanne, die die vorliegende Erfindung verkörpert;
• 8 eine Querschnittsansicht einer alternativen Ölwanne von 7;
• 9 die Wanne von 8 mit einer Klapptür in einer geschlossenen Stellung und demselben Ölstand in jedem der drei Volumina;
• 10 die Ölwanne von 8 mit dem Sekundärvolumen und Zwischenvolumen mit Öl gefüllt und überschüssigem Öl, das über eine zweite Überlaufwand und eine erste Überlaufwand in ein Primärvolumen fließt;
• 11 die Wanne von 8 mit einer geöffneten Klapptür, wobei der Stand im Zwischenvolumen ungefähr auf dieselbe Höhe wie der im Primärvolumen abgesenkt ist und das gesamte zurückgeführte Öl in das Sekundärvolumen fließt;
• 12 die Wanne von 8, wenn der Motor abgestellt wurde und sich das Öl in den drei Volumina angleichen kann;
• 13 eine alternative Wanne, die die vorliegende Erfindung verkörpert;
• 14 eine Ausführungsform des Motors von 1, der eine alternativen Ölwanne 103A umfasst;
• 15 eine Draufsicht auf die Wanne von 14 wobei eine obere Wannenwand angebracht ist;
• 16 eine Draufsicht auf die Wanne von 14, wobei die obere Wannenwand entfernt wurde;
• 17 und 18 Ströme zu verschiedenen Zeitpunkten um die Schwallbleche in der Nähe einer Aufnahmekammer der Wanne von 14;
• 19 eine Querschnittsansicht der Wanne von 14;
• 20 den gleichen Ölstand in jedem der drei Volumina innerhalb der Wanne von 14;
• 21 die Wanne von 14 kurz nach dem Motorstart, wenn ein Sekundärvolumen und ein Zwischenvolumen mit Öl gefüllt sind;
• 22 die Ölwanne, wenn der Ölstand im Zwischenvolumen gesunken ist und der Ölstand im Sekundärvolumen zu sinken begonnen hat;
• 23 eine Draufsicht auf eine andere alternative Wanne, die die vorliegende Erfindung verkörpert.

One or more embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

• 1 a vehicle including an internal combustion engine having an oil pan embodying the present invention;
• 2 a plan view of the oil pan;
• 3 a cross-sectional view of the oil pan;
• 4 an equal oil level in each of the three volumes of the pan;
• 5 the tub shortly after engine start, when a secondary volume and an intermediate volume have filled with oil;
• 6 the tub, when the oil in the intermediate volume has warmed up and the oil levels in the intermediate volume and secondary volume have started to decrease;
• 7 a perspective view of an alternative oil pan embodying the present invention;
• 8th a cross-sectional view of an alternative sump of 7 ;
• 9 the tub of 8th with a hinged door in a closed position and the same oil level in each of the three volumes;
• 10 the sump of 8th filled with the secondary volume and intermediate volume with oil and excess oil flowing through a second overflow wall and a first overflow wall into a primary volume;
• 11 the tub of 8th with an open flap door, the level in the intermediate volume being lowered to about the same level as that in the primary volume, and all the returned oil flowing into the secondary volume;
• 12 the tub of 8th when the engine has stopped and the oil in the three volumes can equalize;
• 13 an alternative tub embodying the present invention;
• 14 an embodiment of the engine of 1 who has an alternative oil pan 103A includes;
• 15 a top view of the tub of 14 an upper tub wall being attached;
• 16 a top view of the tub of 14 with the upper tub wall removed;
• 17 and 18 Streams at various times around the baffles near a receiving chamber of the tub of 14 ;
• 19 a cross-sectional view of the tub of 14 ;
• 20 the same oil level in each of the three volumes within the tub of 14 ;
• 21 the tub of 14 shortly after engine start, when a secondary volume and an intermediate volume are filled with oil;
• 22 the oil sump when the oil level in the intermediate volume has dropped and the oil level in the secondary volume has started to decrease;
• 23 a plan view of another alternative trough embodying the present invention.

DETAILED DESCRIPTION

In 1 is a vehicle 101 shown. The vehicle 101 includes an internal combustion engine 102 holding an oil pan 103 having. The internal combustion engine 102 (hereinafter referred to simply as "the engine 102 ") May have a construction which is generally known in the art, with the exception of the oil pan 103 , which will be described in more detail below.

In the present embodiment, the vehicle is 101 a passenger car, but in Alternative embodiments may be the vehicle 101 be another type of road vehicle or other than a road vehicle that includes an internal combustion engine.

2 shows a plan view of the oil pan 103 , and 3 shows a cross-sectional view of the tub 103 through the in 2 pictured level 201 , The oil pan 103 includes a container 202 who has a bottom wall 203 and one from the bottom wall 203 upwardly extending outer wall 204 having. The bottom wall 203 and the outer wall 204 of the container 202 define a volume 205 for absorbing oil (not shown in 2 and 3 ). The volume 205 comprises three volumes: a primary volume 206 ; a secondary volume 207 ; and an intermediate volume 208 , The primary volume 206 suitable for receiving an oil outlet 209 on a pickup tube 210 , or an oil pump, to pump oil from the tub 103 to enable in operation.

A first wall 211 separates the primary volume 206 from the intermediate volume 208 , and a second wall 212 separates the secondary volume 207 from the intermediate volume 208 , A section 213 the first wall 211 may be impermeable to oil, but the first wall 211 comprises a first flow limiting device 214 , which is configured to provide a restricted flow of oil from the intermediate volume 208 to the primary volume 206 to enable. The first flow restricting device 214 is configured to provide a passage for an oil flow from the intermediate volume 208 to the primary volume 206 provide when the oil next to the first flow restrictor 214 is above a first threshold temperature. The first flow restricting device 214 may be configured to allow a slower flow of oil for temperatures below the first threshold temperature.

Similarly, a section 215 the second wall 212 be impermeable to oil, but the second wall 212 includes a second flow restricting device 216 configured to provide a restricted flow of oil from the secondary volume 207 to the intermediate volume 208 to enable. The second flow limiting device 216 is configured to provide a passage for an oil flow from the secondary volume 207 to the intermediate volume 208 provide when the oil next to the second flow restrictor 216 is above a second threshold temperature. The second flow limiting device 216 may be configured to allow a slower flow of oil for temperatures below the second threshold temperature. The second threshold temperature may be identical to the first threshold temperature.

In the first embodiment, the first flow restricting device comprises 214 and the second flow restriction device 216 each a mesh 214A respectively. 216A , Consequently, engine oil is capable of passing through the first and second flow restriction devices 214 and 216 leak when the oil is hot and has a relatively low viscosity and also when it is cold and has a relatively high viscosity. It is understood, however, that the hot oil is capable of doing so more easily through the mesh 214A and 216A to flow when the oil is hot.

In the present embodiment, the holes in the screen fabric 214A and 216A Dimensions of about 0.2 mm; however, in other embodiments, the holes may have dimensions between 0.1mm and 0.5mm.

In alternative embodiments, the first and / or second flow restriction device 214 and 216 one opening in each wall 211 and 212 and a flapper door actuated by a bimetallic strip configured to hold the flapper door in a closed position for temperatures below a threshold temperature and to open the trapdoor above the threshold temperature. The flap doors may allow a relatively slow flow of oil to escape through the corresponding opening when in the closed positions. (An embodiment including a trap door will be described later below with reference to FIG 7 to 12 described.)

The oil pan 103 also includes a first overflow device 217 , which is positioned to provide a first overflow of oil from the intermediate volume 208 into the primary volume 206 allows if the oil is within the intermediate volume 208 is above a predetermined height. The first overflow device 217 includes a first overflow wall 218 to the first overflow of oil from the intermediate volume 208 over the first overflow wall 218 into the primary volume 206 to enable. The first overflow wall 218 can through the first wall 211 provided that is configured to overflow oil over the top of the first wall 211 or through one in the first wall 211 to allow trained opening. In an alternative embodiment, the first overflow wall comprises 218 a wall of a canal extending between the intermediate volume 208 and the primary volume 206 extends. For example, the channel may be provided by an overflow tube. In the embodiment of 2 and 3 includes the first overflow wall 218 one on the first wall 211 fastened element extending from the top of the first wall 211 extends upwards.

During operation of the engine 102 is known to be oil from the tub 103 over the outlet 209 to different parts of the engine 102 pumped. Returned oil falls back into the tub 103 to be reused, and at least a portion of the recirculated oil may fall to the secondary volume as indicated by the arrows 221 displayed. The oil pan 103 but also includes a refill assembly 219 configured to return returned oil to a refill port 220 of the secondary volume 207 to steer and also the overflow of excess recycled oil in the intermediate volume 208 to enable. As the term is used in this document, the term "excess recirculated oil" means oil derived from the engine 102 is returned and available to fill the secondary volume, but that of the secondary volume 207 can not be recorded as it is full.

The refill arrangement 219 includes a second overflow device 222 which is positioned to overflow excess oil returned to the intermediate volume 208 allows. The refill arrangement 219 also includes a first top wall 223 that are above the secondary volume 207 is positioned. The first cover wall 223 has an outer surface 224 on, which runs obliquely to oil, which is on the outside surface 224 falls, to the refill opening 220 and to the intermediate volume 208 via the second overflow device 222 to steer.

In the embodiment of 2 and 3 defines the first top wall 223 an opening 220 that the refill opening 220 provides for the flow of oil from the outside surface 224 into the secondary volume 207 to enable.

The second overflow device 222 includes a second overflow wall 225 to the flow of excess recirculated oil over the second overflow wall 225 into the intermediate volume 208 to enable. Ie. the second overflow wall 225 is arranged to overflow oil into the intermediate volume 208 to allow when the oil level in the secondary volume 207 is at or above a second altitude. In the present embodiment, the second height is substantially at a level with the first height of the first overflow wall 218 but in other embodiments, the first height may be higher than the second height, such that when the intermediate volume is completely filled with oil, the oil levels in the intermediate volume 208 and secondary volume 207 are the same.

In the embodiment of 2 and 3 becomes the second overflow wall 225 provided by an end portion of the first cover wall 223 that is above the second wall 212 is arranged.

In an alternative embodiment, the second wall 212 the second overflow wall 225 configured to overflow oil over the top of the second wall 212 or through one in the second wall 212 to allow trained opening. Alternatively, the second overflow wall 225 comprise a wall of a channel extending between the secondary volume 207 and the intermediate volume 208 extends. For example, the channel may be provided by an overflow tube.

The first cover wall 223 can be shaped to oil from its entire width 226 to the refill opening 220 to direct, and / or, as in 2 and 3 shown, it can be a partition 227 which is higher than the second overflow wall 225 Be provided to prevent oil from entering the exterior surface 224 runs down from the refill opening 220 are far away. Consequently, all the oil must be on the outside surface 224 flows down through the refill opening 220 , or above or next to the refill opening 220 pass before passing over the second overflow wall 225 flows.

The tub 103 can be a second top wall 228 include that from an upper end down over the primary volume 206 , the intermediate volume 208 and part of the first cover wall 223 to a lower end over the first top wall 223 falls off. Thus, during operation, oil falls to the primary volume 206 and to the intermediate volume 208 falls down, on the second top wall 228 and the second cover wall flows 228 on the first cover wall 223 down. In this way, all the oil that goes to the tub 103 is returned to the refill opening 220 be directed. In other embodiments, alternative means may be for directing all of the returned oil back to the first deck 223 to be provided.

Different phases of operation of the oil pan 103 during operation of the engine 102 are in the cross-sectional views of 4 . 5 and 6 shown. In each of the 4 . 5 and 6 The tub contains engine oil 401 , In 4 has the oil 401 in each of the three volumes 206 . 207 and 208 same situation. This situation is given when the engine 102 over a period of time, so that the oil levels in each of the three volumes flowed through the flow restrictors 214 and 216 could match.

If the engine 102 is started for the first time and oil 401 from the primary volume 206 is pumped, the oil level in the primary volume decreases 206 , At this stage is the oil 401 cold and relatively viscous, and the flow through the mesh 214A and 216A is limited to a relatively low Flow rate compared to the rate at which the oil 401 from the primary volume 206 is pumped. That from the primary volume 206 pumped oil 401 lubricates the engine 102 , but eventually falls back to the tub 103 where at least a portion of the returning oil is on the first top wall 223 falls.

The returned oil 401 flows on the outer surface 224 the first cover wall 223 to the intermediate volume 208 down. Initially, however, the recirculated oil drips through the refill opening 220 and starts the secondary volume 207 to fill. If the secondary volume 207 is full and the oil level 401 the upper edge of the second overflow wall 225 has reached, the oil flows over the second overflow wall 225 and starts the intermediate volume 208 to fill. When the intermediate volume is full and the oil level 401 in the intermediate volume 208 the upper edge of the first overflow wall 218 has reached, the oil flows over the first overflow wall 218 and returns to the primary volume 206 back. This situation is in 5 shown.

Thus, in 5 the secondary volume 207 and the intermediate volume 208 completely with oil 401 filled and the oil level in the primary volume 206 is compared to the original in 4 dropped booth. A first share 501 (represented by a dashed outline) of the primary volume 206 extracted oil 401 represents the oil used to control the secondary volume 207 and the intermediate volume 208 fill. A second share 502 (represented by a dashed outline) of the primary volume 206 extracted oil 401 represents the oil around the wetted areas of the engine 102 got stuck around.

Typically, the in 5 displayed state within 15 to 40 seconds after starting the engine 102 achieved while the oil 401 is still relatively cold. From this point, additional returned oil flows to the first top wall 223 generally falls over the second overflow wall 225 and the first overflow wall 218 back to the primary volume 206 , While the engine 102 is running, that is in the engine 102 circulated and to the primary volume 206 recycled oil 401 through the engine 102 warmed up, but the oil 401 in the secondary volume 207 and intermediate volume 208 stays relatively still and cold. Because only the relatively small amount of oil 401 in the primary volume 206 repeated in the engine at this stage 103 is circulated, reaches the oil 401 in the primary volume 206 faster higher temperatures than it would if the entire oil 401 in the engine 103 is circulated. Consequently, the viscosity of the oil decreases 401 That's to lubricate the engine 102 is used faster than it would be if all the oil 401 would be circulated, and so the efficiency of the engine increases 102 similarly faster.

Because the first overflow wall 218 and the second overflow wall 225 extend to about the same height, are the oil levels 401 in the secondary volume 207 and intermediate volume 208 substantially equal in height, and there is no difference in the pressure of the oil from one side of the second flow restrictor 216 to the other side. Consequently, no oil occurs 401 from the secondary volume 207 towards the intermediate volume 208 through the second flow restriction device 216 out.

If the intermediate volume 208 for the first time with oil 401 is filled, the oil is in the intermediate volume 208 relatively cold and has a high viscosity. Consequently, the oil passes only slowly through the first mesh 214A out, and so only a relatively small amount of cold oil from the intermediate volume 208 under the relatively hot oil in the primary volume 206 mixed. It should be noted that while almost all the oil 401 that over the second overflow wall 225 flows, even over the first overflow wall 218 into the primary volume 206 flows, a share of the oil that flows through the second overflow wall 225 flows, the intermediate volume 208 fills to its oil on the same level as that of the secondary volume 207 to keep.

The temperature of the oil in the intermediate volume 208 rises slowly due to transmission through the first wall 211 and the first flow restricting device 214 and also because of the small amounts of hot oil that are used to make up the intermediate volume 208 fill. As the temperature of the oil increases, its viscosity decreases 401 in the intermediate volume 208 and the rate of oil leakage through the mesh 214A increases. Consequently, the proportion of the second overflow wall increases 225 flowing oil, which is used to the intermediate volume 208 refill while over the first overflow wall 218 flowing portion becomes smaller until the rate of passing through the first sieve cloth 214A flowing oil is greater than the rate of the second overflow wall 225 flowing oil. When that happens, the oil level starts 401 in the intermediate volume 208 to sink and no more oil flows over the first overflow wall 218 ,

In an alternative embodiment, a baffle or cover 503 (in 5 represented by a dashed outline) provided by a lower first portion 504 of the intermediate volume 208 extends. A hole 506 makes a passage between one second share 505 of the intermediate volume 208 ready, which is above the cover 503 of the first share 504 located. The hole 506 is provided to allow oil from the second fraction 505 of the intermediate volume 208 on the cover 503 runs down to the initial filling of the intermediate volume 208 to enable. The hole 506 can in the cover 503 be formed or it can be between the cover 503 and the first wall 211 be provided as in 5 shown, or it may be between the cover 503 and the second wall 212 to be provided.

If the intermediate volume 208 is full, as in 5 shown, prevents the cover 503 that is the hot oil 401 that over the second overflow wall 225 flows, with the relatively cold oil 401 in the first share 504 of the intermediate volume 208 mixed. Consequently, the oil can 401 in the relatively small second section 505 of the intermediate volume 208 be heated while the oil is in the first section 504 next to the mesh 214A warmed up more slowly. Consequently, the presence of the baffle or the cover 503 the period from starting the engine 102 until the time when the stand in the intermediate volume 208 begins to sink, lengthen.

When the oil level 401 in the intermediate volume 208 below the level in the secondary volume 207 decreases, a pressure difference across the second screen fabric 216A generated, which causes the oil 401 from the secondary volume 207 through the second mesh 216A into the intermediate volume 208 begins to flow. Oil in the secondary volume 207 is filled up with hot oil, which is the first top wall 223 down and through the refill opening 220 flows.

When the flow rate of oil 401 through the second mesh 216A greater than the rate at which the oil is the secondary volume 207 refills, the oil level starts 401 in the secondary volume 207 to sink. 6 shows the oil pan 103 in this phase, in which the oil level 401 in the intermediate volume 208 has dropped and consequently the oil level 401 in the secondary volume 207 started to sink. From this point in time, essentially the entire falls to the first top wall 223 recycled oil 401 through the refill opening 220 into the secondary volume 207 , and oil 401 flows through the second mesh 216A and the first mesh 214A to the primary volume 206 where it is above the outlet 209 is circulated again. Thus, then the entire oil 401 in the oil pan 103 to lubricate the engine 102 used.

If the engine 102 is turned off, oil flows 401 back to the tub 103 and the oil levels in the three volumes 206 . 207 and 208 match up, leaving the tub 103 again as in 4 shown looks like.

By the above description, it should be understood that: the operation of the tub 103 It allows for a relatively small portion of the oil 401 the engine 102 smears when the engine 102 is turned on for the first time so that the oil used in this phase 401 faster higher temperatures achieved and the efficiency of the engine is improved; ultimately all the oil used and in the engine 102 is circulated; and that in the primary volume 206 existing proportion of the oil 401 at the end of the plant is not the same proportion of the oil as it is in the primary volume 206 was available at the start of operation.

An alternative oil pan 103 for the engine 102 is in a perspective view in 7 and in a cross-sectional view in FIG 8th shown. The oil pan 103 from 7 and 8th has many of the same features as the sump 103 from 2 to 6 on, and features, the two tubs 103 are common, were named the same. Thus, the oil pan of 7 and 8th a container 202 that is a volume 205 defined for receiving oil (not shown in 2 and 3 ). The volume 205 comprises three volumes: a primary volume 206 ; a secondary volume 207 ; and an intermediate volume 208 , The primary volume 206 suitable for receiving an oil outlet 209 (shown in 8th ) on a pickup tube 210 , or an oil pump, to pump oil from the tub 103 to enable in operation.

A first wall 211 separates the primary volume 206 from the intermediate volume 208 , and a second wall 212 separates the secondary volume 207 from the intermediate volume 208 , The first wall 211 comprises a first flow limiting device 214 , which is configured to provide a restricted flow of oil from the intermediate volume 208 to the primary volume 206 to enable. The first flow restricting device 214 is different from that of 2 and 3 to the effect that they have a hinged door 214B instead of a screen cloth. The hinged door 214B includes an actuator configured to cause the door to remain closed at temperatures up to a first threshold temperature and to open when the temperature rises above the first threshold temperature. In the present embodiment, the trap door 214B operated by a bimetallic strip. The bimetallic strip may be of a type typically manufactured for electrical safety shutdowns or thermostats.

The hinged door 214B may be configured to allow some oil leakage when closed, but to allow much greater flow when open.

The second wall 212 includes a second flow restricting device 216 configured to provide a restricted flow of oil from the secondary volume 207 to the intermediate volume 208 to enable. The second flow limiting device 216 is configured to provide a passage for an oil flow from the secondary volume 207 to the intermediate volume 208 provide when the oil next to the second flow restrictor 216 is above a second threshold temperature. The second flow limiting device 216 may be configured to allow a slower flow of oil for temperatures below the second threshold temperature. The second threshold temperature may be identical to the first threshold temperature. In the present embodiment, the second flow restricting device comprises 216 a mesh 216A like that of 2 and 3 ,

The oil pan 103 also includes a first overflow device 217 , which is positioned to provide a first overflow of oil from the intermediate volume 208 into the primary volume 206 allows when the oil is within the intermediate volume above a predetermined level. In the present embodiment, the first wall presents 211 the function of the first overflow device 217 ready. Ie. if the intermediate volume 208 is full, oil can over the first wall 211 into the primary volume 206 to run.

The oil pan 103 from 7 and 8th also includes a refill assembly 219 , which is configured to return returned oil to two refill ports 220 of the secondary volume 207 to steer and also the overflow of excess recycled oil in the intermediate volume 208 to enable. The refill arrangement 219 includes a second overflow device 222 which is positioned to overflow excess oil returned to the intermediate volume 208 allows. The refill arrangement 219 also includes a first top wall 223 that are above the secondary volume 207 is positioned, and the one outer surface 224 which runs obliquely to oil that is on the outside surface 224 falls, to the intermediate volume 208 via the second overflow device 222 to steer.

In the embodiment of 7 and 8th is a hollow 802 to the lower end of the first top wall 223 positioned and the refill openings 220 each include a bore of a tube 803 that rises from the bottom of the hollow 802 extends downwards. A deflection device 804 that includes a baffle is below the ends of the tubes 803 positioned and configured to exit the tubes 803 flowing oil off the screen cloth 216A to steer.

The second overflow device 222 includes a second overflow wall 225 to the flow of excess recirculated oil over the second overflow wall 225 into the intermediate volume 208 to enable. In the embodiment of 7 and 8th becomes the second overflow wall 225 through a side wall of the trough 802 provided.

The first cover wall 223 comes with an upwardly extending vent tube 805 provided with a vent near its topmost end 806 having. The vent pipe 805 is provided to ensure that during filling with oil air from the secondary volume 207 can escape.

The oil pan 103 from 7 and 8th also includes a cover 801 that a first section 504 of the intermediate volume 208 covers. The cover 801 defines two holes 807 extending from a second section 505 of the intermediate volume 208 , which is above the cover 801 located to the first section 504 extend. The holes 807 are sized to the oil flow rate in the first section 504 of the intermediate volume 208 so limit that holes 807 for temperatures above the threshold temperature provide a higher resistance to the flow of oil than the first flow restrictor 214 , Ie. if the flap door 214B open, it is configured to have less resistance to the flow of oil into the primary volume 206 to provide than that of the holes 807 provided resistance to the current.

The oil pan 103 from 7 and 8th can be provided with a second top wall, as described above with respect to 3 described second top wall 228 ,

Different phases of operation of the oil pan 103 from 7 and 8th during operation of the engine 102 are in the cross-sectional views of 9 . 10 . 11 and 12 shown. In each of the 9 . 10 . 11 and 12 contains the tub 103 Engine oil 401 , In 9 is the flap door 214B in the closed position and the oil 401 has in each of the three volumes 206 . 207 and 208 same situation. This situation is given when the engine 102 was switched off over a period of time, so that the oil levels in each of the three volumes 206 . 207 and 208 by flowing through the hinged door 214B and the mesh 216A could match. To compensate it can come while the oil 401 is hot and the flap door 214B is open. Alternatively, for example when the engine 102 previously used only for a very short period of time and the flap door 214B not opened, it can be compensated by leakage Oil past the hinged door 214B come in their closed position.

If the engine 102 is started for the first time, is via the pick-up tube 210 oil 401 from the primary volume 206 pumped to the engine 102 to lubricate. Recycled oil 401 that on the first top wall 223 falls, the first cover wall flows 223 down and into the second volume 207 over the hollow 802 and the refill openings 220 until the secondary volume 207 is full. If the second volume 207 is full, contain the refill openings 220 (ie the holes in the pipes 803 ) and the hollow 802 also oil 401 , If the secondary volume 207 is full, the oil starts 401 , over the second overflow wall 225 on the in the intermediate volume 208 arranged cover 801 to flow, and begin, the intermediate volume 208 to fill. If the intermediate volume 208 is full, the oil is flowing 401 then over the first wall 218 into the primary volume 206 ,

From this point on most of the oil returns 401 that of the primary volume 206 around the engine 102 pumped and to the first cover wall 223 is returned, over the first and the second overflow wall 218 and 225 to the primary volume 206 back. Consequently, the relatively small amount of oil heats up 401 around the engine 102 is pumped quickly, while the oil 401 in the secondary volume 207 and intermediate volume 208 stops cold and still.

The oil pan 103 is in 10 with the oil 401 filled secondary volume 207 and intermediate volume 208 and with excess oil, which has a second overflow wall 225 and a first overflow wall 218 into a primary volume 206 flows, shown. The oil level 401 in the secondary volume 207 is essentially the same as the level in the intermediate volume 208 , Therefore, there is essentially no pressure difference from one side of the mesh 216A to the other side and no flow of oil through the mesh 216A ,

Due to the fact that the closed flap door 214B No perfect seal can be provided if the intermediate volume 208 is full, some oil 401 from the intermediate volume 208 past the hinged door 214B into the primary volume 206 escape. The intermediate volume 208 However, one of the second overflow wall 225 flowing proportion of the oil 401 refilled. The holes 807 in the cover 801 are sufficiently large to allow a flow rate that is at least as high as the rate with the oil on the closed trapdoor 214B passes by, and so does the intermediate volume 208 kept filled up.

When the tub 103 in the state as in 10 can be shown, to the tub 103 returning hot oil with the small amounts of oil in the trough 802 and the second section 505 of the intermediate volume 208 be mixed. The larger amount of oil in the secondary volume 207 remains cold and relatively undisturbed by the returning oil. Likewise, a relatively small amount of heated oil flows through the holes 807 in the cover 801 to the first section 504 of the intermediate volume 208 to pass the closed flap door 214B replace escaping oil. In contrast, oil is in the primary volume 206 the tub 103 repeated through the pickup tube 210 pumped and used to lubricate the engine 102 used while the engine is warming up. As a result, the oil heats up 401 in the primary volume 206 That's to lubricate the engine 102 is used relatively quickly, and similarly, its viscosity decreases relatively quickly.

If the engine 102 and the oil 401 in the primary volume 206 get hot enough, reaches the trapdoor 214B a threshold temperature at which it is moved to its open position. This leads to an increased oil flow rate of the intermediate volume 208 through the hinged door 214B into the primary volume 206 , The holes 807 in the cover 801 are dimensioned so that they have a higher resistance to the oil flow rate than the open hinged door 214B provide, and so the amount of oil in the intermediate volume 208 begins to sink. While the amount of oil in the intermediate volume 208 decreases, a pressure difference occurs over the screen cloth 216A away, which causes the cold oil in the secondary volume 207 through the mesh 216A into the intermediate volume 208 flows. The current through the mesh 216A causes the level in the secondary volume 207 sinks, and so flows from the first top wall 223 returning hot oil into the secondary volume 207 instead of the second overflow wall 225 to flow.

In an alternative embodiment, the cover 801 provided with one or more vent tubes, extending from the general level of the cover 801 extend up to the level above the level local to the oil 401 is reached. The vent tubes allow the escape of air from the second volume 207 while oil 401 flows into the second volume.

The tub 103 is in 11 with the hinged door open 214B represented, wherein the state in the intermediate volume 208 about the same height as the one in the primary volume 206 is lowered and all the returned oil 401 into the secondary volume 207 flows. From this point, returned oil flows through the secondary volume 207 , the mesh fabric 216A to the intermediate volume 208 , and the hinged door 214B to the primary volume 206 , and therefore, the entire oil 401 to lubricate the engine 102 used.

If the engine 102 turned off, the oil can in the three volumes 206 . 207 and 208 match, as in 12 shown. If the oil 401 has cooled sufficiently, the hinged door closes 214B and the tub returns to the in 9 displayed state back.

Another alternative tub 103 embodying the present invention is in operation in 13 shown. The tub 103 from 13 is identical to that with reference to 7-12 except that the hinged door 214B through a mesh 214A which is a flow restrictor 214 between the intermediate volume 208 and the primary volume 206 provides. In this embodiment, when the oil 401 is relatively cold, are the holes 807 in the cover 801 big enough for the flow of oil 401 through it at a rate equal to the flow through the mesh 214A is to allow, and so can the intermediate volume 208 be kept filled, as in 13 shown. If the oil 401 next to the mesh 214A however, when it reaches a threshold temperature, the flow rate through the screen mesh becomes 214A higher than the ones from the holes 807 in the cover 801 is enabled, and so the oil level drops 401 in the intermediate volume 208 ,

In the embodiments described above, this becomes the first top wall 223 recycled oil 401 to the intermediate volume 208 steered and the oil flows from the intermediate volume into the primary volume 207 above. In an alternative embodiment, oil is used 401 However, by a relatively high wall permanently prevented from the intermediate volume 208 into the primary volume 206 overflowing. A first overflow wall is placed between the first top wall 223 and the primary volume 206 provided, and a second overflow wall 225 will be between the first top wall 223 and the intermediate volume 208 provided. The first overflow wall is higher than the second overflow wall 225 , and so will the intermediate volume 208 and the secondary volume 207 filled up to the height of the first overflow wall and then excess oil flows into the primary volume 206 ,

An embodiment of the engine 102 that an alternative oil pan 103A is in the somewhat schematic view of 14 shown. In the present embodiment, the engine includes 102 four cylinders 1402 each of which has a corresponding piston 1403 contains. Thus, cylinder contains 1402A a piston 1403A , Cylinder 1402B contains a piston 1403B , Cylinder 1402C contains a piston 1403C , and cylinders 1402D contains a piston 1403D , Every cylinder 1402 defined together with its corresponding piston 1403 a combustion chamber.

Each of the pistons 1403 is through a corresponding connecting rod 1405 with a crankshaft 1404 connected. The crankshaft 1404 is inside a crankcase 1401 and is supported by front and rear main bearings as well as by intermediate bearings, which are inside the inner walls 1406 are arranged, which the space within the crankcase 1401 in four separate rooms 1407 divide. During operation of the engine 102 contain the rooms 1407 Air released by blow-by gases escaping from the combustion chambers and lubricating the moving parts of the engine 102 used oil droplets is contaminated. For the purposes of the present specification, the mixture of air, blow-by gases and oil droplets will be referred to simply as "air".

The interior of the tub 103A is from the rooms 1407 through an upper marsh wall 1420 the tub 103A , which is an end wall of the rooms 1407 provides, separately.

During operation of the engine 102 causes the pendulum movement of the piston 1402 that the volume of each of the rooms 1407 repeatedly changes. To get a compression of the air inside the rooms 1407 To avoid, passages can be between adjacent rooms 1407 through the inner walls 1406 to be provided. However, in the present embodiment, breathing from one room to another is via the oil sump 103A through in the upper marsh wall 1420 the tub 103A trained slots 1408 provided. One or more slots 1408 be in the upper tub wall 1420 at the bottom of each one of the rooms 1407 provided. Ie. in the present embodiment, in which the engine has four spaces 1407 have one or more slots 1408A at the end of a first room 1407A positioned one or more slots 1408b are at the end of a second room 1407B positioned one or more slots 1408C are at the end of a third room 1407C positioned, and one or more slots 1408D are at the end of a fourth room 1407D positioned.

During operation, the pistons become 1403A and 1403D lowered, reducing the volume of the first room 1407A and the fourth room 1407D is reduced, and the pistons 1403B and 1403C are raised at the same time, increasing the volume of the second room 1407B and the third room 1407C is enlarged. This causes air to pass through the first slot (s) 1408A and the fourth slots 1408D is pressed and thus air from the first and the fourth room, 1407A and 1407D , in the tub 103A and out through the the second slot (s) 1408b and the third slot (s) 1408C in the second and the third room, 1407B and 1407C , can escape. Subsequently, the pistons 1403B and 1403C lowered, thereby increasing the volume of the second room 1407B and the third room 1407C downsized, and the pistons 1403A and 1403D are raised simultaneously, increasing the volume of the first room 1407A and the fourth room 1407D enlarged, air is through the second slot (s) 1408b and the third slot (s) 1408C pressed and can thus from the second and the third room, 1407B and 1407C , in the tub 103A and out through the first slot (s) 1408A and the fourth slot (s) 1408D in the first and the fourth room, 1407A and 1407D , escape.

In this way, there is air between the rooms 1407 forward and back through the tub 103A pumped. The tub 103A includes baffles 1421 and 1422 (schematically in 14 Illustrated) configured to cause that through the pan 103A pumped air takes a tortuous path that causes a separation of the oil droplets from the air in which they are held.

A top view of the tub 103A with mounted upper tub wall 1420 is in 15 shown, and a plan view of the tub 103A with degraded upper tub wall 1420 is in 16 shown. For the sake of clarity, some features became inside the tub 103A at the top view of 15 omitted. The positions of the interior walls 1406 of the motor 102 are indicated by dashed lines in 15 illustrated.

In the embodiment of 15 becomes a slot 1408 in the upper tub wall 1420 at the bottom of each one of the four rooms 1407 provided. In alternative embodiments, multiple slots 1408 for each of the rooms 1407 provided.

The oil pan 103A includes a first plurality of baffles 1421 that have a corresponding number of outer chambers 1501 define. A first baffle 1421A separates a first outer chamber 1501A the tub 103A from a fourth outer chamber 1501D the tub 103A ; a second baffle 1421B separates the second outer chamber 1501A from a second outer chamber 1501B the tub 103A ; a third baffle 1421C separates the second outer chamber 1501B from a third outer chamber 1501C the tub 103A ; and a fourth baffle 1421 D separates the third outer chamber 1501C from the fourth outer chamber 1501D ,

Each of the baffles 1421 extends inwardly from a corresponding first position 1502 next to the outer wall 204 the tub 103A to a second position 1503 next to a receiving chamber 1504 that have an oil outlet 1505 a pickup tube 1506 contains. A gap 1507 is between the second positions 1503 of juxtaposed baffles 1421 provided, in operation, oil flow from the outer chambers 1501 to the receiving chamber 1504 to enable.

In the embodiment of 15 includes the oil pan 103A also a second variety of baffles 1422 that differ from the first variety of baffles 1421 different. The second variety of baffles 1422 is in the form of a ring of lamellae lying on a curve extending across the column 1507 between the second positions 1503 the first baffles 1421 extends to walls for the receiving chamber 1504 provide. The second variety of baffles 1422 separates each of the columns 1507 in several (in this embodiment 6 ) Slots. The baffles 1422 are at an angle to the curve on which they lie, so that the width of the sipe from an outer edge to an inner edge in the same direction of rotation around the receiving chamber 1504 extends. Thus, the baffles cause 1422 in operation, that's out of every single one of the outer chambers 1501 in the receiving chamber 1504 flowing fluid in the same direction of rotation around the receiving chamber 1504 flows around.

In the present embodiment, the second plurality of baffles 1422 24 Baffles arranged to each of the four columns 1507 to separate into six slots. In alternative embodiments, however, other amounts of baffles become 1422 provided. For example, in alternative embodiments, there is only one baffle 1422 in each of the gaps between adjacent ones of the first plurality of baffles 1421 positioned. For example, in one embodiment, the tub has four of the first baffles 1421 and four of the second baffles 1422 on.

In the embodiment of 15 can be any outer chamber 1501 a (oil droplets containing) air flow from the rooms 1407 of the motor 102 via a corresponding slot 1408 receive. The slots 1408 are inside the upper tub wall 1420 positioned so that every outer chamber 1501 Air from a corresponding one of the rooms 1407 receives. In the present embodiment, the second outer chamber receives 1501B Air over the first slots 1408A from the first room 1407A ; the third chamber 1501C receives air through the second slots 1408b from the second room 1407B ; the first outer chamber 1501A receives air through the third slots 1408C from the third room 1407C ; and the fourth outer chamber 1501 D receives air through the fourth slots 1408D from the fourth room 1407D ,

During operation of the engine 102 gets oil from the tub 103A through the pickup tube 1506 over the outlet 1505 in the receiving chamber 1504 pumped. Consequently, oil flows from the outer chambers 1501 through the column 1507 in the receiving chamber 1504 , The second variety of baffles 1422 causes in the receiving chamber 1504 incoming oil in a clockwise direction around the receiving chamber 1504 flows, causing a continuous movement of the oil within the receiving chamber 1504 clockwise.

A share of the in the receiving chamber 1504 Entering oil may be in the form of foam floating on top of the bulk of the oil. The flow of oil within the receiving chamber 1504 clockwise has a centrifugal effect in that the denser component of the foam, ie the oil, is forced towards the outside of the stream where it joins the bulk of the oil and the lighter component, ie air, to the center of the oil receiving chamber 1504 is pushed. Thus, the circular flow of oil within the receiving chamber assists 1504 the elimination of air from the oil before it gets to the engine 102 pumped around.

When the pistons 1403A and 1403D (shown in 14 ), air is released from the rooms 1407A and 1407D through the slots 1408A and 1408D in the outer chambers 1501B and 205D the oil pan 103A pressed. At the same time, air gets into the rooms 1407B and 1407C from the outer chambers 1501C and 205A drawn. Consequently, air is passing through the receiving chamber 1504 pumped, as in 17 illustrates the flows around the baffles 1421 and 1422 near the receiving chamber 1504 shows. Specifically, air containing oil droplets is introduced into the receiving chamber 1504 from the outer chamber 1510B through the slots between the baffles 1422 pressed between the baffles 1421 Federation 1421C Air is also in the receiving chamber 1504 from the outer chamber 1501 D between the baffles 1421A and 1421D pressed. At the same time, air is released from the receiving chamber 1504 in the outer chambers 1501A and 1501C drawn. The air flows into the receiving chamber 1504 from the outer chambers 1501B and 1501 D are relatively focused and have a direction that is essentially clockwise around the receiving chamber 1504 flows. In contrast, from the outer chambers 1501A and 1501C incoming air from the receiving chamber 1504 drafted over a wider range of angles. Consequently, the net flow of the air mass flows within the receiving chamber 1504 in a clockwise direction, as indicated by the circular arrows 1701 is shown.

In addition, the relatively high inertia of the air in the receiving chamber causes 1504 Suspended oil droplets tend to get the oil droplets on a path past the slots between the baffles 1422 move on and inside the receiving chamber 1504 remain. Consequently, the out of the receiving chamber 1504 in the outer chambers 1501 and 1501C pulled air relatively free of oil compared to in the receiving chamber 1504 from the outer chambers 1501B and 1501 D entering air.

Similarly, air is released when the pistons 1403B and 1403C (shown in 14 ) are lowered from the rooms 1407A and 1407C through the slots 1408b and 1408C in the outer chambers 1501C and 1501A (shown in 15 ) of the oil pan 103A pressed. At the same time, air is released from the outer chambers 1501B and 1501D in the rooms 1407A and 1407D pulled while the pistons 1403A and 1403D be raised. Consequently, air is passing through the receiving chamber 1504 as in 18 shown pumped. Specifically, air containing oil droplets is introduced into the receiving chamber 1504 from the outer chamber 1501A through the slots between the baffles 1422 pressed between the baffles 1421A and 1421B Air is also in the receiving chamber 1504 from the outer chamber 1501C between the baffles 1421C and 1421D pressed.

At the same time, air is released from the receiving chamber 1504 in the outer chambers 1501B and 1501D drawn. The air flows into the receiving chamber 1504 from the outer chambers 1501A and 1501C Enter, are relatively focused and have a direction that is essentially clockwise around the receiving chamber 1504 flows. In contrast, from the outer chambers 1501B and 1501D incoming air from the receiving chamber 1504 drafted over a wider range of angles. Consequently, the net flow of the air mass flows within the receiving chamber 1504 in a clockwise direction, as indicated by the circular arrows 1701 is shown.

Since the net air flow within the receiving chamber 1504 for both the upstrokes and downstrokes of each piston 1403 Moved in a clockwise direction, those in the inside of the receiving chamber 1504 Circulating air suspended oil droplets reach high speeds and their impulse tends to urge them outward to the surrounding wall of the receiving chamber 1504 out through the baffles 1422 provided. With the baffles 1422 colliding oil droplets, other oil droplets or the bulk of the oil within the receiving chamber 1504 can combine with other droplets or the bulk of the oil. As the oil droplets are forced outward and removed from the circulating air, the air becomes the center of the receiving chamber 1504 also relatively free of oil droplets.

Another feature of the oil pan 103A is in 16 illustrated. Like the oil pans 103 from 2 to 13 includes the oil pan 103Avon 15 and 16 a first wall 211 that is a primary volume 206 from an intermediate volume 208 separates, and a second wall 212 that has a secondary volume 207 from the intermediate volume 208 separates. In the present embodiment, the first wall extends 211 however, by the amount of the primary volume 206 that the baffles 1422 and the receiving chamber 1504 contains. Similarly, the second wall extends 212 around the outside of the intermediate volume 208 that is about the primary volume 206 extends. The secondary volume 207 extends around the outside of the second wall 212 ,

The first wall 211 and the second wall 212 are through the baffles in four sections 1421 divided. The baffles 1421 also share the secondary volume 207 in four parts and divide the intermediate volume 208 in four parts. Consequently, each of the outer chambers becomes 1501 through the first wall 211 and the second wall 212 in a first part, which is part of the primary chamber 206 is, a second part, the part of the intermediate volume 208 is, and a third part, the part of the secondary volume 207 is, disconnected.

A somewhat schematic cross-sectional view of the tub 103A is in 19 represented the first wall 211 and the second wall 212 within the outer regions 1501 and 1501C shows. In the present embodiment, the entire first wall 211 and the second wall 212 formed from a screen fabric material. The second wall 212 includes two layers 1901 and 1902 of mesh with a second intermediate volume 1903 between the two layers. The secondary volume 207 has a first top wall 1904 on, which is also formed of a mesh. The first cover wall 1904 has a concave outer surface 1905 up, stretching up to a high section 1906 towards a second overflow device 222 to build. The first cover wall 1904 and the second overflow device 222 make a refill arrangement 219 which is configured to allow the flow of recirculated oil through the holes in the first top wall 1904 forming sieve in the second volume 207 to allow and also the overflow of excess recycled oil in the intermediate volume 208 to enable.

A cover 1907 is about a lower first section 1908 of the intermediate volume 208 provided. The cover 1907 is also formed of a mesh, and the cover has a concave outer surface 1909 which slopes upwards to a high section 1910 runs, the first overflow device 217 forms. The concave outer surface 1909 the cover 1907 defines a second section 1911 of the intermediate volume 208 which temporarily contains oil during operation, as described below.

In the embodiment of 19 are the first wall 211 , both layers 1901 and 1902 the second wall 212 , the first top wall 1904 and the cover 1907 in each of the outer chambers 1501 formed from a single web of screen fabric material which is pressed into a mold to those features 211 . 212 . 1904 and 1907 provide. During operation of the oil pan 103A can oil between the secondary volume 207 and the intermediate volume 208 , and between the intermediate volume 208 and the primary volume 206 through the openings formed in the screen fabric material. So this is the first wall 211 forming screen fabric material and that the second wall 212 forming Siebgewebematerial a first flow limiting device 214 or a second flow limiting device 216 ready.

It should be understood that the first wall 211 , the second wall 212 , the first top wall 1904 and the cover 1907 in the outer chamber 1501A from the first baffle 1421A to the second baffle plate 1421B extend. Similarly, the first wall extend 211 , the two layers 1901 and 1902 the second wall 212 , the first top wall 1904 and the cover 1907 in the other outer chambers 1501 between the two baffles 1421 that those outer chambers 1501 define.

The screen fabric material that features 211 . 212 . 1904 and 1907 can be formed of interwoven metal wires that are sufficiently rigid to fit the in 16 and 19 to maintain the illustrated shape. Alternatively, the screen cloth material may be formed of polymer fibers. In some embodiments, the mesh fabric may be carried by a polymeric frame molded to the mesh fabric in the required shape such that the mesh fabric extends between portions of the frame. In alternative embodiments, each of the outer chambers contains 1501 instead of the first top wall 1904 and the cover 1907 comprising screen fabric material, a structure similar to that described with reference to 2 to 6 or 7 to 13 illustrated and described structure is similar.

The baffles 1421 Can be integral with the container 202 be educated. For example, the container 202 and the baffles 1421 be formed of a composite material or a metal alloy in a single molding process.

As described above, via the slots 1408 in the upper tub wall 1420 in the tub 103A blown and drawn from her air, that air from the outer chambers 1501 in the receiving chamber 1504 blown and out of the receiving chamber 1504 in the outer chambers 1501 is pulled. Due to the presence of the first top wall 1904 and the cover 1907 the air generally enters the receiving chamber 1504 from an elevated position above the first overflow device 217 one.

In the present embodiment, the tub includes 103A an air deflector 1912 extending from the upper tub wall 1420 in addition to the second plurality of baffles 1422 extends downwards. The air deflection device 1912 can be part of the upper tub wall 1420 or component of an element comprising the lamellar ring, ie baffles 1422 , be. The air deflection device 1912 includes a curved surface 1913 , which is configured to deflect air downwards as it leaves the outer chambers 1501 in the receiving chamber 1504 flows. Consequently, during operation of the engine 102 airborne oil droplets entering the receiving chamber 1504 be registered, down to the main amount of the oil in the receiving chamber 1504 spun. If, however, air from the receiving chamber 1505 in an outer chamber 1501 Air is drawn from a height range of the receiving chamber 1504 pulled, including the upper end of the receiving chamber 1504 where the concentration of airborne oil droplets is relatively low. This therefore provides a different mechanism to effect that out of the receiving chamber 1504 drawn air is cleaner than the air blown in it.

The oil pan 103A is in operation in 20 . 21 and 22 shown. In each of the 20 to 22 The tub contains engine oil 401 , In 20 has the oil 401 in each of the three volumes 206 . 207 and 208 same situation. This situation is given when the engine 102 over a period of time, so that the oil levels in each of the three volumes flowed through the first wall 211 and the second wall 212 could match.

If the engine 102 is started for the first time and oil 401 over the outlet 1505 and the recording tube 1506 from the primary volume 206 is pumped, the oil level in the primary volume decreases 206 , At this stage is the oil 401 cold and relatively viscous, and the current through the first wall 211 and second wall 212 is limited to a relatively low flow rate compared to the rate at which the oil 401 from the primary volume 206 is pumped. That from the primary volume 206 pumped oil 401 lubricates the engine 102 , but eventually falls back to the tub 103A where at least a portion of the returning oil through the slots 1408 flows and on the first top wall 1904 lands.

In this phase, the returned oil flows 401 through the openings of the mesh fabric, which is the first cover wall 1904 forms and starts the secondary volume 207 to fill. If the secondary volume 207 is full and the oil level 401 the top of the high section 1906 the first cover wall 1904 that the second overflow device 222 has reached, the oil flows through the second overflow device 222 and falls on the cover 1907 , In this phase, this flows onto the cover 1907 falling oil 401 through the holes in the mesh that covers the cover 1907 forms, and begins the intermediate volume 208 to fill.

While filling the secondary volume 207 and the intermediate volume 208 fills the relatively small second intermediate volume 1903 in the second wall 212 also with oil 401 ,

If the intermediate volume 208 is full and the oil level 401 in the intermediate volume 208 the top of the high section 1910 the cover 1907 that the first overflow device 217 forms, the oil flows through the first overflow device 217 and returns to the primary volume 206 back. This situation is in 21 shown.

In 21 are the secondary volume 207 and the intermediate volume 208 completely with oil 401 filled and the oil level in the primary volume 206 is compared to the original in 20 dropped booth. From the date on which the oil 401 over the first overflow device 217 begins to run, lands additional oil returned to the first top wall 1904 falls down, on oil, which is above the first top wall 1904 is located, and flows over into the intermediate volume 208 , The oil that is above the first top wall 1904 Therefore, the oil can warm up, but the oil below the first top wall 1904 is not affected and stays cold. The oil that is above the intermediate volume 208 flows, flows over the cover 1907 and in the primary chamber 206 where it is in the engine 102 over the pickup tube 1506 can be circulated.

While the engine 102 is running, that is in the engine 102 circulated and to the primary volume 206 recycled oil 401 through the engine 102 heated but the oil 401 in the secondary volume 207 and intermediate volume 208 stays relatively still and cold. Because only the relatively small amount of oil 401 in the primary volume 206 repeated in the engine at this stage 103 is circulated, reaches the oil 401 in the primary volume 206 faster higher temperatures than it would if the entire oil 401 in the engine 103 is circulated. Consequently, the viscosity of the oil decreases 401 That's to lubricate the engine 102 is used faster than it would be if all the oil 401 would be circulated, and so the efficiency of the engine increases 102 similarly faster.

Since the first overflow device 217 and the second overflow device 222 extend to about the same height, are the oil levels 401 in the secondary volume 207 and in the intermediate volume 208 essentially the same height, and there is no difference in the pressure of the oil from one side of the second wall 212 to the other side. Consequently, no oil occurs 401 from the secondary volume 207 towards the intermediate volume 208 through the mesh fabric layers 1901 and 1902 out, which is the second wall 212 form.

If the intermediate volume 208 for the first time with oil 401 is filled, the oil is in the intermediate volume 208 relatively cold and has a high viscosity. Consequently, oil can pass through the first wall 211 escape, but only slowly. Almost all the oil 401 that via the second overflow device 222 flows, also flows through the first overflow device 217 into the primary volume 206 but a smaller portion of the oil passes through the second overflow device 222 flows, fills the intermediate volume 208 to its oil on the same level as that of the secondary volume 207 to keep.

While the oil pan 103A is in this state, if the engine 102 temporarily stopped, for example, for a minute at a traffic intersection, oil continues slowly through the first wall 211 leak, and as a result, the oil level in the intermediate volume 208 begin to sink. A pressure difference is therefore over the first layer 1901 the second wall 212 and, as a result, oil begins to flow through the first layer 1901 withdraw. This in turn causes a pressure difference across the second layer 1902 the second wall 212 occurs, and oil from the secondary volume 207 into the second intermediate volume 1903 the second wall 212 begins to withdraw. Due to the high viscosity of the cold oil in the secondary volume 207 However, only a relatively low exit rate occurs. It is understood that the pressure differences across each layer 1901 and 1902 the second wall will be smaller compared to a similar arrangement having only a screen mesh layer.

During operation of the engine 102 the temperature of the oil in the intermediate volume increases 208 due to the transmission through the first wall 211 and also because of the small amounts of hot oil used to make up the intermediate volume 208 replenish slowly. As its temperature rises, the viscosity of the oil decreases 401 in the intermediate volume 208 and the rate of oil leakage through the first wall 211 increases. Consequently, the overflow over the second overflow device 222 flowing proportion of oil used to make up the intermediate volume 208 replenish larger while the portion passing over the first overflow device 217 flows, gets smaller.

The mesh that covers the cover 1907 forms, limits the rate with which oil 401 in the first section 1908 of the intermediate volume 208 can flow. When the oil flow rate through the first wall 211 greater than the oil flow rate through the cover 1907 , the oil level starts 401 in the first part 1908 of the intermediate volume 208 to sink. This causes a pressure difference across the second wall 212 away, that causes the oil 401 from the secondary volume 207 through the second wall 212 into the intermediate volume 208 begins to flow. Oil in the secondary volume 207 is then mixed with hot oil, which passes through the first top wall 1904 forming screen fabric flows, filled.

When the flow rate of oil 401 through the second wall 212 greater than the rate at which the oil is the secondary volume 207 refills, the oil level starts 401 in the secondary volume 207 to sink. 22 shows the oil pan 103A in this phase, in which the oil level 401 in the intermediate volume 208 has dropped and consequently the oil level 401 in the secondary volume 207 started to sink. From this point on, the largest part of the first cover wall falls 1904 recycled oil 401 through the first cover wall 1904 forming sieve tissue in the secondary volume 207 , and oil 401 flows through the second wall 212 and the first wall 211 to the primary volume 206 where it is above the outlet 209 is circulated again. Thus, then the entire oil 401 in the oil pan 103A to lubricate the engine 102 used.

If the engine 102 for a longer period of time, oil flows 401 back to the tub 103A and the oil levels in the three volumes 206 . 207 and 208 Align themselves so that the tub 103A again in the in 20 shown state.

In an alternative embodiment, the oil pan has a first wall surrounding a primary volume and a second wall surrounding the first wall such that the intermediate volume surrounds the primary volume and the secondary volume surrounds the intermediate volume in a similar manner as at the oil pan 103 from 15 to 22 , However, in the alternative embodiment, the tub does not become with baffles 1421 and 1422 as with reference to 15 to 22 described provided.

Another alternative sink 103A embodying the present invention is in the plan view of 23 shown. The tub 103A from 23 is similar to that of 15 to 22 , except for the configuration of its baffles 1421 and the lack of baffles 1422 in the form of the receiving chamber 206 surrounding slats.

The tub 103A from 23 has four baffles 1421 on that are inward from a corresponding first position 1502 , next to the outer wall 204 the tub 103A , to a corresponding second position 1503 , next to the receiving chamber 206 , extend. A gap 2302 is between every baffle 1421 and an end 2303 an adjacent baffle plate 1421 provided. Each of the column 2302 allows an oil flow from a corresponding outer chamber 1501 to the receiving chamber 1504 along a baffle plate 1421 that is at the gap 2302 extends past. For example, the oil from the outer chamber 1501 D through the gap 2302 between the baffle 1421D and the end 2303 the baffle plate 1421A and in the receiving chamber 1504 along the baffle plate 1421D flow. Each of the baffles 1421 has an end portion 2301 up, moving from his second position 1503 around the receiving chamber 206 extends, which causes oil to enter the receiving chamber 206 occurs during operation within the receiving chamber 206 is circulated. In the present embodiment, the end portions extend 2301 along a curve, but in an alternative embodiment, the end portions are straight.

The end sections 2301 the baffles 1421 all extend in the same direction of rotation from the second positions 1503 around the receiving chamber 1504 , In the present example, the end sections extend 2301 all clockwise around the receiving chamber 1504 to an end 2303 the baffle plate 1421 , Consequently, the baffles cause 1421 that oil that enters the receiving chamber 1504 from each of the outer chambers 1501 flows in the same direction of rotation (ie, clockwise in this embodiment) around the receiving chamber 1504 flow. In addition, it causes through the tub 103A by breathing air pumped from room to room, as with reference to 14 to 18 described, in the same direction of rotation (that clockwise in this embodiment) circulated.

The tub 103A from 23 has a first wall 211 , a second wall 212 , a first cover wall 1904 and a cover 1907 like the one above with regard to the tub 103A from 15 to 22 described on.

In the above-described embodiments of 15 to 23 includes the tub 103A : four baffles 1421 extending inward from the outside wall 204 to the receiving chamber 206 extend; and a corresponding number (ie, four) outer chambers 1501 , In some alternative embodiments, the tub includes 103A but only three such baffles 1421 while the trough in other embodiments has more than four such baffles 1421 includes. For example, in one embodiment, the tub has the engine 102 has six cylinders, six baffles 1421 which define six outer regions.

Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be understood that changes may be made to the examples given without departing from the scope of the invention as claimed in the appended claims.

Features described in the foregoing description may be used in combinations that differ from the expressly described combinations.

Although functions have been described with reference to certain features, these functions are executable by other functions, whether described or not.

Although features have been described with reference to particular embodiments, these features may be present in other embodiments as well, whether described or not.

While it has been attempted in the foregoing specification to draw attention to those features of the invention which have been believed to be particularly important, it should be understood that applicant claims protection with respect to each patentable feature or patentable combination of features referred to above and / or illustrated in the drawings, regardless of whether or not they have been given particular significance.

Claims (15)

Oil pan, comprising: a container defining a volume for receiving oil, the volume comprising a primary volume, a secondary volume and an intermediate volume; a first wall separating the primary volume from the intermediate volume, the first wall including first flow restricting means configured to allow a restricted flow of oil from the intermediate volume to the primary volume; a second wall separating the secondary volume from the intermediate volume and including a second flow restrictor configured to allow restricted flow of oil from the secondary volume to the intermediate volume; a first overflow device positioned to allow a first overflow of oil into the primary volume; a refill assembly configured to direct recirculated oil to the secondary volume and allow overflow of excess recirculated oil into the intermediate volume; and an oil outlet for pumping oil from the primary volume to an internal combustion engine. Oil pan after Claim 1 wherein the first overflow device comprises a first overflow wall to allow the first overflow of oil from the intermediate volume via the first overflow wall into the primary volume. Oil pan after Claim 1 or Claim 2 wherein the refill assembly comprises: second overflow means positioned to allow overflow of excess recirculated oil from the refill assembly into the intermediate volume; and a first cover wall positioned to cover the second volume, the first cover wall having an outer surface configured to allow the flow of oil falling on the outer surface toward the intermediate volume via the second overflow device , Oil pan after Claim 3 wherein the first cover wall defines at least one opening to allow the flow of oil from the outer surface into the secondary volume. Oil pan after Claim 3 or Claim 4 wherein the second overflow device comprises a second overflow wall to allow the flow of excess recycled oil into the intermediate volume via the second overflow wall. Oil pan after one of the Claims 1 to 5 wherein: the first overflow device is configured to allow the first overflow of oil when oil within the intermediate volume is above a first level; the refill assembly is configured to allow overflow of excess recirculated oil into the intermediate volume when the oil within the secondary volume is above a second level; and the second oil level is equal to or higher than the first oil level. Oil pan after one of the Claims 1 to 6 wherein the first flow restricting means comprises a flap door configured to move from a closed position to an open position at or above a threshold temperature. Oil pan after one of the Claims 1 to 7 wherein one or both of the first flow restricting means and the second flow restricting means comprises a screen cloth. Oil pan after one of the Claims 1 to 8th wherein the second flow restriction device comprises: a flap door configured to move from a closed position to an open position at or above a threshold temperature. Oil pan after one of the Claims 1 to 9 wherein: the oil pan includes a cover extending over a first portion of the intermediate volume and positioned to allow excess oil from the refill assembly to fall onto the cover; and the cover defines at least one hole to allow oil to enter the first portion of the intermediate volume. Oil pan after Claim 10 wherein: the at least one hole in the cover is dimensioned to provide a first resistance to oil flow at an operating temperature; the first flow restricting means of the first wall is dimensioned to provide a second resistance to the flow of oil at an operating temperature; and the second resistor is less than the first resistor. Oil pan after one of the Claims 3 to 11 wherein the oil pan comprises a second top wall positioned over the primary volume, the second top wall being arranged to direct, in use, oil falling on the second top wall onto the first top wall. Oil pan after one of the Claims 1 to 12 , in which: the container comprises an outer wall and a plurality of baffles configured to direct the flow of oil within the container, the plurality of baffles defining a receiving chamber for receiving an oil outlet and a plurality of outer chambers surrounding the receiving chamber. Vehicle having an oil pan after one of the Claims 1 to 13 includes. A method of circulating oil through a trough of an internal combustion engine, the trough comprising a first wall separating a primary volume from an intermediate volume and a second wall separating a secondary volume from the intermediate volume, the method comprising: Pumping oil from the primary volume of the tub; Allowing the flow of oil returned from the engine to the secondary volume of the pan; depending on whether the secondary volume is full, allowing overflow of returned oil into an intermediate volume of the tub to fill the intermediate volume; and Allowing overflow of oil into the primary volume, wherein: an oil leakage rate through the first wall depends on the temperature of the oil adjacent the first wall; an oil leakage rate through the second wall depends on the difference in fluid pressure across the second wall; and the method comprises, at temperatures of the oil adjacent to the first wall, below a threshold temperature to allow oil to flow into the intermediate volume at a rate that maintains a volume of oil in the intermediate volume sufficient to allow the oil to exit through the second wall to prevent.

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