Oil sump, an internal combustion engine, a vehicle and a method

Abstract

An oil sump, an internal combustion engine, a vehicle and a method are disclosed. The oil sump comprises a container defining a volume for containing oil in which the volume comprises a primary volume for containing an oil outlet, a secondary volume and an intermediate volume. A first wall divides the primary volume from the intermediate volume. The first wall comprises a first restricted flow means configured to enable a restricted flow of oil from the intermediate volume to the primary volume. A second wall comprising a second restricted flow means is arranged to divide the secondary volume from the intermediate volume. A top-up arrangement is configured to direct returned oil to the secondary volume and enable excess returned oil to overflow into the intermediate volume. A first weir means is positioned to enable an overflow of returned oil into the primary volume.

1 . An oil sump comprising:
 a container defining a volume for containing oil, the volume comprising a primary volume, a secondary volume and an intermediate volume;   a first wall dividing the primary volume from the intermediate volume, the first wall comprising a first restricted flow means configured to enable a restricted flow of oil from the intermediate volume to the primary volume;   a second wall dividing the secondary volume from the intermediate volume comprising a second restricted flow means configured to enable a restricted flow of oil from the secondary volume to the intermediate volume;   a first weir means positioned to enable a first overflow of oil into the primary volume;   a top-up arrangement configured to direct returned oil to the secondary volume and enable excess returned oil to overflow into the intermediate volume; and   an oil outlet for pumping oil from the primary volume to an internal combustion engine.   
     
     
         2 . The oil sump of  claim 1 , wherein the first weir means comprises a first weir wall for allowing the first overflow of oil to flow from the intermediate volume over the first weir wall into the primary volume. 
     
     
         3 . The oil sump of  claim 1 , wherein
 the first weir means is configured to enable the first overflow of oil when oil within the intermediate volume is above a first height;   the top-up arrangement is configured to enable the excess returned oil to overflow into the intermediate volume when oil within the secondary volume is above a second height; and   the second height of oil is equal to or higher than the first height of oil.   
     
     
         4 . The oil sump of  claim 1 , wherein the first restricted flow means comprises a trap door configured to move from a closed position to an open position at, or above, a threshold temperature. 
     
     
         5 . The oil sump of  claim 1 , wherein one or both of the first restricted flow means and the second restricted flow means comprises a mesh. 
     
     
         6 . The oil sump of  claim 1 , wherein the second restricted flow means comprises: a trap door configured to move from a closed position to an open position at, or above, a threshold temperature. 
     
     
         7 . The oil sump of  claim 1 , further including a cover extending over a first portion of the intermediate volume and positioned to enable the excess returned oil from the top-up arrangement to fall onto the cover; wherein the cover defines at least one hole to enable oil to enter the first portion of the intermediate volume. 
     
     
         8 . The oil sump of  claim 7 , wherein
 the at least one hole of the cover is dimensioned to provide a first resistance to flow of oil at an operational temperature;   the first restricted flow means of the first wall is dimensioned to provide a second resistance to flow of oil at the operational temperature; and   the second resistance is lower than the first resistance.   
     
     
         9 . The oil sump of  claim 1 , wherein the secondary volume contains a deflection means configured to deflect returned oil entering the secondary volume away from the second restricted flow means of the second wall. 
     
     
         10 . The oil sump of  claim 1 , wherein the first wall surrounds the primary volume and the second wall surrounds the intermediate volume and the first wall. 
     
     
         11 . The oil sump of  claim 1 , wherein:
 the container comprises an outer wall and a plurality of baffles configured to direct flow of oil within the container, the plurality of baffles defining a pickup chamber for containing an oil outlet and a plurality of outer chambers surrounding the pickup chamber.   
     
     
         12 . The oil sump of  claim 11 , wherein at least a portion of each one of the plurality of baffles extends from a respective first position adjacent to the outer wall to a respective second position adjacent to the pickup chamber. 
     
     
         13 . The oil sump of  claim 12 , wherein the plurality of baffles extend from the respective second positions around the pickup chamber in the same rotational direction. 
     
     
         14 . The oil sump of  claim 1 , wherein the top-up arrangement comprises:
 a second weir means positioned to enable the excess returned oil to overflow from the top-up arrangement into the intermediate volume; and   a first cover wall positioned to cover the secondary volume, the first cover wall having an outer surface configured to enable oil falling on the outer surface to flow towards the intermediate volume via the second weir means.   
     
     
         15 . The oil sump of  claim 14 , wherein the first cover wall defines at least one opening to enable oil to flow from the outer surface into the secondary volume. 
     
     
         16 . The oil sump of  claim 14 , wherein the second weir means comprises a second weir wall for allowing the excess returned oil to flow over the second weir wall into the intermediate volume. 
     
     
         17 . The oil sump of  claim 14 , wherein the oil sump comprises a second cover wall positioned over the primary volume, the second cover wall being arranged to direct oil falling on the second cover wall onto the first cover wall. 
     
     
         18 . The oil sump of  claim 14 , wherein the first cover wall comprises a trough, and an opening extends through a tube extending from the trough. 
     
     
         19 . A vehicle comprising the oil sump of  claim 1 . 
     
     
         20 . A method of circulating oil through a sump of an internal combustion engine, the sump comprising a first wall dividing a primary volume from an intermediate volume and a second wall dividing a secondary volume from the intermediate volume, the method comprising:
 pumping oil from the primary volume of the sump;   allowing oil returned from the internal combustion engine to flow into the secondary volume of the sump;   in dependence on the secondary volume being full, allowing returned oil to overflow into the intermediate volume of the sump to fill the intermediate volume;   allowing oil to overflow into the primary volume wherein a first rate of oil leakage through the first wall depends on a temperature of oil neighboring the first wall and a second rate of oil leakage through the second wall depends on a difference in fluid pressure across the second wall; and   at temperatures of the oil neighboring the first wall that are below a threshold temperature, allowing oil to flow into the intermediate volume at a rate that maintains a volume of oil in the intermediate volume sufficient to resist leakage of oil through the second wall.