Oil separator

Abstract

The present disclosure relates to a device for separating oil from crankcase blow-by gases such as gases that leak past the piston rings of an internal combustion engine, from the combustion chambers into the crankcase, and also to a method of separating oil from such crankcase blow-by gases.

1 . A device for separating oil from crankcase blow-by gases, the device comprising:
 a housing;   an inlet arranged to admit the blow-by gases into the housing;   a first outlet arranged to permit oil separated from the blow-by-gases to exit the housing;   a second outlet arranged to permit gases having an oil content lower than that of the admitted blow-by-gases to exit the housing; and   a passageway in the housing, the passageway having a first end proximate to the inlet, and a second end distal from the first end and proximate to the second outlet;   wherein the passageway comprises a plurality of baffles, successive ones of at least some of the baffles extending from alternate ones of first and second walls of the passageway, towards a respective other one of the first and second walls, the baffles being angled at least partly against a direction of flow within the passageway, said direction being from the inlet to the second outlet.   
     
     
         2 . The device of  claim 1  wherein each baffle extends between a base of the housing and a roof of the housing. 
     
     
         3 . The device of  claim 1  wherein the device is arranged to be mounted between cylinder banks in a V-configuration engine. 
     
     
         4 . The device of  claim 3 , wherein at least one of the inlet and first outlet are located in the base of the housing. 
     
     
         5 . The device of any preceding claim wherein the second outlet is positioned closer to the roof than to the base. 
     
     
         6 . The device of any preceding claim wherein the passageway comprises sequentially arranged first and second portions. 
     
     
         7 . The device of  claim 6 , wherein the first and second portions are at least partially separated by a weir comprising a dam and a roof. 
     
     
         8 . The device of  claim 7  wherein the weir is arranged to impart swirl to the flow of gases within the passageway. 
     
     
         9 . The device of any of  claims 7  to  8 , wherein the weir comprises a drain hole at the interface between the weir and the base, arranged to allow separated oil to pass therethrough. 
     
     
         10 . The device of any of  claims 6  to  9  wherein the second portion has a different cross-sectional area than the first portion. 
     
     
         11 . The device of  claim 10  wherein the second portion has a larger cross-sectional area than the first portion. 
     
     
         12 . The device of any of  claims 10  to  11  wherein the difference in the cross-sectional area between the first and second portions is achieved by providing for the width of the passageway between the first and second walls in the first portion to be correspondingly different to the width of the passageway between the first and second walls in the second portion. 
     
     
         13 . The device of any of  claims 6  to  12  wherein the second portion is arranged to provoke greater changes of direction in the gases flowing through that portion than in the first portion. 
     
     
         14 . The device of  claim 13 , wherein the greater changes of direction are provoked by virtue of at least one of: the longitudinal spacing of the baffles being shorter; the angles of the baffles with respect to the walls being more exaggerated; the distance between the tips of the baffles and their respective opposing wall being altered. 
     
     
         15 . The device of any of  claims 6  to  14  wherein the passageway is generally arranged in a U shape, and the first portion and the second portion form respective first and second parts of the U shape. 
     
     
         16 . The device of any preceding claim wherein a tip of each baffle forms a pinch point with the adjacent opposing one of the first and second walls. 
     
     
         17 . The device of any preceding claim wherein the base comprises an oil drain channel for conveying separated oil to the first outlet. 
     
     
         18 . The device of  claim 17  wherein the oil drain channel slopes downwards so as to assist conveyance of the separated oil to the first outlet by gravitational action. 
     
     
         19 . The device of any preceding claim wherein the roof comprises at least one portion that slopes downwards to encourage oil droplets that have accumulated on the roof to be returned to the base by gravitational action. 
     
     
         20 . The device of any preceding claim, wherein at least one of the pinch points is preceded in the passageway by a gas redirection feature. 
     
     
         21 . A motor vehicle, such as a motor car, which includes a device as specified in any of the preceding claims. 
     
     
         22 . A method of separating oil from crankcase blow-by gases, the method comprising:
 admitting blow-by gases into a passageway in a housing via an inlet, the passageway having a first end proximate to the inlet, a first outlet, and a second end distal from the first end and proximate to a second outlet;   passing the blow-by-gases past a plurality of baffles disposed in the passageway, successive ones of at least some of the baffles extending from alternate ones of the first and second walls of the passageway, towards a respective other one of the first and second walls, the baffles being angled at least partly against a direction of flow within the passageway, said direction being from the inlet to the second outlet, such that oil is separated from the blow-by-gases;   permitting oil separated from the blow-by-gases to exit the housing via the first outlet; and   permitting gases having an oil content lower than that of the admitted blow-by-gases to exit the housing via the second outlet.