Oil Separators

Abstract

An oil separator for trapping oil mist contained in blow-by gas includes a separation plate, an upstream oil-mist trapping chamber, and a downstream oil-mist trapping chamber. The upstream and downstream oil-mist trapping chambers are divided by the separation plate. The upstream oil-mist trapping chamber communicates with a flow inlet for blow-by gas. The downstream oil-mist trapping chamber communicates with the upstream oil-mist trapping chamber and communicates with a flow outlet for blow-by gas. A return port formed through the separation plate returns oil mist trapped in the downstream oil-mist trapping chamber into the upstream oil-mist trapping chamber. The return port is positioned vertically above the bottom surface of the upstream oil-mist trapping chamber and is positioned at substantially the same vertical level as the lowermost portion of the bottom surface of the downstream oil-mist trapping chamber.

What is claimed is: 
     
         1 . An oil separator for trapping oil mist contained in blow-by gas, the oil separator comprising:
 an upstream oil-mist trapping chamber in fluid communication with a flow inlet for blow-by gas;   a downstream oil-mist trapping chamber positioned adjacent to the upstream oil-mist trapping chamber and separated from the upstream oil-mist trapping chamber by a separation plate;   a communication port in fluid communication with the upstream oil-mist trapping chamber and the downstream oil-mist trapping chamber;   a flow outlet configured to allow blow-by gas from the downstream oil-mist trapping chamber to flow outside of the oil separator; and   a return port extending through the separation plate and configured to allow oil mist trapped in the downstream oil-mist trapping chamber to return into the upstream oil-mist trapping chamber;   wherein the return port is positioned above a bottom surface of the upstream oil-mist trapping chamber and is positioned at substantially the same height as a lowermost portion of a bottom surface of the downstream oil-mist trapping chamber.   
     
     
         2 . The oil separator of  claim 1 , wherein the separation plate comprises:
 a wall surface facing opposite to the upstream oil-mist trapping chamber; and   a rib formed on the wall surface proximal the return port, wherein the rib is configured to prevent blow-by gas from flowing from the upstream oil-mist trapping chamber into the downstream oil-mist trapping chamber through the return port.   
     
     
         3 . The oil separator of  claim 2 , wherein the rib has a U-shape configuration and extends along the return port. 
     
     
         4 . The oil separator of  claim 2 , wherein the rib has a U-shape configuration and extends in an arc shape around the return port. 
     
     
         5 . The oil separator of  claim 4 , wherein the arc extends more than 180 degrees about the return port. 
     
     
         6 . An oil separator for trapping oil mist contained in blow-by gas, the oil separator comprising:
 a liquid oil trapping chamber including at least one hole configured to allow liquid oil to exit under the force of gravity;   an upstream oil-mist trapping chamber in fluid communication with the liquid oil trapping chamber;   a downstream oil-mist trapping chamber positioned adjacent to the upstream oil-mist trapping chamber and separated from the upstream oil-mist trapping chamber by a separation plate;   a communication port configured to allow the upstream oil-mist trapping chamber to communicate with the downstream oil-mist trapping chamber;   a flow outlet configured to allow blow-by gas from the downstream oil-mist trapping chamber to flow outside of the oil separator; and   a return port formed through the separation plate and configured to allow oil mist trapped in the downstream oil-mist trapping chamber to return into the upstream oil-mist trapping chamber;   wherein the return port is positioned vertically above a bottom surface of the upstream oil-mist trapping chamber and is positioned at substantially the same vertical level as a lowermost portion of a bottom surface of the downstream oil-mist trapping chamber.   
     
     
         7 . An oil separator for trapping oil mist contained in blow-by gas, the oil separator comprising:
 a liquid oil trapping chamber;   an upstream oil-mist trapping chamber downstream of the liquid oil trapping chamber, wherein the liquid oil trapping chamber is in fluid communication with a flow inlet for blow-by gas from the upstream liquid oil trapping chamber;   a downstream oil-mist trapping chamber positioned adjacent to the upstream oil-mist trapping chamber and separated from the upstream oil-mist trapping chamber by a separation plate;   a communication port configured to allow the upstream oil-mist trapping chamber to communicate with the downstream oil-mist trapping chamber;   a flow outlet configured to allow blow-by gas from the downstream oil-mist trapping chamber to flow outside of the oil separator; and   a return port formed through the separation plate such that the return port allows oil mist trapped in the downstream oil-mist trapping chamber to return into the upstream oil-mist trapping chamber;   wherein the return port is located at a level higher than a bottom surface of the upstream oil-mist trapping chamber and is positioned at substantially the same level as a lowermost portion of a bottom surface of the downstream oil-mist trapping chamber.   
     
     
         8 . The oil separator of  claim 7 , wherein the liquid oil trapping chamber includes two holes formed in a bottom portion thereof, wherein the two holes are configured to allow liquid oil to exit the liquid oil trapping chamber under the force of gravity. 
     
     
         9 . The oil separator  claim 8 , wherein the two holes formed in the bottom portion of the liquid oil trapping chamber are laterally spaced apart. 
     
     
         10 . The oil separator of  claim 9 , wherein a first collision wall extends obliquely and upward from proximal a center of the two holes and forms a barrier for large particle size liquid oil contained in blow-by gas, wherein the first collision wall is made of resin material such that the oil adheres thereto. 
     
     
         11 . The oil separator of  claim 7 , wherein the separation plate includes a wall surface facing opposite to the upstream oil-mist trapping chamber and a rib formed on the wall surface proximal the return port such that the rib prevents blow-by gas from flowing from the upstream oil-mist trapping chamber into the downstream oil-mist trapping chamber through the return port. 
     
     
         12 . The oil separator of  claim 7 , wherein the rib has a U-shape configuration and extends about at least a portion of the return port. 
     
     
         13 . The oil separator of  claim 11 , wherein the rib has a U-shape configuration and extends circumferentially in an arc shape around the return port. 
     
     
         14 . The oil separator of  claim 13 , wherein the arc extends angularly more than 180 degrees about the return port. 
     
     
         15 . The oil separator of  claim 11 , wherein the rib is formed in a V-shape configuration. 
     
     
         16 . The oil separator of  claim 11 , wherein the rib is formed in a horseshoe configuration. 
     
     
         17 . The oil separator of  claim 7 , wherein the liquid oil trapping chamber is positioned adjacent to and immediately below the downstream oil-mist trapping chamber. 
     
     
         18 . The oil separator of  claim 7 , wherein the communication port has a square-shaped void configuration. 
     
     
         19 . The oil separator of  claim 7 , wherein the liquid oil trapping chamber is positioned immediately adjacent to the upstream oil-mist trapping chamber. 
     
     
         20 . The oil separator of  claim 7 , wherein the downstream oil-mist trapping chamber is located laterally adjacent to the upstream oil mist trapping chamber, and wherein the downstream oil-mist trapping chamber is located directly above and adjacent to the liquid oil trapping chamber.