Piston with central cooling gallery cooling feature

Abstract

A piston includes an upper crown portion and a lower crown portion with a pair of pin bosses spaced for receipt of a connecting rod. The pin bosses have pin bores aligned with one another along a pin bore axis. The upper crown portion and the lower crown portion form an outer oil gallery and a central oil gallery. The central oil gallery is formed in part by a floor extending radially inwardly from the outer oil gallery to a plateau. To facilitate cooling the central gallery, the plateau has a through opening and the floor has at least one trough depending axially therein. At least one oil flow passage extends in fluid communication between the outer oil gallery and the central oil gallery, wherein at least one oil flow passage is axially aligned with the at least one trough to provide a direct flow of oil to the trough.

1 . A piston, comprising:
 a piston body extending along a central axis along which the piston reciprocates and having an upper crown portion with an upper combustion wall against which combustion forces act and a lower crown portion with a pair of pin bosses spaced for receipt of a small end of a connecting rod therebetween, said pin bosses having pin bores aligned with one another along a pin bore axis, said upper crown portion and said lower crown portion forming an outer oil gallery and a central oil gallery;   said central oil gallery being formed in part by a floor extending radially inwardly from said outer oil gallery to a plateau, said plateau having a through opening and said floor having at least one trough depending axially therein;   at least one oil flow passage extending in fluid communication between said outer oil gallery and said central oil gallery; and   wherein at least one of said at least one oil flow passage is axially aligned with said at least one trough.   
     
     
         2 . The piston of  claim 1  wherein said at least one trough includes a pair of diametrically opposite troughs. 
     
     
         3 . The piston of  claim 2  wherein each one of said pair of troughs has a separate one of said at least one oil flow passage axially aligned therewith. 
     
     
         4 . The piston of  claim 3  wherein said pair of troughs are axially aligned with said pin bore axis. 
     
     
         5 . The piston of  claim 1  wherein said at least one of said at least one oil flow passage is axially spaced from said at least one trough. 
     
     
         6 . The piston of  claim 1  wherein said at least one oil flow passage includes at least one oil flow passage spaced radially from said at least one trough. 
     
     
         7 . The piston of  claim 1  wherein said at least one trough is axially aligned with said pin bore axis. 
     
     
         8 . The piston of  claim 7  wherein said at least one of said at least one oil flow passage is axially aligned with said pin bore axis. 
     
     
         9 . The piston of  claim 1  wherein said at least one trough extends between about 45 to 90 degrees about the central gallery.