Rocker shaft with diamond-like carbon coating

Abstract

A rocker shaft for a valve train of an internal combustion engine, including: a substantially cylindrical outer circumferential surface; and a layer of amorphous hydrocarbon deposited on the substantially cylindrical outer circumferential surface. The rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft. A method of forming rocker shaft for a valve train of an internal combustion engine, including: forming a substantially cylindrical outer circumferential surface; and depositing a layer of amorphous hydrocarbon on the substantially cylindrical outer circumferential surface. The rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft.

1 . A rocker shaft for a valve train of an internal combustion engine, comprising:
 a substantially cylindrical outer circumferential surface; and,   a layer of amorphous hydrocarbon deposited on the substantially cylindrical outer circumferential surface, wherein:
 the rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft. 
   
     
     
         2 . The rocker shaft of  claim 1  wherein the amorphous hydrocarbon includes:
 metal-free amorphous hydrocarbon. 
 
     
     
         3 . The rocker shaft of  claim 1 , wherein the amorphous hydrocarbon includes:
 metal-free amorphous hydrocarbon with sp 2  and sp 3  hybridized carbon.   
     
     
         4 . The rocker shaft of  claim 1 , wherein the rocker shaft includes a channel for flowing pressurized oil. 
     
     
         5 . The rocker shaft of  claim 1 , wherein the rocker shaft is free of a channel for flowing pressurized oil. 
     
     
         6 . A rocker shaft assembly for a valve train of an internal combustion engine, comprising:
 a rocker shaft including:
 a substantially cylindrical outer circumferential surface; and, 
 a layer of metal-free amorphous hydrocarbon deposited on the substantially cylindrical outer circumferential surface; and, a rocker arm: 
 radially disposed about the substantially cylindrical outer circumferential surface; 
 in contact with the layer of amorphous hydrocarbon; and, 
 at least partially rotatable about the rocker shaft. 
   
     
     
         7 . The rocker shaft assembly of  claim 6 , wherein the amorphous hydrocarbon includes metal-free amorphous hydrocarbon. 
     
     
         8 . The rocker shaft assembly of  claim 6 , wherein the metal-free amorphous hydrocarbon includes metal-free amorphous hydrocarbon with sp 2  and sp 3  hybridized carbon. 
     
     
         9 . The rocker shaft of  claim 6 , wherein rocker shaft includes a channel for flowing pressurized oil to the rocker arm. 
     
     
         10 . The rocker shaft of  claim 6 , wherein the rocker shaft is free of a channel for flowing pressurized oil. 
     
     
         11 . A method of forming rocker shaft for a valve train of an internal combustion engine, comprising:
 forming a substantially cylindrical outer circumferential surface; and,   depositing a layer of amorphous hydrocarbon on the substantially cylindrical outer circumferential surface, wherein:
 the rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft. 
   
     
     
         12 . The method of  claim 11 , wherein the amorphous hydrocarbon includes:
 metal-free amorphous hydrocarbon.   
     
     
         13 . The method of  claim 11  wherein the amorphous hydrocarbon includes:
 metal-free amorphous hydrocarbon with sp 2  and sp 3  hybridized carbon. 
 
     
     
         14 . The method of  claim 11 , further comprising:
 forming a channel in the rocker shaft for flowing pressurized oil.   
     
     
         15 . The method of  claim 11 , further comprising:
 forming the rocker shaft without a channel for flowing pressurized oil.