Cam timing system

Abstract

A cam timing system or assembly 10 is provided for use in combination with an internal combustion engine 12 of the type having a pair of substantially identical cylinder banks 13, 15, a crankshaft 14 and a pair of overhead camshafts 16, 18. In the preferred embodiment of the invention, cam timing system 10 includes a pair of conventional sprockets or members 20, 22, which are respectively and fixedly coupled to camshafts 16, 18, and a variable timing control device or apparatus 24, which is operatively coupled to crankshaft 14 and which includes an outer drum portion 40. An interconnecting member or chain 28 operatively engages drum portion 40 and sprockets 20, 22, thereby operatively and rotatably interconnecting sprockets 20, 22 to apparatus 24 . Apparatus 24 is selectively actuated, and is effective to advance and/or delay the rotation of drum portion 40 with respect to crankshaft 14, thereby selectively advancing or delaying the rotation of camshafts 16, 18 with respect to crankshaft 14.

What is claimed is:  
     
         1 ) A cam timing assembly for use with an engine of the type having a rotatable crankshaft and first and second rotatable camshafts, said cam timing assembly comprising: 
 a first sprocket which is selectively coupled to said first rotatable camshaft;    a second sprocket which is selectively coupled to said second rotatable camshaft;    an interconnecting member which is operatively coupled to said first and said second sprocket; and    a timing apparatus which is coupled to said crankshaft, said timing apparatus including a drum portion having a plurality of peripherally disposed teeth which are operatively coupled to said interconnecting member, said drum portion cooperating with said interconnecting member to rotate said first and said second rotatable camshafts in response to said rotation of said crankshaft, said drum portion being further selectively rotatable with respect to said crankshaft, said selective rotation of said drum portion being effective to selectively perform a unique one of the functions of advancing and delaying said rotation of said first and said second rotatable camshafts with respect to said rotation of said crankshaft.    
     
     
         2 ) The cam timing assembly of  claim 1  further comprising: 
 a source of pressurized fluid which is coupled to said timing apparatus, and which selectively provides pressurized fluid to said timing apparatus, thereby causing said drum portion of said timing apparatus to selectively rotate with respect to said crankshaft.  
 
     
     
         3 ) The cam timing assembly of  claim 2  further comprising: 
 a conduit which couples said source of pressurized fluid to said timing apparatus, said conduit including a selectively actuatable valve.  
 
     
     
         4 ) The cam timing assembly of  claim 3  further comprising: 
 a controller, which is communicatively coupled to said selectively actuatable valve, said control assembly being effective to selectively actuate said valve, thereby selectively causing said pressurized fluid to be provided to said timing apparatus.  
 
     
     
         5 ) The cam timing assembly of  claim 4  wherein said controller is further effective to receive data relating to one or more operating conditions of said engine, and to selectively actuate said valve in response to said receipt of said data.  
     
     
         6 ) The cam timing assembly of  claim 1  wherein said engine further comprises a third and a fourth selectively rotatable camshaft and an idler, said cam timing assembly comprising: 
 a third sprocket coupled to said third selectively rotatable camshaft;  
 a fourth sprocket coupled to said fourth selectively rotatable camshaft;  
 said interconnecting member being further coupled to said third sprocket, said fourth sprocket, and said idler; and  
 said selective rotation of said drum portion being further effective to selectively advance and selectively delay said rotation of said third and said fourth selectively rotatable camshafts with respect to said rotation of said crankshaft.  
 
     
     
         7 ) The cam timing assembly of  claim 6  wherein said engine is a “V”-type engine.  
     
     
         8 ) The cam timing assembly of  claim 1  wherein said engine further comprises a third and a fourth selectively rotatable camshaft and an idler which is operatively coupled to said interconnecting member, said cam timing assembly further comprising: 
 a second timing apparatus which is coupled to said third selectively rotatable camshaft, and which includes a second drum portion which is selectively coupled to said interconnecting member; and  
 a third timing apparatus which is coupled to said fourth selectively rotatable camshaft, and which includes a third drum portion which is selectively coupled to said interconnecting member.  
 
     
     
         9 ) The cam timing assembly of  claim 8  wherein said engine is a “V”-type engine.  
     
     
         10 ) A cam timing system for use in combination with an engine of the type having a rotatable crankshaft and first and second rotatable camshafts, said cam timing system comprising: 
 a first belt engaging member which is coupled to said first rotatable camshaft;    a second belt engaging member which is coupled to said second rotatable camshaft;    a timing belt which is coupled to said first and said second belt engaging members; and    a variable timing apparatus which is operatively disposed upon said crankshaft, which is coupled to said timing belt, and which is selectively and rotatably driven by said crankshaft, said variable timing apparatus being effective to selectively cause said timing belt to rotate said first and said second rotatable camshafts at a phase angle with respect to said crankshaft, said variable timing apparatus being further effective to selectively rotate with respect to said crankshaft, thereby selectively altering said phase angle.    
     
     
         11 ) The cam timing system of  claim 10  wherein said engine further includes an oil pump which provides a flow of pressurized oil, and wherein said variable timing apparatus is coupled to said oil pump by way of a conduit.  
     
     
         12 ) The cam timing system of  claim 11  wherein said conduit includes a valve which is selectively actuatable, effective to selectively provide said flow of pressurized oil to said variable timing apparatus.  
     
     
         13 ) The cam timing system of  claim 12  further comprising: 
 at least one sensor which selectively measures engine operating data; and  
 a controller which is communicatively coupled to said at least one sensor, which receives said engine operating data from said at least one sensor, and which selectively actuates said valve based upon said received engine operating data.  
 
     
     
         14 ) The cam timing system of  claim 10  wherein said engine includes a third and a fourth rotatable camshaft and an idler, said cam timing system further comprising: 
 a third belt engaging member which is coupled to said third rotatable camshaft;  
 a fourth belt engaging member which is coupled to said fourth rotatable camshaft;  
 said timing belt being further coupled to said third and fourth belt engaging members and to said idler; and  
 said variable timing apparatus being further effective to selectively cause said timing belt to rotate said third and said fourth rotatable camshafts at a second phase angle with respect to said crankshaft, and to selectively alter said second phase angle.  
 
     
     
         15 ) The cam timing system of  claim 10  wherein said engine further comprises a plurality of intake valves and a plurality of exhaust valves, wherein said first rotatable camshaft selectively opens and closes said intake valves, and wherein said second rotatable camshaft selectively opens and closes said exhaust valves.  
     
     
         16 ) A method for cam timing for use in combination with an engine including a first and a second rotatable camshaft and a rotatable crankshaft, said method comprising the steps of: 
 providing a first and a second member;    disposing said first member on said first rotatable camshaft;    disposing said second member on said second rotatable camshaft;    providing a variable timing apparatus;    operatively disposing said variable timing apparatus upon said crankshaft, effective to allow said rotation of said crankshaft to rotate said variable timing apparatus;    disposing an interconnecting member around said first member, said second member, and said variable timing apparatus, thereby allowing said rotation of said variable timing apparatus to rotatably drive said first and said second rotatable camshafts; and    selectively rotating said variable timing apparatus with respect to said crankshaft, thereby selectively advancing and selectively delaying said rotation of said first and said second camshaft with respect to said rotation of said crankshaft.    
     
     
         17 ) The method of  claim 16  further comprising the steps of: 
 providing a source of pressurized fluid; and  
 operatively coupling said source of pressurized fluid to said variable timing apparatus, thereby selectively causing said variable timing apparatus to rotate with respect to said crankshaft.  
 
     
     
         18 ) The method of  claim 16  wherein said engine further comprises a third and a fourth rotatable camshaft and an idler, said method further comprising the steps of: 
 providing a third member and a fourth member;  
 disposing said third member or said third rotatable camshaft;  
 disposing said fourth member or said fourth rotatable camshaft; and  
 disposing said interconnecting member around said third member, said fourth member and said idler, thereby allowing said variable timing apparatus to rotatably drive said third and said fourth rotatable camshafts and to selectively advance and selectively delay said rotation of said third and said fourth camshafts with respect to said rotation of said crankshaft.