Set of cylinder heads with desmodromic valve operation, for internal combustion engines

Abstract

In a set of heads for the cylinders of internal combustion engines with desmodromic valve operation, each head comprises an assembly of one or two inlet valves, and an assembly of one or two exhaust valves, so as to form heads with two, three and four valves. The assembly of inlet valves is positioned at an angle to the assembly of exhaust valves. The two assemblies are actuated through respective rockers by a single camshaft located substantially along the line running centrally between the two assemblies. The inlet duct and the exhaust duct are located in the same position within the head and have the same connections to the induction and exhaust systems in all the two-, three- and four-valve versions.

What is claimed:  
     
         1 . A set of cylinder heads with desmodromic valve operation, for internal combustion engines, each head being applicable to a cylinder with an axis, and comprising an assembly of one or two inlet valves and an assembly of one or two exhaust valves so as to form a set of heads with two, three and four valves, the assembly of inlet valves being positioned at an angle to the assembly of exhaust valves, a single camshaft located substantially along the line running centrally between the two inlet and exhaust valve assemblies, each inlet valve and each exhaust valve being opened by a respective rocker arm actuated by an opening cam, and closed by a respective rocker arm actuated by a closing cam, an inlet duct connected to the inlet valves and an exhaust duct connected to the exhaust valve, the inlet duct and the exhaust duct being located on opposite sides of the centerline and having connections to the respective induction and exhaust systems, 
 wherein the inlet duct and the exhaust duct of each head are located in the same position within the head itself and have the same connections to the induction and exhaust systems in all the versions with two, three and four valves.    
     
     
         2 . The set of cylinder heads for internal combustion engines according to  claim 1 , wherein the inlet duct is positioned at an angle of between 35 and 55 degrees to the cylinder axis.  
     
     
         3 . The set of cylinder heads for internal combustion engines according to  claim 1  or  2 , wherein the exhaust duct is positioned at an angle of between 80 and 100 degrees to the cylinder axis.  
     
     
         4 . The set of cylinder heads for internal combustion engines according to any of the foregoing claims, wherein the inlet valve assembly is positioned at an angle of between 10 and 20 degrees to the cylinder axis.  
     
     
         5 . The set of cylinder heads for internal combustion engines according to any of the foregoing claims, wherein the exhaust valve assembly is positioned at an angle of between 10 and 20 degrees to the cylinder axis.  
     
     
         6 . A cylinder head for internal combustion engines according to any of the foregoing claims, comprising two inlet valves and one exhaust valve.  
     
     
         7 . The cylinder head for internal combustion engines according to any of the foregoing claims from  1  to  5 , comprising two inlet valves and two exhaust valves.  
     
     
         8 . The cylinder head for internal combustion engines according to any of the foregoing claims from  1  to  5 , comprising one inlet valve and one exhaust valve.  
     
     
         9 . The set of cylinder heads for internal combustion engines according to any of the foregoing claims, comprising two spark plugs.  
     
     
         10 . The set of cylinder heads for internal combustion engines according to  claim 9 , wherein the two spark plugs fire at different moments, with a small phase angle relative to the crank angle, and in that each of the spark plugs is cyclically alternated with the other in firing first.  
     
     
         11 . A motorcycle engine equipped with a cylinder head forming part of the set of cylinder heads according to any of the foregoing claims.  
     
     
         12 . The motorcycle engine according to  claim 11 , comprising two cylinders arranged in a V configuration of 90 degrees.