A Cylinder Head With Valve Deactivators

Abstract

To improve fuel efficiency, some gasoline engines are equipped with valve deactivators in some of the cylinders so that at low torque conditions only a subset of the total number of cylinders are active. In prior art engines, particularly when they have four valves per cylinder, space is tight. It is known to provide a cam carrier in the head between the cylinder head and the camshaft. The cylinder head bolts pass through the head under the cam carrier. According to the present disclosure, the cam carrier, and its associated disadvantages, is obviated by widening the bearings for the camshafts, using smaller diameter head bolts, and putting the orifices tor the head bolts directly through the bearings.

1 - 12 . (canceled) 
     
     
         13 . A method to assemble an engine, comprising:
 casting a cylinder head that comprises combustion chamber tops and a plurality of cam towers, the cam towers having bearing surfaces each having an orifice defined in the bearing surfaces;   bolting the cylinder head to an engine block with bolts passing through the orifices in the bearing surfaces of the cam towers; and   installing followers in the cylinder head, at least one-quarter of the followers being deactivatable followers.   
     
     
         14 . The method of  claim 13 , further comprising:
 installing two intake poppet valves and two exhaust poppet valves into ports formed in each of the combustion chamber tops in the cylinder head.   
     
     
         15 . The method of  claim 13 , further comprising:
 installing a plurality of non-deactivatable followers in the cylinder head.   
     
     
         16 . The method of  claim 13  wherein:
 the cylinder head has four combustion chamber tops; 
 each combustion chamber top has two intake valves and two exhaust valves disposed therein; 
 half of the intake valves and half of the exhaust valves are provided with the deactivatable followers. 
 
     
     
         17 . The method of  claim 13 , further comprising:
 placing camshafts in the cam towers; and   installing cam caps onto cam towers of the cylinder head to thereby capture the camshafts.   
     
     
         18 . The method of  claim 13  wherein the cam towers are unitary with the cylinder head. 
     
     
         19 . The method of  claim 13  wherein the bearing surfaces have a first land on a first side of the orifice and a second land on a second side of the orifice. 
     
     
         20 . The method of  claim 13  wherein:
 the cylinder head has two deactivatable cylinders and two non-deactivatable cylinders, the method further comprising:
 installing deactivatable followers in valves associated with the two deactivatable cylinders; and 
 installing non-deactivatable followers in valves associated with the two non-deactivatable cylinders. 
 
 
     
     
         21 . The method of  claim 13  wherein:
 the cylinder head has four combustion chamber tops; 
 each combustion chamber top has two intake valves and two exhaust valves disposed therein; 
 half of the intake valves are provided with the deactivatable followers. 
 
     
     
         22 . A method to assemble an engine, comprising:
 casting a cylinder head that comprises combustion chamber tops and a plurality of cam towers integrally cast, the cam towers having bearing surfaces each having an orifice defined in the bearing surfaces;   bolting the cylinder head to an engine block with bolts passing through the orifices in the bearing surfaces of the cam towers; and   installing a plurality of deactivatable intake followers in the cylinder head.   
     
     
         23 . The method of  claim 22 , further comprising: installing a plurality of non-deactivatable exhaust followers in the cylinder head. 
     
     
         24 . The method of  claim 22 , further comprising:
 installing two intake poppet valves and two exhaust poppet valves into ports formed in each of the combustion chamber tops in the cylinder head.   
     
     
         25 . The method of  claim 22  wherein:
 the cylinder head has four combustion chamber tops; and 
 half of the intake valves are provided with the deactivatable followers. 
 
     
     
         26 . The method of  claim 25  wherein:
 half of the exhaust valves are provided with the deactivatable followers. 
 
     
     
         27 . The method of  claim 22  wherein the bearing surfaces in the cam towers have a first land on a first side of the orifice and a second land on a second side of the orifice. 
     
     
         28 . The method of  claim 22 , further comprising:
 placing camshafts in the cam towers; and   installing cam caps onto cam towers of the cylinder head to thereby capture the camshafts.   
     
     
         29 . The method of  claim 22  wherein the bolts used to bolt the cylinder head to the engine block are internal drive bolts.