Variable Geometry Cam Shafts For Multiple-Cylinder Internal Combustion Engines

Abstract

A method of conserving fuel in the operation of multi-cylinder internal combustion engines. The present method described here allows a portion of the cylinders of an internal combustion engine to be de-activated when less power is required, thus allowing the engine to provide full power when required, or less power with substantial fuel savings. The present method does so by altering the normal operation of intake and exhaust valves by leaving the intake valve at least partially closed, and the exhaust valve at least partially open. The present method overcomes numerous problems in the prior art, such as excess load placed on the engine caused by trapped gases, damaging thermal gradients across the engine block, and difficulty of retrofitting existing engines.

1 . A method for de-activating and re-activating at least a portion of the cylinders in an internal combustion engine comprising a plurality of cylinders, each having intake and exhaust valves, each cylinder having a normal operating cycle wherein the valves open and close at various times during the cycle:
 de-activating at least a portion of the cylinders by maintaining the exhaust valves at least partially open, and the intake valves at least partially closed; and   re-activating that portion of the cylinders by returning the intake and exhaust valves to the normal operating cycle.   
     
     
         2 . The method of  claim 1 , further comprising responding to a reduced power demand placed on the engine by activating or de-activating a cylinder. 
     
     
         3 . The method of  claim 1 , wherein de-activating a cylinder includes at least partially closing the exhaust valve when the piston nears its uppermost position. 
     
     
         4 . The cylinder receiving an amount of fuel, the method of  claim 1 , comprising reducing the amount of fuel delivered to the de-activated cylinder. 
     
     
         5 . An apparatus for de-activating and re-activating cylinders of an internal combustion engine, each cylinder having intake and exhaust valves, comprising:
 an intake valve assembly in communication with intake valves on a plurality of cylinders, having a normal operating mode allowing normal operation of the intake valves of the plurality of cylinders, and a de-activated mode at least partially closing the intake valves of the plurality of cylinders throughout the combustion cycle;   an exhaust valve assembly in communication with exhaust valves of a plurality of cylinders, having a normal operating mode allowing normal operation of the exhaust valves of the plurality of cylinders, and a de-activated mode at least partially opening the exhaust valve throughout the combustion cycle; and   a controlling assembly for the control of the intake and exhaust valve assemblies.   
     
     
         6 . The apparatus of  claim 5 , wherein the intake and exhaust valve assemblies are adjustable cams in communication with the intake and exhaust valves. 
     
     
         7 . The apparatus of  claim 5 , wherein the controlling assembly is able to place the intake and exhaust valve assemblies in the de-activated mode during periods of low power loading on the engine, and able to place the intake and exhaust valve assemblies in the normal operating mode during periods of relatively higher power loading on the engine. 
     
     
         8 . The apparatus of  claim 6 , wherein the intake adjustable cams comprise two cams connected axially, one allowing normal operation, the other leaving the valve at least partially closed, and wherein the exhaust adjustable cams comprise two cams connected axially, one allowing for normal operation, the other leaving the valve at least partially open, and where the controlling assembly is capable of axially translating the cam shaft. 
     
     
         9 . The apparatus of  claim 7 , wherein the controlling device includes an electronic microcontroller device. 
     
     
         10 . The apparatus of  claim 8 , wherein the controlling assembly for axially translating the cam shaft is electromechanical. 
     
     
         11 . The apparatus of  claim 8 , wherein the controlling assembly for axially translating the cam shaft is hydraulic. 
     
     
         12 . The apparatus of  claim 8 , wherein the controlling assembly for axially translating the cam shaft is pneumatic. 
     
     
         13 . The apparatus of  claim 8 , wherein the adjustable cams and valve controller device can be retrofitted on internal combustion engines. 
     
     
         14 . The apparatus of  claim 8 , wherein the exhaust cam leaving the exhaust valve open at least partially closes the valve when the cylinder piston is near its uppermost position. 
     
     
         15 . The apparatus of  claim 13 , wherein the retrofit can be accomplished without disassembling or modifying the engine block.