No lash dual stem I.C.E. valve

A valve train for an internal combustion engine including at least one cylinder and a cylinder head which partially defines the at least one cylinder, the valve train comprising:

• a camshaft rotatably mounted to the cylinder head;
• at least one cam mounted to the camshaft, the at least one cam including a peripheral groove formed on an axial end face of the at least one cam so as to define an inner cam lobe and an outer cam lobe;
• at least one desmodromic valve corresponding to each cylinder, the at least one desmodromic valve extending through the cylinder head so as to directly engage an associated cam of the at least one cam thereby cyclically opening and closing the at least one desmodromic valve against a port of the corresponding cylinder as the camshaft rotates, the at least one desmodromic valve including:
• a valve stem,
• a valve head formed at a lower end of the valve stem, and
• an upper roller bearing and a lower roller bearing which are rotatably coupled to an upper end of the valve stem via an attachment means,
• wherein the upper and lower roller bearings are arranged within the peripheral groove of the associated cam so as to respectively engage an outer bearing surface of the inner cam lobe and an inner bearing surface of the outer cam lobe.

A valve train for an internal combustion engine including at least one cylinder and a cylinder head which partially defines the at least one cylinder, the valve train comprising:

• a camshaft rotatably mounted to the cylinder head;
• at least one cam mounted to the camshaft, the at least one cam including a peripheral groove formed on an axial end face of the at least one cam so as to define an inner cam lobe and an outer cam lobe;
• at least one desmodromic valve assembly corresponding to each cylinder, the at least one desmodromic valve assembly extending through the cylinder head, the at least one desmodromic valve assembly including:
• an upper valve stem including an upper end and a lower end, and
• a lower valve stem including a lower end defining a valve head, and an upper end defining a shared housing configured to slidably receive the lower end of the upper valve stem;
• a center-pivot rocker arm assembly arranged between the at least one desmodromic valve assembly of the corresponding cylinder and an associated cam of the at least one cam, the rocker arm assembly configured to transfer actuating motions from the associated cam to the at least one desmodromic valve assembly so as to cyclically open and close the at least one desmodromic valve assembly against a port of the corresponding cylinder as the camshaft rotates, the rocker arm assembly including:
• a cam end configured to engage the associated cam via a first roller bearing and a second roller bearing, and
• a valve end pivotally coupled to the at least one desmodromic valve assembly,
• wherein the associated cam actuates the at least one desmodromic valve assembly via the rocker arm assembly such that (i) the upper valve stem moves into contact with a lower contact surface of the shared housing when opening the at least one desmodromic valve assembly, and (ii) the upper valve stem is pulled towards an upper stop of the shared housing so as to seal the valve head against a valve seat of the port when closing the at least one desmodromic valve assembly.