System for controlling fluid flow

A method for controlling fluid flow to or from a cylinder of an internal combustion engine, the method comprising:

• rotating, with a source of rotation, at least two rotary valves accommodated in a cylinder head associated with the cylinder, and being arranged to selectively open or close flow openings in the cylinder head;
• and
• varying the speed of rotation of the rotary valves between at least two different speeds during a single rotation thereof;
• wherein the rotating of the rotary valves is performed by transmitting rotation from the source of rotation to the rotary valves by a mechanical drive train including
• a first noncircular element rotatably coupled to the source of rotation;
• a second non-circular element rotatably coupled to a first drive shaft on which one of the at least two rotary valves is mounted;
• and
• a third non-circular element rotably coupled to a second drive shaft on which one of the at least two rotary valves is mounted;
• the first non-circular element being rotatably coupled to the second and third non-circular elements to cause a speed variation in the second and third non-circular elements upon a constant rotation of the first non-circular element;
• wherein the first, second, and third non-circular elements are elliptical gears.

A system for controlling fluid flow to or from a cylinder of an internal combustion engine, the system comprising:

• a first drive shaft having a rotary valve mounted thereon;
• a second drive shaft having a rotary valve mounted thereon;
• a cylinder head accommodating the rotary valves and at least part of the drive shafts therein, the rotary valves being arranged to selectively open or close flow openings in the cylinder head;
• a source of rotation;
• and
• a mechanical drive train rotatably coupling the source of rotation to the drive shaft, the mechanical drive train including
• a circular element rotatably coupled to the source of rotation,
• a first non-circular element rotatably coupled to the first drive shaft,
• a second non-circular element rotatably coupled to the second drive shaft, and
• a third non-circular element rotatably coupled to the circular element;
• wherein the third non-circular element is rotatably coupled to the first and second non-circular elements to cause a speed variation in the rotation of the first and second non-circular elements upon a constant rotation of the circular element;
• and
• wherein the first, second, and third non-circular elements are elliptical gears.