Engine with work stroke and gas exchange through piston rod

An internal combustion engine, comprising:

• a cylinder having a first combustion chamber at a first end and a second combustion chamber at a second end;
• an exhaust port in a wall of the cylinder;
• a first cylinder head located at an end of the first combustion chamber;
• a second cylinder head located at an end of the second combustion chamber;
• a double-faced piston slidably mounted within the cylinder and configured to move in a first work stroke from the first end of the cylinder to the second end of the cylinder, and to move in a second work stroke from the second end of the cylinder to the first end of the cylinder, wherein the first work stroke includes a first expansion stroke portion during which chemical energy from combustion in the first combustion chamber is converted into mechanical power of the piston up until the piston reaches the exhaust port, and a first non-expansion stroke portion during which the piston continues to move toward the second end of the cylinder past the exhaust port and gases are exchanged between the first combustion chamber and a location outside the cylinder, and wherein the second work stroke includes a second expansion stroke portion and a second non-expansion stroke portion,
• wherein the cylinder and the piston are sized such that a total distance of the first work stroke is greater than that of the first expansion stroke portion or the first non-expansion stroke portion.