Internal combustion engine

An internal combustion engine provided with a cylinder block able to move relative to a crankcase and a cylinder head attached to the top part of the cylinder block, comprising:

• a block movement mechanism arranged at just one side of the internal combustion engine when viewing the internal combustion engine from an axial direction of a crankshaft that is supported at the crankcase and the block movement mechanism configured to make the cylinder block move relative to the crankcase;
• support members supporting a first side surface of the cylinder block;
• and
• pushing members pushing against the side surface of the cylinder block at a position opposite to where the first side surface is being supported by the support members, wherein
• the block movement mechanism comprises:
• a single control shaft supported by one of the crankcase or the cylinder block and having a main shaft part and eccentric parts with an axial center at a position offset by a predetermined amount from the axial center of the main shaft part;
• coupling members with one end parts of the coupling members attached to the eccentric parts and with the other end parts attached to the crankcase or the cylinder block and connecting the control shaft and the other of the crankcase or the cylinder block;
• and
• an actuator for making the control shaft rotate within a predetermined range of rotation in both directions to make the axial center of the eccentric parts swing about the axial center of the main shaft part in the direction of relative movement of the cylinder block, and wherein
• the support members comprise a first support member and a second support member that are provided on a side of arrangement of the block movement mechanism while separated by predetermined intervals in the direction of relative movement of the cylinder block, and respectively support the side surface of the top side and the bottom side of the cylinder block, and
• the pushing members comprise a first pushing member and a second pushing member that are provided at the opposite side of arrangement of the block movement mechanism while separated by predetermined intervals in the direction of relative movement of the cylinder block, and respectively push the side surface of the top side and the bottom side of the cylinder block, and wherein
• the first support member supports the side surface of the cylinder block at a position where a block rotating force trying to make the cylinder block rotate toward the block movement mechanism about the control shaft when the fuel is burned is applied, and
• the second pushing member pushes the side surface of the cylinder block located on the bottom side of the cylinder block relative to the first support member.