A cylinder sleeve used in a V-type block of a crank circular slider mechanism, the V-type block including a piston, which has a receiving hole for receiving a circular slider therein, a block having a main journal hole, and a group of adjacent cylinders arranged in a V form intersecting at an intersection portion of the main journal hole, each of the cylinders in the group of adjacent cylinders extending through the main journal hole respectively, wherein the cylinders each extend through the main journal hole with an axial length beyond the main journal hole, the axial length being long enough for providing a reciprocating range required for reciprocating motion of a part of the piston located beneath the receiving hole, the cylinder sleeve comprising:
- a thin wall cylinder body whose axial length is sized so as to receive the piston of the crank circular slider mechanism and to accommodate an entirety of the reciprocating motion, the thin wall cylinder body of the cylinder sleeve being provided with a through hole having an axis intersecting perpendicularly a central axis of the thin wall cylinder body,
- wherein the through hole is located in the cylinder sleeve in an axial direction such that the through hole faces the main journal hole and is coaxial with the through hole after the cylinder sleeve is fitted with a corresponding cylinder, the through hole being structured for passage of a crank pin of a crankshaft and is also referred to as a crankshaft passage hole, and
- wherein a part of a side wall of the cylinder sleeve is cut out to form an avoidance opening, which is located so that a circle corresponding to a perimeter of the crankshaft passage hole faces the avoidance opening, and so that the avoidance opening is structured to accommodate a second cylinder sleeve that intersects the cylinder sleeve, and
- wherein the cylinder sleeve having the avoidance opening and the crankshaft passage hole includes two sides with a width sufficient for providing a guiding plan for a guiding portion of the piston fitted in the cylinder sleeve.