Internal combustion engine with cylinder insert

An internal combustion engine including:

• an engine block having a head seat surface and a cylinder opening extending from the head seat surface into an interior of the engine block, the cylinder opening having
• a cylinder opening surface, and
• a cylinder opening cylindrical wall that is cylindrical about a longitudinally extending cylindrical axis and has a wall upper surface located at a recess depth below the head seat surface, the cylinder opening wall having a cylinder opening inner cylindrical diameter and a cylinder opening outer dimension such that there is a gap between the cylinder opening cylindrical wall and the cylinder opening surface;
• and
• a cylinder insert residing within the cylinder opening and having an insert upper surface substantially flush with the head seat surface of the engine block, the cylinder insert comprising
• a smooth cylindrical inner surface that is cylindrical about the longitudinally extending cylindrical axis, and
• a stepped outer surface formed of three longitudinal regions, the outer surface including
• a first longitudinal region adjacent to the insert upper surface and having a first wall thickness such that the first longitudinal region contacts the cylinder opening surface,
• a second longitudinal region remote from the first longitudinal region and having a second wall thickness less than the first wall thickness, the second longitudinal region being received within the cylinder opening inner wall,
• a third longitudinal region intermediate between and continuous with the first longitudinal region and the second longitudinal region, the third longitudinal region having a third wall thickness intermediate between the first wall thickness and the second wall thickness, and
• a support shoulder between the second longitudinal region and the third longitudinal region, the support shoulder resting upon the wall upper surface.

An internal combustion engine including:

• an engine block having a head seat surface and a cylinder opening extending from the head seat surface into an interior of the engine block, the cylinder opening having
• a cylinder opening surface, and
• a cylinder opening cylindrical wall that is cylindrical about a longitudinally extending cylindrical axis and has a wall upper surface located at a recess depth below the head seat surface, the cylinder opening wall having a cylinder opening inner cylindrical diameter and a cylinder opening outer dimension such that there is a gap between the cylinder opening cylindrical wall and the cylinder opening surface;
• and
• a cylinder insert residing within the cylinder opening and having an insert upper surface substantially flush with the head seat surface of the engine block, the cylinder insert comprising
• a smooth cylindrical inner surface that is cylindrical about the longitudinally extending cylindrical axis, and
• a stepped outer surface formed of three longitudinal regions, the outer surface including
• a first longitudinal region adjacent to the insert upper surface and having a first wall thickness such that the first longitudinal region contacts the cylinder opening surface,
• a second longitudinal region remote from the first longitudinal region and having a second wall thickness less than the first wall thickness, the second longitudinal region being received within the cylinder opening inner wall,
• a third longitudinal region intermediate between and continuous with the first longitudinal region and the second longitudinal region, the third longitudinal region having a third wall thickness intermediate between the first wall thickness and the second wall thickness, and
• a support shoulder between the second longitudinal region and the third longitudinal region, the support shoulder resting upon the wall upper surface, wherein the gap serves as a water-cooling jacket extending over a length of the second longitudinal region and a length of the third longitudinal region.