Abstract: Each of a plurality of cylinder liners has a cooling liquid groove at its outer circumferential surface and has a flat surface over an entire axial length at a part of the outer circumferential surface. The cylinder liners are inserted in bores of a cylinder block with flat surfaces of adjacent liners abutting each other and the grooves at the flat surfaces being coincident with each other.

Abstract: A cylinder liner comprises an outer circumferential surface provided with a plurality of groups of annular grooves, a longitudinal groove communicating the annular grooves with each other and forming an outlet for a cooling liquid in each of the groups of annular grooves, and a longitudinal groove communicating the annular grooves with each other and forming an inlet for the cooling liquid in each of the groups of annular grooves. The outlet communicates in series with the inlet in the adjoining groups of annular grooves. Sectional areas of the annular grooves in the same group of annular grooves are decreased from an upstream side toward a downstream side.

Abstract: A cylinder liner is fitted in a cylinder bore of a cylinder block of a multiple-cylinder engine. The cylinder liner has an outer circumferential surface having a plurality of annular grooves and a plurality of longitudinal grooves connected thereto, in which a cooling liquid is flowed in the grooves. A part in an axial direction of a crankshaft of a bottom of at least one of the annular grooves is coated with a sprayed coating of metal, and a sectional area of the annular groove provided with the sprayed coating varies in a circumferential direction.

Abstract: A cylinder liner having an outer circumferential surface having a plurality of groups of annular grooves, wherein each of the groups of annular grooves has two longitudinal grooves communicating the individual annular grooves with each other, forming an outlet and an inlet for the cooling oil and disposed at locations spaced apart by 180.degree. in a circumferential direction, and the outlet communicates with the inlet in series in the adjoining groups of annular grooves. The outer circumferential surface has further a longitudinal groove connected to the lower end of the longitudinal groove forming the outlet of the lowermost group of annular grooves, a circumferential groove connected to the lower end of the longitudinal groove, and a longitudinal groove having the upper end connected to the circumferential groove and the lower end released, and the lowermost longitudinal groove is disposed at a circumferential position differing from the longitudinal grooves in the groups of annular grooves.