Cylinder bore surface profile and process

摘要

An engine block has a cylinder bore wall comprising a first portion having a first diameter and a second portion axially adjacent to the first portion having a second diameter greater than the first diameter. A series of parallel, circumferentially-extending grooves is formed in the second portion to roughen the surface and enhance adhesion of a later-applied, sprayed-on metallic coating. A non-masking section is formed between the first and the second portions to provide for a less-abrupt corner between the larger diameter and smaller diameter portions and eliminate any spray-masking that may otherwise. The non-masking section may be a flat or a curved chamfer. The non-masking section may be a non-grooved section of constant diameter.

主权项

1. An engine block having a cylinder bore wall with a longitudinal axis, the wall comprising:
a first portion having a first diameter; a second portion axially adjacent to the first portion having a second diameter greater than the first diameter, and a plurality of parallel, circumferentially-extending, alternating grooves and teeth formed therein; and an un-roughened section immediately adjacent to an end surface between the first and the second portions, the un-roughened section having an axial length at least two times a width of the grooves and a diameter substantially equal to one of a first bore diameter measured to peaks of the teeth and a second bore diameter measured to bottoms of the grooves.