# US 2020/0011237 A1 · Internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0011237 A1 - Document ID: US20200011237A1 - Status: Published application - Kind: A1 - Application number: 16/452,786 - Filed: 2019-06-26 - Published: 2020-01-09 - Earliest claimed: 2018-07-04 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Toyota Jidosha Kabushiki Kaisha - Inventors: Naoki NISHIKAWA; Akio KAWAGUCHI; Hideo YAMASHITA; Keisuke TANAKA; Toshio HORIE; Yoshifumi WAKISAKA; Fumio SHIMIZU - Web page: https://patentgrep.com/patent/US20200011237A1 ## CPC - F02B 77/02: Surface coverings of combustion-gas-swept parts (of pistons F02F3/10; of cylinders and cylinder heads F02F1/00) - F02F 3/10: having surface coverings (F02F3/02 takes precedence) - C25D 11/005: {Apparatus specially adapted for electrolytic conversion coating (apparatus in general for electrolytic coating C25D17/00)} - C25D 11/022: {Anodisation on selected surface areas} - C25D 11/04: of aluminium or alloys based thereon - C25D 11/045: {for forming AAO templates} - C25D 11/08: containing inorganic acids - C25D 11/26: of refractory metals or alloys based thereon - C25D 21/02: Heating or cooling - F02B 77/11: Thermal or acoustic insulation - F02F 3/14: within combustion chambers - F02F 2001/008: {Stress problems, especially related to thermal stress} - F02F 2001/249: {with flame plate, e.g. insert in the cylinder head used as a thermal insulation between cylinder head and combustion chamber} - F05C 2203/0869: Aluminium oxide - F05C 2251/048: Heat transfer - F05C 2253/12: Coating - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES - C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR - F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES ## Abstract The present embodiment relates to an internal combustion engine having an anodic oxide coating formed on at least a portion of an aluminum-based wall surface facing a combustion chamber. The anodic oxide coating has a plurality of nanopores extending substantially in the thickness direction of the anodic oxide coating, a first micropore extending from the surface toward the inside of the anodic oxide coating, and a second micropore present in the inside of the anodic oxide coating; the surface opening diameter of the nanopores is 0 nm or larger and smaller than 30 nm; the inside diameter of the nanopores is larger than the surface opening diameter; the film thickness of the anodic oxide coating is 15 μm or larger and 130 μm or smaller; and the porosity of the anodic oxide coating is 23% or more. ## Claims ### Claim 1 An internal combustion engine, comprising: an anodic oxide coating formed on at least a portion of an aluminum-based wall surface facing a combustion chamber, wherein the anodic oxide coating has a plurality of nanopores extending substantially in a thickness direction of the anodic oxide coating, a first micropore extending from a surface toward an inside of the anodic oxide coating, and a second micropore present in the inside of the anodic oxide coating; a surface opening diameter of the nanopores on the surface of the anodic oxide coating is 0 nm or larger and smaller than 30 nm; an inside diameter of the nanopores in the inside of the anodic oxide coating is larger than the surface opening diameter; a film thickness of the anodic oxide coating is 15 μm or larger and 130 μm or smaller; and a porosity of the anodic oxide coating is 23% or more. ### Claim 2 (depends on 1) The internal combustion engine according to claim 1, wherein a difference between the surface opening diameter and the inside diameter of the nanopores is 7 nm or larger. ### Claim 3 (depends on 1) The internal combustion engine according to claim 1, wherein the nanopores do not open to the surface of the anodic oxide coating. ### Claim 4 (depends on 3) The internal combustion engine according to claim 3, wherein a difference between the surface opening diameter and the inside diameter of the nanopores is 20 nm or larger. ### Claim 5 (depends on 1) The internal combustion engine according to claim 1, wherein an aluminum-based material constituting the aluminum-based wall surface contains at least one metal selected from Si and Cu; and a content of the metal in the aluminum-based material is 5% by mass or more. ### Claim 6 (depends on 1) The internal combustion engine according to claim 1, wherein no sealing material is disposed on the anodic oxide coating. ### Claim 7 (depends on 6) The internal combustion engine according to claim 6, wherein the anodic oxide coating is exposed to the combustion chamber. ### Claim 8 (depends on 1) The internal combustion engine according to claim 1, wherein the internal combustion engine has a piston; and the anodic oxide coating is formed at least on a piston top surface. ### Claim 9 (depends on 8) The internal combustion engine according to claim 8, wherein the anodic oxide coating formed on the piston top surface comprises a thin-film portion having the film thickness of 15 μm or larger and 60 μm or smaller. ### Claim 10 (depends on 9) The internal combustion engine according to claim 9, wherein the thin-film portion is disposed in a portion substantially contributing to a formation of a tumble flow in the piston top surface. ### Claim 11 (depends on 10) The internal combustion engine according to claim 10, wherein the film thickness of the anodic oxide coating formed on the piston top surface except for the thin-film portion is larger than 60 μm and 100 μm or smaller. ### Claim 12 (depends on 9) The internal combustion engine according to claim 9, wherein the piston top surface comprises a cavity portion; and the thin-film portion is disposed in the cavity portion. ### Claim 13 (depends on 12) The internal combustion engine according to claim 12, wherein the piston top surface further comprises valve recess portions; and the thin-film portion is also disposed in the valve recess portions in addition to the cavity portion. ### Claim 14 (depends on 12) The internal combustion engine according to claim 12, wherein the piston top surface further comprises a squish portion; and the film thickness of the anodic oxide coating in the squish portion is larger than 60 μm and 100 μm or smaller. ### Claim 15 (depends on 9) The internal combustion engine according to claim 9, wherein the thin-film portion is disposed in a central region including a center of the piston top surface; and the film thickness of the anodic oxide coating disposed in an outer region positioned on an outer side of the central region is larger than 60 μm and 100 μm or smaller. ### Claim 16 (depends on 15) The internal combustion engine according to claim 15, wherein a ratio between an area of the central region and an area of the outer region is 1:5 to 5:1.