# US 11,994,084 B2 · Cylinder head, cylinder block, internal combustion engine, and method for manufacturing cylinder head

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- Number: US 11,994,084 B2
- Document ID: US11994084B2
- Status: Granted
- Kind: B2
- Application number: 17/911,861
- Filed: 2021-04-15
- Published: 2023-04-27
- Granted: 2024-05-28
- Earliest claimed: 2020-04-16
- Assignees: Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.
- Applicants: Mitsubishi Heavy Industries Engine & Turbocharger, Ltd.
- Inventors: Masayuki Iizumi; Motoi Kawashima; Takuya Kumagai; Makoto Sakaguchi; Kazunori Sawazaki; Hideho Narita; Ryuji Katayama
- Web page: https://patentgrep.com/patent/US11994084B2

## CPC

- F02F 1/24: Cylinder heads
- F02F 1/40: cylinder heads with means for directing, guiding, or distributing liquid stream
- C21D 1/09: by direct application of electrical or wave energy; by particle radiation
- C21D 5/00: Heat treatments of cast-iron
- C21D 9/0068: {for particular articles not mentioned below}
- F02F 11/002: {involving cylinder heads}
- C21D 2221/00: Treating localised areas of an article
- C21D 2221/01: End parts (e.g. leading, trailing end)
- C22C 37/00: Cast-iron alloys
- F02F 2200/00: Manufacturing
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

The present invention suppresses leakage of combustion gas from a contact surface. A cylinder head (20) is attached to a cylinder block. The surface (26) of the side of the cylinder head (20) that is attached to the cylinder block includes a first region (AH1) and a second region (AH2) that has higher hardness than the first region (AH1).

## Claims

### Claim 1

A cylinder head to be attached to a cylinder block with an opening formed on a first surface of the cylinder block, wherein
a second surface of the cylinder head on a side to be attached to the cylinder block includes a first portion overlapping the opening and a second portion overlapping the first surface except the opening; and
the second portion includes a first region and a second region having hardness higher than that of the first region.

### Claim 2 (depends on 1)

The cylinder head according to claim 1, wherein
the second region is formed on the second surface around the first portion that is exposed to combustion gas of the cylinder head.

### Claim 3 (depends on 2)

The cylinder head according to claim 2, wherein
the second region is formed in a part of an entire circumference surrounding the first portion, the first region is formed in a portion other than the second region in the entire circumference surrounding the first portion.

### Claim 4 (depends on 2)

The cylinder head according to claim 2, wherein
a fluid circulation port through which fluid other than the combustion gas circulates is formed on the second surface, and the second region is formed between the first portion and the fluid circulation port.

### Claim 5 (depends on 2)

The cylinder head according to claim 2, wherein
a plurality of fastening holes into which fastening members are inserted are formed around the first portion on the second surface, which is exposed to the combustion gas, along a circumferential direction, and
in the circumferential direction, the second region is formed between a first fastening hole and a second fastening hole where a distance therebetween is a longest distance among distances between the fastening holes adjacent to each other in the circumferential direction.

### Claim 6 (depends on 1)

An internal combustion engine comprising:
the cylinder head according to claim 1; and
the cylinder block.