# US 10,309,293 B2 · 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 10,309,293 B2
- Document ID: US10309293B2
- Status: Granted
- Kind: B2
- Application number: 15/506,971
- Filed: 2015-08-11
- Published: 2017-10-05
- Granted: 2019-06-04
- Earliest claimed: 2014-10-07
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Manabu Tateno
- Web page: https://patentgrep.com/patent/US10309293B2

## CPC

- F02B 23/0603: {at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head}
- F02B 23/101: {the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts}
- F02F 1/24: Cylinder heads
- F02B 2023/0612: {the material having a high temperature and pressure resistance, e.g. ceramic}
- F02B 2023/102: {the spark plug being placed offset the cylinder centre axis}
- 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 2253/12: Coating
- Y02T 10/12: Improving ICE efficiencies
- 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
- F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A thermal insulation film is formed on a bottom surface of a cylinder head facing a top surface of a piston. The thermal insulation film in a region (a circumferential region) of a bottom surface of the cylinder head configuring a squish area in a circumferential edge of a cavity region is formed to be thinner than the thermal insulation film in a region (a cavity region) of the bottom surface of the cylinder head facing a cavity. The thermal insulation film in the circumferential region is polished, and surface roughness thereof is equal to or lower than 3 μm. The thermal insulation film in the cavity region is not polished, and surface roughness thereof is 3 to 8 μm on average.

## Claims

### Claim 1

An internal combustion engine including a top surface of a piston, on which a cavity is formed, and a bottom surface of a cylinder head that configures a combustion chamber together with the top surface of the piston, and has a thermal insulation film, which has a lower thermal conductivity and a lower thermal capacity per unit volume than a base material, formed thereon,
wherein the bottom surface of the cylinder head includes a cavity region and a circumferential region, both of which configure the combustion chamber, wherein the cavity region faces the cavity on the piston and the circumferential region configures a squish area in a circumferential edge of the cavity region, and
wherein an arithmetic mean roughness of the thermal insulation film across the circumferential region is formed to be smaller than an arithmetic mean roughness of the thermal insulation film across the cavity region.

### Claim 2 (depends on 1)

The internal combustion engine according to claim 1,
wherein a film thickness of the thermal insulation film in the circumferential region is formed to be thinner than a film thickness of the thermal insulation film in the cavity region.

### Claim 3 (depends on 1)

The internal combustion engine according to claim 1,
wherein the film thickness of the thermal insulation film in the circumferential region is formed to change continuously in a connection portion with the cavity region, and become thinner with increasing distance from the cavity region.

### Claim 4 (depends on 1)

The internal combustion engine according to claim 1,
wherein on the top surface of the piston, a thermal insulation film that has a lower thermal conductivity and a lower thermal capacity per unit volume than a piston base material is formed, and
an arithmetic mean roughness of the thermal insulation film across the top surface of the piston is formed to be equivalent to the arithmetic mean roughness of the thermal insulation film across the circumferential region.

### Claim 5 (depends on 4)

The internal combustion engine according to claim 4,
wherein a film thickness of the thermal insulation film in a circumferential edge of the cavity is formed to be thinner than a film thickness of the thermal insulation film in the cavity.