Internal combustion engine

Patent metadata

Field	Value
Publication number	US-10309293-B2
Application number	US-201515506971-A
Country	US
Kind code	B2
Filing date	Aug 11, 2015
Priority date	Oct 7, 2014
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

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.

First claim

The invention claimed is:

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.

2. 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.

3. 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.

4. 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.

5. 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.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tateno Manabu

Classifications

• F02F2001/249

  with flame plate, e.g. insert in the cylinder head used as a thermal insulation between cylinder head and combustion chamber · CPC title

• F02B23/0603 Primary

  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 · CPC title

• F02F1/24

  Cylinder heads · CPC title

• Y02T10/125

  Cross-Sectional Technologies · mapped topic

• F02B23/101

  the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts · CPC title