Internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorManabu Tateno
Life of this patent
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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.
Claims5
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.
Dependencies are inferred from the claim text.