Piston for internal combustion engine and manufacturing method therefor

Abstract

Provided is a piston for an internal combustion engine, the piston enabling both an improvement in heat efficiency and a reduction in emissions, and enabling the prevention of overheating of the piston to prevent the occurrence of knocking, pre-ignition, and a drop in air filling efficiency. This piston (100a) for an internal combustion engine constitutes a portion of a combustion chamber (9) of an internal combustion engine (200) and includes a substrate (103), a first film (101) provided on a section of the top surface of the substrate (103) contacting the combustion chamber (9), and a second film (102) provided on another section of the top surface. The piston for the internal combustion engine is characterized in that: the first film (101) has a lower heat conductivity and heat capacity than the substrate (103), and the second film (102) has a lower heat conductivity than the substrate (103) and a higher heat capacity than the first film (101).

Description

technical field [0001] The present invention relates to a piston for an internal combustion engine and a manufacturing method thereof. Background technique [0002] In an internal combustion engine such as a gasoline engine, part of the heat generated by combustion is exhausted from the combustion chamber through the wall surface to the outside and becomes a loss. To improve the thermal efficiency of the internal combustion engine, it is necessary to reduce this cooling loss. Therefore, there are known methods of improving the thermal insulation of the combustion chamber by forming a film of low thermal conductivity and low heat capacity on the piston surface occupying a relatively large area among the combustion chamber wall surfaces, and by making the piston surface temperature relatively large. The heat flux on the piston surface is reduced by following the combustion gas temperature in the cylinder with a small delay (so-called temperature swing adiabatic method). [0...

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Problems solved by technology

[0003] On the other hand, when fuel droplets adhere to the surface of the piston with such a low heat capacity, the temperature of the piston at the adhered part decreases, and the gasification property of the fuel deteriorates.

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