ENGINE COMBUSTION CHAMBER STRUCTURE, AND INNER WALL STRUCTURE OF THROUGH CHANNEL

Provided is an engine combustion chamber structure wherein the thermal efficiency of an engine and fuel consumption are improved. Also provided is an inner wall structure for a through channel, through which exhaust gas or intake gas of the engine passes. An engine combustion engine structure is provided with a heat-insulating member (1) on the inner wall of an engine constituent member (21) which constitutes an engine combustion chamber, the heat-insulating member (1) containing a heat-insulating porous layer (3) formed from ceramics, and a surface dense layer (2) formed on the surface of the heat-insulating porous layer (3) and formed from ceramics. The surface dense layer (2) of the heat-insulating member (1) has an open porosity of 5% or less, and preferably the heat-insulating porous layer (3) has a larger open porosity than the open porosity of the surface dense layer (2).