The present invention generally relates to internal combustion engines and more particularly, to a method of determining a configuration or profile of a piston employed in an internal combustion engine, which is so arranged that, with a covering layer which may be comparatively readily abraded being formed on an outer peripheral surface of a piston, the piston is built in an internal combustion engine for operation, so that the configuration of the piston obtained after abrasion of the above covering layer is regarded as the form of the piston required for designing.
Conventionally, for determining a piston profile for an internal combustion engine as referred to above, there has been disclosed, for example, in Japanese Patent Application Tokugansho No. 55-116340 (Japanese Laid Open Patent Application Tokkaisho No. 57-39916), a method in which a composite material including epoxy resin, flake aluminum and molybdenum disulfide is applied onto an outer peripheral surface of a piston for baking at a predetermined temperature so as to form a covering layer thereon.
In the known method as described above, however, there have been problems as described hereinbelow.
In the first place, when the piston formed with the covering layer as described above is to be subjected to the operation, the outer surface thereof is not sufficiently smooth for the actual operation. Moreover, in the case where the internal combustion engine to be dealt with for the determination of the piston profile or form is of an engine of a type having a small compression pressure, for example, a gasoline engine with a less displacement for a small-sized motor vehicle, it takes a considerable time until the covering layer formed on the outer peripheral surface of the piston is abraded to a desired configuration, since an external force acting on such covering layer is generally small, and if the content of molybdenum disulfide is reduced or temperature for baking the composite material is lowered, the smoothness on the external surface of the piston as referred to above is still more reduced. Particularly, when the baking temperature is excessively lowered, another disadvantage such as separation of the covering layer during operation may possibly take place.