Control method for internal combustion engine and control device for internal combustion engine

Abstract

According to the present invention, an internal combustion engine (1): can modify a mechanical compression ratio by modifying the range in which a piston (33) slides along a cylinder bore (32); and can control the flow of cooling water inside a water jacket (31a) that is provided around the cylinder bore (32). When a cooling water temperature (Tw) at the water jacket (31a), which correlates with acylinder bore wall temperature, is below a prescribed temperature (Twth), the flow of cooling water inside the water jacket (31a) is suspended, which rapidly increases the cylinder bore wall temperature and rapidly stops the condensation of water on an inner circumferential surface (32a) of the cylinder bore (32), making it possible to delay the progress of corrosion of the inner circumferentialsurface (32a) of the cylinder bore (32).

Description

technical field [0001] The present invention relates to a control method and a control device of an internal combustion engine capable of changing a compression ratio. Background technique [0002] For example, Patent Document 1 discloses an internal combustion engine including: a fuel injection valve for in-cylinder injection that injects fuel into a combustion chamber; a fuel injection valve for port injection that injects fuel into an intake port; and a variable compression mechanism , which can change the mechanical compression ratio. [0003] In this patent document 1, when there is a possibility of corrosion at the front end of the nozzle of the fuel injection valve for in-cylinder injection, the mechanical compression ratio of the internal combustion engine is increased, or the total amount of fuel injection is switched to fuel injection from the port. The port of the injection valve injects, thereby suppressing the generation of corrosion. [0004] However, Patent ...

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Problems solved by technology

Moreover, when the mechanical compression ratio is lowered, the corroded part after peeling off of the corroded part may be re-corroded, which may lead to the development of corrosion in the cylinder bore.

[0007] That is, in an internal combustion engine capable of changing the mechanical compression ratio, there is room for further improvement in terms of suppressing the development of corrosion that may occur in the internal combustion engine.

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