SLIDING STRUCTURE FOR INTERNAL COMBUSTION ENGINE, METHOD FOR CONTROLLING IDLING OPERATION AND METHOD FOR CONTROLLING OPERATION OF INTERNAL COMBUSTION ENGINE

摘要

Regarding a sliding structure for an internal combustion engine of the present invention, a cylinder has a plurality of recesses formed in a stroke center region. Piston rings are configured to have inclined surfaces formed on an outer circumferential surface thereof, and a lubricating oil flows into a gap between the inner wall surface and the outer circumferential surface that relatively move via the inclined surfaces, thereby enabling fluid lubrication. At any RPM equal to or greater than an RPM for an idling operation of the internal combustion engine, a friction coefficient (hereafter, a center friction coefficient) at a place of the stroke center region through which the piston rings pass at the highest speed is set to be less than a center friction coefficient when it is assumed that the recesses are not formed in the stroke center region. On the other hand, at the RPM, a friction coefficient (hereafter, an outside friction coefficient) when the piston rings pass through any place in an outside region that is outside the stroke center region is set to be less than an outside friction coefficient when it is assumed that the plurality of recesses are formed in the outside region. As a result, it is possible to achieve further improved low fuel efficiency for the dimple liner technique.