Patent ID: 9027933
Filing Date: 2015-05-12
Classification: F02F,F16J

Abstract:
1. An engine comprising: a first land, a first ring groove, a second land, a second ring groove, a third land, a third ring groove, and a piston skirt formed on a piston peripheral wall in the above-recited order from a side of a piston head; a first pressure ring fitted in the first ring groove; a second pressure ring fitted in the second ring groove; an oil ring fitted in the third ring groove; and an indentation formed at the second land, wherein a corner at a boundary between an outer peripheral face of the second land and a second-land-side end face of the second ring groove is planed off with a tapered face having a diameter reducing toward the second ring groove and the tapered face forms the indentation of the second land, and an angle of the tapered face to a cylinder-side imaginary extension line of the second-land-side end face of the second ring groove is 30° to 60° and a percentage of a value obtained by dividing a depth of the tapered face in a radial direction of a piston by a depth of the second ring groove in the radial direction of the piston is 20% to 30%.