US 10,190,534 B2Granted

Two-cycle engine

AssigneeMaruyama Mfg. Co., Inc.

InventorTerutaka Yasuda

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Abstract

A peripheral wall portion of a piston is provided with a through hole penetrating through the peripheral wall portion. A cylinder is provided with a scavenging passage having a first opening being open in a bore surface and configured to make a bore section and a crank chamber communicate with each other and is provided with a communication passage having a second opening being open in the bore surface on the other side with respect to the first opening and configured to make the bore section and the scavenging passage communicate with each other. The cylinder and piston are configured so that the through hole overlaps the second opening to communicate with the communication passage in a partial interval of a scavenging stroke in which the first opening becomes open in the bore surface on one side of the piston with reciprocal motion of the piston.

Claims19

Dependent claims

A two-cycle engine comprising:

a cylinder having a bore section of a cylindrical shape and a combustion chamber connected continuously to one side of the bore section in an axial direction;
a crankcase arranged on the other side of the cylinder in the axial direction and having a crank chamber connected continuously to the other side of the bore section;
and
a piston arranged in the bore section and being reciprocally movable along the axial direction between the combustion chamber and the crank chamber,
wherein the piston has a crown portion opposed to the combustion chamber and a peripheral wall portion of a cylindrical shape provided continuously from the crown portion and extending along a bore surface of the bore section, wherein an interior space of the piston is at least partially formed by an inner side of the crown portion and the peripheral wall, the peripheral wall being provided with at least one through hole penetrating completely through the peripheral wall portion into the interior space of the piston,
wherein the cylinder is provided with at least one scavenging passage having a first opening being open in the bore surface and configured to make the bore section and the crank chamber communicate with each other, and at least one communication passage having a second opening being open in the bore surface on the other side with respect to the first opening and configured to make the bore section and the scavenging passage communicate with each other,
wherein the second opening is located at a position corresponding to the through hole of the piston in a circumferential direction of the bore section,
wherein the cylinder and the piston are configured so that the through hole overlaps the second opening to communicate with the communication passage at least in a partial interval of a scavenging stroke in which the first opening becomes open in the bore surface on the one side of the piston with reciprocal motion of the piston, the scavenging passage additionally in communication with the interior space of the piston via the through hole and the communication passage, when the through hole overlaps the second opening via the through hole and the communication passage, when the through hole overlaps, and
wherein the scavenging passage includes a pair of suction-side scavenging passages arranged away from each other in the circumferential direction of the bore section, and a pair of exhaust-side scavenging passages arranged away from each other in the circumferential direction of the bore section and arranged on an exhaust port side with respect to a suction-side scavenging passages.

6 more elements

A two-cycle engine comprising:

a crankcase including a crank chamber;
a cylinder comprising
a combustion chamber located at an opposite end of the cylinder from the crank chamber;
a bore section located between the crank chamber and the combustion chamber;
and
a side wall circumferentially surrounding the bore section and including a first opening located adjacent to the bore section and a second opening located adjacent to the bore section,
wherein a scavenging passage is at least partially formed in the side wall and fluidly couples the first opening with the crank chamber, and
wherein a communication passage is at least partially formed in the side wall and fluidly couples the second opening with the scavenging passage;
and
a piston mounted in the bore section of the cylinder, the piston comprising a peripheral wall extending along the side wall of the cylinder, an interior space of the piston located on an inner side of the peripheral wall, and a through hole penetrating completely through the peripheral wall into the interior space of the piston,
wherein the piston is configured to align the through hole with the second opening in the side wall of the cylinder to fluidly couple the through hole with the communication passage while the first opening fluidly couples the crank chamber with the bore section, and wherein the scavenging passage is fluidly coupled with the interior space of the piston via the through hole and the communication passage, when the through hole is aligned with the second opening, and
wherein the scavenging passage includes a pair of suction-side scavenging passages arranged away from each other in the circumferential direction of the bore section, and a pair of exhaust-side scavenging passages arranged away from each other in the circumferential direction of the bore section and arranged on an exhaust port side with respect to a suction-side scavenging passages.

9 more elements

A two-cycle engine comprising:

a crankcase including a crank chamber;
a cylinder comprising
a combustion chamber located at an opposite end of the cylinder from the crank chamber;
a bore section located between the crank chamber and the combustion chamber and;
a side wall circumferentially surrounding the bore section and including a first opening located adjacent to the bore section and a second opening located adjacent to the bore section;
wherein a scavenging passage is at least partially formed in the side wall and fluidly couples the first opening with a crank-chamber opening,
wherein the scavenging passage comprises a central portion located between the first opening and the crank-chamber opening, and
wherein a communication passage is at least partially formed in the side wall and fluidly couples the second opening with the scavenging passage at a location between the central portion and the crank-chamber opening;
a piston mounted in the bore section of the cylinder, the piston comprising a peripheral wall extending along the side wall of the cylinder, an interior space of the piston located on an inner side of the peripheral wall, and a through hole formed penetrating completely through the peripheral wall into the interior space of the piston,
wherein the piston is configured to align the through hole with the second opening in the side wall of the cylinder to fluidly couple the through hole with the communication passage, and wherein the scavenging passage is fluidly coupled with the interior space of the piston via the through hole and the communication passage, when the through hole is aligned with the second opening and
wherein the scavenging passage includes a pair of suction-side scavenging passages arranged away from each other in the circumferential direction of the bore section, and a pair of exhaust-side scavenging passages arranged away from each other in the circumferential direction of the bore section and arranged on an exhaust port side with respect to a suction-side scavenging passages.

8 more elements

Dependencies are inferred from the claim text.