Abstract: A thermal insulator for a cylinder bore wall section having a shape conforming to a shape of the groove-like coolant passage in a setting position of the thermal insulator, in which each of the bore wall insulating sections includes a rubber member, a rear surface pressing member, and elastic members, a coolant passage opening through which coolant flowing on a rear surface side of the supporting section passes to flow to an inner side of the supporting section is formed on at least one place of upper portions of supporting section inter-bore portions, the supporting section has a guide wall formed in a vicinity of the coolant passage opening, and has an inclined wall formed on the rear surface side of the supporting section bore portion, and only a center or a vicinity of the center in an arc direction of each of the bore wall insulating sections is fixed to the supporting section.

Abstract: There is provided a water jacket spacer set in a groove-like coolant passage of a cylinder block of an internal combustion engine including cylinder bores and set in an entire circumferential direction or a part in a circumferential direction of the groove-like coolant passage when viewed in the circumferential direction, wherein a coolant passage opening through which coolant flowing on the rear surface side of the water jacket spacer passes to flow to an inner side of the water jacket spacer is formed on at least one place of upper portions of inter-bore portions, a guide wall for guiding the coolant is formed in a vicinity of the coolant passage opening, such that the coolant flows into the coolant passage opening; and an inclined wall is formed on the rear surface side of bore portions of a position where the coolant is supplied into the groove-like coolant passage, the inclined wall extending with an upward inclination to create a flow of the coolant toward the coolant passage opening.

Abstract: A heat retention material cartridge fixed to a base member of a heat retention tool of a cylinder bore's bore wall for heat retention of the cylinder bore wall, which includes a thermosensitive expansion rubber, a back-side pressing member, a rectangular opening, a front-side abutting plate cooperative with the back-side pressing member for sandwiching an outer edge portion of the thermosensitive expansion rubber, and an elastic member attached member to which an elastic member is attached. A convex portion being convex toward the side of the back-side pressing member is formed in a portion of the front-side abutting plate where the outer end is not sandwiched by bendable portions. And, the outer edge portion of the thermosensitive expansion rubber is formed in such a manner that the outer end of the thermosensitive expansion rubber is positioned inside an apex of the convex portion.

Abstract: A heat retention material cartridge fixed to a base member of a heat retention tool of a cylinder bore's bore wall for heat retention of the cylinder bore wall, which includes a thermosensitive expansion rubber, a back-side pressing member, a rectangular opening, a front-side abutting plate cooperative with the back-side pressing member for sandwiching an outer edge portion of the thermosensitive expansion rubber, and an elastic member attached member to which an elastic member is attached. A convex portion being convex toward the side of the back-side pressing member is formed in a portion of the front-side abutting plate where the outer end is not sandwiched by bendable portions. And, the outer edge portion of the thermosensitive expansion rubber is formed in such a manner that the outer end of the thermosensitive expansion rubber is positioned inside an apex of the convex portion.

Abstract: There is provided a water jacket spacer set in a groove-like coolant passage of a cylinder block of an internal combustion engine including cylinder bores and set in an entire circumferential direction or a part in a circumferential direction of the groove-like coolant passage when viewed in the circumferential direction, wherein a coolant passage opening through which coolant flowing on the rear surface side of the water jacket spacer passes to flow to an inner side of the water jacket spacer is formed on at least one place of upper portions of inter-bore portions, a guide wall for guiding the coolant is formed in a vicinity of the coolant passage opening, such that the coolant flows into the coolant passage opening; and an inclined wall is formed on the rear surface side of bore portions of a position where the coolant is supplied into the groove-like coolant passage, the inclined wall extending with an upward inclination to create a flow of the coolant toward the coolant passage opening.

Abstract: A thermal insulator for a cylinder bore wall includes bore wall insulating sections set for each of the bore walls of the cylinder bores, and a supporting section having a shape conforming to a shape of the groove-like coolant passage in a setting position of the thermal insulator, in which each of the bore wall insulating sections includes a rubber member, a rear surface pressing member, and elastic members, a coolant passage opening through which coolant flowing on a rear surface side of the supporting section passes to flow to an inner side of the supporting section is formed on at least one place of upper portions of supporting section inter-bore portions, the supporting section has a guide wall formed in a vicinity of the coolant passage opening, and has an inclined wall formed on the rear surface side of the supporting section bore portion, and only a center or a vicinity of the center in an arc direction of each of the bore wall insulating sections is fixed to the supporting section.

Abstract: A cylinder bore wall thermal insulator set in a groove-like cooling water channel of a cylinder block of an internal combustion engine including cylinder bores and for insulating all bore walls of all the cylinder bores or a part of the bore walls of all the cylinder bores includes bore wall insulating sections having an arcuate shape when viewed from above and for insulating a wall surface on the cylinder bore side of the groove-like cooling water channel and a supporting section made of synthetic resin and having a shape conforming to a shape of the groove-like cooling water channel in a setting position of the thermal insulator, the bore wall insulating sections being fixed to the supporting section. The bore wall insulating sections include rubber members, rear surface pressing members, and elastic members.

Abstract: A heat retention material cartridge fixed to a base member of a heat retention tool of a cylinder bore's bore wall for heat retention of the cylinder bore wall, which includes a thermosensitive expansion rubber, a back-side pressing member, a rectangular opening, a front-side abutting plate cooperative with the back-side pressing member for sandwiching an outer edge portion of the thermosensitive expansion rubber, and an elastic member attached member to which an elastic member is attached. A convex portion being convex toward the side of the back-side pressing member is formed in a portion of the front-side abutting plate where the outer end is not sandwiched by bendable portions. And, the outer edge portion of the thermosensitive expansion rubber is formed in such a manner that the outer end of the thermosensitive expansion rubber is positioned inside an apex of the convex portion.

Abstract: A cylinder bore wall thermal insulator set in a groove-like cooling water channel of a cylinder block of an internal combustion engine including cylinder bores and for insulating all bore walls of all the cylinder bores or a part of the bore walls of all the cylinder bores includes bore all insulating sections having an arcuate shape when viewed from above and for insulating a wall surface on the cylinder bore side of the groove-like cooling water channel and a supporting section made of synthetic resin and having a shape conforming to a shape of the groove-like cooling water channel in a setting position of the thermal insulator, the bore wall insulating sections being fixed to the supporting section. The bore wall insulating sections include rubber members, rear surface pressing members, and elastic members.

Abstract: In the process of starting by a recoil starter, a maximum value detection section of an ECM detects a maximum value of pressure (basic atmospheric pressure) in an intake pipe detected by a pressure sensor, within a predetermined range of crank angle after activation of the ECM. An idling control unit gives feedback control on an ISC valve based on engine speed detected by an engine speed sensor, to thereby keep idling engine speed at a specified value. A correction unit corrects a basic atmospheric pressure detected by the maximum value detection section based on the duty ratio of the ISC valve in idling, and uses the result as the atmospheric pressure. A storage unit 9d stores a map in which the duty ratio of the ISC valve in idling is correlated with the amount of correction to be made on the basic atmospheric pressure.

Abstract: In the process of starting by a recoil starter, a maximum value detection section of an ECM detects a maximum value of pressure (basic atmospheric pressure) in an intake pipe detected by a pressure sensor, within a predetermined range of crank angle after activation of the ECM. An idling control unit gives feedback control on an ISC valve based on engine speed detected by an engine speed sensor, to thereby keep idling engine speed at a specified value. A correction unit corrects a basic atmospheric pressure detected by the maximum value detection section based on the duty ratio of the ISC valve in idling, and uses the result as the atmospheric pressure. A storage unit 9d stores a map in which the duty ratio of the ISC valve in idling is correlated with the amount of correction to be made on the basic atmospheric pressure.