Oil distribution blocks and oil distribution systems equipped therewith. Such an oil distribution block includes a rigid block body configured to be secured to a cylinder head of an engine, an oil inlet, and an oil outlet. The oil inlet is configured to be releasably coupled to a first oil distribution line or a fitting therebetween, receive a flow of oil therefrom, and route the oil to an inlet of a cooling passage of the cylinder head. The oil outlet is configured to be releasably coupled to a second oil distribution line or a fitting therebetween, receive a flow of oil from an outlet of the cooling passage of the cylinder head, and route the oil to the second oil distribution line. The oil inlet and the oil outlet are configured to threadably couple with the first and second oil distribution lines, respectively, or the fittings therebetween.

An HT cooling system cools at least a cylinder block with HT cooling water. An LT cooling system cools an intake port with LT cooling water that is at a lower temperature than the HT cooling water. A controller performs an ignition retard control that involves correcting the ignition timing based on the result of detection of a knock by a knock sensor, and a cooling enhancement control that involves enhancing cooling by the LT cooling system in the case where a knock is detected compared with the case where no knock is detected. The way of cooling by the HT cooling system is unchanged whether a knock is detected.

An HT cooling system cools at least a cylinder block with HT cooling water. An LT cooling system cools an intake port with LT cooling water that is at a lower temperature than the HT cooling water. A controller performs an ignition retard control that involves correcting the ignition timing based on the result of detection of a knock by a knock sensor, and a cooling enhancement control that involves enhancing cooling by the LT cooling system in the case where a knock is detected compared with the case where no knock is detected. The way of cooling by the HT cooling system is unchanged whether a knock is detected.

A water jacket spacer is provided that ensures that a cylinder bore wall has a uniform temperature. When a contact member that comes in contact with the all surface of a groove-like coolant passage is provided to either or both of the inner wall side and the outer wall side of the water jacket spacer along the longitudinal direction of the water jacket spacer to divide the groove-like coolant passage into an upper part and a lower part, it is possible to separately control the flow rate of the coolant that flows through the upper passage of the groove-like coolant passage, and the flow rate of the coolant that flows through the lower passage of the groove-like coolant passage, and separately adjust the degree of cooling with respect to the upper part and the lower part of the cylinder bore wall.

A water jacket spacer is provided that ensures that a cylinder bore wall has a uniform temperature. When a contact member that comes in contact with the all surface of a groove-like coolant passage is provided to either or both of the inner wall side and the outer wall side of the water jacket spacer along the longitudinal direction of the water jacket spacer to divide the groove-like coolant passage into an upper part and a lower part, it is possible to separately control the flow rate of the coolant that flows through the upper passage of the groove-like coolant passage, and the flow rate of the coolant that flows through the lower passage of the groove-like coolant passage, and separately adjust the degree of cooling with respect to the upper part and the lower part of the cylinder bore wall.

An engine coolant system includes a variable-opening valve having a plurality of tubes in fluid flow communication with an engine block and a radiator. The coolant system also includes an electrically-powered pump arranged to cycle coolant through the radiator and the engine block to regulate an engine temperature. The coolant system further includes a controller programmed to store a baseline relationship between pump speed and pump power draw using a nonlinear scale. The controller is also programmed to detect a steady state operating condition of the pump, and identify an operational relationship between real-time pump speed and a pump power draw. The controller is further programmed to detect a coolant leak based on a deviation between the baseline relationship and the operational relationship.

An engine coolant system includes a variable-opening valve having a plurality of tubes in fluid flow communication with an engine block and a radiator. The coolant system also includes an electrically-powered pump arranged to cycle coolant through the radiator and the engine block to regulate an engine temperature. The coolant system further includes a controller programmed to store a baseline relationship between pump speed and pump power draw using a nonlinear scale. The controller is also programmed to detect a steady state operating condition of the pump, and identify an operational relationship between real-time pump speed and a pump power draw. The controller is further programmed to detect a coolant leak based on a deviation between the baseline relationship and the operational relationship.

A prechamber assembly includes a cylinder head including a coolant cavity, a prechamber body located within the cylinder head, the prechamber body including a nozzle, and an annular sleeve radially surrounding a portion of the prechamber body. The sleeve includes a plurality of coolant inlet holes. A portion of the prechamber body is radially spaced from the sleeve to form a coolant sleeve annulus extending along a length of the prechamber body above the coolant inlet holes. The coolant cavity and the coolant sleeve annulus are in fluid communication through the plurality of coolant inlet holes.

A prechamber assembly includes a cylinder head including a coolant cavity, a prechamber body located within the cylinder head, the prechamber body including a nozzle, and an annular sleeve radially surrounding a portion of the prechamber body. The sleeve includes a plurality of coolant inlet holes. A portion of the prechamber body is radially spaced from the sleeve to form a coolant sleeve annulus extending along a length of the prechamber body above the coolant inlet holes. The coolant cavity and the coolant sleeve annulus are in fluid communication through the plurality of coolant inlet holes.

A water jacket coolant passage division member includes: a partition member that has a planar shape that conforms to a groove-like coolant passage provided to a cylinder block that is provided to an internal combustion engine; an inner-side rubber member that is provided to an inner side of the partition member, and comes in contact with a cylinder bore-side wall surface of the groove-like coolant passage; and an outer-side rubber member that is provided to an outer side of the partition member, and comes in contact with an outer wall surface of the groove-like coolant passage. An internal combustion engine in which a cylinder bore wall has a uniform temperature can be provided by utilizing the water jacket coolant passage division member.