An engine is provided with a cylinder head defining a coolant jacket therein that is formed from a series of passages interconnected by a series of curved junctions to direct coolant about spark plugs, exhaust valves, and an integrated exhaust manifold in the head. The cooling jacket has a first longitudinal passage with an annular section about a spark plug, a second longitudinal passage with an annular section about an exhaust valve, and a third passage surrounding an integrated exhaust manifold and fluidly connecting the first and second passages. The first passage has a continuously decreasing area and the second passage has a continuously increasing area in a direction of coolant flow.

A cylinder head containing an exhaust system manifold for an engine includes screw holes formed through a fastening face of the cylinder head and an exhaust pipe, and outlet cooling channels that are provided adjacent to an outlet of a confluence of the manifold, and are disposed between the screw holes and the outlet. Coolant flows through the outlet cooling channels.

The present invention is configured such that: a cylinder block includes an introducing portion provided at a first side of a cylinder row, cooling liquid being introduced through the introducing portion to a water jacket, a restrictor portion provided in a vicinity of the introducing portion and configured to restrict the cooling liquid, introduced through the introducing portion, from flowing to an intake-side portion of the water jacket, and a discharging portion provided at a middle portion of the cylinder row at an intake side, the cooling liquid being discharged from the water jacket through the discharging portion; and an exhaust-side portion of the water jacket is formed such that a passage cross-sectional area of a cylinder axis direction upper side of the exhaust-side portion is larger than the passage cross-sectional area of a cylinder axis direction lower side of the exhaust-side portion.

An internal combustion engine includes an intake air temperature adjustment apparatus that adjusts the temperature of intake air, and a control apparatus that operates at least the intake air temperature adjustment apparatus. When the internal combustion engine operates in a stoichiometric EGR mode, the control apparatus operates the intake air temperature adjustment apparatus so that the temperature of intake air entering a combustion chamber enters a first temperature region. When the internal combustion engine operates in a lean mode, the control apparatus operates the intake air temperature adjustment apparatus so that the temperature of intake air entering a combustion chamber enters a second temperature region that is a lower temperature region than the first temperature region.

A cylinder cooling apparatus for an engine may include a plurality of intake ports disposed in a cylinder head and communicating with a corresponding plurality of cylinders, a water supply line extending inside from a side of the cylinder head and communicating with the intake ports, and a water pump supplying water to the intake ports through the water supply line.

The control apparatus operates an engine water temperature adjustment apparatus so that the temperature of cooling water that passes through an engine head enters a first temperature region in a lean mode, and operates the engine water temperature adjustment apparatus so that the temperature of the cooling water enters a second temperature region that is lower than the first temperature region in a stoichiometric mode. When knocking is detected after switching is started from the stoichiometric mode to the lean mode, the control apparatus performs any one of a first operation to operate a variable valve apparatus so as to retard the closing timing of an intake valve, a second operation to operate an oil jet apparatus so as to increase an oil jet amount, and a third operation to operate an EGR apparatus so as to increase an EGR amount.

A cooling structure of an engine includes a cylinder head and a coolant temperature sensor. The cylinder head gas a first water jacket for cooling a combustion chamber and a second water jacket for cooling an exhaust manifold. The cylinder head includes a joining portion where coolants from the first water jacket and the second water jacket join together. The joining portion has a first coolant passage. A second coolant passage is disposed downstream of the joining portion. The temperature sensing portion is disposed in the second coolant passage. A coolant outlet of the second water jacket is defined in the first coolant passage, and is located at a position on the cylinder head cover attachment surface side in the first coolant passage. The temperature sensing portion is located at a position on the cylinder block attachment surface side in the second coolant passage.

An engine cylinder block includes a control valve and stratified layers defining a network internal to the cylinder block. The network includes a main feed line in fluid communication with the control valve, and branched and winding arterial channels extending from the main feed line with diameters that taper to define nozzles configured to spray coolant on sides of pistons carried within the cylinder block.

The present invention is related to a method for manufacturing a water cooling system (20) inside a casted cylinder head (10), the water cooling system (20) comprising an upper water jacket (21) and a lower water jacket (22) and wherein a transition channel (23) is located between the upper water jacket (21) and the lower water jacket (22). Further, the invention is related to a water cooling system (20) inside a casted cylinder head (10), comprising an upper water jacket (21) and a lower water jacket (22) wherein the upper water jacket (21) and the lower water jacket (22) are fluidly connected by at least one transition channel (23).

A cylinder head includes: an exhaust port configured to lead out exhaust gas from combustion chamber; an intake port configured to introduce fresh air into the combustion chamber; and an EGR gas passage in which EGR gas flows, wherein exhaust outlets of the exhaust port and an EGR gas inlet of the second EGR pipe are located on a first side of the cylinder head and, and a fresh air inlet communicated to the intake port and an EGR gas outlet of the EGR gas passage are located on a second side which is opposite from the first side.