Cylinder head structure for internal combustion engine

A cylinder head structure for an internal combustion engine, the cylinder head structure comprising:

• a cylinder head;
• a first camshaft and a second camshaft one of which is structured for an intake valve and the other is structured for an exhaust valve;
• a first hydraulic lash adjuster disposed in the cylinder head, corresponding to the first camshaft;
• a second hydraulic lash adjuster disposed in the cylinder head, corresponding to the second camshaft,
• a cam carrier that is fixed to an upper part of the cylinder head and supports the first camshaft;
• an oil source-pressure passage disposed inside the cylinder head and positioned between the first and second camshafts when viewed in a direction of a cylinder axis;
• and
• an oil passage that leads from the oil source-pressure passage to the first hydraulic lash adjuster and includes a cam carrier internal passage passing inside the cam carrier,
• wherein:
• the first hydraulic lash adjuster is positioned further outward in a widthwise direction of the internal combustion engine than a corresponding one of centerlines of valve stems of the intake valve and the exhaust valve;
• the second hydraulic lash adjuster is positioned between the centerlines of the valve stems of the intake valve and the exhaust valve, in the widthwise direction of the internal combustion engine;
• the oil source-pressure passage extends vertically inside cylinder head, and is connected to the cam carrier internal passage at a joint surface between the cylinder head and the cam carrier;
• the cam carrier internal passage passes above the first camshaft and is connected to a first cylinder head internal oil passage for the first hydraulic lash adjuster, when viewed in the direction of the cylinder axis;
• and
• the second hydraulic lash adjuster is connected to the oil source-pressure passage via a second cylinder head internal oil passage for the second hydraulic lash adjuster, without passing through the cam carrier.