A breather chamber structure for an internal combustion engine wherein the breather chamber can be disposed compactly and the degree of freedom in the layout of the parts of the internal combustion engine can be raised. The breather chamber structure includes a crankcase, a cylinder body provided upwardly on the crankcase, and a breather chamber configured to separate oil from oil mist in the crankcase. The breather chamber includes a crankcase side breather chamber provided in the crankcase and open to a joining plane between the crankcase and the cylinder body, and a cylinder side breather chamber provided in the cylinder body and open to the joining plane.

An electric variable valve timing apparatus includes a sprocket unit and an electric motor. The electric motor is fixed to a chain cover with bolts. The chain cover includes plural bosses each having an internal thread to which one of the bolts is threaded. The bosses extend from the chain cover toward the sprocket unit to positions at which the bosses face an outer periphery of the sprocket unit in a radial direction. The bosses are arranged such that, when the sprocket unit moves downward from an attaching position, at which the sprocket unit is attached to the camshaft, at least two bosses are engaged with the sprocket unit to restrict downward movement of the sprocket unit, and that the sprocket unit is allowed to move between a location outside of a space covered by the chain cover and the attaching position.

An internal combustion engine has a crankcase having a first crankcase portion fastened to a second crankcase portion along a first plane, a crankshaft, a cylinder block defining two cylinders, two pistons, and a cylinder head. A crankshaft support defines a crankshaft support aperture. A central portion of the crankshaft is received in the crankshaft support aperture. At least one fastener fastens the crankshaft support to the cylinder block. The at least one fastener is perpendicular to a crankshaft axis and is disposed in a second plane. The crankshaft axis is normal to the first plane. The second plane is one of coplanar with and parallel to the first plane.

A composite cylinder block for an internal combustion engine includes a main block body made of a metal material and an outer member made of a synthetic resin material. The main block body has a lower deck, a base part and a cylinder wall. The outer member has an upper deck and a water jacket constituting wall surrounding the cylinder wall to define a water jacket. An outer-member-side mating surface is provided with a welding rib on a lower end of the water jacket constituting wall and is heat-welded to a top surface of the base part by heating the main block body from the lower side and pressing the outer-member-side mating surface against the main block body. The welded surfaces of the main block body and the outer member are in one plane orthogonal to a cylinder axis direction.

A cylinder head structure that can increase the rigidity of an area corresponding to an area between cylinder bores and improve a sealing force of an inter-bore corresponding portion positioned above between adjacent cylinders when enhancing the sealing force between a cylinder block and the cylinder head to improve engine output. The cylinder head structure includes: insertion walls through which right and left fastening bolts arranged between adjacent cylinders pass; a head upper wall connecting upper end portions of a pair of the insertion walls; and a cylinder head bottom wall, and a head cooling water channel is surrounded by those four walls (insertion walls, head upper wall, cylinder head bottom wall), and a vertical wall in a state of extending left and right spanning the head upper wall and the cylinder head bottom wall to block the head cooling water channel is formed between the pair of insertion walls.

An internal combustion engine includes a first cylinder block, a first head, a first overhead structure, a second cylinder block, a second head, a second overhead structure, a first through-bolt aperture, and a first through-bolt. The first head is in contact with the first cylinder block. The first overhead structure is in contact with the first head opposite the first cylinder block. The second cylinder block is in contact with the first cylinder block opposite the first head. The second head is in contact with the second cylinder block opposite the first cylinder block. The second overhead structure is in contact with the second head opposite the second cylinder block. The first through-bolt aperture is defined through the first overhead structure, the first head, the first cylinder block, the second cylinder block, the second head, and the second overhead structure.

A composite cylinder block for an internal combustion engine includes a main block body made of a metal material and an outer member made of a synthetic resin material. The main block body has a lower deck, a base part and a cylinder wall. The outer member has an upper deck and a water jacket constituting wall surrounding the cylinder wall to define a water jacket. An outer-member-side mating surface is provided with a welding rib on a lower end of the water jacket constituting wall and is heat-welded to a top surface of the base part by heating the main block body from the lower side and pressing the outer-member-side mating surface against the main block body. The welded surfaces of the main block body and the outer member are in one plane orthogonal to a cylinder axis direction.

An internal combustion engine includes a first cylinder block, a first head, a first overhead structure, a second cylinder block, a second head, a second overhead structure, a first through-bolt aperture, and a first through-bolt. The first head is in contact with the first cylinder block. The first overhead structure is in contact with the first head opposite the first cylinder block. The second cylinder block is in contact with the first cylinder block opposite the first head. The second head is in contact with the second cylinder block opposite the first cylinder block. The second overhead structure is in contact with the second head opposite the second cylinder block. The first through-bolt aperture is defined through the first overhead structure, the first head, the first cylinder block, the second cylinder block, the second head, and the second overhead structure.

The present application relates to rib structure on cylinder block. A cylinder block having a top surface, an inner bottom surface, a cylinder opening on the top surface, and a head boss positioned on the top surface, centered on a first axis, and configured to engage with a fastener at an initial position, which defines a first depth. The cylinder block includes a first main boss positioned on the inner bottom surface, centered on a second axis, and configured to engage with a first main fastener at a first end position, which defines a second depth. The cylinder block includes a second main boss positioned on the inner bottom surface and configured to engage with a second main fastener at a second end position, which defines a third depth. The cylinder block includes a first rib path extending from the first depth to the second depth and a second rib path extending from the first depth to the third depth.

The present disclosure relates to an engine assembly for a vehicle. The engine assembly comprises an engine including a cylinder head and an engine block. The engine block comprises a cylinder block and a crankcase having a crankshaft. The engine may be used in different models of the vehicle having different characteristics by interchanging or replacing the cylinder head from a plurality of cylinder heads and/or a cylinder block from a plurality of cylinder blocks, while keeping one or more engine components such as the crankcase, a timing chain, or a valve cover the same. Accordingly, the engine is adaptable to different vehicles.