An engine block includes one or more cylinder bores wherein each cylinder bore is surrounded by a cylinder bore wall. The cylinder bore wall includes a liner stop mechanism to locate a liner in the cylinder bore. The cylinder bore includes a mid-portion that spans between an upper end and a lower end, wherein the liner stop mechanism can be located near the upper end, near the lower end, or the mid-portion. The engine block has an outer cylinder block wall that is exterior to the cylinder bore wall. The outer cylinder block wall includes a first rib positioned above the liner stop mechanism and a second rib positioned below the liner stop mechanism relative to a cylindrical axis of the cylinder bore. The first and second ribs straddle the liner stop mechanism to reduce rotation and buckling of the liner during operation of the engine.

An engine block includes one or more cylinder bores at least partially surrounded by a cylinder bore wall. The cylinder bore wall includes a liner stop mechanism to support a liner in the cylinder bore. The engine block has an outer cylinder block wall that is exterior to the cylinder bore wall. The outer cylinder block wall includes at least one rib located relative to the liner stop mechanism to reduce rotation and buckling of the liner during operation of the engine.

In an internal combustion engine that includes a cylinder block and a cylinder head, and has a cam chain chamber on a side of the cylinder block, a beam member that traverses the cam chain chamber is disposed in the cam chain chamber.

A cylinder head [20, 120] mountable onto a cylinder block [16] of an engine [10] is disclosed. The cylinder head [20, 120] includes at least one fastener boss [28, 128] configured for receiving a fastener [24], and the cylinder head [20, 120] is securely fastened onto the cylinder block [16] of the engine [10] by the fastener [24]. A boss cutout [30, 130] is formed on a lower portion of the at least one fastener boss [28, 128] that abuts the cylinder block [16] such that a contact pressure balance of sealing pressures around the cylinder block [16] is evenly distributed.

A cylinder block for an internal combustion engine includes a metal section and a resin section. The metal section includes: a cylinder liner; head bolt female screw portions that are screwed onto male screw portions of head bolts that fasten the cylinder block and a cylinder head; crank cap bolt female screw portions that are screwed onto male screw portions of crank cap bolts that fasten the cylinder block and crank caps and columnar portions that connect the head bolt female screw portions; and the crank cap bolt female screw portions. The cylinder liner and the columnar portions are integrated with each other.

Systems and methods are provided for a cylinder block having one or more bulkheads. The bulkheads provide a dual-wall structure that may enhance the stiffness of the cylinder block in bending and torsion. The bulkheads may also provide an oil drain to allow oil to directly drain through a hollow core of the bulkhead. An overflow outlet may be formed in an inner wall of a bulkhead. In some implementations, a cylinder block with bulkheads may increase an oil capacity of an engine.

A crankcase assembly for an engine comprising: a crankcase comprising a crank sump; the crank sump comprising primary and secondary sump volumes; one or more crankcase oil catchers, the crankcase oil catchers comprising surfaces to catch dispersed oil in the crankcase and direct the oil away from a crankcase casing wall and towards the crank sump, wherein the crankcase oil catchers are provided above a crankshaft and below a piston of the engine; and one or more guides to collect oil and guide the oil to the primary sump volume. At least a portion of the guide is movable between a first configuration in which the guide collects the captured oil that would otherwise have.

A cylinder block that can be used commonly in a longitudinally mounted engine and a transversely mounted engine without increasing a manufacturing cost. The cylinder block comprises an attachment flange joined to a transmission or a transaxle, and an oil pan or the oil pan and a ladder frame are attached to a lower end thereof. The attachment flange comprises: a first flange formed on an outer periphery thereof; a first joint surface formed on the first flange to be joined to a matching surface of the transmission; a second flange extending in the inner side of the first flange; and a second joint surface formed on the second flange to be joined to a matching surface of the transaxle.

An internal combustion engine has a cylinder block and a cylinder head fixed to each other with a plurality of bolts, and a piston fitted in a cylinder bore of the cylinder block so as to be able to reciprocate. A portion of the cylinder bore having a minimum diameter in a travel range of a skirt across which the skirt travels as the piston reciprocates is located within a range facing the skirt when the piston is at a bottom dead center. A clearance between the skirt and the minimum-diameter portion has a minimum value of a clearance between the skirt and a wall surface of the cylinder bore.

An engine includes a cylinder, a rocker chamber, an air filter, a crankcase and a rocker chamber cover, wherein the rocker chamber cover is disposed above the cylinder. The engine further includes a cover plate, wherein the cover plate is located at the top of the rocker chamber cover, and the rocker chamber cover and the cover plate are spliced to form a separation cavity and a connection channel. According to the engine provided by the invention, the top structure of the rocker chamber is re-designed and the top space of the rocker chamber is sufficiently used so as to achieve the objects of optimizing a lubricating system and reducing emission, as well as reducing the manufacturing cost and difficulty.