A cylinder block includes a support wall part that rotatably supports a crank shaft. The support wall part has a fitting recess part to which a bearing cap can be fitted. In each of the left and right corner parts where a bottom surface and a fitting surface of the fitting recess part intersect, a notch groove is formed that extends in the array direction of cylinder bores and has a substantially arc-shaped cross section when cut by the virtual plane along the extension direction thereof. As a result, stress having a greater value as the location becomes closer to the center part in the extension direction of the notch groove can be substantially uniform in the extension direction of said notch groove, and it is possible to effectively mitigate the stress concentration.

Provided is a power generation apparatus, which includes an internal combustion engine, and a rotary electric machine disposed adjacent to the internal combustion engine in an axial direction. The rotary electric machine includes coils to which an electric current is supplied from an external power apparatus via an electric power supply cable. Terminal parts connected to the coils and connection terminals of the electric power supply cable are connected in a predetermined connection space that is formed in part of a lower block of an engine block of the internal combustion engine.

An engine block, an engine subassembly, and method for providing and manufacturing an engine block. The engine block includes a plurality of cylinder barrels positioned in the engine block, at least one oil jacket channel formed in the engine block, and an oil inlet port positioned in a peripheral wall of the engine block and connected to the at least one oil jacket channel. The at least one oil jacket channel includes a plurality of curved channel sections. Each curved channel section in the plurality of curved channel sections extends about at least a portion of a circumferential portion of a respective cylinder barrel in the plurality of cylinder barrels. The at least one oil jacket channel extends between adjacent cylinder barrels of the plurality of cylinder barrels in the engine block.

A quantitative one-way oil gas lubricant system and a method for a 4-stroke engine, including a preceding stage quantitative oil intake orifice that is connected to a lubricant case on a wall of a crankcase of the 4-stroke engine, and a final stage quantitative airflow orifice disposed at a cylinder cover of the 4-stroke engine, are provided. A diameter of the preceding stage quantitative oil intake orifice D.sub.1 and a diameter of the final stage quantitative airflow orifice satisfy an equation: D.sub.1/D.sub.3=0.8-1.5, wherein a one-way connected oil gas lubricant channel is disposed between the preceding stage quantitative oil intake orifice and the final stage quantitative airflow orifice. A lubricant oil sucked from the preceding quantitative oil intake orifice by the crankcase flows along the oil gas lubricant channel and lubricates the engine parts that the channel passes through in turns. Finally, a minute quantity of waste oil gas that flows out from the final stage quantitative airflow orifice is introduced into a cylinder of the 4-stroke engine and is to be burned completely. The supply quantity of the lubricant oil may be controlled, and no extra lubricant oil gas may flow out from the final stage quantitative airflow orifice, therefore, the quantitative and one-way lubricating is realized.

In some embodiments, a fuel rail for a two-stroke internal combustion engine includes a fuel rail body, a fuel inlet component integrated within the fuel rail body as a one-piece component and in fluidic contact with a fuel line, one or more fuel exit ports in fluidic contact with a cylinder of a combustion engine, and one or more fasteners adapted to secure the fuel rail body to a cylinder wall of the cylinder of the combustion engine.

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.

An engine block, an engine subassembly, and method for providing and manufacturing an engine block. The engine block includes a plurality of cylinder barrels positioned in the engine block, at least one oil jacket channel formed in the engine block, and an oil inlet port positioned in a peripheral wall of the engine block and connected to the at least one oil jacket channel. The at least one oil jacket channel includes a plurality of curved channel sections. Each curved channel section in the plurality of curved channel sections extends about at least a portion of a circumferential portion of a respective cylinder barrel in the plurality of cylinder barrels. The at least one oil jacket channel extends between adjacent cylinder barrels of the plurality of cylinder barrels in the engine block.

The present invention relates to a portable work machine including an engine placed in an internal space of an engine case, an ignition coil for igniting the engine provided closer to the engine, and a high voltage cord routed to connect the ignition coil to an ignition plug of the engine. The portable work machine includes a passage portion for housing and guiding the high voltage cord on a route from an area in which the ignition coil is placed to an area in which the ignition plug is placed, in which the passage portion is arranged on an upper face side of the engine case.

A ladder frame, for an engine, includes a crank cap portion made of cast iron, and a frame portion made of an aluminum alloy and formed integrally with the crank cap portion. The crank cap portion includes a first peripheral portion extending concentrically with an axis of a crankshaft and including a support surface. The support surface supports the crankshaft and is formed into an arc shape concentric with the axis. The frame portion includes a second peripheral portion extending in an arc shape along the first peripheral portion on a side opposite to the support surface.