An exhaust valve system for a two-stroke internal combustion engine having: at least one exhaust valve movable between open and closed positions; an actuator for moving the at least one exhaust valve; a valve position sensor; a controller communicating with the actuator and the valve position sensor. The controller being programmed for: controlling the actuator to attempt to move the at least one exhaust valve to a desired one of the open and closed positions; determining if the at least one exhaust valve has failed to reach the desired position based on the position of the at least one exhaust valve sensed by the valve position sensor; and controlling the actuator to move the at least one exhaust valve to an intermediate position when the at least one exhaust valve has failed to reach the desired position.

Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

In an internal combustion engine, an oil return passage extending from a breather chamber can be formed without increasing the number of component parts and without increasing the size of the internal combustion engine. The internal combustion engine (1) comprises an engine block (30) defining a cylinder (2); a case member (19) fastened to a lower part of the engine block to define a crank chamber jointly with the engine block; a bearing member (50) fastened to the engine block in the crank chamber to rotatably support a crankshaft; a breather chamber (113) defined in the engine block; an inlet passage (112) formed in the engine block to communicate the crank chamber with the breather chamber; a connection pipe (114) communicating the breather chamber with an intake device; and an oil return passage (150) formed at least in the bearing member, and extending from a bottom part of the breather chamber to an oil return port (147) opening at an outer surface of the bearing member. The oil return port may be provided in a lower part of the bearing member.

An engine includes a cylinder block including a cylinder hole, a crank shaft as an offset crank, and a connecting rod that connects the piston and the crank shaft. An inclined surface is provided on an entire circumference of a crank-shaft-side opening edge of one end of the cylinder hole. When viewed in the axial direction of the crank shaft, a boundary line between the inclined surface and the cylinder hole extends towards the other end of the cylinder hole as it extends toward an offset side on which the crank shaft is offset from the center axis of the cylinder hole. The offset crank engine has the entire circumference of the crank-shaft-side opening edge of the cylinder hole chamfered without any bad influence on the sliding surface and posture of the piston to avoid interference between the crank-shaft-side opening edge of the cylinder hole and the connecting rod.

Aluminum alloys having improved properties are provided. The alloy includes about 8 to about 12 weight percent silicon, about 0.5 to about 1.5 weight percent copper, about 0.2 to about 0.4 weight percent magnesium, 0 to about 0.5 weight percent iron, about 0.3 to about 0.6 weight percent manganese, 0 to about 1.5 weight percent nickel, and 0 to about 0.5 weight percent zinc. Aluminum may be present in an amount between about 80 and 91 weight percent. The alloy may include about 0.1 to about 0.5 weight percent each of trace elements such as titanium, vanadium, and/or zirconium, and up to about 0.25 weight percent of all other trace elements. In addition, the alloy may contain about 0.03 to about 0.1 weight percent of strontium, sodium, and/or antimony, and up to 5 ppm phosphorus. Also disclosed is a high pressure die cast article, such as an engine block.

Provided is an apparatus for supplying lubricant to a timing chain installed in an engine, the apparatus including an injection hole configured for injecting lubricant from an oil pump, and an inner cover having a guide groove configured to receive lubricant injected from the injection hole and guide the lubricant toward a engagement place between the timing chain and a sprocket, wherein the inner cover has a guide groove provided at a position facing an injection hole of a counter surface portion that is spaced apart from a cylinder block and faces the guide groove.

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

An internal combustion engine includes a crankshaft. The crankshaft includes multiple crank journals, at least two crank pins positioned between two of the multiple crank journals that neighbor one another, and at least one pin arm. Each pin arm may be positioned between two of the crank pins neighboring one another. Arrangements may include multiple crankshaft supports and multiple thrust bearings. These elements may be distributed about the crankshaft such that two or more of the multiple crankshaft supports have at least one associated thrust bearing. Each of the crankshaft supports having the associated thrust bearing may support one of the multiple the crank journals. Each thrust bearing may be positioned between the crankshaft and the crankshaft support having the associated thrust bearing.

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.

A cylinder liner is provided that includes a cylinder bore capable of housing a piston, a top end having an annular flange, a first cylindrical section, a second cylindrical section, and an annular ridge that separates the first cylindrical section and the second cylindrical section. When employed in an a liner bore of an engine bock, the cylinder liner provides for two channels that allow for coolant to be supplied to the cylinder liner.