A crankshaft oil supply structure includes: an upper engine block having upper end saddles positioned at both ends thereof and an upper crank saddle positioned between the upper end saddles; a lower engine block formed with a plurality of lower crank saddle; an upper end bearing formed with an end bearing hole and mounted on each of the upper end saddles; an upper main bearing formed with a main bearing hole and mounted on the upper crank saddle; a lower bearing mounted on each lower crank saddle of the plurality of lower crank saddles; and a crankshaft formed with an end journal supported by the upper end bearing, a main bearing journal supported by the upper main bearing, and a crank pin journal. In particular, the main bearing hole is larger than the end bearing hole.

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.

A crankshaft and conrod assembly (100) comprising a crankshaft (110) and a conrod (150), wherein the crankshaft (110) comprises at least one main journal (111) and one crankpin journal (112), where the crankshaft (110) is provided with an oil supply structure for supplying the crankpin journal (112) with lubrication oil and the conrod (150) with an oil pressure, wherein the oil supply structure comprises: an oil supply conduit (113) provided between the main journal and the crankpin journal (112), at least a first and a second oil supply opening (114, 115) provided at the crankpin journal (112), and a connection point (116) where the oil supply conduit (113) connects to the first and second oil supply opening (114, 115).

A rotary engine having a crankshaft, a housing provided with lobe accommodating portions arranged to surround the crankshaft, and combustion chambers communicating with the lobe accommodating portions, a rotor rotatable eccentrically with respect to the crankshaft and provided with lobes continuously accommodated in the lobe accommodating portions, a housing cover provided with a bearing portion through which the crankshaft is inserted so as to be rotatably supported, and a lubricating unit to supply oil to the bearing portion, wherein the lubricating unit includes an oil pan to accommodate oil therein, an oil pump to pump up oil filled in the oil pan, and an oil supply passage having both ends located in the oil pump and the bearing portion, respectively, is provided. This structure may allow direct and effective lubrication of the bearing portion, and can employ a journal bearing.

A crankshaft assembly for a vehicle, a method of operating a crankshaft assembly, and a method of manufacturing a crankshaft assembly. The crankshaft assembly includes a crankshaft, a first pin bearing journal and a main journal, an oil passage having a main passage wall, the oil passage extending from the first pin bearing journal to or through the main bearing journal, a crankpin exit hole located in the main passage wall, and a blocking element positioned in the oil passage, wherein the blocking element is located in a radially outward position with respect to the crankpin exit hole.

To provide an internal combustion engine that can be manufactured at low cost and be downsized by simplifying its lubrication system in the crankcase. An engine 9 includes: a crankcase; a cylinder equipped with a cylinder bore; a crankshaft; a balancer mechanism for reducing vibration of the engine by power transmitted from the crankshaft; a breather chamber provided on a top surface of the crankcase and disposed behind the cylinder; and a lubrication system for supplying lubricating oil to the crankshaft and the balancer mechanism. The balancer mechanism includes a first balancer disposed at a position farther from the cylinder bore than an idler gear. The lubrication system includes a balancer lubricating-oil passage branching off from a main gallery and reaching the first balancer across the breather chamber in a plan view.

A substantially tubular supply line (2, 11) of a main oil gallery (1, 10) for distributing lubricating or cooling oil to bearing points of a crankshaft of an internal combustion engine. The supply line (2, 11) has at least one inflow opening (3, 5, 6, 13) arranged on the supply line (2, 11) and feed lines (4, 12) having feed line openings (7.1, 7.2) on the supply line (2, 11) for feeding the lubricating or cooling oil to the bearing points of the crankshaft in the crankcase. The inflow opening (3, 5, 6, 7.1, 7.2, 13) is formed in a flow-favorable manner and may define a funnel shape.

The oil filter device is disposed on a side portion of one side of a cylinder body in a width direction in a cylinder head side with respect to an engine case in a space between center lines of main lubricating oil passages and a cylinder axis line of the cylinder body, and includes an oil pump disposed on the engine case and further lubricating oil passages that connect to the main lubricating oil passage.

An engine is described having a crankcase, a liner and a head assembly. The crankcase is split along a plane defining a two part crankcase, where fluid passages are passing through only one of the crankcase portions, so as to not require crossing the split line. A connecting rod also includes a tapered end, and the piston has a complementary carrier receiving the connecting rod.

The internal combustion engine comprises: operating members and operating by a predetermined pressure or more of oil pressure; a hydraulic oil path supplying hydraulic oil to the operating members through crank journals; a lubricating oil path supplying lubricating oil to crankpins through the crank journals; a hydraulic control valve linearly controlling an oil pressure supplied to the operating members due to change of that opening degree; and a control device. The control device controls the opening degree of the hydraulic control valve so that when operating the operating members, the predetermined pressure or more of oil pressure is supplied to the operating members, and controls the opening degree of the hydraulic control valve so that when not operating the operating members, less than the predetermined pressure of oil pressure is supplied to the operating members.