An engine case includes bearings, an oil pump, lubricating oil passages, and a relief device. The bearings rotatably support a crankshaft and a camshaft. The oil pump and the lubricating oil passages are configured to pressure-feed lubricating oil to the bearings. The relief device is configured to adjust a pressure of the lubricating oil. The lubricating oil passages include main lubricating oil passages. The main lubricating oil passages include communication portions linearly formed with extending portions. The communication portions communicate between the respective bearings of the crankshaft and the camshaft from outside the engine case. The extending portions extend from outside the engine case to the bearing of the camshaft. The relief device is disposed having a relief valve and a relief hole at the extending portions.

A four-stroke engine lubrication system comprises: an engine body in which a crank shaft chamber and an air valve distribution chamber are arranged; a cylinder head cover fixed onto the engine and communicated with the atmosphere; and an oil storage tank which is configured to store lubricating oil, arranged on the engine body, located at one side of a cam, and provided with an oil mist generation device therein, wherein an oil outlet passage of the oil mist generation device communicates the oil storage tank with the crank shaft chamber via an oil outlet pipe; the crank shaft chamber is communicated with the air valve distribution chamber via a check valve; the air valve distribution chamber is communicated with the oil storage tank via a pipe; the air valve distribution chamber is communicated with the cylinder head cover; and the cylinder head cover is communicated with the oil storage tank.

An engine lubrication structure supplies oil from an oil pump to individual components of an engine in which a balancer shaft is disposed parallel with a crank shaft in a crank case, the engine includes a turbocharger which compresses intake air using exhaust gas of the engine; a main gallery which supplies oil to a bearing of the crank shaft and a bearing of the balancer shaft and a sub-gallery which supplies, to individual components of the engine, oil that has been supplied to the bearing of the balancer shaft are provided in the crank case; and an oil passage which supplies oil to the turbocharger is connected to the sub-gallery.

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.

An oil supply apparatus includes: an oil pump; a main oil supply path; a sub oil supply path connected to the main oil supply path; a first oil supply section which is connected to the main oil supply path and which supplies oil to a crank bearing section of a specific crank journal; a second oil supply section which is connected to the sub oil supply path and which supplies oil to a crank bearing section of a crank journal other than the specific crank journal; and a control apparatus which sets, as a target oil pressure, a highest required oil pressure among required oil pressures required from a plurality of hydraulic operating sections in accordance with an operation state of the engine, and which controls the discharge amount of the oil pump so that an oil pressure detected by an oil pressure sensor equals the target oil pressure.

The present disclosure relates to a device for lubricating an internal combustion engine having a crankshaft, which is connected to at least one connecting rod. The device has at least one first flow limiter, in particular a restrictor, for reducing a lubricating fluid flow of a lubricating fluid stream passed to the at least one first flow limiter. The device has a plurality of crankshaft bearings for the rotatable support of the crankshaft, wherein the plurality of crankshaft bearings is provided in fluid communication downstream of the at least one first flow limiter. The device has at least one big end bearing for the rotatable support of the at least one connecting rod, wherein the at least one big end bearing is provided in fluid communication downstream of at least one crankshaft bearing of the plurality of crankshaft bearings.

An engine lubrication structure supplies oil from an oil pump to individual components of an engine in which a balancer shaft is disposed parallel with a crank shaft in a crank case, the engine includes a turbocharger which compresses intake air using exhaust gas of the engine; a main gallery which supplies oil to a bearing of the crank shaft and a bearing of the balancer shaft and a sub-gallery which supplies, to individual components of the engine, oil that has been supplied to the bearing of the balancer shaft are provided in the crank case; and an oil passage which supplies oil to the turbocharger is connected to the sub-gallery.

A vehicular engine insert may be configured to be disposed within a crankcase of the vehicular engine such that it comprises a body having a passage for a fluid flowable through the crankcase, a nozzle projecting outwardly from the body, and a channel through a thickness of the vehicular engine insert that creates a fluid interconnection between the passage and the nozzle such that the nozzle and the passage are substantially orthogonal to one another.

There is provided a bearing apparatus of a crankshaft for an internal combustion engine. The bearing apparatus includes a crankshaft having a plurality of journal portions and a plurality of crank pin portions; a main bearing supporting the crankshaft; and a bearing housing holding the main bearing. The plurality of journal portions include a first journal portion having a lubricating oil passage and a second journal portion not having the lubricating oil passage. The first and second journal portions and are supported by the first and second main bearings and. The bearing housing includes an Al alloy upper housing and an Fe alloy lower housing. The groove depth of the oil groove of the upper half bearing of the second main bearing is one half or less than the groove depth of the oil groove of the upper half bearing of the first main bearing.

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.