An internal combustion engine includes: an oil filter that is mounted to a mounting surface formed on a crankcase and clarifies an oil flowing in; an oil cooler that is disposed on a front side of the crankcase, cools the oil flowing in from the oil filter and returns the oil into a flow path in the crankcase; and a bracket formed on a front wall of the crankcase and having the mounting surface. An outflow port through which the oil flows out toward the oil cooler and an inflow port through which the oil flows in from the oil cooler are disposed in the bracket. Accordingly, in the internal combustion engine, routes of oil passages can be simplified as much as possible.

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.

An internal combustion engine includes a crankcase in which a crankshaft is rotatably mounted in bearings including bearing covers, to which at least one connecting rod carrying a piston is linked. The piston is movable in a cylinder covered by a cylinder head forming a combustion chamber and gas exchange valves are arranged in the cylinder head, which are actuated by at least one camshaft, which is connected to a gear train gear wheel situated on the crankshaft via a differential gear. A mass differential gear including two balance shafts is present. The mass differential gear is situated in a gear frame and attached to the crankcase below the crankshaft and driven by a mass shaft drive gear situated on the crankshaft, which is arranged axially essentially next to the gear train gear wheel/idler gear. The gear train gear wheel/idler gear is arranged on the main bearing cover.

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 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 aspect of the invention is directed to a lubricating structure of an internal combustion engine for feeding oil from an oil pump to respective portions of the internal combustion engine where a balancer shaft is disposed in parallel with a crankshaft in a crankcase, wherein: a main gallery and an oil passage are provided in the crankcase so that oil can be delivered from the oil pump to the main gallery and the oil of the main gallery can be guided by the oil passage to pass through a bearing of the balancer shaft; and the oil passage feeds the oil that has passed through the bearing of the balancer shaft to a cylinder head.

An internal combustion engine that includes an oil baffle in the oil sump. The internal combustion engine may include a crankcase comprising an oil sump containing an oil reservoir, a crankshaft, and an oil baffle positioned within the oil sump. The crankshaft may be a vertical crankshaft and a first balance shaft may extend upward from the oil baffle. The crankshaft may be positioned within the oil baffle and a drivetrain may, also optionally, be positioned in the oil baffle. The internal combustion engine may be configured such that the oil reservoir has a first oil level when the internal combustion engine is off and a second oil level when the internal combustion engine is running at normal operating conditions. The first oil level is above a floor of the oil baffle. The second oil level may, also, be above the floor of the oil baffle.

A lubricating structure of an internal combustion engine that feeds oil to a driveshaft of a transmission disposed in parallel with a crankshaft and a balancer shaft in a crankcase, wherein the balancer shaft is disposed below the crankshaft and the driveshaft is disposed at rear of the crankshaft, and a main gallery, a first oil passage, a second oil passage and a third oil passage are formed in the crankcase as defined herein, and a lubricating structure of an internal combustion engine that feeds oil to a bearing of a balancer shaft disposed in parallel with a crankshaft in a crankcase, wherein a main gallery, a first oil passage, and a second oil passage are formed in the crankcase as defined herein.

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 internal combustion engine that includes an oil baffle in the oil sump. The internal combustion engine may include a crankcase comprising an oil sump containing an oil reservoir, a crankshaft, and an oil baffle positioned within the oil sump. The crankshaft may be a vertical crankshaft and a first balance shaft may extend upward from the oil baffle. The crankshaft may be positioned within the oil baffle and a drivetrain may, also optionally, be positioned in the oil baffle. The internal combustion engine may be configured such that the oil reservoir has a first oil level when the internal combustion engine is off and a second oil level when the internal combustion engine is running at normal operating conditions. The first oil level is above a floor of the oil baffle. The second oil level may, also, be above the floor of the oil baffle.