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 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 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.

Provided is a balancer device for an internal combustion engine, which includes: an upper-side housing to be mounted to an internal combustion engine; a lower-side housing fixed to the upper-side housing; a balancer main body accommodated in a space defined by the upper-side housing and the lower-side housing; and an oil pump fixed at least to the upper-side housing. An end surface portion of the upper-side housing and an end surface portion of the oil pump are mounted in contact with each other, and an end surface portion of the lower-side housing and the end surface portion of the oil pump are mounted to each other so as to define a predetermined gap.

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.

Provided is a balancer device for an internal combustion engine, which includes: an upper-side housing to be mounted to an internal combustion engine; a lower-side housing fixed to the upper-side housing; a balancer main body accommodated in a space defined by the upper-side housing and the lower-side housing; and an oil pump fixed at least to the upper-side housing. An end surface portion of the upper-side housing and an end surface portion of the oil pump are mounted in contact with each other, and an end surface portion of the lower-side housing and the end surface portion of the oil pump are mounted to each other so as to define a predetermined gap.