Patent ID: 8875686
Filing Date: 2014-11-04
Classification: F01M

Abstract:
1. An internal combustion engine comprising: an intake passageway having a throttle valve; an oil pan from which oil is pressure-fed to a lubrication site through operation of an oil pump and in which the oil having been used for lubrication of the lubrication site runs down and collects; a blow-by gas process device having a discharge passageway that connects a portion of the intake passageway on a downstream side of the throttle valve in an intake flow direction and an interior of a crankcase in communication, a one-way valve that permits gas to be discharged only in a direction from the interior of the crankcase to the intake passageway through the discharge passageway; a pressure chamber disposed in the interior of the crankcase and to which an end portion of the discharge passageway is open; and a forced introduction device, which is connected to a crankshaft, that introduces oil scattered in the interior of the crankcase into an interior of the pressure chamber, before the oil mixes with the oil collected in the oil pan, wherein: the pressure chamber has a window portion configured to connect the interior of the pressure chamber and the interior of the crankcase, other than the pressure chamber; the forced introduction device introduces the scattered oil into the interior of the pressure chamber through the window portion; at least a portion of the window portion overlaps with a projection portion in an inner side wall of the crankcase, wherein the projection portion is an area of the inner side wall onto which an operation loci of the forced introduction device projects when viewed from a direction orthogonal to a direction of an axis of the crankshaft; the forced introduction device is at least one of a connecting rod and a counter weight; the window portion is an opening, the opening being disposed below the axis of the crank shaft in a vertical direction and directly facing the forced introduction device; and the internal combustion engine includes no intermediate structure between the window portion and the forced introduction device, wherein movement of the forced introduction device directs gas from the interior of the crankcase directly through the window, so that the gas moves into the pressure chamber and then through the discharge passageway via an oil separator.