Patent attributes
A four-stroke internal combustion engine is described, with at least one cylinder(9), a crankcase (3) which forms a crankcase pump and is connected via a valve (15, 18) each to an air manifold (16) for fresh air on the one hand and to an intake manifold (17) connecting the crankcase (3) with an intake port (11) of the cylinder (9) on the other hand, and with a reservoir (25) for lubricating oil arranged on a conveying device (26) for lubricating oil, with an oil circulation comprising the crankcase (3) as well as an oil separator (19) provided in the intake manifold (17) and with a device (23) for injecting fuel into the intake manifold (17) or into the combustion chamber (29) of the cylinder (9). In order to provide advantageous constructional conditions it is proposed that the conveying device (26) connected to the reservoir (25) comprises a duct (27) for injecting lubricating oil into the crankcase (3) and that the intake manifold leads to the oil separator (19) by circumventing the reservoir (25).
