An internal combustion engine is provided with one or more oil drain-back passages. The oil drain-back passage include an entrance into a crankcase via a crankcase breathing window, the crankcase breathing window disposed within and through a bulkhead wall of the crankcase. Thus, each oil drain-back passage may be routed from a cylinder head of the engine to a crankcase breathing window where oil may then enter the crankcase and flow downward into an oil pan coupled to the crankcase.

An internal combustion engine is provided with one or more oil drain-back passages. The oil drain-back passage include an entrance into a crankcase via a crankcase breathing window, the crankcase breathing window disposed within and through a bulkhead wall of the crankcase. Thus, each oil drain-back passage may be routed from a cylinder head of the engine to a crankcase breathing window where oil may then enter the crankcase and flow downward into an oil pan coupled to the crankcase.

A cylinder for a reciprocating piston system, with a cylinder running surface, which is finished by machining by means of a tool with a geometrically defined cutting edge, wherein the finished cylinder running surface has a multiplicity of pores and/or cavities and is formed from a grey cast iron material with a proportion of the surface area that is taken up by pores of 2 to 10% or is formed from a thermally sprayed layer of iron or a thermally sprayed layer of ceramic with a proportion of the surface area that is taken up by pores of 5 to 25%. A method is also provided for finishing a cylinder in which a cylinder running surface of the cylinder is finished by machining by a tool with a geometrically defined cutting edge such that after the finishing the cylinder surface has a multiplicity of pores and/or cavities.

A cylinder for a reciprocating piston system, with a cylinder running surface, which is finished by machining by means of a tool with a geometrically defined cutting edge, wherein the finished cylinder running surface has a multiplicity of pores and/or cavities and is formed from a grey cast iron material with a proportion of the surface area that is taken up by pores of 2 to 10% or is formed from a thermally sprayed layer of iron or a thermally sprayed layer of ceramic with a proportion of the surface area that is taken up by pores of 5 to 25%. A method is also provided for finishing a cylinder in which a cylinder running surface of the cylinder is finished by machining by a tool with a geometrically defined cutting edge such that after the finishing the cylinder surface has a multiplicity of pores and/or cavities.

The present invention relates to techniques for lowering friction between moving surfaces of, for example, an internal combustion engine. Friction reduction is achieved by adding texture modifications to surfaces that come in contact with each other. Texture modifications that reduce friction in accordance with the present invention include dimples of varying geometries and depths ion the surfaces of components. The present invention also relates to the fabrication technique for applying the textures to the surfaces. In another embodiment, the patterned soft mask is applied onto a large surface (flat or curved including cylindrical rollers surfaces) to be followed by electrochemical etching to imprint the textures onto the component. And, in another embodiment, a diamond-like-carbon (DLC) film may be applied to the turbine component to also reduce friction.

The present invention relates to techniques for lowering friction between moving surfaces of, for example, an internal combustion engine. Friction reduction is achieved by adding texture modifications to surfaces that come in contact with each other. Texture modifications that reduce friction in accordance with the present invention include dimples of varying geometries and depths ion the surfaces of components. The present invention also relates to the fabrication technique for applying the textures to the surfaces. In another embodiment, the patterned soft mask is applied onto a large surface (flat or curved including cylindrical rollers surfaces) to be followed by electrochemical etching to imprint the textures onto the component. And, in another embodiment, a diamond-like-carbon (DLC) film may be applied to the turbine component to also reduce friction.

A cylinder sleeve for an internal combustion engine may include a bore-through cylindrical body having an inner sliding surface. The inner surface may have a surface finish with a rugosity defined by a valley-and-peak structure. The rugosity of the inner surface may have a ratio between a peak density and a mean radius of curvature of peaks that is higher than 150 and lower than 400. The rugosity may also have a ratio between the mean radius of curvature of peaks and an average height of peaks that is lower than 1500.

There is provided a lubrication structure of an internal combustion engine. A transmission chamber is arranged adjacently at the rear of a crank chamber. An oil chamber communicates with a bottom part of the transmission chamber. A feed pump supplies oil in the oil chamber to a lubrication target part. A scavenging pump sucks the oil in the crank chamber and discharges the oil to the transmission chamber. The feed pump and the scavenging pump are arranged coaxially in a width direction of the internal combustion engine. At least a part of the scavenging pump is arranged higher than a lower end of the crank chamber. A rear end of the scavenging pump is arranged at the same position as a rear end of the crank chamber or in front of the rear end of the crank chamber in a front and rear direction.

A combined oil filter and restrictor assembly is disclosed having an oil flow restrictor interposed between first and second filters so that, irrespective of the direction of oil flow through the restrictor, debris cannot enter a small diameter bore 32 in a body of the restrictor thereby reducing the likelihood of restrictor blockage. The combined oil filter and restrictor assembly includes a metal threaded member that enables the combined oil filter and restrictor assembly to be easily and quickly assembled to or removed from a component such as a cylinder head of a variable displacement engine. The combined oil filter and restrictor assembly can be used to provide a restricted flow of oil from oil supply passages to signal oil passages used for controlling the operation of deactivatable hydraulic lash adjusters so as to purge the signal oil passages when the deactivatable hydraulic lash adjusters are not deactivated.

A combined oil filter and restrictor assembly is disclosed having an oil flow restrictor interposed between first and second filters so that, irrespective of the direction of oil flow through the restrictor, debris cannot enter a small diameter bore 32 in a body of the restrictor thereby reducing the likelihood of restrictor blockage. The combined oil filter and restrictor assembly includes a metal threaded member that enables the combined oil filter and restrictor assembly to be easily and quickly assembled to or removed from a component such as a cylinder head of a variable displacement engine. The combined oil filter and restrictor assembly can be used to provide a restricted flow of oil from oil supply passages to signal oil passages used for controlling the operation of deactivatable hydraulic lash adjusters so as to purge the signal oil passages when the deactivatable hydraulic lash adjusters are not deactivated.