Engine includes: crankcase housing crankshaft extending in vertical direction; cylinder block mounted on side of crankcase and formed with cylinder; cylinder head mounted on side of cylinder block and provided with air inlet port and air outlet port communicating with cylinder; cylinder head cover mounted on side of cylinder head and covering air inlet port and air outlet port; mount case including: supporting portion provided below crankcase and cylinder block and supporting crankcase and cylinder block; and extending portion extending from supporting portion below cylinder head and cylinder head cover; oil pan provided below mount case and storing lubricating oil; and communication tube communicating first space formed between cylinder head and cylinder head cover and second space formed between mount case and oil pan. Communication tube is provided between cylinder head cover and extending portion.

Engine includes: crankcase housing crankshaft extending in vertical direction; cylinder block mounted on side of crankcase and formed with cylinder; cylinder head mounted on side of cylinder block and provided with air inlet port and air outlet port communicating with cylinder; cylinder head cover mounted on side of cylinder head and covering air inlet port and air outlet port; mount case including: supporting portion provided below crankcase and cylinder block and supporting crankcase and cylinder block; and extending portion extending from supporting portion below cylinder head and cylinder head cover; oil pan provided below mount case and storing lubricating oil; and communication tube communicating first space formed between cylinder head and cylinder head cover and second space formed between mount case and oil pan. Communication tube is provided between cylinder head cover and extending portion.

In an internal combustion engine, the cylinder block includes a first blowby gas passage and a first oil return passage. The cylinder head includes a second blowby gas passage connecting the first blowby gas passage with a connection passage connected with a gas-liquid separator, an oil return chamber separated from a valve operating chamber and the second blowby gas passage by first and second partition walls, respectively, and provided with a first oil return hole connected with the gas-liquid separator, and a second oil return passage connecting the valve operating chamber with the first oil return passage. The first partition wall is formed with a second oil return hole connecting the oil return chamber with the valve operating chamber. The second partition wall is formed with a ventilation hole connecting the oil return chamber with the second blowby gas passage at a higher position than the second oil return hole.

A valve for controlling a gas stream between a first side and a second side of the valve is described. A valve opening is passage for the gas stream between the first side and the second side. A valve closure with a valve plate closes the valve opening. A valve mount is arranged toward the second side and on which the valve closure is mounted. The valve closure is pretensioned in the direction of the first side to close the valve toward the second side by the valve plate. The valve plate has an opening element which can be opened toward the first side in the event of an overpressure on the second side.

A diffuser for a jet pump of a separator comprises an inlet defining a first flow area; an outlet in fluid communication with the inlet through which fluid exits the diffuser, in which a flow path extends from the inlet to the outlet, and in which the outlet defines a second flow area greater than the first flow area so that a velocity of fluid flowing through the inlet is greater than a velocity of fluid flowing through the outlet; and a communication port extending through a wall of the diffuser with an inlet in communication with an interior of the diffuser and an outlet in communication with an exterior of the diffuser, in which the communication port inlet is between the diffuser inlet and the diffuser outlet, so that contaminants separated from the fluid stream are removed through the communication port.

An internal combustion engine includes a block containing a crankshaft and a crankcase surrounding the crankshaft, a plurality of combustion chambers configured to receive an intake fluid and generate exhaust fluid, an exhaust circuit configured to direct the exhaust fluid away from the plurality of combustion chambers, an intake circuit configured to supply the intake fluid to the plurality of combustion chambers, a turbine disposed in the exhaust circuit and having a turbine shaft configured to be driven by the exhaust fluid, a crankcase ventilation circuit configured to direct crankcase fluid away from the crankcase, and a pump disposed in the crankcase ventilation circuit and having a rotor configured to be driven by the turbine shaft to propel the crankcase fluid through the crankcase ventilation circuit.

An abnormality diagnosis system of an air-fuel ratio sensor acquires a blowby gas flow ratio showing a ratio of the flow of blowby gas to the flow of gas to a combustion chamber and an output current of an air-fuel ratio sensor during fuel cut control in which an internal combustion engine stops the feed of fuel to the combustion chamber and at a plurality of points of time of different flows of blowby gas passing through a blowby gas passage and flowing to the downstream side of a throttle valve in the intake passage, calculate an output current of the air-fuel ratio sensor corresponding to a blowby gas flow ratio smaller than the blowby gas flow ratios acquired at the plurality of points of time, based on the acquired blowby gas flow ratio and output current, and judge the air-fuel ratio sensor for abnormality based on the calculated output current.

An abnormality diagnosis system of an air-fuel ratio sensor acquires a blowby gas flow ratio showing a ratio of the flow of blowby gas to the flow of gas to a combustion chamber and an output current of an air-fuel ratio sensor during fuel cut control in which an internal combustion engine stops the feed of fuel to the combustion chamber and at a plurality of points of time of different flows of blowby gas passing through a blowby gas passage and flowing to the downstream side of a throttle valve in the intake passage, calculate an output current of the air-fuel ratio sensor corresponding to a blowby gas flow ratio smaller than the blowby gas flow ratios acquired at the plurality of points of time, based on the acquired blowby gas flow ratio and output current, and judge the air-fuel ratio sensor for abnormality based on the calculated output current.

An internal combustion engine, having a cylinder crankcase delimiting a crank chamber and a lubricant pan accommodating a lubricant sump, which has a lubricant pan upper part arranged between the crank chamber and the lubricant sump and a lubricant pan lower part fastened on the lubricant pan upper part. Multiple ridges originate from a base component of the lubricant pan upper part in the direction of the lubricant sump, which ridges partially intersect and thus form chambers which are peripherally closed in section between them, and lubricant passage openings formed in the lubricant pan upper part open into at least part of the chambers, via which openings the crank chamber and the lubricant sump are fluidically connected.

An internal combustion engine, having a cylinder crankcase delimiting a crank chamber and a lubricant pan accommodating a lubricant sump, which has a lubricant pan upper part arranged between the crank chamber and the lubricant sump and a lubricant pan lower part fastened on the lubricant pan upper part. Multiple ridges originate from a base component of the lubricant pan upper part in the direction of the lubricant sump, which ridges partially intersect and thus form chambers which are peripherally closed in section between them, and lubricant passage openings formed in the lubricant pan upper part open into at least part of the chambers, via which openings the crank chamber and the lubricant sump are fluidically connected.