A method and apparatus for providing constant fresh air ventilation to the engine crankcase is disclosed. The apparatus is adapted for use with an internal combustion engine having a crankcase, an intake manifold and an air input attached to the manifold. The system includes an integrated vacuum actuator connected to the intake manifold, an actuator duct positioned between the vacuum actuator and the air input, an air-from-oil separator associated with the crankcase, a separator duct and separator control valve positioned between the separator and the intake manifold, and a bypass duct and bypass control valve between the separator duct and the actuator duct. The air input comprises an initial intake pipe and an intermediate intake pipe with the intermediate intake pipe being positioned between the initial intake pipe and the intake manifold. A fresh air control pipe and regulator assembly is attached to the intermediate intake pipe.

An oil drain structure for an oil mist separator including a drain pipe extending from the oil mist separator into the internal combustion engine, the drain pipe having an oil discharge hole extending through a lower end portion of the drain pipe along an axial direction of the drain pipe, and a check valve including a valve body disposed below the lower end portion of the drain pipe, the valve body acting to open and close the oil discharge hole from a side of a lower surface of the lower end portion of the drain pipe, a valve head portion fitted into the drain pipe with a fine clearance as an orifice and being moveable in the axial direction of the drain pipe, and a stem portion extending through the oil discharge hole to connect the valve body and the valve head portion with each other.

An internal combustion engine has a crankcase and a crankcase ventilation system having a switchable shut-off valve, and sensors that detect different operating parameters of the engine, including a load variable of the engine. An estimated load parameter is determined based on the different detected operating parameters using a dynamic model, and a corrective value of a characteristic value is determined as a function of a deviation between the estimated load variable and the detected load variable. To implement a diagnosis, diagnosis switching cycle(s) are controlled, in which the shut-off valve is set to a closed switched position for a first time and set to an open switched position for a second time. A diagnosis value representative of a shut-off valve being in a correct or incorrect state is determined based on a change to the corrective value in response to the one or the plurality of diagnosis switching cycles.

An internal combustion engine having manifold ports and positive crankcase ventilation (PCV) passages integrated into the cam cover is disclosed. The engine system comprises a cam cover having an internal, gas-passing passage, a PCV valve associated with the passage, an oil separator associated with the PCV valve, and an intake manifold having a port, the port being associated with the PCV valve. An oil separator is fitted between the gas-passing passage and the PCV valve. The oil separator is mounted on the cam cover. A manifold chamber is also provided and the PCV oil separator is associated with the manifold chamber.

Methods and systems are provided for enhancing crankcase ventilation in a boosted engine. During boosted conditions, a crankcase may be ventilated via vacuum generated at an aspirator coupled in a compressor bypass passage. However, when the aspirator is plugged, pressure in the crankcase may be relieved by flowing crankcase gases through an aspirator bypass passage.

A method is provided for removing leaked crankcase fluid from a crankcase of an internal combustion engine during operation thereof, the method including the steps of measuring as operation parameter value of the internal combustion engine; comparing the measured operation parameter value with a preset parameter range defining a mode of operation of the internal combustion engine for determining if the internal combustion engine is in the mode of operation; guiding the leaked crankcase fluid from the crankcase to an intake of the internal combustion engine if it is determined that the internal combustion engine is in the mode of operation; and guiding the leaked crankcase fluid from the crankcase to an ambient environment of the internal combustion engine if it s determined that the internal combustion engine is not in the mode of operation.

An engine assembly is provided with an intake manifold having a manifold body downstream of a fresh air intake port. The manifold body has a wall defining first and second apertures spaced apart from one another. A positive crankcase ventilation (PCV) device is provided with a PCV pipe having a first end in fluid communication with a crankcase and a second end connected to first and second PCV branches. The first and second PCV branches are in fluid communication with the first and second apertures. A method is provided and directs a first portion of gases from the crankcase to the first aperture via the PCV pipe and the first PCV branch, and directs a second portion of gases from the crankcase to the second aperture via the PCV pipe and the second PCV branch.

A blow-by gas processing device is configured to allow a crankcase and a downstream side of a throttle valve of an intake system to communicate to introduce blow-by gas into the intake system. The device includes a positive crankcase ventilation ( ) valve, a PCV valve cover, and a PCV hose. The valve is attached to a cylinder block and adjusts a flow rate of the blow-by gas. The valve cover is coaxially with the valve and is attached to the cylinder block to cover the valve. The hose is coupled to the valve cover and allows the valve cover and the intake system to communicate. An inner diameter of the valve cover on a tip end side with respect to a plane including a tip end surface of the valve is greater than that on a base end side with respect to the plane.