A method of operating an exhaust valve of a two-stroke internal combustion engine is disclosed. The engine has a cylinder and a piston movably disposed within the cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid from the cylinder. The exhaust valve is configured to cyclically obstruct the exhaust port. The method includes: rotating the exhaust valve in a first direction for clearing the exhaust port before the piston uncovers the exhaust port during a downstroke of the piston, the first direction being opposite a direction of rotation of a crankshaft of the engine; and rotating the exhaust valve in the first direction for at least partially closing the exhaust port before the piston fully covers the exhaust port during an upstroke of the piston, said rotating of the exhaust valve relative to the rotation of the crankshaft at least partially counterbalancing the crankshaft.

A cylinder head cover integrated with an active oil mist separator may include a cylinder head cover body, a booster, and an oil mist separator. The cylinder head cover body may be provided with an exhaust passage and a separation passage. The booster may be mounted outside the cylinder head cover body. The booster may have a booster intake port and a booster exhaust port. The booster intake port may be connected with the exhaust passage. The booster exhaust port may be connected with the separation passage. The oil mist separator may be mounted in the separation passage and the oil mist separator may be located on a downstream side of the booster.

An apparatus and a method are provided for a crankcase breather vent assembly to direct blow-by gases out of an engine crankcase. A vent base comprising a generally cylindrical vessel communicates received blow-by gases into an interior cavity of a breather vent that comprises a filter medium. Baffles disposed within an interior cavity of the vent base capture oil carried along with the blow-by gases. The captured oil is directed to an oil sump of the engine by way of a suitable hose. A bonnet fastenably receives the breather vent and is configured to reduce a buildup of oil residue on nearby engine components. An outer profile of the breather vent is tapered along a longitudinal dimension of the filter medium to facilitate unrestricted air flow through the filter medium when the bonnet is installed onto the breather vent.

A device and a method for diagnosing a positive crankcase ventilation (PCV) breather line. The device includes: a crankcase pressure sensor that is installed on the PCV breather line including a front end connected to an intake line and a rear end connected to a crankcase and detects a pressure inside the crankcase; and a processor that diagnoses an abnormality of the PCV breather line based on the pressure of the crankcase.

Systems are provided for a crankcase ventilation system. In one example, a crankcase ventilation (CCV) system for an engine configured to transmit crankcase gases into a clean side air duct, the clean side air duct comprising a sensor and a crankcase ventilation spigot, wherein the crankcase ventilation spigot is configured to be disposed downstream of the sensor, the crankcase ventilation spigot having an outlet configured to direct crankcase gases emerging from the crankcase ventilation spigot away from the sensor.

An abnormality determination device of an internal combustion engine in which a breather line connects an intake-air path positioned upstream from a forced-induction system and a crankcase includes an intake-air flow rate sensor that detects an intake air flow rate in the intake-air path, a pressure sensor that detects a pressure of the breather line, and an abnormality determination unit that determines abnormality of the breather line. The abnormality determination unit estimates an intake air resistance of the intake-air path from the pressure when the engine is under low load conditions under which the intake air flow rate is less than a predetermined value and the pressure when the engine is under high load conditions under which the intake air flow rate is the predetermined value or greater and determines abnormality of the breather line when the intake air resistance is less than a threshold.

A breather includes a case, which has an internal space, an insertion portion, and a valve structure. The insertion portion includes a connecting passage that connects the internal space and an external space. The valve structure includes a valve member in the connecting passage, a locking portion that restricts displacement of the valve member, and a spring that presses the valve member against the locking portion. The insertion portion includes a seating portion that is inclined such that the connecting passage narrows as the distance from the locking portion increases. The valve member includes a plate portion, and a ventilating portion that is a radially inward recess on the edge of the plate portion. The valve structure connects the external space and the internal space to each other via the ventilating portion in a state in which the valve member is in contact with the seating portion.

The present invention comprises an apparatus and method for replacing an original equipment manufacturer air-oil separator apparatus having an integral pressure control valve (“OEM-AOS” system) in a vehicle. The OEM-AOS system is disconnected from the engine air intake. The integral pressure control valve is disabled. An accumulator for collecting oil from by-pass combustion gas is connected to the OEM-AOS system. A discrete pressure control valve (“discrete-PCV”) is connected to the accumulator and to the engine air intake. The discrete-PCV is located within the vehicle at an easily accessible location so that it can be quickly accessed and replaced when necessary. The accumulator includes a sensor that is operable to send a warning signal to a vehicle operator when the vehicle needs to be serviced to remove condensed oil from the accumulator.

A crankcase ventilation system is disclosed that includes a PCV valve, a spigot and a tube connector. The PCV valve is enclosed in a module housing that encloses a plunger, and a spring. The module housing defines an inlet opening, and an outlet opening and is assembled inside an engine component. The spigot is attached to an outer surface of the engine and is in fluid communication with the PCV valve through the outlet opening. The tube connector is in fluid communication with the tube connector and the PCV valve. An intake manifold of the engine provides vacuum to the PCV valve, through the tube, the tube connector and the spigot. If one of the tube, tube connector, or spigot is detached from the engine, the PCV valve is retained in the engine and is held closed by the spring biasing the plunger against the inlet opening.

The invention relates to an oil decantation system (1) comprising: (i) a separator device (6) designed to trap the oil droplets (107) that are present in a flow of a blow-by gas (110); and (ii) a jet pump (5) positioned upstream of the separator device (6) and designed to accelerate and draw the flow of the blow-by gas (110) before it enters said separator device (6).