A method and a system for diagnosing positive crankcase ventilation (PCV) systems are disclosed. In one example, the method diagnoses a PCV system based on a pressure that may be observed during engine cranking. In another example, the PCV system is diagnosed during vehicle driving conditions after the engine exits cranking.

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.

A blowby gas treatment device includes a pressure control valve, a fresh air induction pipe, a first blowby gas pipe, a second blowby gas pipe, a shutoff valve, a one-way valve, and a PCV valve. A leak diagnosis includes a first-stage diagnosis to determine whether or not falling of a pressure in a crank case after closing of the shutoff valve under a non-supercharging condition is normal. A second-stage diagnosis is implemented by moving the pressure control valve from a fully opened state into a fully closed state, and determining whether an intake air quantity in each state is equal to each other. When the intake air quantity in each state is equal to each other, presence of an in-system leak is determined. When a fully closed state intake air quantity is different from a fully opened state intake air quantity, presence of an out-of-system leak is determined.

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.

A system in one embodiment includes at least one cylinder, a supplemental boost supply, and a supply line. The at least one cylinder is configured for use in a reciprocating internal combustion engine, and includes a combustion portion and a crank portion on opposite sides of a piston. The at least one cylinder also includes an intake port and an exhaust port in fluid communication with the combustion portion. The supplemental boost supply is configured to provide a supplemental air supply to the combustion portion of the engine when the engine is idling to increase pressure in the combustion portion. The supply line couples the supplemental boost supply to the intake port.

A blowby gas treatment device includes a pressure control valve, a fresh air induction pipe, a first blowby gas pipe, a second blowby gas pipe, a shutoff valve, a one-way valve, and a PCV valve. A leak diagnosis includes a first-stage diagnosis to determine whether or not falling of a pressure in a crank case after closing of the shutoff valve under a non-supercharging condition is normal. A second-stage diagnosis is implemented by moving the pressure control valve from a fully opened state into a fully closed state, and determining whether an intake air quantity in each state is equal to each other. When the intake air quantity in each state is equal to each other, presence of an in-system leak is determined. When a fully closed state intake air quantity is different from a fully opened state intake air quantity, presence of an out-of-system leak is determined.

The invention enables an adequate crankcase negative pressure in an internal combustion engine, in all operating ranges to the extent possible and using a suction device for the crankcase ventilation of an internal combustion engine, which suction device is equipped with a housing, a controllable electric motor and a compressor for conveying crankcase gas, which compressor is driven by the electric motor, the compressor having connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor.

A fluid conduit allowing a fluid to flow therethrough is provided, which can increase airtightness by a partition wall without reducing the accuracy of a size or a shape of an orifice provided in the partition wall. A partition wall 10 of a fluid conduit 1 is formed by joining an upper-side partition wall portion 11 and a lower-side partition wall portion 12 by welding. The lower-side partition wall portion 12 includes a joint-side portion 13 and an orifice-side portion (a wall portion 31), and while providing a joint portion 19 to the upper-side partition wall portion 11 in the joint-side portion 13, the orifice 32 is provided in the orifice-side portion, so that the joint portion 19 and the orifice 32 are disposed in a position shifted from each other when viewed from a joint direction.

A fluid conduit allowing a fluid to flow therethrough is provided, which can increase airtightness by a partition wall without reducing the accuracy of a size or a shape of an orifice provided in the partition wall. A partition wall 10 of a fluid conduit 1 is formed by joining an upper-side partition wall portion 11 and a lower-side partition wall portion 12 by welding. The lower-side partition wall portion 12 includes a joint-side portion 13 and an orifice-side portion (a wall portion 31), and while providing a joint portion 19 to the upper-side partition wall portion 11 in the joint-side portion 13, the orifice 32 is provided in the orifice-side portion, so that the joint portion 19 and the orifice 32 are disposed in a position shifted from each other when viewed from a joint direction.

The invention enables an adequate crankcase negative pressure in an internal combustion engine, in all operating ranges to the extent possible and using a suction device for the crankcase ventilation of an internal combustion engine, which suction device is equipped with a housing, a controllable electric motor and a compressor for conveying crankcase gas, which compressor is driven by the electric motor, the compressor having connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor.