Various systems and methods are provided for reducing an amount of oil reaching a crankcase overpressure sensor. In one example, a system may include a cast wall protruding perpendicularly from an internal wall of crankcase, the cast wall at least partially surrounding a sensor port for a crankcase overpressure (COP) sensor, the sensor port fluidically coupled to the COP sensor via an internal passage; and a cover plate fixedly coupled to the cast wall, the cover plate parallel to the internal wall. In this way, oil may be blocked from reaching the COP sensor, while air may flow through the internal passage to the COP sensor.

Systems, devices and methods for diagnosing malfunctioning in a crankcase ventilation (CCV) system are provided. A controller includes a processor and a memory storing instructions that cause the processor to: receive a plurality of pressure values including (i) a first pressure value indicative of a pressure of fluid flowing from a crankcase to a breather assembly of a system, (ii) a second pressure value indicative of a pressure of fluid flowing through a first tube coupled to the breather assembly, and (iii) a third pressure value indicative of a pressure of fluid flowing through a second tube coupled to the breather assembly; determine a pair of pressure differences based on the first pressure value, the second pressure value, and the third pressure value; and detect a malfunctioning in the CCV system based on the pair of pressure differences.

A blow-by gas leak diagnostic device includes a first PCV flow path, a second PCV flow path, a fresh air inlet, a pressure measurement unit, a first valve that opens and closes the first PCV flow path, a second valve that opens and closes the second PCV flow path, a third valve that opens and closes the fresh air inlet, a valve control unit, and a leak diagnosis unit. The valve control unit controls an opening degree of the third valve when a downstream side of an intake manifold with respect to a throttle valve has a negative pressure, and the second valve is in a closed state. The leak diagnosis unit diagnoses presence or absence of a leak in the first PCV flow path on the basis of an inner pressure of the first PCV flow path measured by the pressure measurement unit.

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 using an air fuel ratio feedback control, and determining whether or not a sensed intake air quantity obtained by an air flow meter is equal to an actual intake air quantity flowing into a cylinder set. When the sensed intake air quantity is equal to the actual intake air quantity, presence of an in-system leak is determined, and when the actual intake air quantity is larger, presence of an out-of-system leak is determined.

Systems, devices and methods for diagnosing malfunctioning in a crankcase ventilation (CCV) system can include a controller receiving a plurality of pressure values. The plurality of pressure values include a first pressure value indicative of pressure of gases flowing between a crankcase and a breather assembly, a second pressure value indicative of pressure of gases flowing through a CCV tube from the breather assembly, and a third pressure value representing pressure of gases in a tube connected to the CCV tube. The controller can calculate a pair of pressure differences including a first pressure difference between the first pressure value and the second pressure value and a second pressure difference between the first pressure value and the third pressure value. The controller can detect a malfunctioning or defect in the CCV system based on the pair of pressure differences falling within a predefined clustering region.

The ventilator-equipped engine is configured to: guide a blow-by gas generated in a crankcase to an intake passage through an inside of a cylinder head, an inside of a head cover, and a pressure regulating valve; and to directly introduce fresh air into an internal space of the cylinder head by providing a fresh air introduction passage that extends across the intake passage and the cylinder head.

An anomaly diagnostic device for an onboard internal combustion engine includes a parameter deriving unit and a leaking anomaly diagnostic unit. The parameter deriving unit is configured to derive a determination parameter such that, when a PCV pressure sensor value that indicates a pressure detected by a PCV pressure sensor is less than an atmospheric pressure, a value of the determination parameter increases as the difference between the PCV pressure sensor value and the atmospheric pressure increases. The leaking anomaly diagnostic unit is configured to perform a leaking anomaly diagnostic process that diagnoses that there is an anomaly at a portion of a blow-by gas passage that is closer to an intake passage than to a connection portion of the PCV pressure sensor when the determination parameter derived when an intake air amount changes is less than a threshold.

Methods and systems are provided for assessing a state of a vent hose that fluidically couples a crankcase of an engine to an engine air intake system. In one example, a method may include sealing the crankcase from the vent hose, initiating cranking of the engine, monitoring a series of pressure pulsations during a monitoring window duration via a pressure sensor positioned between a crankcase oil separator and the vent hose, and indicating a presence of degradation associated with the vent hose based on the series of pressure pulsations and the monitoring window duration. In this way, diagnosis of a state of the vent hose may be reliably assessed without crankcase pressures confounding pressure measurements as recorded via the pressure sensor.

Systems, devices and methods for diagnosing malfunctioning in a crankcase ventilation (CCV) system can include a controller receiving a plurality of pressure values. The plurality of pressure values include a first pressure value indicative of pressure of gases flowing between a crankcase and a breather assembly, a second pressure value indicative of pressure of gases flowing through a CCV tube from the breather assembly, and a third pressure value representing pressure of gases in a tube connected to the CCV tube. The controller can calculate a pair of pressure differences including a first pressure difference between the first pressure value and the second pressure value and a second pressure difference between the first pressure value and the third pressure value. The controller can detect a malfunctioning or defect in the CCV system based on the pair of pressure differences falling within a predefined clustering region.

Methods and systems are provided for assessing a state of a vent hose that fluidically couples a crankcase of an engine to an engine air intake system. In one example, a method may include sealing the crankcase from the vent hose, initiating cranking of the engine, monitoring a series of pressure pulsations during a monitoring window duration via a pressure sensor positioned between a crankcase oil separator and the vent hose, and indicating a presence of degradation associated with the vent hose based on the series of pressure pulsations and the monitoring window duration. In this way, diagnosis of a state of the vent hose may be reliably assessed without crankcase pressures confounding pressure measurements as recorded via the pressure sensor.