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 sensor support portion supports a physical quantity sensor. A flow path housing portion forms a measurement flow path, which accommodates a support tip end portion of the sensor support portion. The sensor support portion includes a support front surface, which includes a front fixed portion away from the support tip end portion and fixed to an inner surface of the flow path housing portion. The physical quantity sensor includes a sensor exposure surface exposed from the support front surface. A separation distance between an end portion of the front fixed portion and an end portion of the sensor exposure surface is smaller than a separation distance between the end portion of the sensor exposure surface and the support tip end portion.

A flow rate measurement system outputs a measurement value which represents a magnitude of a flow rate and a flow direction of a fluid that flows through a particular main passage. The system includes a bypass passage disposed in the main passage, a detection unit disposed in the bypass passage that outputs a detection value corresponding to a magnitude of a flow rate and a flow direction of the fluid flowing through the bypass passage, and a calculation unit that, by using the detection value, calculates the measurement value by compensating as needed for a delay in the change in flow rate in the bypass passage with respect to the change in flow rate in the main passage. The compensation is based on whether a change of flow direction has occurred in the main passage or the bypass passage.

A method for controlling a speed of a turbocharger that is in operative connection with a compressor, the steps including: provision of a setpoint for the speed of the turbocharger on the basis of a model-based precontrol for a calculation of a desired boost pressure ahead of the turbocharger; determination of an actual value for the speed of the turbocharger; control of an actuator of the turbocharger in order to compensate for the difference between the desired value and the actual value for the speed of the turbocharger. Amain signal and a subsidiary signal are provided during the determination of the actual value for the speed of the turbocharger, wherein the main signal and the subsidiary signal are combined in order to validate the actual value for the speed of the turbocharger.

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.

A physical quantity sensing device is installed to a circuit board and is configured to output a signal, which corresponds to a physical quantity of air flowing through a physical quantity measurement passage. A physical quantity measurement passage inlet, which is communicated with the physical quantity measurement passage, includes a first inner surface and a second inner surface. A second distance, which is measured from the physical quantity sensing device to the second inner surface in a plate thickness direction of the circuit board, is larger than a first distance, which is measured from the circuit board to the first inner surface in the plate thickness direction of the circuit board.

A physical quantity measuring device detects a physical quantity of gas flowing in a flow passage. The physical quantity measuring device includes a sensor element that outputs a detection signal according to the physical quantity, a case that is provided to the flow passage and houses the sensor element, and a protrusion that protrudes from a passage wall surface facing the flow passage. The case includes a measurement chamber that houses the sensor element and an inflow port that is configured to cause a part of gas flowing in the flow passage to flow into the measurement chamber therethrough. The protrusion is configured to guide gas flowing along the passage wall surface toward the inflow port.

An apparatus and a method are provided for an aircharger air intake system for filtering and conducting an airstream to an air intake of an engine. The aircharger air intake system includes an air filter comprising a filter medium configured to entrap particulates flowing within the airstream. An air box comprising one or more sidewalls and a mount wall is configured to support the air filter within an engine bay. The air box is configured to be mounted, or fastened, onto the engine. An intake tube is coupled with the air filter and configured to conduct the airstream to the air intake of the engine. The intake tube is configured to be coupled with an air temperature sensor or a mass air sensor of the engine. An adapter is configured to couple the intake tube with the air intake.

An apparatus and a method are provided for an aircharger air intake system for filtering and conducting an airstream to an air intake of an engine. The aircharger air intake system includes an air filter comprising a filter medium configured to entrap particulates flowing within the airstream. An air box comprising one or more sidewalls and a mount wall is configured to support the air filter within an engine bay. The air box is configured to be mounted, or fastened, onto the engine. An intake tube is coupled with the air filter and configured to conduct the airstream to the air intake of the engine. The intake tube is configured to be coupled with an air temperature sensor or a mass air sensor of the engine. An adapter is configured to couple the intake tube with the air intake.

A physical quantity measurement device includes a housing forming a measurement flow path through which the fluid flows and a container space that houses a part of a detection unit. An inner surface of the housing includes a housing intersecting surface that intersects an arrangement direction in which the measurement flow path and the container space are arranged, a housing flow path surface extending from the housing intersecting surface toward the measurement flow path, and a housing container surface extending from the housing intersecting surface toward the container space. The housing includes a housing partition that protrudes from the inner surface toward the detection unit and contacts the detection unit between the housing and the detection unit such that the housing partition separates the measurement flow path and the container space from each other.