Abstract: An air flow rate measuring device for a vehicle measures an air flow rate based on an output value of a sensing unit disposed under an environment in which an air flows. The air flow rate measuring device includes a processor programmed to calculate a standard deviation from sampling data in the output value for at least one cycle of a pulsation waveform of the air, calculate a kurtosis of the pulsation waveform from the output value, estimate the pulsation error that is correlated with the standard deviation and the kurtosis, and correct the air flow rate to mitigate the pulsation error by using the pulsation error.

Abstract: A physical quantity measurement device measures a physical quantity of a fluid. The device includes a passage flow channel, a branch flow channel, a flow channel partition portion that separates the passage flow channel and the branch flow channel to have the branch flow channel branch off from the passage flow channel, and a physical quantity detector. The flow channel partition portion has a partition top portion as an upstream-side end that is not exposed through the inflow port.

Abstract: A physical quantity measurement device that measures a physical quantity of a fluid has an inflow port and an outflow port, and includes a passage flow channel, a branch flow channel, and a physical quantity detector. An inner peripheral surface of the passage flow channel extends over a pair of facing surfaces, which face each other across the flow passage boundary portion and the inflow port on an upstream side of the flow channel boundary portion. The inner peripheral surface further includes an inflow step surface which forms a step facing the inflow port side.

Abstract: A method is for adjusting a flow measuring device that includes a housing and a flow sensor. The housing includes a bypass flow passage which is formed to take in a part of a mainstream of air. The sensor is disposed in the bypass flow passage and outputs an electrical signal in accordance with a flow rate of air. The bypass flow passage is formed in an asymmetrical shape with respect to the sensor in upstream and downstream directions of the mainstream. A flow from an upstream side toward a downstream side of the mainstream is a forward flow. A flow from the downstream side toward the upstream side of the mainstream is a backward flow. According to the method, an output from the sensor in a backward-flow region is obtained. Furthermore, the output of the sensor in the backward-flow region is adjusted to have a desired output characteristic.

Abstract: An air flow rate measuring device measures an air flow rate based on an output value of a sensing unit placed in an environment that allows air to flow therethrough. The air flow rate measuring device includes: an acquisition unit configured to acquire the output value; a storage unit configured to store uneven flow information that indicates an uneven flow state of the air in the environment; a pulsation error correction unit configured to correct the air flow rate by using at least one of the uneven flow information and the output value such that the pulsation error Err in the air flow rate caused by the uneven flow becomes smaller.

Abstract: 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.

Abstract: A temperature sensor differs from a relative humidity sensor in responsiveness when the temperature of air changes. An absolute humidity acquisition unit acquires absolute humidity of air from outputs from the temperature sensor and the relative humidity sensor. A delay adjustment unit is to delay an output from one of the temperature sensor and the relative humidity sensor, which is a high response sensor having a higher responsiveness, and to reconcile change-behaviors of the output from the temperature sensor and the output from the relative humidity sensor in response to a temperature change in air. The absolute humidity acquisition unit acquires the absolute humidity based on the output from the other of the temperature sensor and the relative humidity sensor, which is a low response sensor having a lower responsiveness, and the sensor signal, which is from the high response sensor and delayed in the delay adjustment unit.

Abstract: A temperature sensor and a relative humidity sensor are placed in an environment allowing air to flow and are displaced in an upstream-downstream direction of the airflow. An absolute humidity acquisition unit acquires absolute humidity of air from outputs from the temperature sensor and the relative humidity sensor. A delay adjustment unit delays an output from one of the temperature sensor and the relative humidity sensor placed upstream and to reconcile change-behaviors of outputs from the temperature sensor and the relative humidity sensor in response to a state change in air. The absolute humidity acquisition unit acquires the absolute humidity based on the output from the other of the temperature sensor and the relative humidity sensor placed downstream and an output acquired from the one sensor placed upstream and delayed in the delay adjustment unit.

Abstract: A plate-like flow sensor is located in a bypass passage such that a front-to-rear direction of the flow sensor is substantially along a width direction of the bypass passage. The flow sensor divides a flow from its upstream into a first flow, which passes on its front side, and a second flow, which passes on its rear side. The bypass passage has a bent portion in which the first flow and the second flow merge on a downstream side of the flow sensor. A flow deflection unit changes a turning quantity of at least one of the first flow and the second flow such that a turning quantity of the first flow and a turning quantity of the second flow are substantially conformed in the bent portion.

Abstract: An air flow measuring device takes in part of intake air flowing through an intake passage. The device includes a housing and a sensor. The housing defines a bypass flow passage through which taken-in intake air passes and which has an outlet that opens on an outer wall of the housing. The sensor is accommodated in the bypass passage to produce an electrical signal as a result of heat transfer between taken-in intake air and the sensor. The outlet of the bypass passage includes vertical and non-vertical openings. The vertical opening opens toward a downstream side of a flow of intake air in the intake passage and is provided perpendicular to the flow of intake air. The non-vertical opening is provided non-perpendicularly to the flow of intake air in the intake passage. The outlet is a continuous stretch of opening where the vertical and non-vertical openings are continuously formed.

Abstract: An air flow measuring device includes a housing, a sensor, and a throttle that is provided on an outer wall surface of the housing. The throttle merges together a bypass-passing flow and an outside-passing flow, and guides the merged flow toward the downstream side with the merged flow narrowed. The throttle includes two raised portions and a cover that bridges between the two raised portions and is opposed to the outer wall surface of the housing. The cover includes an inner surface exposed to the throttle, and an outer surface exposed to outside of the throttle. A peripheral border of the cover includes an upstream edge which defines the outer surface on the upstream side. At least a region of the outer surface including the upstream edge is swollen more outwardly in a shape of a projecting curved surface further on the downstream side.

Abstract: A flow measuring device includes a housing, a support, and a flow measurement element. The housing defines a passage therein and includes a passage narrowing part, which reduces a cross-sectional area of the passage, in a predetermined part of the passage. The support has a platy shape and is disposed along a flow direction of fluid flowing in the passage. The flow measurement element is located inside the passage narrowing part and is disposed on a surface of the support. The flow measurement element detects a flow rate of fluid flowing in the passage. The passage narrowing part has an inner wall surface that gradually reduces a width of the passage from a center side to both end sides of the passage in a height direction of the passage, which is perpendicular to a direction of the width of the passage.

Abstract: A bypass passage receives a part of air flowing through a duct. A sub-bypass passage is branched from an intermediate portion of the bypass passage to separate dust contained in air flowing through the duct. A flow rate sensor is located in the sub-bypass passage for detecting the flow rate of air. A first wall surface and a second wall surface of the bypass passage are located upstream from the branch. The first wall surface is located on the side of the branch. The second wall surface is opposed to the first wall surface. Both the first wall surface and the second wall surface are curved to direct airflow to move away from the branch.

Abstract: A plate-like flow sensor is located in a bypass passage such that a front-to-rear direction of the flow sensor is substantially along a width direction of the bypass passage. The flow sensor divides a flow from its upstream into a first flow, which passes on its front side, and a second flow, which passes on its rear side. The bypass passage has a bent portion in which the first flow and the second flow merge on a downstream side of the flow sensor. A flow deflection unit changes a turning quantity of at least one of the first flow and the second flow such that a turning quantity of the first flow and a turning quantity of the second flow are substantially conformed in the bent portion.

Abstract: A converting map for an area of a backward air-flow is set based on a relationship between an output and a flow-rate, which are obtained in an air flow in which pulsation including the backward air-flow is generated. The backward air-flow has a dynamic property. The converting map of the present disclosure has a conversion characteristic, which is close to a characteristic in the backward air-flow. Accordingly, it is not necessary to correct the converting map by complicated processes and thereby accuracy of measurement for the area of the backward air-flow is increased.

Abstract: An airflow measuring device has a bypass passage accommodating a thermal-type sensor configured to conduct heat transfer with air. A mainstream of intake air partially flows through the bypass passage and flows out of an outlet, as an after-bypass-passage flow. The mainstream partially flows along the outer surface of the airflow measuring device, without passing through the bypass passage, as an outside-passage flow. The outer surface of the airflow measuring device defines a throttle at the downstream of the outlet. The throttle merges the after-bypass-passage flow with the outside-passage flow and guides the merged flow to the downstream.

Abstract: An air flow measuring device includes a housing, a sensor, and a throttle that is provided on an outer wall surface of the housing. The throttle merges together a bypass-passing flow and an outside-passing flow, and guides the merged flow toward the downstream side with the merged flow narrowed. The throttle includes two raised portions and a cover that bridges between the two raised portions and is opposed to the outer wall surface of the housing. The cover includes an inner surface exposed to the throttle, and an outer surface exposed to outside of the throttle. A peripheral border of the cover includes an upstream edge which defines the outer surface on the upstream side. At least a region of the outer surface including the upstream edge is swollen more outwardly in a shape of a projecting curved surface further on the downstream side.

Abstract: A bypass passage receives a part of air flowing through a duct. A sub-bypass passage is branched from an intermediate portion of the bypass passage to separate dust contained in air flowing through the duct. A flow rate sensor is located in the sub-bypass passage for detecting the flow rate of air. A first wall surface and a second wall surface of the bypass passage are located upstream from the branch. The first wall surface is located on the side of the branch. The second wall surface is opposed to the first wall surface. Both the first wall surface and the second wall surface are curved to direct airflow to move away from the branch.

Abstract: An air flow measuring device takes in part of intake air flowing through an intake passage. The device includes a housing and a sensor. The housing defines a bypass flow passage through which taken-in intake air passes and which has an outlet that opens on an outer wall of the housing. The sensor is accommodated in the bypass passage to produce an electrical signal as a result of heat transfer between taken-in intake air and the sensor. The outlet of the bypass passage includes vertical and non-vertical openings. The vertical opening opens toward a downstream side of a flow of intake air in the intake passage and is provided perpendicular to the flow of intake air. The non-vertical opening is provided non-perpendicularly to the flow of intake air in the intake passage. The outlet is a continuous stretch of opening where the vertical and non-vertical openings are continuously formed.

Abstract: An airflow measuring device has a bypass passage accommodating a thermal-type sensor configured to conduct heat transfer with air. A mainstream of intake air partially flows through the bypass passage and flows out of an outlet, as an after-bypass-passage flow. The mainstream partially flows along the outer surface of the airflow measuring device, without passing through the bypass passage, as an outside-passage flow. The outer surface of the airflow measuring device defines a throttle at the downstream of the outlet. The throttle merges the after-bypass-passage flow with the outside-passage flow and guides the merged flow to the downstream.