Abstract: A flowmeter is configured to measure a flow rate of a gas flowing through a main passage. The flowmeter includes a housing and a flow rate detector. The housing is made of a resin and includes a bypass passage branched off from the main passage. The flow rate detector is disposed in the bypass passage and transmits detection signals in accordance with the flow rate of the gas flowing through the main passage. The housing includes a non-insulation portion including graphite.

Abstract: An air flow rate measuring device is configured to measure a flow rate of air flowing through a main flow path. The air flow rate measuring device includes a housing, a board, a land portion, and an insulating portion. The housing is provided in the main flow path. The board is provided in the housing. The land portion includes multiple lands via which the board is configured to be mounted with a physical quantity sensor that is configured to detect a physical quantity of air. The insulating portion electrically insulates between the multiple lands against foreign matter or water flowing with the air.

Abstract: An airflow meter includes a housing including a base surface, a rear surface, a first side surface, a second side surface, a flow-rate inlet portion, a flow-rate outlet portion, a passage, and a physical quantity inlet portion, a flow rate detector, a board, and a physical quantity detector mounted on a board surface. The physical quantity inlet portion includes a first inner surface, a second inner surface, a third inner surface, and a fourth inner surface. The physical quantity detector is configured to output signals according to a physical quantity of air flowing through a board passage. The board, the first inner surface, the third inner surface, and the fourth inner surface are arranged to reduce a cross-sectional area of the board passage from the base surface toward the rear surface.

Abstract: A thin film is formed on a substrate on which an opening having two opposite sides are formed, and forms a membrane. The thin film has an upstream temperature sensor and a downstream temperature sensor on both sides of a heater. A heat conductive member covers the two sides and is arranged on both sides of the heater, the upstream temperature sensor, and the downstream temperature sensor so as to promote heat conduction from the heater to the substrate. When an end of the opening on the membrane side is defined as an upper end and an end on the side away from the membrane is defined as a lower end, the heat conductive member covers from the upper end to the lower end of the opening in a normal direction of the membrane.

Abstract: A sensor recess portion is provided on a sensor back surface. A membrane portion provided with a detection element forms a bottom surface of the sensor recess portion. A sensor support portion includes a back support portion, a support recess portion, a support hole, and a support recess inner wall surface. The back support portion covers an opening of the sensor recess portion. The support recess portion is provided on a side opposite from a physical quantity sensor. The support hole penetrates the back support portion and communicates with the opening. The support recess inner wall surface extends from the support recess bottom portion and is inclined with respect to a center line of the support hole.

Abstract: 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.

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 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 flowmeter is configured to measure a flow rate of a gas flowing through a main passage. The flowmeter includes a housing and a flow rate detector. The housing is made of a resin and includes a bypass passage branched off from the main passage. The flow rate detector is disposed in the bypass passage and transmits detection signals in accordance with the flow rate of the gas flowing through the main passage. The housing includes a non-insulation portion including graphite.

Abstract: An air flow meter includes an inward part that is positioned inward of an intake pipe and an outward part that is positioned not inward but outward of the intake pipe. The air flow meter further includes a first detector provided in the inward part, and a second detector provided at a position closer to the outward part than the first detector.

Abstract: 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.

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 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.