This invention provides a fluid mechanism that can arrange a plurality of fluid device units and external fluid devices mounted as a set on the fluid device units effectively and compactly. Each of the fluid device units is arranged with respective side surfaces in a longitudinal direction of the fluid device unit tightly attached, and the external fluid devices are arranged side-by-side external to and outside of the fluid device unit in the width direction. Furthermore, as for an introducing path and a discharging path that connect the external fluid devices and the fluid device unit, the introducing path, which is short, is connected to the discharging path, which is long.

This invention provides a fluid mechanism that can arrange a plurality of fluid device units and external fluid devices mounted as a set on the fluid device units effectively and compactly. Each of the fluid device units is arranged with respective side surfaces in a longitudinal direction of the fluid device unit tightly attached, and the external fluid devices are arranged side-by-side external to and outside of the fluid device unit in the width direction. Furthermore, as for an introducing path and a discharging path that connect the external fluid devices and the fluid device unit, the introducing path, which is short, is connected to the discharging path, which is long.

A sensor arrangement is described for determining at least one parameter of a fluid medium flowing through a measuring channel, particularly of an intake air mass flow of an internal combustion engine. The sensor arrangement includes a sensor housing, in particular a plug-in sensor which is introduced or may be introduced into a flow tube and in which the measuring channel is formed, and at least one sensor chip which is situated in the measuring channel for determining the parameter of the fluid medium. The sensor chip is attached to a sensor carrier protruding into the measuring channel. The sensor carrier is designed in such a way that it has a chord. The chord has a length of 4.5 mm to 6.5 mm. In a preferred refinement, the sensor carrier is shaped like a double ellipse or a diving board.

A sensor arrangement is described for determining at least one parameter of a fluid medium flowing through a measuring channel, particularly of an intake air mass flow of an internal combustion engine. The sensor arrangement includes a sensor housing, in particular a plug-in sensor which is introduced or may be introduced into a flow tube and in which the measuring channel is formed, and at least one sensor chip which is situated in the measuring channel for determining the parameter of the fluid medium. The sensor chip is attached to a sensor carrier protruding into the measuring channel. The sensor carrier is designed in such a way that it has a chord. The chord has a length of 4.5 mm to 6.5 mm. In a preferred refinement, the sensor carrier is shaped like a double ellipse or a diving board.

An airflow-rate detecting device capable of detecting humidity has a housing, a flow rate sensor, a humidity sensor, a humidity sensor case, and a dust separating portion. The housing therein defines a bypass passage into which a part of air flowing in a duct flows. The flow rate sensor is disposed in the bypass passage. The humidity sensor detects a humidity of air flowing in the duct at an outside of the housing. The humidity sensor case houses the humidity sensor and therein defines an interior space into which a part of air flowing in the duct flows as a target air of which humidity is detected by the humidity sensor. The dust separating portion removes dust from the target air before the target air flows into the interior space.

An airflow-rate detecting device capable of detecting humidity has a housing, a flow rate sensor, a humidity sensor, a humidity sensor case, and a dust separating portion. The housing therein defines a bypass passage into which a part of air flowing in a duct flows. The flow rate sensor is disposed in the bypass passage. The humidity sensor detects a humidity of air flowing in the duct at an outside of the housing. The humidity sensor case houses the humidity sensor and therein defines an interior space into which a part of air flowing in the duct flows as a target air of which humidity is detected by the humidity sensor. The dust separating portion removes dust from the target air before the target air flows into the interior space.

Mass flow controllers and methods for controlling mass flow controllers are disclosed. A method includes providing a gas through a thermal mass flow sensor of the mass flow controller and processing a flow sensor signal from the thermal mass flow sensor of the mass flow controller to produce a measured flow signal. The measured flow signal is corrected to produce a corrected flow signal by gradually changing non-linearity correction to the measured flow signal when a flow rate of the gas changes. A valve of the mass flow controller is controlled using the corrected flow signal and a setpoint signal.

To obtain a chip package positioning structure capable of adjusting a tilt and a position of a chip package with respect to the circuit board and reducing mounting variations. The chip package positioning and fixing structure that positions and fixes, to a circuit board 4, a chip package 5 in which a flow rate detection element 53 is sealed with a resin so that a detection portion is at least exposed, in which the chip package includes a solder fixation portion 52 that fixes the chip package to the circuit board by soldering, and a positioning portion 514 that performs positioning to the circuit board, and the positioning portion is provided closer to the flow rate detection element from the solder fixation portion.

To obtain a chip package positioning structure capable of adjusting a tilt and a position of a chip package with respect to the circuit board and reducing mounting variations. The chip package positioning and fixing structure that positions and fixes, to a circuit board 4, a chip package 5 in which a flow rate detection element 53 is sealed with a resin so that a detection portion is at least exposed, in which the chip package includes a solder fixation portion 52 that fixes the chip package to the circuit board by soldering, and a positioning portion 514 that performs positioning to the circuit board, and the positioning portion is provided closer to the flow rate detection element from the solder fixation portion.

A physical quantity measurement device includes a passage flow channel having an inflow port and an outflow port, a branch flow channel branched from the passage flow channel and having a branch inlet into which the fluid flows from the passage flow channel. The branch flow channel has an inclined branch path inclined with respect to the passage flow channel, and the inclined branch path extends from the branch inlet toward the outflow por. An inclination angle of the branch flow channel at the branch inlet with respect to a virtual straight line connecting the inflow port and the outflow port is smaller than or equal to a predetermined value.