An outlet of a sub passage that returns measured gas, which has passed through a flow sensor, from the sub passage to a main passage opens on an outer wall of a housing toward a downstream side in a reference direction. The outer wall of the housing includes a protrusion on the downstream side of the outlet. When the outlet and the protrusion are projected onto a projection plane perpendicular to the reference direction, the outlet and the protrusion partly overlap with each other on the projection plane. A relationship of θ1<θ2<90° is satisfied, where: θ1 is assumed to be an angle formed between a direction from an upstream end to a top, and the reference direction; and θ2 is assumed to be an angle formed between a direction from a downstream end to the top, and the reference direction.

An outlet of a sub passage that returns measured gas, which has passed through a flow sensor, from the sub passage to a main passage opens on an outer wall of a housing toward a downstream side in a reference direction. The outer wall of the housing includes a protrusion on the downstream side of the outlet. When the outlet and the protrusion are projected onto a projection plane perpendicular to the reference direction, the outlet and the protrusion partly overlap with each other on the projection plane. A relationship of θ1<θ2<90° is satisfied, where: θ1 is assumed to be an angle formed between a direction from an upstream end to a top, and the reference direction; and θ2 is assumed to be an angle formed between a direction from a downstream end to the top, and the reference direction.

A flowmeter is inserted into a main passage through which a target fluid flows. The flowmeter includes a housing, a sub passage, an inlet portion, an outlet portion, a flow rate detector, and a protrusion. The housing includes a side surface and a tip end surface. A part of the target fluid flows into the sub passage from the main passage. The target fluid flows into the sub passage through the inlet portion and flows out of the sub passage through the outlet portion. The flow rate detector is configured to detect a flow rate of the target fluid flowing through the sub passage. The tip end surface includes a first end area and a second end area. The protrusion protrudes from the tip end surface and is located in both the first end area and the second end area.

Disclosed is a process and mass liquid flow (MLF) meter for measuring water cut, the MLF meter including a variable speed pump, a blind mixing T, a Coriolis meter, a differential pressure sensor, and a backpressure valve, and the process including maintaining a velocity of an emulsion through a Coriolis meter within a predetermined threshold from a predetermined velocity by controlling the variable speed pump, maintaining a pressure within the MLF meter to above a minimum pressure by controlling the backpressure valve, measuring a differential pressure across the Coriolis meter utilizing the differential pressure sensor, measuring a mass flow in the MLF meter utilizing the Coriolis meter, determining a viscosity based on the measured differential pressure and mass flow, and determining water cut of the emulsion based on the determined viscosity.

A bidirectional flow switch includes a housing having a flow passage therethrough. A body is disposed moveably in the flow passage and biased towards a first position at zero flow. A magnetic sensor is proximate the housing. A magnet is disposed with respect to the body and the magnetic sensor so that when the body is at the first position, the magnetic sensor is at a first state and so that the magnetic sensor is at a second state when a flow rate through the flow passage is greater than a threshold flow rate that moves the body from the first position.

A flow dampener for dampening pulsation in a fluid flow includes a body shell, a flexible membrane, and two flow ports. The body shell has an interior surface and an elongate groove formed on the interior surface. The flexible membrane is sealed to the interior surface of the body shell and covers the elongate groove. In some embodiments, the flexible membrane is over-molded onto the body shell. The flexible membrane cooperates with the elongate groove to form an elongate flow path for the fluid flow. The flexible membrane has a thickness in a range from 0.5 mm to 6 mm. As the membrane is flexible, it vibrates as the fluid flows through the elongate flow path, absorbs kinetic energy in the fluid flow, and thereby dampens pulsation in the fluid flow.

Provided is a cylinder intake air amount estimation apparatus for an internal combustion engine, which is capable of highly precisely calculating a cylinder intake air amount based on an AFS intake air amount in a control system for an engine including a supercharger. A cylinder intake air amount calculation part calculates the cylinder intake air amount based on an intake opening intake air amount by using a physical model of an intake system derived based on a volume efficiency acquired by considering an intake manifold as a reference, which is a volume efficiency of air entering a cylinder from the intake manifold, a virtual intake manifold volume, and a stroke volume per cylinder, the physical model being adapted to the control system for an engine including a supercharger.

A decrease in the accuracy after switching of the heating state can be reduced. The physical quantity detecting device includes: a flow rate detecting unit configured to include a heating element to measure a flow rate of a fluid to be measured; a heating element control unit configured to switch a control state of the heating element to any one of a heating state and a heating suppression state; and a signal processing unit configured to process a measured value of the flow rate detecting unit. When the heating element control unit switches the control state, the signal processing unit processes an estimated value determined based on a measured value of the flow rate detecting unit before the switching for a predetermined period immediately after the switching.

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.

An air flow rate measurement device includes a flow rate detection unit, a detected flow rate response compensation unit, a pulsation amplitude calculation unit, a correction value calculation unit, and an error correction unit. The flow rate detection unit detects a detected flow rate. The detected flow rate response compensation unit advances a response time of the detected flow rate and calculating a compensation flow rate which is an output obtained by compensating for a response delay of the detected flow rate. The pulsation amplitude calculation unit calculates a pulsation amplitude correlated with a pulsation amplitude in the detected flow rate. The correction value calculation unit calculates a pulsation correction value which is a value for correcting the compensation flow rate based on the pulsation amplitude. The error correction unit corrects the compensation flow rate based on the pulsation correction value.