Air flow rate measurement device

Patent metadata

Field	Value
Publication number	US-2016377470-A1
Application number	US-201615193402-A
Country	US
Kind code	A1
Filing date	Jun 27, 2016
Priority date	Jun 29, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

An air flow rate measurement device includes a casing, a flow rate measurement portion, a first protrusion and a second protrusion. The casing is disposed in a main flow passage in which an air flows, and the casing defines a bypass passage therein to take in a part of the air flowing in the main flow passage. The flow rate measurement portion is housed in the casing and measures a flow rate of the air flowing in the bypass passage. The first protrusion protrudes from a side surface of the casing in the main flow passage. The second protrusion protrudes from the side surface of the casing in the main flow passage. The second protrusion is spaced from the first protrusion in a flow direction of the air in the main flow passage. The air flow rate measurement device is capable of limiting a generation of a separated vortex.

First claim

What is claimed is:

1 . An air flow rate measurement device comprising:
a casing disposed in a main flow passage in which an air flows, the casing defining a bypass passage therein to take in a part of the air flowing in the main flow passage; a flow rate measurement portion being housed in the casing and measuring a flow rate of the air flowing in the bypass passage; a first protrusion protruding from a side surface of the casing in the main flow passage; and a second protrusion protruding from the side surface of the casing in the main flow passage, the second protrusion being spaced from the first protrusion in a flow direction of the air in the main flow passage.

2 . The air flow rate measurement device according to claim 1 , wherein
a plurality of the first protrusions and a plurality of the second protrusions are provided on the side surface of the casing, the plurality of first protrusions are spaced from each other in a direction perpendicular to the flow direction, and the plurality of second protrusions are spaced from each other in the direction perpendicular to the flow direction.

3 . The air flow rate measurement device according to claim 2 , wherein the first protrusions and the second protrusions are arranged alternately in the direction perpendicular to the flow direction.

4 . The air flow rate measurement device according to claim 2 , wherein
a direction in which the air flows in the main flow passage from one side toward another side is defined as a forward flow direction, the first protrusions are located upstream of the second protrusions in the forward flow direction, and a number of the first protrusions is larger than a number of the second protrusions.

5 . The air flow rate measurement device according to claim 1 , wherein
a direction in which the air flows in the main flow passage from one side toward another side is defined as a forward flow direction, a direction in which the air flows in the main flow passage from the other side toward the one side is defined as a backward flow direction, the first protrusion is located upstream of the second protrusion in the forward flow direction, an edge surface of the first protrusion opposed to an air flow in the forward flow direction is angled with respect to the forward flow direction, and an edge surface of the second protrusion opposed to an air flow in the backward flow direction is oblique to the backward flow direction.

6 . The air flow rate measurement device according to claim 4 , wherein
a direction in which the air flows in the main flow passage from the another side toward the one side is defined as a backward flow direction, an edge surface of the first protrusion opposed to the air flowing in the forward flow direction is oblique to the forward flow direction, and an edge surface of the second protrusion opposed to the air flowing in the backward flow direction is angled with respect to the backward flow direction.

7 . The air flow rate measurement device according to claim 4 , wherein the bypass passage includes a first bypass passage extending straight in the flow direction, and a second bypass passage branched from the first bypass passage, the second bypass passage having a bypass outlet from which the air passed through the flow rate measurement portion is discharged, the bypass outlet facing downstream in the forward flow direction,
the first bypass passage includes an inlet from which a part of the air flowing in the main flow passage is introduced in the first bypass passage, and an dust discharge port from which a dust contained in the air introduced in the first bypass passage is discharged to the main flow passage.

8 . The air flow rate measurement device according to claim 7 , wherein the first protrusion, the second protrusion and the bypass outlet are aligned in the flow direction.

Assignees

• Denso Corp

Inventors

• Itou Kengo

Classifications

• G01F15/14 Primary

  Casings, e.g. of special material · CPC title

• G01F5/00

  Measuring a proportion of the volume flow · CPC title

• F02M35/10386

  for flow rate (air flow meters in air cleaners F02M35/021; circuit arrangements for generating control signals by measuring intake air flow F02D41/18) · CPC title

• G01F1/6845

  Micromachined devices · CPC title

• F01D17/02

  Arrangement of sensing elements · CPC title