Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
  • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
  • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
  • G01F1/6842—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow with means for influencing the fluid flow

Definitions

• the invention relates to a device for measuring the mass of a flowing medium according to the preamble of claim 1.
• a device (DE-OS 44 07 209) is already known which is used to measure the intake air mass
• Internal combustion engine has a measuring element housed in a measuring channel.
• the measuring element is designed, for example, in the form of a ceramic substrate or as a micromechanical component.
• the device has a slender, cuboid shape that extends radially in the direction of a plug-in axis and is inserted into an opening in a wall of an intake line.
• the wall of the suction line delimits a flow cross section, which in the case of a cylindrical suction line has approximately a circular cross section.
• the intake line represents, for example, an intake pipe of an internal combustion engine, through which the internal combustion engine can draw in air from the environment.
• the radial position of the device is fixed in the opening of the wall of the suction line such that the measuring channel of the measuring part of the device is aligned parallel to the medium flowing in the suction line. In the radial direction, the measuring part of the device preferably protrudes approximately into the middle of the flow cross section of the suction line.
• Openings are provided in which screws can be inserted to connect the device to the suction line.
• claim 1 has the advantage that scattering of the characteristic curves resulting from installation tolerances are significantly reduced, so that essentially constant characteristic curves without scattering can be expected during mass production or installation of the device.
• a device 1 is partially shown in a sectional view, which is used to measure the mass of a flowing medium, in particular the intake air mass of internal combustion engines.
• the complete structure of such a device can be found, for example, in DE-OS 44 07 209, the disclosure of which is to be part of the present patent application.
• the device 1 preferably has a slender, cuboid shape that extends radially in the direction of a plug-in axis 10.
• the plug-in axis 10 is identified by a point in the drawing and extends perpendicular to the drawing plane into the drawing plane of the drawing.
• the device 1 is introduced in a known manner into an opening of a suction line 4 which is recessed from a wall 2 and fastened to the suction line 4, for example by means of a screw connection.
• the intake line 4 represents, for example, an intake pipe of a mixture-compressing, spark-ignited internal combustion engine, through which the internal combustion engine can draw in air from the environment.
• the suction line 4 delimits a flow cross section which, in the case of a cylindrical suction line 4, has an approximately circular cross section, in the middle of which an axis 11 extends in the axial direction in the direction of the flowing medium indicated by arrows 17, parallel to an inner wall 3 of the suction line 4 .
• the device 1 has a radial extension, so that a cuboid measuring part 15 of the device 1 with a rectangular cross section, shown hatched in the drawing, projects, for example, into the middle of the flow cross section of the suction line 4.
• the measuring part 15 of the device 1 there is a measuring channel 20 running in the axial direction and a radially adjoining deflecting channel 21, for example having an S shape intended.
• the medium flowing in the suction line 4 enters the measuring channel 20 via an inlet mouth 22, for example, which has a rectangular cross section, and passes from the measuring channel 20 into the deflection channel 21 in order to leave it through a dashed, for example radial, outlet opening 23.
• the measuring channel 20 has two side surfaces 24, 25 which are designed to converge in the axial direction towards the deflection channel 21, in the direction of a measuring channel axis 12 extending centrally in the measuring channel 20.
• the measuring channel axis 12 of the measuring channel 20 and the axis 11 of the suction line 4 are oriented perpendicular to the plug axis 10.
• a measuring element 28 for example in the middle of the measuring channel axis 12 is accommodated, which is for example in the form of a plate-shaped
• Ceramic substrate is formed and is aligned with its side surfaces 29 parallel to the measuring channel axis 12 in order to flow around the medium flowing in the measuring channel 20. It is also possible, as disclosed for example in DE-OS 43 38 891, the measuring element 28 as a micromechanical
• the tapering design of the measuring channel 20 has the effect that in the area of the measuring element 28 there is an almost undisturbed, uniform parallel flow which runs along the measuring channel axis 12 and is indicated in the drawing by corresponding arrows 18.
• the measuring channel 20 with its measuring channel axis 12 is not aligned parallel to the axis 11 of the suction line 4, but is arranged rotated by an angle ⁇ with respect to the axis 11 or the medium flowing in the suction line 4.
• the rotated installation position of the measuring part 15 or the measuring channel 20 results in that, downstream of the inlet mouth 22 on the circumference of the measuring part 15, a one-sided detachment region 30, indicated in the drawing by a line, is formed in the flow which is stable, in particular not from flow changes characterized flow state upstream of the inlet mouth 22 of the measuring channel 20 causes.
• the detachment area 30 extends from the inlet opening 22 along an outer surface 31 of the measuring part 15 which extends downstream in the suction line 4, without the flow again being applied to the outer surface 31.
• the detachment area 30 is essentially based on the flow 17 in the direction of the wall 2 of the suction line
• the measuring element 28 does not change its position in the measuring channel 20 with the rotation of the measuring part 15, so it takes on the same inclination with respect to the axis 11 of the suction line 4 as the measuring channel axis 12.
• the plug-in axis 10 can be provided as the axis of rotation for the rotated installation of the device 1. However, it is also possible to provide a different axis of rotation, for example offset to the plug-in axis 10.

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Volume Flow (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7780870

Family Applications (1)

Country Status (8)

Families Citing this family (11)

Family Cites Families (7)

• 1995
  • 1995-12-21 DE DE19547915A patent/DE19547915A1/de not_active Withdrawn
• 1996
  • 1996-07-24 JP JP9523190A patent/JPH11501126A/ja not_active Abandoned
  • 1996-07-24 KR KR1019970705734A patent/KR100254718B1/ko not_active IP Right Cessation
  • 1996-07-24 EP EP96928322A patent/EP0821781A1/de not_active Withdrawn
  • 1996-07-24 RU RU97115453/28A patent/RU2179708C2/ru not_active IP Right Cessation
  • 1996-07-24 WO PCT/DE1996/001359 patent/WO1997023767A1/de not_active Application Discontinuation
  • 1996-07-24 CN CN96190748A patent/CN1083569C/zh not_active Expired - Fee Related
  • 1996-07-24 US US08/860,376 patent/US5925820A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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