System, devices and methods for measuring differential and absolute pressure utilizing two MEMS sense elements

Patent metadata

Field	Value
Publication number	US-9638559-B1
Application number	US-201615040355-A
Country	US
Kind code	B1
Filing date	Feb 10, 2016
Priority date	Feb 10, 2016
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

Featured are systems and methods for measuring differential and absolute pressure of a flowing fluid/gas in a fluid system. In such a method the fluid system is configured with first and second pressure taps that are spaced from each so the second pressure tap is downstream of the first pressure tap in a direction of flow. An absolute pressure sense element and a differential pressure sense element are provided, where the absolute pressure sense element is first fluidly coupled to one of the first or second pressure tap to measure an absolute pressure representative of the flowing fluid/gas. The differential pressure sense element is second fluidly coupled to each of the first and second pressure taps so as to measure a differential pressure of the flowing fluid/gas between the first and second pressure taps.

First claim

What is claimed is:

1. A method for measuring absolute and differential pressure of a flowing fluid in a fluid system, comprising the step(s) of:
configuring the fluid system so as to include a first pressure tap and a second pressure tap that are spaced from each other such that the second pressure tap is downstream of the first pressure tap in a direction of flow;
providing an absolute pressure sense element and first fluidly coupling the absolute pressure sense element to one of the first or second pressure tap so as to thereby measure an absolute pressure representative of the flowing fluid at the respective pressure tap to which it is fluidly coupled;
providing a differential pressure sense element and second fluidly coupling the differential pressure sense element to each of the first and second pressure taps so as to measure a differential pressure of the flowing fluid between the first and second pressure taps; and
wherein said first and second fluidly coupling further includes disposing a non-compressible medium between the respective absolute and differential pressure sense elements and the respective first and second pressure taps.

2. The method of claim 1 , wherein said first fluidly coupling further includes fluidly coupling the absolute pressure sense element to the first pressure tap so as to thereby measure an absolute pressure representative of the flowing fluid at the first pressure tap location.

3. The method of claim 1 , further comprising the step of providing a fluid channel between the second pressure tap and the differential pressure sense element the fluid channel containing the non-compressible medium, the fluid channel being configured and arranged so as to communicate a second pressure representative of the flowing fluid at the second pressure tap location to the differential pressure sense element.

4. The method of claim 3 , further comprising the step of communicating a first pressure representative of the flowing fluid at the first pressure tap location to the differential pressure sense element.

5. The method of claim 1 , further comprising the step(s) of:
locating a restrictive pressure device in the fluid system disposed between the first and second pressure taps such that the first pressure tap is at a higher pressure than the second pressure tap.

6. The method of claim 5 , wherein the restrictive pressure device is one of a restrictive venturi, an orifice or a throttle plate.

7. The method of claim 1 , further comprising the step(s) of:
providing at least one digital processing mechanism;
wherein each of the at least one digital processing mechanism is configured and arranged for controlling operation of the absolute pressure sense element and controlling operation of the differential pressure sense element; and
wherein each of the at least one digital processing mechanism is configured and arranged for providing an output representative of the absolute pressure being measured and for providing an output representative of the differential pressure being measured.

8. The method of claim 7 , wherein each of the at least one digital processing mechanism is an ASIC.

9. The method of claim 7 , wherein:
said providing at least one digital processing mechanism includes providing a first digital processing mechanism and a second digital processing mechanism;
the first digital processing mechanism is configured and arranged for controlling operation of the absolute pressure sense element and for providing an output representative of the absolute pressure being measured; and
the second digital processing mechanism is configured and arranged for controlling operation of the differential pressure sense element and for providing an output representative of the differential pressure being measured.

10. The method of claim 1 , wherein the flowing fluid is a gas and wherein the method further comprises the step(s) of:
providing a temperature sensing device and configuring the fluid system so that the temperature sensing device measures a temperature of the flowing gas and provides an output of the measured temperature, wherein the absolute pressure sense element provides an output of the measured absolute pressure and the differential pressure sense element provides an output of the measured differential pressure; and
using the outputs of the measured temperature, absolute pressure and differential pressure to determine a mass flow rate of the flowing gas in the fluid system.

11. The method of claim 1 , wherein each of the absolute pressure sense element and the differential pressure sense element comprise a MEM sense element.

12. The method of claim 1 , wherein the flowing fluid is one of an exhaust gas of an exhaust gas recirculation system or intake air of an intake system.

13. A method for determining a mass flow rate of a flowing gas in a fluid system, comprising the step(s) of:
configuring the fluid system so as to include a first pressure tap, a second pressure tap, a restrictive pressure device and a temperature sensing device;
wherein the first and second pressure taps are spaced from each other such that the second pressure tap is downstream of the first pressure tap in a direction of flow;
wherein the restrictive pressure device is disposed between the first and second pressure taps such that the first pressure tap is at a higher pressure than the second pressure tap;
wherein the temperature sensing device is coupled to and arranged in the fluid system so that the temperature sensing device measures a temperature of the flowing gas and provides an output of the measured temperature;
providing an absolute pressure sense element and first fluidly coupling the absolute pressure sense element to one of the first or second pressure taps so as to thereby measure an absolute pressure representative of the flowing gas at the respective pressure tap to which it is fluidly coupled and providing an output thereof;
providing a differential pressure sense element and second fluidly coupling the differential pressure sense element to each of the first and second pressure taps so as to measure a differential pressure of the flowing gas between the first and second pressure taps and providing an output thereof;
wherein said first and second fluidly coupling further includes disposing a non-compressible medium between the respective absolute and differential pressure sense elements and the respective first and second pressure taps; and
using the outputs of the measured temperature, absolute pressure and differential pressure to determine a mass flow rate of the flowing gas in the fluid system.

14. The method of claim 13 , wherein the flowing gas is one of an exhaust gas of an exhaust gas recirculation system or intake air of an intake system both of an internal combustion engine.

15. An apparatus for measuring absolute and differential pressure of a flowing fluid in a fluid system, comprising:
a housing including a plurality of cavities that are fluidly coupled in spaced relation to the fluid system and so as to be fluidly coupled to the flowing fluid;
a sensing module mounted to the housing; and
wherein the sensing module includes:
an absolute pressure sense element that is first fluidly coupled to one of the plurality of cavities so as to thereby measure an absolute pressure representative of the flowing fluid to which the said one cavity is fluidly coupled to,
a differential pressure sense element that is second fluidly coupled to said one cavity and to another of the plurality of cavities so the differential pressure sense element measures a differential pressure of the flowi

Assignees

• Sensata Technologies Inc
• Sensata Technologies Inc

Inventors

• Zummo Peter
• Bender Victor

Classifications

• G01F1/88 Primary

  with differential-pressure measurement to determine the volume flow · CPC title

• G01L23/24

  {specially adapted} for measuring pressure in inlet or exhaust ducts of internal-combustion engines · CPC title

• F02D41/0072

  Estimating, calculating or determining the EGR rate, amount or flow (sensors in EGR systems F02M26/45) · CPC title

• G01F1/86

  Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure · CPC title

• G01L15/00

  Devices or apparatus for measuring two or more fluid pressure values simultaneously · CPC title