Differential pressure sensor

Abstract

The present invention relates to a pressure sensor (1) comprising: at least one pressure-sensitive element (21, 22), a protective housing (5) in which the pressure-sensitive element (21, 22) is housed, and a chamber (6) connected to atmospheric pressure formed in the housing (5). The pressure-sensitive element (21, 22) comprises a first face (7, 7') in fluidic communication with a first pressure inlet P1 for measuring a first pressure and a second face (9, 9'), opposite the first face, in fluidic communication with the chamber (6), the pressure inlet being formed by a conduit (71, 72). The sensor comprises a means for protecting the pressure-sensitive element (21, 22) (51, 52, 53, 54). Figure for the abstract: Fig. 3.

Description

Title of the invention: Differential pressure sensor

[0001] The present invention relates to a pressure sensor, and more particularly a differential pressure sensor for, for example, measuring the pressure of a circuit equipped with a particulate filter or of an engine exhaust gas recirculation circuit.

[0002] Such a pressure sensor is used in the exhaust systems of internal combustion vehicles. It can, for example, be used to measure a pressure difference at two different points in an exhaust line, such as before and after a particulate filter.

[0003] Differential pressure sensors comprising a protective housing with two pressure-sensitive elements are already known.

[0004] The protective housing includes a first pressure inlet PI communicating via a first conduit with a first pressure-sensitive element to measure a first pressure, and a second pressure inlet P2 communicating via a second conduit with a second pressure-sensitive element to measure a second pressure. One of the two sensing elements converts the two obtained values ​​into a pressure differential, which is communicated to the engine control unit. In some applications, one of the conduits is open to the atmosphere.

[0005] A drawback of this configuration arises from the fact that foreign elements other than particles, such as insects, enter the tube and reach the sensing element. This results in a disruption of the pressure measurement and the differential pressure measurement, as well as damage to the sensing element.

[0006] The invention therefore aims to overcome these drawbacks of the prior art by proposing a differential pressure sensor configured to allow an optimized differential pressure measurement.

[0007] To this end, the present invention proposes a pressure sensor comprising: - at least one pressure-sensitive element, - a protective housing in which the pressure-sensitive element is housed, - a chamber connected to atmospheric pressure formed in the housing. - the pressure-sensitive element comprising a first face in fluidic communication with a first pressure inlet PI to measure a first pressure and a second face, opposite the first face, in fluidic communication with the chamber, the pressure inlet being formed by a conduit,

[0008] the sensor comprising a means for protecting the pressure-sensitive element.

[0009] According to one embodiment of the invention, the means of protecting the sensitive element is a restriction of the cross-section of a pressure inlet conduit.

[0010] According to one embodiment of the invention, the section restriction is formed by the conduit itself.

[0011] According to one embodiment of the invention, the diameter of the opening of the section restriction section is less than or equal to 1mm.

[0012] According to one embodiment of the invention, the means of protecting the sensitive element is an added part, perforated by openings, added in a conduit.

[0013] According to one embodiment of the invention, the added part is made of metal or plastic or a breathable membrane.

[0014] According to one embodiment of the invention, the added part is a perforated plate, or a foam or sintered fiber.

[0015] According to one embodiment of the invention, the added part is held mechanically in a conduit either by clipping, by force assembly, by gluing or by welding.

[0016] According to one embodiment of the invention, the means of protecting the sensitive element is formed by a total sealing element of the conduit at its inlet or any other place along the conduit, an additional opening being formed on the sensor directly or by an additional part, the diameter of this opening being less than or equal to 1mm.

[0017] The invention also relates to a vehicle engine component comprising a pressure sensor according to the invention.

[0018] Other objects, features and advantages of the invention will be better understood and will become more apparent upon reading the description given below, with reference to the accompanying figures, given by way of example and in which: - Figure 1 is a cross-sectional view of a differential pressure sensor according to the invention. - Figure [Fig. 2] is an elevational view of a differential pressure sensor according to the invention, - Figure 3 is a cross-sectional view of a differential pressure sensor according to the invention. - Figure 4 is a view of a differential pressure sensor according to the invention, according to a first embodiment of the invention. - Figure 5 is a cross-sectional view of a detail of a differential pressure sensor according to the invention, according to the first variant of the invention. - Figure 6 is an elevational view of a differential pressure sensor according to the invention, according to a second embodiment of the invention. - Figure 7 is a view of a differential pressure sensor according to the invention, according to a third embodiment of the invention. - Fig. 8 is a cross-sectional view of a differential pressure sensor according to the invention according to a fourth variant of the invention.

[0019] Fig. 1 represents a pressure sensor 1 for measuring a pressure difference in a component of a vehicle engine such as a particulate filter system.

[0020] This pressure sensor 1 includes at least one pressure-sensitive element 21, 22 also called a chip.

[0021] According to one embodiment of the invention, the pressure sensor 1 is a differential pressure sensor comprising a first pressure-sensitive element 21 and a second pressure-sensitive element 22 electrically connected to each other by electrical connection means 3.

[0022] According to one embodiment of the invention, the electrical connection means 3 are formed by at least one visible tab 31 to 37 [Fig.1] and [Fig.4].

[0023] According to one embodiment of the invention, each of the sensitive elements is associated with at least three tabs 31 to 37. These three tabs allow communication between the sensitive elements and with the engine control unit.

[0024] According to one embodiment of the invention, each of the sensitive elements 21, 22 is associated with at least three tabs 31 to 37.

[0025] According to one embodiment of the invention, the first sensitive element 21 is associated with four tabs 34 to 37 and the second sensitive element is associated with three tabs 31 to 33.

[0026] The pressure sensor 1 also includes a protective housing 5 in which the pressure-sensitive elements 21, 22 are housed. The protective housing 5 includes a chamber 6 connected to atmospheric pressure.

[0027] According to one embodiment of the invention, the first pressure-sensitive element 21 comprises a first face 7 in fluidic communication with a first pressure inlet PI to measure a first pressure and a second face 9, opposite to the first face, in fluidic communication with the chamber 6 [Fig.5].

[0028] Similarly, the second pressure-sensitive element 22 comprises a first face 7' in fluidic communication with a second pressure inlet P2 to measure a second pressure and a second face 9', opposite to the first face, in fluidic communication with the chamber 6 [Fig.5].

[0029] According to one embodiment of the invention, the pressure inlets PI and P2 are respectively formed by a first conduit 71 and a second pressure inlet conduit 72.

[0030] According to an example of application of the invention, the first conduit 71 is connected upstream of the particle filter and the second conduit 72 is connected downstream of the particle filter.

[0031] According to one embodiment of the invention, chamber 6 and the first pressure inlet PI are hermetically sealed from each other by the first pressure-sensitive element 21. Similarly, chamber 6 and the second pressure inlet P2 are hermetically sealed from each other by the second pressure-sensitive element 22.

[0032] According to one embodiment of the invention, the two pressure-sensitive elements 21, 22 are pressure-sensitive elements that measure a differential pressure. More specifically, the first face of the first pressure-sensitive element 21 is in contact with a medium having a pressure Pb. The first face of the second pressure-sensitive element 22 is in contact with a medium having a pressure P2. According to one embodiment of the invention, the first pressure-sensitive element 21 calculates the pressure difference between P1 and P2, and sends the resulting differential pressure value to the vehicle's engine control unit.

[0033] The second faces 9, 9' of the first 21 and of the second pressure-sensitive element 22 are in fluidic communication with the chamber 6 which is at atmospheric pressure Patm.

[0034] According to one embodiment of the invention, the pressure sensor 1 includes at least one support 40 for the sensitive elements supporting the pressure-sensitive elements 21, 22 [Fig.5].

[0035] According to one embodiment of the invention, an orifice 41, 42 is provided in the support 40 of the sensitive element. Each orifice 41, 42 is closed by one of the pressure-sensitive elements 21, 22.

[0036] According to one embodiment of the invention, the pressure sensor 1 includes a connector 32 for connecting it to an external electronic control device (not shown).

[0037] According to one embodiment of the invention, the housing comprises a cover or hood 15, illustrated [Fig. 2], for example removable, including a main face 20. The main face 20 is preferably flat. This cover 15 provides mechanical and chemical protection for the sensitive components as well as the various tabs located within the body. This cover 15 can be glued, welded, or clipped in place.

[0038] According to one application example of the invention, the sensor measures the pressure differential between the pressure PI or P2 arriving in one of the ducts and atmospheric pressure. In this case, communication between at least one of the two sensing elements and atmospheric pressure is necessary. For this purpose, the cover 15, or the housing, has an opening 151.

[0039] According to one embodiment of the invention, when the hood or housing has an opening, the opening 151 is protected by a breathable membrane 60 [Fig.3] which allows air to pass through at atmospheric pressure without allowing moisture to pass through, to avoid damaging sensitive components 21, 22 or having corrosion at the tabs 31 to 37 or having short circuits.

[0040] In the context of the invention, the sensor includes a means of protecting at least one sensitive element 21, 22. Thus, when in certain applications a conduit, and for example the conduit 72 which measures the pressure downstream of the particle filter is not connected to the particle filter and is in the open air, the presence of the means of protection prevents the passage of foreign elements such as insects.

[0041] According to one embodiment of the invention, the protection means is located at the level of the second conduit 72 which measures the pressure downstream of the particle filter.

[0042] According to one embodiment of the invention, the protection means is a restriction 51 of the cross-section of a pressure inlet conduit [Fig.4].

[0043] According to one embodiment of this variant, the restriction of section 51 is formed by the conduit itself.

[0044] According to one embodiment of the invention, the diameter of the opening in the section restriction is less than or equal to 1 mm. For example, the diameter of the opening in the restriction is 0.95 mm. According to one embodiment of the invention, the opening has any shape that prevents an element with a diameter of 1 mm from passing through.

[0045] This local air passage cross-section dimension prevents an insect or a particle greater than or equal to 1 mm from passing through, thus protecting at least one of the sensitive elements from insect particles and allowing air to pass through this duct and the proper functioning of the sensor.

[0046] According to one embodiment of the invention, the protective means is formed by an added part 52, perforated by openings 521, added into one of the conduits. According to one embodiment of the invention, the added part 52 is made of metal or plastic or a breathable membrane.

[0047] According to one embodiment of the invention, the added part is a perforated plate, or a foam or sintered fiber.

[0048] According to one embodiment of the invention, the added part is held mechanically in the conduit either by clipping, by force assembly, by gluing or by welding.

[0049] According to one embodiment of the invention, the diameter of the openings 521 of the added part is less than or equal to 1 mm. For example, the diameter of the restriction opening is 0.95 mm. According to one embodiment of the invention, the opening 521 of the added part has any shape that prevents an element with a diameter of 1 mm from passing through.

[0050] This local air passage cross-sectional dimension prevents an insect or a particle larger than or equal to 1 mm from passing through, thus protecting at least one of the sensitive elements of insect particles and allows air to pass through this duct and the proper functioning of the sensor.

[0051] According to an embodiment of the invention illustrated in Figure [Fig. 7], the protection means is formed by a total sealing element of the conduit at its inlet or at any other point along the conduit 72. In this embodiment, another opening 53 is formed on the sensor directly or by an additional part 53. According to one embodiment of the invention, the diameter of this opening is less than or equal to 1 mm. For example, the diameter of the restriction opening is 0.95 mm. According to one embodiment of the invention, the opening of the additional part 53 has any shape that prevents an object with a diameter of 1 mm from passing through.

[0052] According to one embodiment of the invention, the additional part 53 is made of metal or plastic or a breathable membrane.

[0053] According to one embodiment of the invention, the additional part 53 is a perforated plate, or a foam or sintered fiber.

[0054] According to one embodiment of the invention, the additional part 53 is held mechanically in the conduit either by clipping, by force assembly, by gluing or by welding.

[0055] According to an embodiment of the invention illustrated [Fig. 8], the protection means is formed by the removal of the sensitive element. According to one embodiment of this embodiment, the sensitive element is replaced by an open replacement insert 54 or by a shape formed directly in the housing. According to one embodiment of the invention, the diameter of the opening in the replacement insert 54 is less than or equal to 1 mm. For example, the diameter of the opening in the replacement insert 54 is 0.95 mm. According to one embodiment of the invention, the opening in the replacement insert 54 has any shape that prevents an object 1 mm in diameter from passing through it.

[0056] According to one embodiment of this variant of the invention, the conduit is closed, so the pressure differential between the upstream of the particle filter and atmospheric pressure is achieved by the remaining conduit and the pressure measured via the breathing membrane 60. In this case, the remaining sensitive element is programmed specifically to measure the pressure differential between ambient pressure and the pressure arriving through the conduit without waiting for information from a second sensitive element.

[0057] The invention also relates to a vehicle engine component comprising a pressure sensor as defined above.

[0058] The scope of the present invention is not limited to the details given above and allows for embodiments in many other specific forms without departing from the field of application of the invention. Therefore, the present embodiments The implementation details should be considered as illustrations, and may be modified without, however, departing from the scope defined by the claims supported by the description.

Claims

1.

2.

3.

4.

5.

6.

7.

8. Demands Pressure sensor (1) comprising: - at least one pressure-sensitive element (21, 22), - a protective housing (5) in which the pressure-sensitive element (21, 22) is housed, - a chamber (6) connected to the atmospheric pressure formed in the casing (5). - the pressure-sensitive element (21, 22) comprising a first face (7, 7') in fluidic communication with a first pressure inlet PI to measure a first pressure and a second face (9, 9'), opposite to the first face, in fluidic communication with the chamber (6), the pressure inlet being formed by a conduit (71, 72), characterized in that it includes a means of protection (51, 52, 53, 54) of the pressure-sensitive element (21, 22), preventing the passage of foreign elements. Sensor (1) according to claim 1 in which the means of protecting the sensing element is a restriction (51) of the cross-section of a pressure inlet conduit (71, 72). Sensor (1) according to claim 2 in which the section restriction (51) is formed by the conduit (71, 72) itself. Sensor (1) according to claim 2 in which the diameter of the opening of the restriction section (51) is less than or equal to 1mm. Sensor (1) according to claim 1 in which the means for protecting the sensitive element is an added part (52), perforated by openings (521), added in a conduit (71, 72). Sensor (1) according to claim 5 in which the added part (52) is made of metal or plastic or a breathable membrane. Sensor (1) according to claim 5 or 6 wherein the added part (52) is a perforated plate, or a foam or sintered fiber. Sensor (1) according to claim 5 to 7 in which the added part (52) is mechanically held in a conduit (71, 72) either by clipping, by force assembly, by gluing or by welding.

9. Sensor (1) according to claim 1 wherein the means for protecting the sensing element is formed by a total sealing element of the conduit at its inlet or any other place along the conduit, an additional opening being formed on the sensor directly or by an additional part (53), the diameter of this opening being less than or equal to 1mm.

10. Vehicle engine component comprising a pressure sensor according to claims 1 to 9.

Images