CN109386358B

CN109386358B - Integrated particulate matter sensor for diesel particulate matter filter

Info

Publication number: CN109386358B
Application number: CN201710690291.5A
Authority: CN
Inventors: 林伟青; 陈晓兵
Original assignee: Bosch Automotive Diesel Systems Co Ltd
Current assignee: Bosch powertrain Co.,Ltd.
Priority date: 2017-08-14
Filing date: 2017-08-14
Publication date: 2021-07-27
Anticipated expiration: 2037-08-14
Also published as: CN109386358A

Abstract

The application discloses an integrated form particulate matter sensor (1) for diesel particulate filter includes: a housing (100); an inner shell (110) located within the outer shell (100); a filter cartridge (300) mounted in an inner housing (110) and an electric heater (200) capable of heating the filter cartridge (300), an inlet (100a) of the integrated particulate sensor (1) being defined between the inner housing (110) and the outer housing (100), the inner housing (110) defining an outlet (110a) of the integrated particulate sensor (1) such that a gas flow can flow through the filter cartridge (300) via the inlet (100a) and out of the outlet (110a), wherein the integrated particulate sensor (1) further comprises a radio frequency antenna (500), the radio frequency antenna (500) and the inner housing (110) being arranged such that a radio frequency signal emitted via the radio frequency antenna (500) is received by the radio frequency antenna (500) after propagating through the filter cartridge (300). The application also discloses adopt the diesel vehicle of integrated form particulate matter sensor.

Description

Integrated particulate matter sensor for diesel particulate matter filter

Technical Field

The application relates to an integrated particle sensor for determining the soot content of a fuel particle filter of a diesel vehicle.

Background

In order to meet the increasingly stringent exhaust emission requirements of diesel vehicles, diesel particulate filters are widely used in diesel vehicles. The diesel particulate filter is mainly installed in an exhaust emission treatment system of a diesel vehicle, and can filter out most pollutant Particulate Matters (PM) in engine exhaust, so that the exhaust emission is compliant.

Generally, in a diesel vehicle, an oxidation catalyst and a diesel particulate filter are connected in series in the exhaust pipe in series downstream of an exhaust gas outlet of the diesel engine. For a common small diesel vehicle, an Electronic Control Unit (ECU) instructs a sensor to constantly monitor an exhaust pressure difference between an inlet and an outlet of a diesel particulate filter, estimates an amount of soot particles trapped in the diesel particulate filter in real time by using the monitored exhaust pressure difference, and instructs an injector in a diesel engine to increase an amount of injected fuel after the amount of the soot particles exceeds a critical value, resulting in the discharge of exhaust gas containing more Hydrocarbons (HC) at the outlet of the engine, which reacts through an oxidation catalyst to increase an exhaust temperature at the outlet of the oxidation catalyst, so that the soot particles trapped in the diesel particulate filter are combusted and regenerated.

In many cases, it is difficult to accurately obtain the amount of soot particles accumulated in the diesel particulate filter by reverse estimation based on the exhaust pressure difference in medium or heavy duty diesel vehicles having a large engine displacement. Diesel particulate filter regeneration initiated based on an inaccurate exhaust pressure differential may result in diesel particulate filter burn-out.

Furthermore, current particulate matter sensors are only capable of monitoring whether the diesel particulate filter has failed and cannot provide concentration or mass flow information of the particulate matter.

Sensors based on rf technology have been used in diesel vehicles to monitor soot levels in diesel particulate filters, but such technology requires the installation of rf transmitters and receivers, compensation temperature sensors, and related electronics in the overall exhaust system, at high installation and post-maintenance costs. In addition, the radio frequency technology is greatly influenced by the geometric shape of a filter element of the diesel particulate filter, has requirements on the material of the filter element, and cannot be used for the silicon carbide-based diesel particulate filter.

Disclosure of Invention

In view of the above, the present application is directed to a novel particulate matter sensor that can conveniently and accurately monitor the amount of soot accumulated in a diesel particulate matter filter.

According to one aspect of the present application, there is provided an integrated particulate matter sensor for a diesel particulate filter, comprising: a housing; an inner shell positioned within the outer shell; a filter element mounted in the inner housing and an electric heater capable of heating the filter element, an inlet of the integrated particulate sensor being defined between the inner housing and the outer housing, the inner housing defining an outlet of the integrated particulate sensor such that an air flow can flow through the filter element via the inlet and out the outlet, wherein the integrated particulate sensor further comprises a radio frequency antenna, the radio frequency antenna and the inner housing being arranged such that a radio frequency signal emitted via the radio frequency antenna is received by the radio frequency antenna after propagating through the filter element.

According to another aspect of the present application, there is also provided a diesel vehicle including an exhaust pipe in which a diesel particulate filter is disposed, wherein the aforementioned integrated particulate sensor is detachably connected to the exhaust pipe in a gas-tight manner, so that an inlet and an outlet of the integrated particulate sensor are located inside the exhaust pipe upstream or downstream of the diesel particulate filter.

Adopt the integrated form particulate matter sensor of this application, can measure the soot volume in the engine exhaust gas directly reliably to confirm the soot volume of gathering in the diesel particulate matter filter in view of the above, provide accurate judgement basis for the regeneration of diesel particulate matter filter. In addition, because the radio frequency antenna is arranged inside the integrated particle sensor, the propagation of radio frequency signals is not influenced by the material and the shape of a filter element of the diesel particle filter any more. That is, the integrated form particulate matter sensor of this application can be applicable to the diesel vehicle of various load specifications.

Drawings

The foregoing and other aspects of the present invention will be more fully understood from the following detailed description, taken together with the following drawings. It is noted that the drawings may not be to scale for clarity of illustration and that this does not detract from the understanding of the invention. In the drawings:

FIG. 1 schematically illustrates a cross-sectional view of an integrated particulate matter sensor according to one embodiment of the present application; and is

Fig. 2 schematically shows a schematic view of the installation of an integrated particle sensor according to the application in a diesel vehicle.

Detailed Description

In the various figures of the present application, features that are structurally identical or functionally similar are denoted by the same reference numerals.

Fig. 1 schematically shows a longitudinal cross-sectional view of an integrated particle sensor 1 according to one embodiment of the present application, the integrated particle sensor 1 being used for soot measurement of engine exhaust gases of diesel vehicles, in order to determine the amount of soot accumulated in a diesel particle filter, providing a basis for its regeneration.

As shown in fig. 1, the integrated particulate matter sensor 1 includes a housing 100, which is substantially cylindrical, for example, cylindrical, open at one end and closed at the other end. An inner shell 110 is substantially coaxially fixed within the outer shell 100, for example, and may be connected by reinforcing ribs, such that the inner shell 110 is separated from both the cylindrical inner wall and the closed end of the outer shell 100 by a gap through which air flow can pass.

The inner shell 110 is also generally cylindrical, e.g., cylindrical, with one end being open, forming an open end, and the other end having a wall end that tapers inwardly, forming a narrowed end. Thus, the gap between the inner wall of the outer casing 100 and the outer wall of the inner casing 110 forms the inlet 100a of the integrated particulate matter sensor 1, which inlet 100a is substantially annular, e.g., circular, as viewed in cross-section in this embodiment of the present application. The opening of the narrowed end of the inner casing 110 forms an outlet 110a of the integrated particle sensor 1, the outlet 110a projecting beyond the inlet 100a, viewed in the longitudinal direction. The outlet 110a is surrounded by the inlet 100a, viewed in the cross-sectional direction.

An electric heater 200 is disposed inside the inner case 110. For example, a plurality of elongated electric heaters 200 are arranged at regular intervals on the inner wall of the inner case 110. A filter cartridge 300 is further disposed inside the inner case 110 such that the outside of the filter cartridge 300 is surrounded by the electric heater 200. The filter element 300 is constructed in a labyrinth manner. For example, the filter element 300 can be manufactured and arranged in the inner housing 110 in a manner having a porous configuration such that the gas flow flows from the inlet 100a into the open end of the aforementioned inner housing 110 and can flow through the interior of the filter element 300 and finally exit the integrated particulate sensor 1 via the outlet 110a provided at the narrowed end. The electric heater 200 can be energized to generate heat as needed to burn the soot particles accumulated inside the filter element 300. For this, the electric heater 200 is connected to the electric wire 210. The electric wire 210 is led to the outside through the closed end of the housing 100.

A temperature sensor 400 is also provided at the closed end of the housing 100 for measuring the temperature of the air flow before it passes through the filter element 300, thereby providing a temperature compensation value for subsequent data processing. Further, a radio frequency antenna 500 is also provided at the closed end of the housing 100. In the embodiment of the present application, the rf antenna 500 is, for example, a duplex antenna, i.e., the rf signal transmitting end and the rf signal receiving end are integrated together. Temperature sensor 400 and rf antenna 500 extend outside of housing 100 via

wires

410 and 510, respectively. For example,

wires

210, 410, and 510 may together form a cable that is connected to subsequent processing circuitry.

The rf antenna 500 is disposed opposite to the outlet 110a in the longitudinal direction across the filter cartridge 300. As shown in fig. 1, the wall section 120 of the inner housing 110 defines an outlet 110a, and the wall section 120 of the inner housing 110 is formed to be contracted and inclined toward the filter cartridge 300. Thus, when an rf signal is emitted from the rf sensor 500, propagation through the filter element 300 can be mostly reflected back to the rf sensor 500 and received. Therefore, through reasonable design of the inner shell, the radio frequency signal is not influenced by the geometric shape of the filter element. In addition, the filter element 300 may be made of a suitable material suitable for radio frequency detection, such as cordierite. That is to say, if the particulate matter in the exhaust pipe of diesel vehicle was detected to the integrated form particulate matter sensor 1 of this application, the filter core material that will not receive diesel particulate matter filter itself influences.

An attachment feature, such as an external thread, may also be provided on the outer wall of the housing 100 of the integrated particulate matter sensor 1 for detachable connection to the exhaust pipe of a diesel vehicle.

Fig. 2 schematically shows a schematic view of the installation of an integrated particle sensor 1 according to the application in a diesel vehicle. The diesel vehicle includes an exhaust pipe 600 so that exhaust gas from the engine can flow through the inside of the exhaust pipe 600 from left to right as shown in the drawing. The diesel particulate filter DPF and the oxidation catalyst DOC are arranged in this order in the interior of the exhaust pipe 600 so that the diesel particulate filter DPF is located upstream of the oxidation catalyst DOC.

A screw hole is provided on exhaust pipe 600 so that integrated particulate matter sensor 1 is detachably connected to exhaust pipe 600 in a gas-tight manner, and integrated particulate matter sensor 1 partially protrudes radially into the interior of exhaust pipe 600 after the connection is in place. The integrated particle sensor 1 is located between the diesel particle filter DPF and the oxidation catalyst DOC. The cable of the integrated particle sensor 1 can for example be connected to a controller 700, which controller 700 is then connected to the electronic control unit ECU of the diesel vehicle. The controller 700 receives the measured temperature value from the temperature sensor 400 and feeds back to the electronic control unit ECU. Under the instruction of the electronic control unit ECU, the controller 700 can control the radio frequency electric wire 500 and the heating element 200 to act correspondingly. Alternatively, the controller 700 may be omitted and the electronic control unit ECU receives data and controls the relevant components directly.

When the integrated particulate matter sensor 1 is mounted in place on the exhaust pipe 600, as the engine exhaust gas flows through the inside of the exhaust pipe 600, as indicated by the arrows in fig. 1 and 2, the engine exhaust gas also flows through the inside of the integrated particulate matter sensor 1, in particular, the filter element 300. That is, the degree to which soot particles are accumulated in the filter element 300 is correlated with the degree to which soot particles are accumulated in the filter element of the diesel particulate filter DPF. Therefore, the soot mass density of the detection filter element 300 can directly reflect the soot mass density in the filter element of the diesel particulate filter DPF.

For example, in operation, the controller 700 controls the rf antenna 500 to transmit rf signals at regular intervals. The transmitted rf signal is reflected by the wall section 120 of the inner housing 110 forming the outlet 110a after propagating through the filter element 300, and is received by the rf antenna 500 after propagating through the filter element 300 again. The received signals are transmitted to the ECU for analysis via the controller 700. Essentially, the amplitude attenuation of the received RF signal is proportional to the amount of soot accumulated in the filter element 300. Therefore, on the premise of considering the temperature compensation, the soot amount of the DPF can be determined by calibrating the relationship between the amplitude attenuation of the radio frequency signal and the soot amount accumulated in the filter element 300 in advance. After determining that the amount of soot accumulated in the filter cartridge 300 reaches a certain level by analyzing the received rf signal, the ECU may instruct the controller 700 to energize the electric heater 200 and burn the soot particles in the filter cartridge 300, thereby regenerating the filter cartridge 300. Alternatively, the electronic control unit ECU may determine when to regenerate the diesel particulate filter DPF based on the detection signal of the integrated particulate matter sensor 1.

Adopt the integrated form particulate matter sensor of this application can the direct measurement soot volume in the engine exhaust to confirm the soot volume of gathering in the diesel particulate matter filter DPF in view of the above, provide accurate foundation for the regeneration of diesel particulate matter filter DPF. Furthermore, the construction of the integrated particle sensor itself and the choice of material for the filter element make its operation independent of the diesel particle filter DPF. Therefore, the integrated particulate matter sensor can be suitable for diesel particulate matter filters of various specifications of heavy-duty diesel vehicles. Furthermore, because the rf signal propagates within the specially designed filter element and the inner housing, the likelihood of the rf signal amplitude attenuation being disturbed by other factors is minimized. That is, the integrated particulate matter sensor of the present application can more accurately record the amount of soot in the engine exhaust.

In alternative embodiments, the electric heater 200 may be disposed in the inner housing 110 at any location that facilitates heating of the filter cartridge 300, for example, the electric heater 200 may even be disposed in the filter cartridge 300. Furthermore, to further prevent the emitted RF signals from escaping, in an alternative embodiment, the inner housing 110 may be extended until the closed end of the outer housing 100, such that the extended section of the inner housing 110 is provided with perforations for the airflow to pass through. In this way, it is ensured that the radio frequency signals emitted by the radio frequency antenna 500 all propagate through the filter element 300. Furthermore, in alternative embodiments, the inner shell 110 may also be disposed non-coaxially with the outer shell 100. In an alternative embodiment, the integrated particle sensor may also be arranged downstream of the diesel particle filter DPF in the exhaust pipe 600. In an alternative embodiment, the rf antenna 500 of the present application may be replaced with two simplex rf antennas, for example, one simplex antenna being disposed as a transmitting antenna at the location of the antenna 500 as shown in fig. 1 and the other simplex antenna being disposed as a receiving antenna near the exit 110a as shown in fig. 1.

Further, the integrated particulate matter sensor may be detachably and airtightly attached to the exhaust pipe 600 of the diesel vehicle using other suitable attachment means than a screw connection. For example, in an alternative embodiment, a snap-fit structure may be provided between the housing 100 of the integrated particulate matter sensor and the exhaust pipe 600 for detachable connection therebetween.

Although specific embodiments of the invention have been described herein in detail, they have been presented for purposes of illustration only and are not to be construed as limiting the scope of the invention. Various substitutions, alterations, and modifications may be devised without departing from the spirit and scope of the present invention.

Claims

1. An integrated particle sensor (1) for a diesel particle filter, comprising:

a housing (100);

an inner shell (110) located within the outer shell (100);

a filter element (300) mounted in the inner housing (110) and an electric heater (200) capable of heating the filter element (300), an inlet (100a) of the integrated particulate sensor (1) being defined between the inner housing (110) and the outer housing (100), the inner housing (110) defining an outlet (110a) of the integrated particulate sensor (1) such that an air flow can flow through the filter element (300) via the inlet (100a) and out the outlet (110a), wherein the integrated particulate sensor (1) further comprises a radio frequency antenna (500), the radio frequency antenna (500) and the inner housing (110) being arranged such that a radio frequency signal emitted via the radio frequency antenna (500) is received by the radio frequency antenna (500) after propagating through the filter element (300).

2. The integrated particulate sensor (1) of claim 1, wherein the outer casing (100) is cylindrical with an open end and a closed end, the inlet (100a) being defined by the open end and the inner casing (110), the inner casing (110) also being cylindrical, the outlet (110a) being defined by a wall section (120) of the inner casing (110) facing the closed end.

3. The integrated particulate sensor (1) of claim 2, wherein the radio frequency antenna (500) is disposed at a closed end of the housing (100) and longitudinally opposite the outlet (110 a).

4. The integrated particulate sensor (1) of claim 3, wherein the wall section (120) of the inner housing (110) defining the outlet (110a) is inclined towards the radio frequency antenna (500).

5. The integrated particulate matter sensor (1) of any one of claims 1 to 4, further comprising a temperature sensor (400) for measuring a temperature of the gas flow.

6. The integrated particulate sensor (1) of any one of claims 1 to 4, wherein the electric heater (200) is a plurality of electric heaters (200) evenly spaced in an inner wall of the inner casing (110), and the plurality of electric heaters (200) surround the filter element (300).

7. The integrated particulate sensor (1) of claim 5, wherein the RF antenna (500) and/or the temperature sensor (400) are arranged such that the airflow passes through the filter element (300) after passing through the RF antenna (500) and/or the temperature sensor (400).

8. The integrated particulate sensor (1) of any one of claims 1 to 4, wherein the filter element (300) is made of cordierite.

9. The integrated particulate sensor (1) of any one of claims 1 to 4, wherein the outlet (110a) projects in a longitudinal direction beyond the inlet (100 a).

10. The integrated particulate sensor (1) of claim 5, wherein the electric heater (200) is a plurality of electric heaters (200) evenly spaced in an inner wall of the inner casing (110), and the plurality of electric heaters (200) surround the filter element (300).

11. The integrated particle sensor (1) of claim 5, wherein the filter element (300) is made of cordierite.

12. The integrated particle sensor (1) of claim 6, wherein the filter element (300) is made of cordierite.

13. The integrated particle sensor (1) of claim 7, wherein the filter element (300) is made of cordierite.

14. The integrated particulate matter sensor (1) according to claim 5, wherein the outlet (110a) protrudes in a longitudinal direction beyond the inlet (100 a).

15. The integrated particulate matter sensor (1) of claim 6, wherein the outlet (110a) projects in a longitudinal direction beyond the inlet (100 a).

16. The integrated particulate matter sensor (1) of claim 7, wherein the outlet (110a) projects in a longitudinal direction beyond the inlet (100 a).

17. The integrated particulate matter sensor (1) of claim 8, wherein the outlet (110a) projects in a longitudinal direction beyond the inlet (100 a).

18. A diesel vehicle comprising an exhaust pipe (600) in which a Diesel Particulate Filter (DPF) is disposed within the exhaust pipe (600), wherein the integrated particulate sensor (1) according to any one of claims 1 to 17 is detachably air-tightly connected to the exhaust pipe (600) so that an inlet (100a) and an outlet (110a) of the integrated particulate sensor (1) are located upstream or downstream of the Diesel Particulate Filter (DPF) inside the exhaust pipe (600).