KR101593670B1 - Particular Matter Sensor and exhaust gas purification system using the same - Google Patents

Abstract

The present invention relates to a particulate matter sensor, which has a simple structure and is not required for the correction of the temperature, and to an exhaust gas purification system using the same. Accordingly, the sensor comprises: an insulation substrate; a first electrode unit equipped with a plurality of first electrodes which are not electrically connected, and formed by being exposed to one side of the insulation substrate; a second electrode unit equipped with a plurality of second electrodes, and formed inside the insulation substrate; and a heater unit formed on the other side of the insulation substrate for heating the first and second electrode units. The first electrodes and the second electrodes are correspondingly formed to each other. In addition, the capacitance between the first electrode and the second electrode can be measured by a particulate matter accumulated between the first electrodes.

Description

TECHNICAL FIELD The present invention relates to a particulate matter sensor and an exhaust gas purification system using the particulate matter sensor.

The present invention relates to a particulate matter sensor and an exhaust gas purification system using the same.

Generally, there is a growing interest in a post-treatment apparatus for purifying exhaust gas as the exhaust regulation is further strengthened. Particularly, regulations on Particulate Matter (PM) for diesel vehicles are becoming more stringent.

In order to reduce the emission of particulate matter, a diesel particulate filter (DPF) is installed at the rear end of the engine to burn particulate matter and filter it. However, if the diesel particulate filter is aged or defective after installation, the filtering efficiency is reduced. Accordingly, since 1989, on-board diagnosis (OBD) system for detecting whether the diesel particulate filter is operating normally in real time is required.

Currently developed PM sensors have a problem that the PM accumulated on the surface of the sensor can not be removed naturally and the resistance of the electrode changes depending on the temperature of the electrode used as the sensor.

Therefore, a heater capable of removing PM accumulated on the surface of the sensor has to be built in, and an additional temperature sensor is installed to know the temperature of the electrodes used.

This method has an advantage that the sensing method is simple, but since the heater and the temperature sensor must be built in together, the structure becomes complicated and the unit price is increased. Further, there is a problem that an algorithm capable of correcting the influence of temperature is required.

Japanese Patent Laid-Open No. 2009-85959 (published on April 23, 2009)

An object of the present invention is to provide a particulate matter sensor that is simple in structure and does not require temperature correction, and an exhaust gas purification system using the particulate matter sensor.

According to an aspect of the present invention, A first electrode part formed on one surface of an insulating substrate and having a plurality of first electrodes which are not electrically connected; A second electrode part formed inside the insulating substrate and having a plurality of second electrodes; And a heater portion formed on the other surface of the insulating substrate and heating the first and second electrode portions, wherein the plurality of first electrodes and the plurality of second electrodes are formed to correspond to each other, The first electrodes are electrically connected to each other to measure a capacitance between the first electrode and the second electrode.

The plurality of first electrodes and the plurality of second electrodes are arranged in the longitudinal direction of the insulating substrate, and the plurality of first electrodes and the plurality of second electrodes are arrayed in the width direction of the insulating substrate .

The first electrode unit may further include a first electrode lead electrically connecting the plurality of first electrodes and a first connection terminal connected to the first electrode lead, A second electrode lead connected to the second electrode lead, and a second connection terminal connected to the second electrode lead.

Also, since the particulate matter is deposited sequentially between the first electrodes, the electrostatic capacitance between the first electrode and the second electrode can be increased as the area of the first electrode is widened by electrically connecting the first electrodes.

An exhaust manifold; An exhaust gas particulate filter for removing particulates contained in the exhaust gas discharged from the exhaust manifold; And a particulate matter sensor disposed on an outlet side exhaust pipe connected to the exhaust gas particulate filter and detecting particulate matter passing through the exhaust gas particulate filter and escaping to the downstream side, wherein the particulate matter sensor comprises an insulating substrate, A second electrode part formed inside the insulating substrate and including a plurality of second electrodes, and a second electrode part formed on the other surface of the insulating substrate, The plurality of first electrodes and the plurality of second electrodes are formed so as to correspond to each other, and the first electrodes are electrically connected to the first electrodes by the particulate matter accumulated between the first electrodes. So that the electrostatic capacity between the first electrode and the second electrode can be measured.

The particulate matter sensor used in the exhaust gas purifying system according to an embodiment of the present invention may be a particulate matter sensor using particulate matter deposited between the first electrode and the first electrodes and the distance between the first and second electrodes, There is provided a particulate matter sensor capable of easily detecting a particulate matter passing through an exhaust gas particulate filter without passing through the exhaust gas particulate filter and measuring the electrostatic capacity between the one electrode portion and the second electrode portion .

Further, since a temperature sensor is not required as in the prior art, there is no need for an algorithm capable of correcting the influence of temperature. Thus, the structure of the particulate matter sensor is simplified, A material sensor can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the overall configuration of an exhaust gas purifying system for a diesel engine for a vehicle. FIG.
2 is a perspective view schematically showing a particulate matter sensor according to an embodiment of the present invention.
3 is an exploded perspective view of the particulate matter sensor of Fig.
FIGS. 4A and 4B are plan views illustrating first and second electrode units according to FIGS. 2 and 3. FIG.
5 is an enlarged cross-sectional view taken along the line A-A 'in Fig.
6 is a cross-sectional view showing an operating state of a particulate matter sensor according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the overall configuration of an exhaust gas purifying system for a diesel engine for a vehicle. FIG.

1, the exhaust gas purifying system 100 may include a turbine 130 installed in the exhaust manifold 120 of the engine 110 and a turbocharger 140 interlocked with the turbine 130, The compressed air can be passed through the cooler 150 and sent to an intake manifold (not shown), and a part of the combustion exhaust discharged from the exhaust manifold 120 passes through the valve 160 and the cooler, Can be refluxed into a manifold (not shown).

A diesel oxidation catalyst (not shown) and an exhaust gas particulate filter 170 are installed in the exhaust pipe 180 connected to the exhaust manifold 120 to treat the combustion exhaust gas. That is, while the combustion exhaust gas discharged to the exhaust pipe 180 passes through the diesel oxidation catalyst (not shown) on the upstream side, hydrocarbon (HC), carbon monoxide (CO) and nitrogen monoxide NO of unburned fuel can be oxidized Particulate matter (PM) composed of soot, soluble organic component (SOF) and inorganic component can be collected while passing through the exhaust gas particulate filter 170 on the downstream side.

The diesel oxidation catalyst (not shown) can raise the exhaust temperature by oxidation combustion of the supplied fuel or oxidize and remove the SOF component in the particulate matter when the exhaust gas particulate filter 170 is forcibly regenerated. In addition, NO 2 produced by the oxidation of NO can be used as an oxidizing agent for the particulate matter deposited in the downstream exhaust gas particulate filter 170, thereby enabling continuous oxidation.

The exhaust gas particulate filter 170 may be formed with a plurality of fine holes passing through a cell wall for partitioning the gas flow path and can capture particulate matter in the exhaust gas introduced into the exhaust gas particulate filter 170. It may be configured as a continuous regenerative diesel particulate filter in which the diesel oxidation catalyst and the exhaust gas particulate filter 170 are integrated.

A differential pressure sensor 190 may be installed in the exhaust pipe 180 to monitor the amount of particulate matter deposited in the diesel particulate filter 170. The differential pressure sensor 190 is connected to the upstream side and the downstream side of the exhaust gas particulate filter 170 and can output a signal corresponding to the differential pressure between the upstream and downstream sides thereof.

In addition, a temperature sensor (not shown) is provided upstream of the diesel oxidation catalyst and upstream and downstream of the exhaust gas particulate filter 170, and the respective exhaust temperatures can be monitored.

Based on these outputs, the control circuit (not shown) monitors the catalytic active state of the diesel oxidation catalyst and the particulate matter trapping state of the diesel particulate filter 170. When the particulate matter trapping amount exceeds the allowable amount, The regeneration control for burning and removing can be performed.

The particulate matter sensor 200 is installed on an outlet side exhaust pipe 182 connected to the other side of the exhaust gas particulate filter 170 and can detect particulate matter passing through the exhaust gas particulate filter 170 and escaping to the downstream side .

FIG. 2 is a perspective view schematically showing a particulate matter sensor according to an embodiment of the present invention, FIG. 3 is an exploded perspective view of the particulate matter sensor of FIG. 2, and FIGS. 4A and 4B are cross- 1 and the second electrode unit, and FIG. 5 is an enlarged cross-sectional view taken along the line A-A 'in FIG.

4A and 4B, the first and second electrode units 220 and 230 may be formed in black so that the first electrode unit 220 and the second electrode unit 230 can be clearly distinguished from each other, The particulate matter sensor according to an embodiment will be described in detail.

2, the particulate matter sensor 200 includes an insulating substrate 210, an insulating substrate 210, and a plurality of first electrodes 222, which are exposed on one surface of the insulating substrate 210, A second electrode part 230 formed on the other surface of the insulating substrate 210 and having a plurality of second electrodes 232 formed on the insulating substrate 210, And a heater unit 240 for heating the units 220 and 230.

As the insulating substrate 210, a heat-resistant insulator such as a glass material, a ceramic material, alumina, spinel, or titanium dioxide can be used.

As shown in FIGS. 2 and 3, the first electrode unit 220 may be exposed on the surface of the insulating substrate 210.

The first electrode unit 220 may further include a plurality of first electrodes 222, a first electrode lead 224, and a first connection terminal 226,

4A, the plurality of first electrodes 222 are not electrically connected to each other, and only the first electrodes 222 at the edges of the plurality of first electrodes 222 are electrically connected to each other And may be connected to the second electrode lead 224.

The first electrode lead 224 may be formed at both ends of the first electrodes 222 to electrically connect the first electrode 222 formed on the outer periphery of the plurality of first electrodes 222, The leads 224 may be connected to the first connection terminals 226 formed on the other surface of the insulating substrate 210.

The second electrode unit 230 may be formed inside the insulating substrate 210 and the second electrode unit 230 may include a plurality of second electrodes 232, a second electrode lead 234, Terminal 236. < / RTI >

4A, the plurality of second electrodes 232 may be formed in a bent shape on one side of the insulating substrate 210 so that the plurality of second electrodes 232 may be electrically connected to each other .

The second electrode leads 234 may be formed on both ends of the second electrodes 232 to electrically connect the plurality of second electrodes 232 and the second electrode leads 234 may be formed on both sides of the insulating substrate 210 And may be connected to the second connection terminal 236 formed on the other surface side.

The plurality of first electrodes 222 provided on the first electrode unit 220 and the plurality of second electrodes 232 provided on the second electrode unit 230 may be formed on the insulating substrate 210 in correspondence with each other. have.

4B and 5, the plurality of first electrodes 222 and the plurality of second electrodes 232 may be arranged in parallel in the longitudinal direction of the insulating substrate 210, The arrangement of the first electrodes 222 and the plurality of second electrodes 232 may be arranged to correspond to each other in the width direction of the insulating substrate 210.

In addition, spaces 228 may be formed between the first electrodes 222, and particulate matter may be deposited in the spaces 228 formed between the first electrodes 222.

Particularly, particulate matter is sequentially deposited from the first space 228a of the entire spaces 228 formed in the first electrode unit 220, and subsequently, particulate matter is accumulated in the entire spaces 228 .

The area of the first electrode 222 can be sequentially widened by connecting the first electrodes 222 with the particulate matter deposited therebetween, and the first electrode unit 220 and the second electrode unit 230 can be sequentially formed. Can be measured.

A specific capacitance measurement method will be described later with reference to Fig.

The heater unit 240 may be formed on the bottom surface of the insulating substrate 210 and one end of the heater unit 240 may be electrically connected to the pair of connection terminals 242.

The heater 240 may be installed to remove particulate matter accumulated on the first electrode unit 220. Specifically, when the heater unit 240 is heated for a predetermined time and for a predetermined time, The particulate matter deposited on the substrate 330 can be removed.

In addition, since the exhaust gas downstream of the exhaust gas particulate filter (170 in FIG. 1) is at a high temperature of about 300 ° C or higher and about 650 ° C or higher in heating the heater, the general metal is likely to be oxidized when used as a heater, (240) may be formed of a material which is not easily oxidized at a high temperature.

6 is a cross-sectional view showing an operating state of a particulate matter sensor according to an embodiment of the present invention.

6, the particulate matter P that has flowed to the outlet-side exhaust pipe 182 through the exhaust gas particulate filter 170 (Fig. 1) flows into the particulate matter sensor 182 provided at one side of the outlet- The particulate matter P may be deposited on the spaces 228 formed between the first electrodes 222. In this case,

Particularly, one first electrode 222a of a plurality of first electrodes 222 and one first electrode 222b adjacent to one first electrode 222a are separated by a particulate matter The capacitance between the first electrode 222 and the second electrode 232 can be measured by electrically connecting the electrode 222a and the first electrode 222b adjacent to the first electrode 222a.

The capacitance between the first electrode 222 and the second electrode 232 can be measured by the formula C =? A / t, where A is the distance between the first electrode 222 and the second electrode 232 on both sides of the space 228 in which the particulate matter P is deposited And t is the distance between the first electrode 222 and the second electrode 232 on which the particulate matter P1 is deposited and the distance between the first electrode unit 220 and the first electrode unit 220, And the second electrode unit 230 can be measured.

Here, the first electrodes 222 are connected to each other by the particulate matter whenever the particulate matter P1 is sequentially deposited from the first space among the spaces 228 formed in the first electrode unit 220 And the area of the first electrode 222 are sequentially widened.

As the area of the first electrode 222 is increased, the plurality of first electrodes 222 are electrically connected to increase the capacitance between the first electrode unit 220 and the second electrode unit 230 have.

For example, if three first electrodes 222 are formed on an insulating substrate 210, the area of each first electrode 222 is 1, and the area of the space 228 is 1, The area A of the capacitance can have an area from a minimum of 1 to a maximum of 5, whereby the magnitude of the capacitance can also be increased from a minimum of 1 to a maximum of 5 times.

That is, assuming that the area of the arbitrary first electrode 222a is constant, the electrostatic capacity can be increased in proportion to the area of the space 228, and the area of the first electrodes 222 and the area of the deposited particulate matter By adjusting the area by the user, the size of the capacitance can be adjusted to the size desired by the user.

Therefore, the particulate matter sensor used in the exhaust gas purifying system can measure the area of the particulate matter deposited between the first electrode and the first electrodes, and the distance between the first electrode and the second electrode, It is possible to easily detect the particulate matter passing through the exhaust gas particulate filter and escaping to the downstream side without the necessity of correcting the temperature by measuring the electrostatic capacity between the electrode portions.

Further, since a temperature sensor is not required as in the prior art, there is no need for an algorithm capable of correcting the influence of temperature, so that the structure of the particulate matter sensor is simplified, thereby reducing the cost of the particulate matter sensor.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: exhaust gas purification system 110: engine
120: exhaust manifold 130: turbine
140: Turbocharger 150: Cooler
160: valve (160) 170: exhaust gas particulate filter
180: Exhaust pipe 182: Exhaust pipe
190: differential pressure sensor 200: particulate matter sensor
210: insulating substrate 220: first electrode part
222: first electrode 224: first electrode lead
226: first connection terminal 230: second electrode portion
232: second electrode 234: second electrode lead
236: second connection terminal 240: heater part

Claims (5)

An insulating substrate;
A first electrode part formed on one surface of the insulating substrate and having a plurality of first electrodes that are not electrically connected;
A second electrode part formed inside the insulating substrate and having a plurality of second electrodes; And
And a heater unit formed on the other surface of the insulating substrate and heating the first and second electrode units,
Wherein the plurality of first electrodes and the plurality of second electrodes are arranged in the longitudinal direction of the insulating substrate,
Wherein the plurality of first electrodes and the plurality of second electrodes are arranged so as to correspond to each other in the width direction of the insulating substrate,
Wherein the first electrodes are electrically connected to each other by a particle image accumulated between the first electrodes to measure a capacitance between the first electrode and the second electrode. delete The method according to claim 1,
The first electrode unit further includes a first electrode lead electrically connecting the plurality of first electrodes and a first connection terminal connected to the first electrode lead,
Wherein the second electrode unit further includes a second electrode lead electrically connecting each of the plurality of second electrodes and a second connection terminal connected to the second electrode lead. The method according to claim 1,
Particulate matter is sequentially deposited between the first electrodes to electrically increase the electrostatic capacity between the first electrode and the second electrode as the first electrodes are electrically connected to each other to increase the area of the first electrode Particulate matter sensor. An exhaust manifold;
An exhaust gas particulate filter for removing particulates contained in the exhaust gas discharged from the exhaust manifold;
And a particulate matter sensor disposed on an exhaust pipe connected to the exhaust gas particulate filter and detecting particulate matter passing through the exhaust gas particulate filter and flowing downstream,
The particulate matter sensor includes an insulating substrate, a first electrode unit formed on the insulating substrate, the first electrode unit including a plurality of first electrodes which are not electrically connected to each other, and a plurality of A second electrode portion provided with a second electrode and a heater portion formed on the other surface of the insulating substrate and heating the first and second electrode portions,
Wherein the plurality of first electrodes and the plurality of second electrodes are arranged in the longitudinal direction of the insulating substrate,
Wherein the plurality of first electrodes and the plurality of second electrodes are arranged so as to correspond to each other in the width direction of the insulating substrate,
Wherein the first electrodes are electrically connected to each other by a particle image accumulated between the first electrodes to measure a capacitance between the first electrode and the second electrode.

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