WO2020209069A1 - Control device - Google Patents

Abstract

According to the present invention, this particulate matter detection sensor has an element part (200) that is a part for detecting a particulate matter and a heat generation unit (211) that is a part configured as an electric heater for heating the element part. A control device (20) of the particulate matter detection sensor comprises: a temperature acquisition unit (12) for acquiring the temperature of the element part; a heat generation adjustment unit (13) for adjusting the heat generation amount of the heat generation unit on the basis of the temperature of the element part acquired by the temperature acquisition unit; and a storage unit (14) for storing a correspondence relationship between the value of electric power consumed in the heat generation unit and the temperature of the element part. The temperature acquisition unit is configured to acquire the temperature of the element part on the basis of the value of the electric power consumed in the heat generation unit and the correspondence relationship.

Description

Control device Cross-reference of related applications

This application is based on Japanese Patent Application No. 2019-075127 filed on April 10, 2019, which claims the benefit of its priority, and the entire contents of the patent application are: Incorporated herein by reference.

The present disclosure relates to a control device for a particulate matter detection sensor.

Vehicles in recent years are required to reduce particulate matter emitted with exhaust gas. For this reason, the exhaust pipe through which the exhaust gas passes is provided with a filter for collecting particulate matter, a particulate matter detection sensor for detecting particulate matter on the downstream side of the filter, and the like.

As described in Patent Document 1 below, the particulate matter detection sensor has an element portion which is a portion for detecting particulate matter. A set or a plurality of sets of electrodes separated from each other are formed in the element portion. When the particulate matter is deposited on the element portion, an electric current flows between the electrodes formed on the element portion. According to the particulate matter detection sensor, the amount of deposited particulate matter can be detected based on the magnitude of the electric current.

When the amount of particulate matter deposited in the element part becomes moderately large, the magnitude of the above current becomes constant, and it becomes impossible to detect newly deposited particulate matter. Therefore, the particulate matter detection sensor is generally provided with a heat generating portion for heating the element portion. The heat generating portion is configured as an electric heater formed in the vicinity of the element portion. When electric power is supplied to the heat generating portion and the element portion is heated by the heat generating portion, the particulate matter accumulated on the element portion is burned and removed. This makes it possible to continue to detect the amount of particulate matter.

JP-A-2017-15677

When the element portion is heated by the heat generating portion, if the temperature of the element portion is not sufficiently raised, a part of the particulate matter will not be removed and will remain in the element portion. On the other hand, if the temperature of the element portion rises too much, the element portion may be damaged, the electrode material may evaporate, or a pollutant may be fused to the element portion. Therefore, it is preferable that the heating of the element portion by the heat generating portion is appropriately performed while acquiring the temperature of the element portion.

However, if a dedicated sensor for acquiring the temperature of the element unit is provided, there is a problem that the number of parts increases and the size of the particulate matter inspection also increases. Therefore, in the control device described in Patent Document 1, the temperature of the element portion is acquired based on the electric resistance value of the heat generating portion.

However, the correspondence between the electric resistance value of the heat generating part and the temperature of the element part is not always constant, and may change as the heat generating part deteriorates. If the correspondence relationship changes from the initial one, it will not be possible to accurately acquire the temperature of the element unit.

An object of the present disclosure is to provide a control device capable of accurately acquiring the temperature of an element unit.

The control device according to the present disclosure is a control device for a particulate matter detection sensor. The particulate matter detection sensor to be controlled has an element portion that detects the particulate matter and a heat generating portion that is a portion configured as an electric heater for heating the element portion. This control device is consumed by the temperature acquisition unit that acquires the temperature of the element unit, the heat generation adjustment unit that adjusts the heat generation amount of the heat generation unit based on the temperature of the element unit acquired by the temperature acquisition unit, and the heat generation unit. It is provided with a storage unit that stores the correspondence between the value of the electric power and the temperature of the element unit. The temperature acquisition unit acquires the temperature of the element unit based on the value of the electric power consumed in the heat generating unit and the correspondence relationship.

In the control device having the above configuration, the correspondence relationship between the value of the electric power consumed in the heat generating unit and the temperature of the element unit is stored in the storage unit. The present inventors have confirmed that the correspondence is generally constant regardless of whether or not the heat generating portion is deteriorated. It is considered that this is because the value of the electric power consumed in the heat generating portion corresponds to the electric energy used for heating the element portion. Therefore, the temperature acquisition unit can accurately acquire the temperature of the element unit based on the above correspondence.

According to the present disclosure, a control device capable of accurately acquiring the temperature of the element unit is provided.

FIG. 1 is a diagram schematically showing a configuration of a control device according to the first embodiment. FIG. 2 is a cross-sectional view showing the configuration of a particulate matter detection sensor. FIG. 3 is a diagram showing the appearance of the element portion of the particulate matter detection sensor. FIG. 4 is an exploded assembly view showing the configuration of the element portion of the particulate matter detection sensor. FIG. 5 is a diagram for explaining an outline of control performed by the control device according to the first embodiment. FIG. 6 is a flowchart showing a flow of processing executed by the control device according to the first embodiment. FIG. 7 is a diagram showing an example of the first correspondence relationship. FIG. 8 is a flowchart showing a flow of processing executed by the control device according to the first embodiment. FIG. 9 is a flowchart showing a flow of processing executed by the control device according to the second embodiment. FIG. 10 is a diagram for explaining a correction method of the second correspondence relationship. FIG. 11 is a diagram for explaining a method for correcting the second correspondence, which is performed by the control device according to the third embodiment. FIG. 12 is an exploded view showing the configuration of the element portion of the particulate matter detection sensor according to the fourth embodiment. FIG. 13 is a diagram showing the relationship between the electric resistance value of the heat generating portion and the temperature of the element portion.

Hereinafter, this embodiment will be described with reference to the attached drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as possible in each drawing, and duplicate description is omitted.

The first embodiment will be described. The control device 10 according to the present embodiment is mounted on the vehicle MV together with the particulate matter detection sensor 20, and is configured as a device for controlling the particulate matter detection sensor 20. Prior to the description of the control device 10 and the particulate matter detection sensor 20, the configuration of the vehicle MV will be described first with reference to FIG.

FIG. 1 schematically shows only the configuration of the internal combustion engine 110 and its exhaust system among the vehicle MVs. The vehicle MV includes an internal combustion engine 110, an exhaust pipe 130, and a particle filter 120.

The internal combustion engine 110 is a so-called engine. The internal combustion engine 110 burns fuel to generate a driving force for driving the vehicle MV. The exhaust pipe 130 is a pipe for discharging the exhaust gas generated by the combustion of the internal combustion engine 110 to the outside.

The particle filter 120 is provided in the middle of the exhaust pipe 130 and is a filter for collecting particulate matter contained in the exhaust gas. The particle filter 120 is also referred to as a DPF (Diesel Particulate Filter) or a GPF (Gasoline Particulate Filter). The particle filter 120 is configured by forming a large number of lattice-like passages in porous ceramics and alternately closing the inlet side and the outlet side thereof. Since a known configuration of the particle filter 120 can be adopted, specific illustrations and explanations thereof will be omitted.

Subsequently, the configuration of the particulate matter detection sensor 20 according to the present embodiment will be described. As shown in FIG. 1, the particulate matter detection sensor 20 is arranged at a position on the exhaust pipe 130 on the downstream side of the particle filter 120. The particulate matter detection sensor 20 is a sensor for detecting the amount of particulate matter contained in the exhaust gas that has passed through the particle filter 120. By providing such a particulate matter detection sensor 20, it is possible to prevent exhaust gas containing a large amount of particulate matter from being discharged to the outside. Further, when an abnormality occurs in the particle filter 120, the abnormality can be detected quickly.

The specific configuration of the particulate matter detection sensor 20 will be described with reference to FIG. Reference numeral 130 in FIG. 2 is a cross section of a pipe wall constituting the exhaust pipe 130. In the figure, the space above the pipe wall is the space outside the exhaust pipe 130, and the space below the pipe wall is the space inside the exhaust pipe 130. The particulate matter detection sensor 20 is inserted from the outside through the through hole 131 formed in the exhaust pipe 130, and a part of the through hole 131 projects toward the inside of the exhaust pipe 130.

The particulate matter detection sensor 20 has an element unit 200 inside. The element unit 200 is an element configured as a portion for detecting a particulate matter. FIG. 3 shows the appearance of the element unit 200. FIG. 4 shows a specific configuration of the element unit 200 as an exploded view.

As shown in FIG. 4, the element unit 200 is configured by laminating a plurality of substrates which are rectangular plate-shaped members. Each substrate is made of ceramics. The substrate 210 arranged on the lowermost side in FIG. 4 has a heat generating portion 211, a lead electrode 212, 213, and a sense electrode 214 formed on the upper surface thereof. All of these are one electrode pattern, which is formed on the upper surface of the substrate 210 by, for example, screen printing.

The heat generating portion 211 is a portion configured as an electric heater that generates heat by receiving power supply. The heat generating portion 211 is formed at a position close to one end side along the longitudinal direction of the substrate 210. The heat generating unit 211 is provided as a heater for heating the detection surface 201, which will be described later, among the element units 200.

The lead electrodes 212 and 213 are a pair of electrodes formed to supply electric power to the heat generating portion 211. The lead electrodes 212 and 213 are formed so as to extend from the heat generating portion 211 to the other end portion along the longitudinal direction of the substrate 210. The width and length of the lead electrode 212 and the width and length of the lead electrode 213 are substantially equal to each other. The power wiring 27 shown in FIG. 2 is connected to the lead electrodes 212 and 213. The power wiring 27 is a pair of wirings provided for supplying electric power from the control device 10 to the heat generating portion 211. The power wiring 27 is provided so as to connect the lead electrodes 212 and 213 and the control device 10 so that power can be supplied from the control device 10 to the heat generating portion 211. One of the pair of power wires 27 is connected to the lead electrode 212, and the other is connected to the lead electrode 213.

A through hole (not shown) is formed in the portion of FIG. 4 with the reference numeral 212A so as to penetrate the substrate 210. One of the power wirings 27 is connected to the lead electrode 212 from the outside via the through hole. Similarly, through holes (not shown) are formed in the portion of FIG. 4 with reference numeral 213A so as to penetrate the substrate 210. The other of the power wirings 27 is connected to the lead electrode 213 from the outside via the through hole.

One end of the sense electrode 214 is connected to the connection portion CP between the lead electrode 213 and the heat generating portion 211. The sense electrode 214 is formed so as to extend from the connection portion CP along the longitudinal direction of the substrate 210. The sense electrode 214 is an electrode formed for acquiring the potential at the connection portion CP between the lead electrode 213 and the heat generating portion 211.

The sense wiring 28 shown in FIG. 2 is connected to the sense electrode 214. The sense wiring 28 is provided so as to connect the sense wiring 28 and the control device 10 so that the control device 10 can acquire the potential of the connection portion CP. Through holes (not shown) are formed in the portion of FIG. 4 with reference numeral 214A so as to penetrate the substrate 210. The sense wiring 28 is connected to the sense electrode 214 from the outside via the through hole.

As described above, in the particulate matter detection sensor 20 according to the present embodiment, the pair of lead electrodes 212 and 213 for supplying electric power to the heat generating portion 211 and the connecting portion between one lead electrode 213 and the heat generating portion 211 are connected. A sense electrode 214 for acquiring the potential in the CP is provided. The effect of providing the sense electrode 214 and the sense wiring 28 will be described later.

Electrodes 221 and 222 are formed on the surface of the substrate 220 arranged on the upper side of the substrate 210 on the side opposite to the substrate 210. All of these are one electrode pattern, and are formed by, for example, screen printing, like the heat generating portion 211 and the like described above. The electrode 221 is formed so as to extend along an edge on one end side along the longitudinal direction of the substrate 220, specifically, an edge on the same side as the side on which the heat generating portion 211 is formed. The electrode 222 is formed so as to extend along the longitudinal direction of the substrate 220 from the end portion of the electrode 221 along the lateral direction of the substrate 220, specifically, the end portion on the back side of the paper surface of FIG. There is.

Electrodes 231 and 232 are formed on the surface of the substrate 230 arranged further above the substrate 220 on the side opposite to the substrate 220. All of these are one electrode pattern, and are formed by, for example, screen printing, like the heat generating portion 211 and the like described above. The electrode 231 is formed so as to extend along an edge on one end side along the longitudinal direction of the substrate 230, specifically, an edge on the same side as the side on which the heat generating portion 211 is formed. The electrode 232 is formed so as to extend along the longitudinal direction of the substrate 230 from the end portion of the electrode 231 along the lateral side of the substrate 230, specifically, the end portion on the front side of the paper surface of FIG. There is.

In FIG. 4, a plurality of the above-mentioned substrates 220 and the substrates 230 are arranged alternately between the lowermost substrate 210 and the uppermost substrate 240. Therefore, as shown in FIG. 3, the electrodes 221 and 231 are exposed on the detection surface 201, which is the end surface of the element unit 200 along the longitudinal direction, and these are arranged so as to be arranged alternately. It is in a state of being.

A pair of electrodes 241 and 242 are formed on the surface of the uppermost substrate 240 in FIG. 4 opposite to the substrate 230 and the like. All of these are formed on one side along the longitudinal direction of the substrate 240, specifically, at a position near the end on the side opposite to the side on which the heat generating portion 211 is formed.

The electrode 241 is formed at a position of the electrode 222 that overlaps the portion of the electrode 222 that is designated by the reference numeral 222A. Similarly, the electrode 242 is formed at a position of the electrode 232 that is vertically overlapped with the portion of the electrode 232 having the reference numeral 232A.

Through holes are formed at positions of the substrates 220, 230, and 240 that vertically overlap with reference numeral 222A so as to penetrate each substrate. The electrodes 241 are electrically connected to the respective electrodes 222 and 221 via these through holes.

Similarly, through holes are formed at positions of the substrates 220, 230, and 240 that vertically overlap with reference numeral 232A so as to penetrate each substrate. The electrodes 242 are electrically connected to the respective electrodes 232 and 231 via these through holes.

The detection wiring 26 shown in FIG. 2 is connected to the electrodes 241 and 242. The detection wiring 26 is a pair of wirings connecting the electrodes 241 and 242 and the control device 10. One of the pair of detection wires 26 is connected to the electrode 241 and the other is connected to the electrode 242.

The control device 10 applies a predetermined voltage between the electrode 241 and the electrode 242 via the pair of detection wirings 26. At this time, a voltage is also applied between the electrodes 221 and 231 exposed on the detection surface 201. When no particulate matter is deposited on the detection surface 201, no current flows between the electrodes 221 and 231. On the other hand, when the particulate matter is deposited on the detection surface 201, since the particulate matter is a conductor, a current flows between the electrode 221 and the electrode 231. The current increases as the amount of particulate matter deposited on the detection surface 201 increases.

The control device 10 detects the magnitude of the current as the magnitude of the current flowing through the pair of detection wirings 26. The control device 10 can detect the amount of deposited particulate matter on the detection surface 201 of the element unit 200 based on the magnitude of the current. The control device 10 can detect the amount of the particulate matter passing through the exhaust pipe 130, for example, based on the time change of the accumulated amount of the particulate matter.

When the amount of particulate matter deposited on the detection surface 201 becomes moderately large, the magnitude of the current becomes constant. Therefore, the control device 10 cannot detect the newly deposited particulate matter. In this case, the control device 10 supplies electric power to the heat generating unit 211 to generate heat, and heats the detection surface 201 of the element unit 200 to burn the particulate matter accumulated on the detection surface 201. As a result, the particulate matter is removed from the detection surface 201, so that the control device 10 can continue to detect the amount of the particulate matter.

The other configurations of the particulate matter detection sensor 20 will be described with reference to FIG. 2 again. The particulate matter detection sensor 20 has a holding portion 21, a housing 22, a fastening portion 23, and covers 24 and 25, in addition to the element portion 200 described above.

The holding portion 21 is a member for holding the element portion 200, and is formed of ceramics which is an insulator. The element unit 200 is held by the holding unit 21 in a state where the detection surface 201 at the tip thereof is projected toward the inside of the exhaust pipe 130.

The housing 22 is a cylindrical member made of metal. The housing 22 is a member that generally forms the outer shape of the particulate matter detection sensor 20, and surrounds the holding portion 21 from the outside. The end of the housing 22 that is arranged inside the exhaust pipe 130 is open, and the element portion 200 projects from the end.

The fastening portion 23 is a portion for fixing the particulate matter detection sensor 20 to the exhaust pipe 130. The fastening portion 23 is arranged so as to surround a part of the housing 22 from the outer peripheral side. The fastening portion 23 is made of metal.

A male screw (not shown) is formed on the outer peripheral surface of the fastening portion 23. Further, a female screw (not shown) is formed on the inner peripheral surface of the through hole 131 formed in the exhaust pipe 130. The male screw on the outer peripheral surface of the fastening portion 23 is screwed into the female screw on the inner peripheral surface of the through hole 131. As a result, the particulate matter detection sensor 20 is fastened and fixed to the exhaust pipe 130.

Both the covers 24 and 25 are attached to the tip of the housing 22, and are provided so as to double cover the periphery of the element portion 200 protruding from the tip. Of these, the cover 25 is provided on the inside, and the cover 24 is provided on the outside. A plurality of through holes are formed in each of the covers 24 and 25. A part of the exhaust gas passing through the exhaust pipe 130 enters the inside of the covers 24 and 25 through these through holes. A part of the particulate matter contained in the exhaust gas is deposited on the detection surface 201 of the element unit 200, and is detected by the control device 10 as described above.

Each of the detection wiring 26, the power wiring 27, and the sense wiring 28 described above is connected to the tip of the portion of the particulate matter detection sensor 20 that protrudes toward the outside of the exhaust pipe 130. In FIG. 2, a pair of detection wirings 26 are bundled, and these are drawn like one wiring. Similarly, a pair of power wires 27 and a sense wire 28 are bundled together, and these are drawn like a single wire.

Returning to FIG. 1, the configuration of the control device 10 according to the present embodiment will be described. The control device 10 is configured as a computer system having a CPU, ROM, RAM, and the like. As described above, the control device 10 is configured as a device for controlling the particulate matter detection sensor 20. The control device 10 includes a deposit amount calculation unit 11, a temperature acquisition unit 12, a heat generation adjusting unit 13, and a storage unit 14 as functional control blocks.

The deposit amount calculation unit 11 is a part that performs a process of calculating the deposit amount of the particulate matter on the detection surface 201. The deposit amount calculation unit 11 applies a predetermined voltage between the pair of detection wirings 26, that is, between the electrodes 221 and 231 and calculates the deposit amount based on the magnitude of the current flowing through them.

It is known that the relationship between the amount of deposit and the current is not always the same and changes according to the temperature of the detection surface 201. Specifically, as the temperature of the detection surface 201 increases, the electrical resistance of the particulate matter decreases, so that the value of the acquired current increases. Therefore, the deposit amount calculation unit 11 accurately calculates the deposit amount of the particulate matter by multiplying the deposit amount calculated based on the current by a correction value based on the temperature of the detection surface 201. There is. The relationship between the temperature of the detection surface 201 and the correction value has been measured in advance, and is stored as a map in the storage unit 14 of the control device 10. The deposit amount calculation unit 11 is configured to calculate the above correction value by referring to the temperature of the element unit 200 acquired by the temperature acquisition unit 12 described below and the map.

The temperature acquisition unit 12 is a unit that performs a process of acquiring the temperature of the element unit 200. The temperature acquisition unit 12 acquires the temperature of the element unit 200 based on the value of the electric power consumed by the heat generating unit 211. Further, the temperature acquisition unit 12 may acquire the temperature of the element unit 200 based on the electric resistance value of the heat generating unit 211. Each specific acquisition method will be described later. The temperature of the element unit 200 acquired by the temperature acquisition unit 12 is substantially equal to the temperature of the detection surface 201 of the element unit 200.

The heat generation adjusting unit 13 performs a process of adjusting the heat generation amount of the heat generation unit 211, specifically, the value of the current supplied to the heat generation unit 211, based on the temperature of the element unit 200 acquired by the temperature acquisition unit 12. It is a part. The heat generation adjusting unit 13 adjusts the amount of heat generated by the heat generating unit 211 so that the temperature of the element unit 200 approaches a predetermined target temperature. As a result, the temperature of the element unit 200 can always be maintained at an appropriate temperature.

The storage unit 14 is a non-volatile storage device, and includes various information necessary for the control performed by the control device 10. The specific contents of the information stored in the storage unit 14 will be described later.

The control device 10 having the above configuration may be configured as a dedicated device for controlling the particulate matter detection sensor 20, but may be configured as a part of another device. .. For example, the control device 10 may be configured as a part of the ECU that controls the internal combustion engine 110.

The outline of the control performed by the control device 10 will be described with reference to FIG. FIG. 5 shows an example of the time change of the temperature of the element unit 200 in the period after the start of the internal combustion engine 110 is performed. In this example, immediately after the internal combustion engine 110 is started, the heat generation adjusting unit 13 energizes the heat generating unit 211, and the heat generating unit 211 heats the element unit 200. As a result, the temperature of the element unit 200 rises and then is maintained at a temperature T3 higher than the room temperature. This state continues until time t1 shown in FIG.

In the period immediately after the internal combustion engine 110 is started, water droplets often adhere to the inner surface of the exhaust pipe 130, and a part of the water droplets reaches the element portion 200 of the particulate matter detection sensor 20. I have something to do. At this time, if the temperature of the element unit 200 rises too much, the element unit 200 may be damaged due to the water exposure. On the other hand, if the temperature of the element unit 200 is too low, water droplets may adhere to the surface of the element unit 200, and the contaminants contained in the water droplets may cause poisoning of the element unit 200.

Therefore, the temperature of the element unit 200 during the period up to time t1 is lower than the temperature at which the element unit 200 is damaged due to water exposure, and the surface of the element unit 200 is water repellent due to the so-called Leidenfrost effect. Is preferably the temperature at which Therefore, the temperature T3, which is the target temperature in the period, is preferably set in the range of 350 ° C. to 650 ° C.

The control performed during the period from the start of the internal combustion engine 110 to the time t1 is the control for preventing the element unit 200 from being damaged due to water reception as described above. Therefore, the control is also referred to as "water resistance control" below.

When the temperature of the exhaust pipe 130 rises sufficiently, for example, to 100 ° C. or higher, the possibility of moisture adhering to the inner surface of the exhaust pipe 130 decreases. Therefore, the control device 10 ends the above-mentioned water resistance control when it is confirmed that the temperature of the exhaust pipe 130 reaches 100 ° C. or higher, and shifts to the combustion control. The above time t1 is the time when the transition from the water resistance control to the combustion control is performed in this way. The temperature of the exhaust pipe 130 may be acquired by a temperature sensor (not shown).

Combustion control is a control performed to further raise the temperature of the element unit 200 to burn and remove particulate matter accumulated on the detection surface 201. The target temperature of the element unit 200 at this time is set to a temperature T4 higher than the temperature T3. However, if the target temperature is set too high, the element portion 200 may be damaged due to excessive temperature rise, the electrode material may evaporate, or a contaminant may be fused to the element portion 200. .. From the above, it is preferable that the target temperature of the element unit 200 in the combustion control is set in the range of 600 ° C. to 900 ° C.

Combustion control is performed only for a preset period of time. After the combustion control is performed, the process shifts to the collection control. In FIG. 5, the time at which the transition from the combustion control to the collection control is performed is shown as the time t2.

The collection control is a control performed to collect particulate matter, deposit it on the detection surface 201, and detect the deposited amount. In the collection control, as described above, a voltage is applied between the electrodes 221 and 231 and the amount of particulate matter deposited is calculated based on the magnitude of the current flowing between the electrodes. Particulate matter floating around the detection surface 201 is attracted to the detection surface 201 by an electrostatic force and is deposited on the detection surface 201.

At this time, if the temperature of the element unit 200 is higher than the temperature of the exhaust gas, the particulate matter floating around the detection surface 201 receives a thermophoretic force in a direction away from the detection surface 201. As a result, the collection of particulate matter on the detection surface 201 is hindered. In order to prevent such a phenomenon, the current supplied to the heat generating unit 211 is set to 0 during the period when the collection control is performed.

During the period when the collection control is performed, as described above, the temperature of the detection surface 201 is acquired, and the correction value for the deposited amount is calculated based on the temperature. Acquisition of such a temperature is performed periodically during the period during which collection control is performed.

Collection control is performed only for a preset period of time. When the collection control is completed, the control shifts to poison resistance control. In FIG. 5, the time at which the transition from the collection control to the poison resistance control is performed is shown as the time t3.

The poison resistance control is a control performed to heat the element unit 200 by the heat generating unit 211 to prevent new particulate matter and contaminants that cause poisoning from adhering to the detection surface 201. Is. The target temperature of the element unit 200 at this time is set to a temperature T2 lower than the temperature T4. The target temperature is preferably set in a range higher than the temperature of the exhaust gas at that time and 900 ° C. or lower.

Poison resistance control is continued until the next detection of the accumulated amount by the particulate matter detection sensor 20. When the accumulation amount is detected again by the particulate matter detection sensor 20, the poison resistance control is shifted to the combustion control, and the collection control is subsequently performed.

Among the controls described above, in the water resistance control, the combustion control, and the poison resistance control, the control device 10 is in an operation mode in which the heat generation adjustment unit 13 adjusts the heat generation amount of the heat generation unit 211. .. Such an operation mode is also referred to as a "heat generation mode" below. It can be said that the water resistance control, the combustion resistance control, and the poison resistance control are all controls performed in the heat generation mode and are different from each other at the set target temperature value.

On the other hand, in the collection control, the control device 10 has an operation mode in which the temperature acquisition unit 12 acquires the temperature of the element unit 200 without adjusting the heat generation amount of the heat generation unit 211 by the heat generation adjustment unit 13. It has become. Such an operation mode is also referred to as a "temperature acquisition mode" below. The control device 10 is configured to be able to execute two types of operation modes including a heat generation mode and a temperature acquisition mode in this way.

The flow of processing executed in the heat generation mode will be described with reference to FIG. The series of processes shown in FIG. 6 is a process that is repeatedly executed every time a predetermined control cycle elapses during the period in which the heat generation mode is executed.

In the first step S01 of the process, a process of acquiring the value of the power consumed by the heat generating unit 211 is performed. Here, the value of the power consumed in the heat generating unit 211 is calculated and acquired by multiplying the value of the current flowing through the heat generating unit 211 by the value of the voltage applied to the heat generating unit 211 and the duty of the current. To.

The specific calculation method will be explained. First, the control device 10 acquires the value of the voltage applied between the pair of power wirings 27 by, for example, a sensor (not shown). The voltage is also referred to as "total voltage" below.

Subsequently, the control device 10 acquires the value of the current flowing through the pair of power wirings 27 by a sensor (not shown). The current is also referred to as "total current" below. The value of the total current is equal to the value of the current flowing through the heating unit 211.

Next, the control device 10 acquires the potential of the connection portion CP shown in FIG. 4 by, for example, a sensor (not shown) connected to the sense wiring 28. After that, the value of the voltage applied to both ends of the lead electrode 213 is calculated based on the potential of the connection portion CP. The value can also be said to be the value of the voltage drop occurring in the lead electrode 213.

As described above, the width and length of the lead electrode 212 and the width and length of the lead electrode 213 are substantially equal to each other. Therefore, it is presumed that the lead electrode 212 also has a voltage drop of the same value as the voltage drop at the lead electrode 213.

The control device 10 subtracts the value of the voltage drop occurring in the lead electrode 213 and the voltage drop occurring in the lead electrode 212 from the total voltage described above, so that the voltage applied to the heat generating portion 211 is applied. Calculate the value of. After that, the value of the electric power consumed in the heat generating unit 211 is calculated by multiplying the value of the voltage by the value of the total current and the duty of the current.

After the value of the electric power consumed by the heat generating unit 211 is calculated, the process proceeds to step S02. In step S02, the temperature acquisition unit 12 performs a process of acquiring the temperature of the element unit 200.

The specific method will be explained. The storage unit 14 stores the correspondence between the value of the electric power consumed by the heat generating unit 211 and the temperature of the element unit 200. The correspondence is also referred to as a "first correspondence" below. FIG. 7 shows an example of the first correspondence. As shown in the figure, the larger the value of the electric power consumed by the heat generating unit 211, the higher the temperature of the element unit 200. Such a first correspondence is created based on an experiment or the like conducted in advance and is stored in the storage unit 14.

The temperature acquisition unit 12 acquires the temperature of the element unit 200 based on the value of the electric power acquired in step S01 and the first correspondence relationship. Since the temperature of the element unit 200 calculated in this way is the temperature in the vicinity of the heat generating unit 211 and the detection surface 201 of the element unit 200, it can also be referred to as the temperature of the detection surface 201.

In step S03 following step S02, it is determined whether or not the temperature of the element unit 200 acquired in step S02 matches the target temperature at this time. The “target temperature” referred to here is the temperature T4 or the like in the example of FIG.

When the temperature of the element unit 200 matches the target temperature, the series of processes shown in FIG. 6 is completed. If the temperature of the element unit 200 does not match the target temperature, the process proceeds to step S04. In step S04, the value of the current supplied to the heat generating unit 211 is adjusted so that the temperature of the element unit 200 approaches the target temperature.

For example, when the temperature of the element unit 200 is higher than the target temperature, the duty of the current is changed so that the value of the current supplied to the heat generating unit 211 becomes smaller than before. On the contrary, when the temperature of the element unit 200 is lower than the target temperature, the duty of the current is changed so that the value of the current supplied to the heat generating unit 211 becomes larger than before. The process is performed by the heat generation adjusting unit 13.

The above control is also a control that adjusts the heat generation amount of the heat generation unit 211 so that the value of the power consumed by the heat generation unit 211 matches the target power value corresponding to the target temperature of the element unit 200. it can. In step S03, instead of determining whether or not the temperature acquired in step S02 matches the target temperature, whether or not the value of the power acquired in step S01 matches the target power value is determined. It may be determined. In this case, the conversion from the target temperature to the target power value may be performed based on the first correspondence.

By the way, when the temperature acquisition unit 12 acquires the temperature of the element unit 200, it is conceivable to acquire the temperature of the element unit 200 based on the electric resistance value of the heat generating unit 211 as in the conventional case. FIG. 13 shows an example of the correspondence between the electric resistance value of the heat generating portion 211 and the temperature of the element portion 200. A conventional method for acquiring the temperature of the element unit 200 will be described with reference to FIG.

Line L0 in FIG. 13 shows the correspondence between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 when the heat generating unit 211 is not deteriorated. Based on this correspondence, when R0 is acquired as the electric resistance value of the heat generating portion 211, T22 can be acquired as the temperature of the element unit 200 corresponding to this.

However, the correspondence between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 is not always constant, and may change as the heat generating unit deteriorates. Line L1 in FIG. 13 shows the correspondence between the electric resistance value of the heat generating portion 211 and the temperature of the element portion 200 when the heat generating portion 211 is deteriorated. When the heat generating portion 211 is deteriorated, even if the temperature of the element portion 200 is the same, the electric resistance value of the heat generating portion 211 becomes larger than that when the heat generating portion 211 is not deteriorated.

Therefore, when R0 is acquired as the electric resistance value of the heat generating unit 211 when the heat generating unit 211 is deteriorated, the actual temperature of the element unit 200 is T21, but this is not the case. Will get a different T22.

As described above, the correspondence relationship between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 changes with the deterioration of the heat generating unit 211. Therefore, the temperature of the element unit 200 is adjusted based on the correspondence relationship. Obtaining may not be appropriate.

On the other hand, the present inventors consider whether or not the first correspondence relationship, which is the correspondence relationship between the value of the electric power consumed in the heat generation unit 211 and the temperature of the element unit 200, is deteriorated in the heat generation unit 211. It has been confirmed that the temperature is almost constant. It is considered that this is because the value of the electric power consumed by the heat generating unit 211 corresponds to the electric energy used for heating the element unit 200.

Therefore, in the present embodiment, as described above, the temperature acquisition unit 12 is configured to acquire the temperature of the element unit 200 based on the value of the electric power consumed by the heat generating unit 211 and the first correspondence relationship. ing. As a result, even when the heat generating portion 211 is deteriorated, the temperature of the element portion 200 can always be accurately acquired, and the temperature can be appropriately adjusted.

The first correspondence relationship stored in the storage unit 14 may be a single correspondence relationship referred to in all possible temperature ranges of the temperature of the element unit 200, but the temperature range that the element unit 200 can take. May be divided into a plurality of temperature ranges, and a plurality of correspondences may be individually set corresponding to each temperature range. That is, the first correspondence may be stored for each of a plurality of temperature ranges of the element unit 200.

For example, the first correspondence relationship referred to when the water resistance control is performed is stored as corresponding to the temperature range from 350 ° C. to 650 ° C., and is referred to when the combustion control is performed. The 1 correspondence is stored as corresponding to the temperature range from 600 ° C to 900 ° C, and the first correspondence referred to when the poison resistance control is performed is the temperature from the exhaust gas temperature to 900 ° C. It may be stored as corresponding to the region.

Further, each temperature range may be a temperature range that overlaps with each other as described above, but may be a temperature range that does not overlap with each other. For example, a temperature range of 300 ° C. or higher and lower than 400 ° C., a temperature range of 400 ° C. or higher and lower than 500 ° C., a temperature range of 500 ° C. or higher and lower than 600 ° C., and so on. It may be assumed that the first correspondence set individually for each temperature range is stored.

When the temperature range of the element unit 200 changes, the inclination of the first correspondence may change slightly due to the influence of, for example, the temperature distribution along the longitudinal direction of the element unit. However, if the first correspondence relationship set individually in advance for each temperature range is used, the temperature of the element unit 200 can be accurately acquired while considering the change of the first correspondence relationship as described above. It becomes possible.

By the way, as the value of the electric power consumed by the heat generating unit 211, it is conceivable to use the value of the electric power obtained by multiplying the above-mentioned total voltage by the total current and the duty of the current. However, the electric power value calculated in this way includes not only the heat generating portion 211 but also the electric power value consumed by the lead electrode 212 and the lead electrode 213. The temperature of the lead electrode 212 and the lead electrode 213 tends to be lower than that of the heat generating portion 211, and the amount of the temperature decrease changes depending on the situation. As a result, the value of the electric power obtained by multiplying the total voltage by the total current changes under the influence of the temperature of the lead electrode 212 and the like. Therefore, it is difficult to accurately calculate and obtain the temperature of the heating unit 211 based on the value of the electric power obtained by multiplying the total voltage by the total current.

Therefore, in the present embodiment, a three-wire sensor having a sense electrode 214 is used as the particulate matter detection sensor 20, and the temperature acquisition unit 12 determines the value of the electric power consumed by the heat generating unit 211. It is configured to acquire based on the potential of the connecting portion CP acquired via the sense electrode 214. As a result, the value of the electric power consumed by the heat generating unit 211 can be acquired while eliminating the influence of the temperature of the lead electrode 212 and the like, and the temperature of the element unit 200 can be accurately acquired based on this. There is.

The flow of processing executed in the temperature acquisition mode will be described with reference to FIG. The series of processes shown in FIG. 8 is a process that is repeatedly executed every time a predetermined control cycle elapses during the period during which the temperature acquisition is executed.

In the first step S11 of the process, a process of supplying a current to the heat generating unit 211 is performed. Here, a minute current is supplied to the heat generating unit 211 so that the heat generated by the heat generating unit 211 can be ignored.

In step S12 following step S11, a process of calculating and acquiring the electric resistance value of the heat generating portion 211 is performed. Here, the value of the voltage applied to the heat generating unit 211 is calculated by the method described above, and then the value of the voltage is divided by the value of the total current to calculate the electric resistance value of the heat generating unit 211. Will be done.

In step S13 following step S12, a process of stopping the supply of current to the heat generating portion 211 is performed.

In step S14 following step S13, the temperature acquisition unit 12 performs a process of acquiring the temperature of the element unit 200. At this time, the value of the electric power consumed by the heat generating unit 211 is 0. Therefore, the temperature acquisition method in step S14 is different from the temperature acquisition method in step S02 of FIG.

The temperature acquisition method in step S14 will be described. In the storage unit 14, in addition to the first correspondence relationship described above, the correspondence relationship between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 is also stored. The correspondence is also referred to as a "second correspondence" below. An example of the second correspondence is shown by line L0 in FIG. As shown in the figure, the larger the electric resistance value of the heat generating portion 211, the higher the temperature of the element portion 200. Based on the electric resistance value acquired in step S12 and the second correspondence relationship, the temperature of the element unit 200 can be acquired.

As described above, in the temperature acquisition mode, the temperature acquisition unit 12 temporarily supplies a current to the heat generation unit 211, and based on the electric resistance value of the heat generation unit 211 acquired at that time and the second correspondence relationship. , It is configured to acquire the temperature of the element unit 200. As a result, it is possible to acquire the temperature of the element unit 200 even in the temperature acquisition mode in which the element unit 200 is not heated by the heat generating unit 211.

In step S15 following step S14, a correction value is calculated based on the temperature of the element unit 200 acquired in step S14, and a process of calculating the accumulated amount of particulate matter using the correction value is performed. Is as described above.

Note that the execution frequency of the processes from step S11 to S14 and the execution frequency of the processes in step S15 may be different from each other. That is, the temperature of the element unit 200 may be acquired and the correction value based on the temperature may be updated at a frequency different from the frequency at which the deposition amount is calculated.

The second embodiment will be described. The second embodiment is different from the first embodiment in the content of the processing executed by the control device 10. In the following, the points different from the first embodiment will be mainly described, and the points common to the first embodiment will be omitted as appropriate.

The flow of processing executed in the heat generation mode of this embodiment will be described with reference to FIG. The series of processes shown in FIG. 9 is a process executed in place of the series of processes shown in FIG. Of the steps shown in FIG. 9, the steps common to those shown in FIG. 6 are designated by the same reference numerals as those shown in FIG.

After the process of acquiring the temperature of the element unit 200 is performed in step S02, the process proceeds to step S21 in this embodiment. In step S21, a process of calculating and acquiring the electric resistance value of the heat generating unit 211 is performed. Since the specific method is the same as the method described in step S12 of FIG. 8, the description thereof will be omitted here.

In step S22 following step S21, a process of correcting the second correspondence stored in the storage unit 14 is performed.

As described above, the second correspondence relationship, which is the correspondence relationship between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200, may change as the heat generating unit 211 deteriorates. Therefore, in the present embodiment, the second correspondence is corrected in step S22 of the heat generation mode.

The correction method will be described with reference to FIG. FIG. 10 shows an example of the correspondence between the electric resistance value of the heat generating portion 211 and the temperature of the element portion 200 in the same manner as in FIG. Line L0 in FIG. 10 shows the correspondence between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 when the heat generating unit 211 is not deteriorated. That is, it shows the second correspondence relationship stored in the storage unit 14 at the time when the particulate matter detection sensor 20 is manufactured. Further, line L1 in FIG. 10 shows the correspondence between the electric resistance value of the heat generating portion 211 and the temperature of the element portion 200 when the heat generating portion 211 is deteriorated. That is, it shows the correct second correspondence when the heat generating portion 211 is deteriorated.

As shown in the figure, when the actual temperature of the element unit 200 is 700 ° C., the electric resistance value of the heat generating unit 211 is 2.8Ω when no deterioration occurs, and 3.2Ω when deterioration occurs. It becomes. At this time, if the temperature of the element unit 200 is to be acquired based only on the second correspondence as in the conventional case, a temperature higher than the actual temperature of 700 ° C. will be acquired.

However, when step S21 of FIG. 9 is executed and the electric resistance value of the heat generating unit 211 is acquired, the control device 10 acquires the accurate temperature of the element unit 200 based on the first correspondence. Therefore, as in the example of FIG. 10, even when deterioration has occurred and 3.2 Ω is acquired as the electric resistance value of the heat generating portion 211, the control device 10 actually performs the element portion 200 at this time. It is known that the temperature of is 700 ° C.

As described above, the temperature of the element unit 200 acquired based on the electric resistance value of the heat generating unit 211 and the second correspondence relationship is different from the actual temperature of the element unit 200 acquired in step S02 of FIG. In that case, the temperature acquisition unit 12 corrects the second correspondence stored in the storage unit 14. In the example of FIG. 10, the initial second correspondence shown by the line L0 is corrected so as to become the second correspondence shown by the line L1.

Specifically, for each electric resistance value included in the second correspondence relationship, that is, for each electric resistance value corresponding to each temperature of the element unit 200, (3.2 / 2.8) uniformly. The second correspondence can be corrected by multiplying the values and using the obtained value as a new electrical resistance value. The above (3.2 / 2.8) is the second correspondence between the electric resistance value of the heat generating portion 211 acquired in step S21 of FIG. 9 and the temperature acquired in step S02 of FIG. 9 before correction. It is a coefficient obtained by dividing by the electric resistance value obtained from. This coefficient is a coefficient calculated based on a combination of the temperature of the element unit 200 acquired in step S02 of FIG. 9 and the electric resistance value of the heat generating unit 211 acquired in step S21 of FIG. it can.

When such a correction is performed, the line L0, which is the second correspondence relationship before the correction, moves in parallel so that the point P10 in FIG. 10 overlaps the point P20, and coincides with the line L1 which is the correct second correspondence relationship. It will be.

As described above, in the heat generation mode, the temperature acquisition unit 12 acquires the temperature of the element unit 200 based on the value of the electric power consumed by the heat generation unit 211 and the first correspondence relationship, and the heat generation unit 211 at that time. The electric resistance value of is also acquired in step S21 of FIG. After that, based on the temperature of the element unit 200 acquired in step S02 of FIG. 9 and the electric resistance value of the heat generating unit 211 acquired in step S22 of FIG. 9, the second correspondence relationship is established in step S22 of FIG. to correct. Therefore, even when the heat generating portion 211 is deteriorated, it is possible to accurately acquire the temperature of the element portion 200 based on the second correspondence.

Return to Fig. 9 and continue the explanation. After the process of step S22 is performed, the process proceeds to step S03. The processing executed thereafter is the same as that of the first embodiment described with reference to FIG.

The third embodiment will be described. The third embodiment is different from the second embodiment in the method of correcting the second correspondence. In the following, the points different from the second embodiment will be mainly described, and the points common to the second embodiment will be omitted as appropriate.

The line L0 shown in FIG. 11 shows the correspondence between the electric resistance value of the heat generating unit 211 and the temperature of the element unit 200 when the heat generating unit 211 is not deteriorated. That is, it shows the second correspondence relationship stored in the storage unit 14 at the time when the particulate matter detection sensor 20 is manufactured. Further, line L1 in FIG. 11 shows the correspondence between the electric resistance value of the heat generating portion 211 and the temperature of the element portion 200 when the heat generating portion 211 is deteriorated. That is, it shows the correct second correspondence when the heat generating portion 211 is deteriorated.

In the present embodiment, each electric resistance value included in the second correspondence relationship, that is, each electric resistance value corresponding to each temperature of the element unit 200 is not uniformly multiplied by the same value, but individually. Is multiplied by a different value to correct the second correspondence. In the example of FIG. 11, each electricity included in the second correspondence is such that the point P14 overlaps the point P24, the point P13 overlaps the point P23, the point P12 overlaps the point P22, and the point P11 overlaps the point P21. The resistance value is corrected individually.

Each correction method is the same as the method described with reference to FIG. For example, when changing the point P11 so as to overlap the point P21, the electric resistance value corresponding to the temperature T11 in the second correspondence relationship is multiplied by a predetermined coefficient, and the obtained value is used as a new electric resistance value. The correction is made. The "predetermined coefficient" corresponds to (3.2 / 2.8) in the example of FIG. 10, and is T11 which is the actual temperature of the element unit 200 and the heat generating unit 211 acquired at this time. It is a coefficient calculated based on the combination with the electric resistance value of. Specifically, it is a coefficient obtained by dividing the electric resistance value of the heat generating unit 211 by the electric resistance value obtained from T11, which is the actual temperature of the element unit 200, and the second correspondence relationship before correction. ..

The correction amount required when the element unit 200 is at a high temperature and the correction amount required when the element unit 200 is at a low temperature do not always match each other. In this case, the uniform correction as shown in FIG. 10 may not be able to properly correct the second correspondence in all temperature ranges.

Therefore, the temperature acquisition unit 12 according to the present embodiment acquires a plurality of combinations of the temperature of the element unit 200 and the electric resistance value of the heat generation unit 211 in the heat generation mode, and establishes a second correspondence relationship based on the plurality of combinations. It is supposed to be corrected. In the present embodiment, the corresponding electrical resistance values are corrected individually for each temperature from T11 to T14 in FIG. 11 instead of uniformly. Therefore, the second correspondence can be appropriately corrected in all temperature ranges.

The correction at each temperature from T11 to T14 may be performed individually each time the electric resistance value or the like at each temperature is acquired, and all the electric resistance values or the like at each temperature from T11 to T14 are acquired. It may be done at the same time.

The accuracy of these temperature corrections will be higher if they are carried out under predetermined engine conditions. For example, if the heat generation mode is controlled under the condition that there is no gas flow velocity before the engine is started and the series of processes shown in FIG. 9 is executed, the second correspondence relationship is appropriately corrected after eliminating the environmental impact such as the flow velocity. It becomes possible.

The fourth embodiment will be described. The fourth embodiment is different from the first embodiment only in the configuration of the element unit 200 included in the particulate matter detection sensor 20, and the other configurations and control methods are the same as those in the first embodiment.

The configuration of the element unit 200 according to the present embodiment will be described with reference to FIG. FIG. 12 shows a specific configuration of the element unit 200 as an exploded view. As shown in the figure, the element unit 200 according to the present embodiment is also configured by laminating a plurality of substrates which are rectangular plate-shaped members as in the first embodiment. Each substrate is made of ceramics.

The substrate 210 arranged on the lowermost side in FIG. 12 has a heat generating portion 211, a lead electrode 212, 213, and a sense electrode 214 formed on the upper surface thereof. All of these are one electrode pattern, which is formed on the upper surface of the substrate 210 by, for example, screen printing. The function of each electrode is the same as the function in the first embodiment described with reference to FIG. In the present embodiment, the connection portion between the lead electrode 212 and the heat generating portion 211 is a “connection portion CP”, and the sense electrode 214 is connected to this connection CP.

The substrate 250 arranged above the substrate 210 is simply an insulating plate on which electrodes and the like are not printed.

A pair of electrodes 222 and 232 are formed on the surface of the substrate 260 arranged further above the substrate 250 on the side opposite to the substrate 250. One electrode 222 is formed so as to extend a portion of the substrate 260 on the back side of the paper surface along the longitudinal direction of the substrate 260. The other electrode 232 is formed so that the portion of the substrate 260 on the front side of the paper surface extends along the longitudinal direction of the substrate 260.

A plurality of electrodes 221 and 231 are formed on the portion of the substrate 260 on the upper side of the heat generating portion 211. All of these are linear electrodes formed so as to extend along the lateral direction of the substrate 260, and are arranged so as to be alternately arranged along the longitudinal direction of the substrate 260 at predetermined intervals. ing.

The ends of each of the plurality of electrodes 221 are connected to the electrode 222, and together with the electrode 222, the whole becomes one electrode pattern. Similarly, the ends of each of the plurality of electrodes 231 are connected to the electrode 232, and together with the electrode 232, the whole thereof forms one electrode pattern.

A pair of electrodes 241 and 242 are formed on the surface of the uppermost substrate 240 in FIG. 12 opposite to the substrate 260 and the like. The electrode 241 is connected to the electrode 222 via a through hole (not shown). The electrode 242 is connected to the electrode 232 through a through hole (not shown). Similar to the first embodiment, the detection wiring 26 shown in FIG. 2 is connected to the electrodes 241 and 242.

A rectangular opening 243 is formed in a portion of the substrate 240 directly above the electrodes 221 and 231. Through the opening 243, the respective electrodes 221 and 231 are exposed to the outside. This exposed portion corresponds to the detection surface 201 in this embodiment.

The control device 10 applies a predetermined voltage between the electrodes 241 and 242 via the pair of detection wirings 26 shown in FIG. At this time, a voltage is also applied between the electrodes 221 and 231 exposed on the detection surface 201. When no particulate matter is deposited on the detection surface 201, no current flows between the electrodes 221 and 231. On the other hand, when the particulate matter is deposited on the detection surface 201, since the particulate matter is a conductor, a current flows between the electrode 221 and the electrode 231. The current increases as the amount of particulate matter deposited on the detection surface 201 increases.

The control device 10 detects the magnitude of the current as the magnitude of the current flowing through the pair of detection wirings 26. The control device 10 can detect the amount of deposited particulate matter on the detection surface 201 of the element unit 200 based on the magnitude of the current. The control device 10 can detect the amount of the particulate matter passing through the exhaust pipe 130, for example, based on the time change of the accumulated amount of the particulate matter.

Even when the particulate matter detection sensor 20 having the element unit 200 having the above-described configuration is used, the same control as in each embodiment can be performed, and the various described above can be performed. It is possible to produce the same effect as the effect of.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those skilled in the art with appropriate design changes to these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-mentioned specific examples, its arrangement, conditions, shape, etc. is not limited to the illustrated one, and can be appropriately changed. The combination of each element included in each of the above-mentioned specific examples can be appropriately changed as long as no technical contradiction occurs.

The controls and methods described in the present disclosure are provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be realized by a computer. The control device and control method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor including one or more dedicated hardware logic circuits. The control device and control method described in the present disclosure is composed of a combination of a processor and memory programmed to perform one or more functions and a processor including one or more hardware logic circuits. It may be realized by one or more dedicated computers. The computer program may be stored on a computer-readable non-transitional tangible recording medium as an instruction executed by the computer. The dedicated hardware logic circuit and the hardware logic circuit may be realized by a digital circuit including a plurality of logic circuits or an analog circuit.

Claims (8)

1. It is a control device (10) of the particulate matter detection sensor (20).
   The particulate matter detection sensor has an element portion (200) which is a portion for detecting the particulate matter and a heat generating portion (211) which is a portion configured as an electric heater for heating the element portion. It is a thing
   A temperature acquisition unit (12) for acquiring the temperature of the element unit and
   A heat generation adjusting unit (13) that adjusts the amount of heat generated by the heat generating unit based on the temperature of the element unit acquired by the temperature acquisition unit.
   A storage unit (14) for storing the correspondence between the value of the electric power consumed in the heat generating unit and the temperature of the element unit is provided.
   The temperature acquisition unit is a control device configured to acquire the temperature of the element unit based on the value of the electric power consumed in the heat generating unit and the corresponding relationship.
2. The control device according to claim 1, wherein the correspondence relationship is stored for each of a plurality of temperature ranges of the element unit.
3. A heat generation mode, which is a mode in which the heat generation amount is adjusted by the heat generation adjustment unit, and
   The claim is configured so that the temperature acquisition mode, which is a mode in which the temperature acquisition unit acquires the temperature of the element unit without adjusting the heat generation amount by the heat generation adjustment unit, can be executed. The control device according to 1 or 2.
4. In the heat generation mode, the heat generation adjustment unit is
   The control device according to claim 3, wherein the amount of heat generated is adjusted so that the value of the electric power consumed in the heat generating unit matches the target power value corresponding to the target temperature of the element unit.
5. In the storage unit
   In addition to the first correspondence, which is the correspondence,
   The second correspondence relationship, which is the correspondence relationship between the electric resistance value of the heat generating portion and the temperature of the element portion, is also stored.
   In the temperature acquisition mode, the temperature acquisition unit
   A current is temporarily supplied to the heat generating portion, and the temperature of the element portion is acquired based on the electric resistance value of the heat generating portion acquired at that time and the second correspondence relationship. The control device according to claim 3 or 4.
6. In the heat generation mode, the temperature acquisition unit
   The temperature of the element unit is acquired based on the value of the electric power consumed in the heat generating unit and the first correspondence relationship, and the electric resistance value of the heat generating unit at that time is also acquired.
   The control device according to claim 5, wherein the second correspondence is corrected based on the acquired temperature of the element unit and the electric resistance value of the heat generating unit.
7. In the heat generation mode, the temperature acquisition unit
   The control device according to claim 6, wherein a plurality of combinations of the temperature of the element portion and the electric resistance value of the heat generating portion are acquired, and the second correspondence relationship is corrected based on the plurality of combinations.
8. The particulate matter detection sensor has
   A pair of lead electrodes (212, 213) for supplying electric power to the heat generating portion, and
   A sense electrode (214) for acquiring an electric potential at a connection portion between one of the lead electrodes and the heat generating portion is provided.
   The control device according to any one of claims 1 to 7, wherein the temperature acquisition unit acquires a value of electric power consumed in the heat generating unit based on a potential acquired via the sense electrode.

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