JP2021076547A - Device, method, and program for measuring particulate material - Google Patents

Abstract

To allow a measurement of a PM deposition amount as well when a filter formed of a conductor is used.SOLUTION: A DPF is irradiated with a microwave obtained by performing a frequency sweep on a reference sine wave integral multiple times, an impedance change amount, which is the difference between an impedance calculated from a reflection wave of the microwave and a reflection wave when a particulate material is not deposited on the DPF, is calculated, and the amount of particulate materials deposited on the DPF is calculated on the basis of the impedance change amount.SELECTED DRAWING: Figure 2

Description

The present invention relates to a particulate matter measuring device, a particulate matter measuring method, and a particulate matter measuring program.

In a vehicle having a diesel engine, a diesel particulate filter (Diesel Particulate Filter) that is inserted in the middle of the exhaust pipe from the engine to the atmosphere and collects particulate matter (Particulate Matter, hereinafter referred to as PM) contained in the exhaust gas. (Hereinafter referred to as DPF) is known.

When a large amount of collected PM is deposited on the DPF, the exhaust gas becomes difficult to flow, the exhaust pressure of the engine rises, and the engine characteristics deteriorate. Further, if PM is excessively deposited on the DPF, excessive heat is generated during DPF regeneration, which may damage the filter. In order to prevent this, it is necessary to perform DPF regeneration in which extra fuel is injected to raise the temperature of the DPF and the PM collected in the DPF is burned and removed before the PM is excessively accumulated. .. However, if the DPF regeneration is performed more than necessary, the fuel is consumed excessively and the fuel consumption is deteriorated. Therefore, it is necessary to accurately measure the PM deposition amount.

Patent Document 1 describes a method of determining the clogging of a filter having a first dielectric constant by using substances having different dielectric constants.

Special Table 2012-507660

In the future, it is expected that the material of DPF20 will shift from the dielectric cordureite to the conductor silicon carbide, so it is necessary to measure the PM deposition amount for the filter formed of the conductor as well. However, in the method of Patent Document 1, when the filter is manufactured by a conductor having a high dielectric constant, the PM deposition amount cannot be measured.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a particulate matter measuring device capable of measuring the amount of PM deposited even when a filter formed of a conductor is used.

The particulate matter measuring device according to the present invention is a substantially cylindrical DPF that collects particulate matter contained in exhaust gas, and a substantially cylindrical housing in which both end surfaces of the DPF are covered. A housing having openings on each of the first and second surfaces, which are both end surfaces, and an antenna provided inside the housing, the first surface and the first surface of the DPF. An antenna arranged between the first end face, which is an end face facing the impedance, a sine wave generator that generates a reference sine wave, which is a sine wave of a reference frequency, and a frequency sweep of the reference sine wave by an integral multiple. A sweeping unit that generates the generated microwave and irradiates the DPF with the microwave via the antenna, a receiving unit that receives the reflected wave reflected by the DPF via the antenna, and the received unit. A reflected wave synthesizing unit that synthesizes reflected waves to calculate a sine wave, an impedance measuring unit that calculates impedance from the reflected wave based on the sine wave, the calculated impedance, and the particulate matter in the DPF. The amount of impedance change, which is the difference from the impedance calculated from the reflected wave in the state where is not deposited, is calculated, and the amount of the particulate matter deposited on the DPF is calculated based on the amount of impedance change. It is characterized by having a quantity calculation unit.

According to the particulate matter measuring apparatus according to the present invention, a DPF (diesel particulate filter) is irradiated with a microwave obtained by sweeping the frequency of a reference sine wave at an integral multiple, and the impedance calculated from the reflected wave and the particles on the DPF. The amount of impedance change, which is the difference from the impedance calculated from the reflected wave in the state where the particulate matter is not deposited, is calculated, and the amount of particulate matter deposited on the DPF is calculated based on the impedance change amount. As a result, the amount of PM deposited can be measured even when a conductor, that is, a filter made of a material having a high dielectric constant is used.

Here, a deposition location calculation unit may be provided for calculating the deposition location on which the particulate matter is deposited on the surface of the DPF based on the square wave.

Here, a sedimentation distribution estimation unit that estimates the deposition distribution of the particulate matter in the DPF based on the sedimentation amount calculated by the sedimentation amount calculation unit and the sedimentation location calculated by the sedimentation site calculation unit is provided. May be good.

Here, the sine wave generation unit may calculate the frequency and amplitude of the reference sine wave based on the natural frequency of the DPF and the shape and capacitance of the housing. This makes it possible to accurately determine the amount of particulate matter deposited.

The method for measuring a particulate substance according to the present invention is a substantially rod-shaped DPF that collects the particulate substance contained in the exhaust gas, and a substantially tubular housing that covers both end faces that accommodate the DPF. A housing having openings on each of the first and second surfaces, which are both end surfaces, and an antenna provided inside the housing, the first surface and the first surface of the DPF. A particulate matter measuring device provided with an antenna provided between the first end face, which is an opposite end face, is a particulate matter measuring method for calculating the amount of the particulate matter deposited, and is a reference. A step of generating a reference sine wave which is a sine wave of a frequency, a step of generating a microwave obtained by sweeping the frequency of the reference sine wave by an integral multiple, and a step of irradiating the DPF with the microwave through the antenna. A step of receiving the reflected wave reflected by the DPF through the antenna, a step of synthesizing the received reflected wave to calculate a sine wave, and a step of calculating a sine wave from the reflected wave based on the sine wave. A step of calculating the impedance, calculating the amount of impedance change which is the difference between the calculated impedance and the impedance calculated from the reflected wave in the state where the particulate substance is not deposited on the DPF, and the impedance change. It is characterized by including a step of calculating the accumulated amount of the particulate matter deposited on the DPF based on the amount.

The particulate matter measurement program according to the present invention comprises a substantially rod-shaped DPF that collects particulate matter contained in exhaust gas, and a substantially tubular housing that covers both end surfaces of the DPF. A housing having openings on each of the first and second surfaces, which are both end surfaces, and an antenna provided inside the housing, the first surface and the first surface of the DPF. It is a particulate matter measurement program that controls a particulate matter measuring device including an antenna provided between the first end face, which is an opposite end face, and uses a sine wave of a reference frequency to control a computer. A sine wave generator that generates a certain reference sine wave, a sweeping unit that generates a microwave obtained by sweeping the frequency of the reference sine wave by an integral multiple, and irradiating the DPF with the microwave through the antenna, and a sweeping unit that is reflected by the DPF. A receiver that receives the reflected wave through the antenna, a reflected wave synthesizer that synthesizes the received reflected wave to calculate a sine wave, and an impedance that calculates impedance from the reflected wave based on the sine wave. Then, the impedance measuring unit that calculates the impedance change amount, which is the difference between the calculated impedance and the impedance calculated from the reflected wave in the state where the particulate matter is not deposited on the DPF, is used as the impedance change amount. Based on this, it functions as a deposit amount calculation unit that calculates the deposit amount of the particulate matter deposited on the DPF.

According to the present invention, the amount of PM deposited can be measured even when a filter formed of a conductor is used.

It is sectional drawing which shows the outline of the particulate matter measuring apparatus 1 which concerns on this invention. It is a functional block diagram of the particulate matter measuring apparatus 1. FIG. It is a figure explaining the processing of the reflected wave synthesis unit 44 and the impedance measurement unit 45, (a) shows an example of the power spectrum which shows the relationship between the frequency and signal strength of the microwave which irradiates DPF20, (b). Shows an example of a square wave generated from a reflected wave, and (c) shows an example of an impedance obtained from the square wave. It is a graph which shows the relationship between the accumulation amount or the accumulation place of PM and a square wave, (a) and (b) show the relationship between the accumulation amount of PM and the waveform, and (c) is from the antenna 30 of the accumulation position of PM. Shows the relationship between distance and waveform It is a flowchart which shows the mechanism which the particulate matter measuring apparatus 1 calculates the deposition distribution of PM. It is sectional drawing which shows the outline of the conventional particulate matter measuring apparatus 100.

Hereinafter, the particulate matter measuring device, the particulate matter measuring method, and the embodiment of the particulate matter measuring program according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an outline of the particulate matter measuring device 1 according to the present invention. The particulate matter measuring device 1 mainly includes a housing 10, a diesel particulate filter 20 (hereinafter referred to as DPF 20), an antenna 30, and a calculation unit 40.

The housing 10 is a substantially cylindrical housing whose both end surfaces are covered, and houses the DPF 20 inside. The housing 10 constitutes a part of an exhaust pipe from the engine to the atmosphere in a vehicle having a diesel engine, for example. The housing 10 has a first opening 13 and a second opening 14 on each of the first surface 11 and the second surface 12, which are both end faces. For example, the first opening 13 is connected to the engine and the second opening 14 is open to the atmosphere.

The DPF 20 is a filter that collects particulate matter contained in exhaust gas, and has a substantially cylindrical shape. The DPF 20 is housed substantially in the center of the housing 10 in the length direction. The DPF 20 is mainly made of ceramic, for example, but in the present embodiment, the DPF 20 uses silicon carbide (SiC) having high thermal conductivity, high strength, and high thermal shock resistance. Silicon carbide is a conductor. The DPF 20 is a honeycomb pore-shaped filter in which adjacent vent holes are alternately closed, and PM contained in the exhaust gas is collected by the honeycomb pores.

The DPF 20 has a first end face 21 and a second end face 22 which are both end faces, the first end face 21 faces the first face 11 and the first opening 13, and the second end face 22 faces the second face 12 and the second. It faces the opening 14. The exhaust gas that has flowed into the housing 10 from the first opening 13 enters the DPF 20 from the first end face 21, the particulate matter (PM) is removed, passes through the second end face 22, and enters the atmosphere from the second opening 14. It is released.

The antenna 30 is provided inside the housing 10. The antenna 30 is arranged between the first surface 11 and the first end surface 21. The antenna 30 converts the electric signal from the sweep unit 42 (detailed later) into microwaves (detailed later), irradiates the microwaves toward the DPF 20, and reflects the microwaves at the DPF 20. The generated reflected wave (detailed later) is received, and the reflected wave is converted into an electric signal and transmitted to the receiving unit 43 (detailed later).

The arrangement position of the antenna 30 is arbitrary, and the shape of the housing 10 is not limited to this. Further, the directivity of the antenna 30 is arbitrary, and may be, for example, omnidirectional, unidirectional, bidirectional, or the like. As will be described later, since the particulate matter measuring device 1 obtains the PM accumulation amount of the DPF 20 based on the change of the reflected wave received by the antenna 30 due to PM, it is sufficient if the state of the change can be measured. ..

FIG. 2 is a functional block diagram of the particulate matter measuring device 1. The antenna 30 is connected to the calculation unit 40 via the directional coupler 35. The directional coupler 35 is a member that separates the microwave and the reflected wave that are applied to the DPF 20. Therefore, one antenna 30 can be shared by the sweep unit 42 and the receiving unit 43. The directional coupler 35 may be included in the antenna 30.

The arithmetic unit 40 is connected to the antenna 30 and includes an arithmetic unit such as a CPU (Central Processing Unit) for executing information processing, and a storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory). .. The arithmetic unit operates according to the program stored in the storage device. The program can be provided by downloading via a network, or can be recorded and provided on various computer-readable recording media.

As software resources, the calculation unit 40 mainly includes a sine wave generation unit 41, a sweep unit 42, a reception unit 43, a reflected wave synthesis unit 44, an impedance measurement unit 45, a PM deposition amount calculation unit 46, and a PM deposition location calculation unit 47. It also has each functional part of the PM deposition distribution estimation part 48.

The sine wave generation unit 41 generates a sine wave having a reference frequency (hereinafter, referred to as a reference sine wave). The frequency band of the reference sine wave is not limited, but may be, for example, a 2.5 MHz band. The amplitude of the reference sine wave is also arbitrary.

However, in order to improve the accuracy, the sine wave generation unit 41 preferably calculates the frequency and amplitude of the reference sine wave based on the natural frequency of the DPF 20 and the shape and capacitance of the housing 10. For example, the frequency and amplitude of the reference sine wave can be calculated from the natural frequency of the DPF 20 and the shape and capacitance of the housing 10 using three-dimensional electromagnetic field analysis. Various known methods can be used for the three-dimensional electromagnetic field analysis.

The sweep unit 42 generates a microwave whose frequency is swept by an integral multiple of the reference sine wave. The frequency of the sine wave irradiated by the sweep unit 42 is, for example, twice, eight times, and 16 times the reference frequency, but is not limited to this. The more types of frequencies to be swept, the higher the measurement accuracy, but the higher the load of arithmetic processing. The most efficient value can be calculated using three-dimensional electromagnetic field analysis.

Further, the sweep unit 42 irradiates the DPF 20 with the generated microwaves via the directional coupler 35 and the antenna 30. The irradiated microwave is reflected by the DPF 20.

The receiving unit 43 receives the reflected wave reflected by the DPF 20 via the antenna 30. Since the directional coupler 35 is provided, the reflected wave is separated from the microwave irradiated to the DPF 20 and received by the receiving unit 43. The reflected wave has a waveform that is attenuated or delayed by DPF20 or PM as compared with the irradiated microwave (detailed later).

The reflected wave synthesizing unit 44 synthesizes the reflected wave received by the receiving unit 43 to calculate a square wave. Specifically, the reflected wave synthesizing unit 44 calculates a square wave by inverse Fourier transforming the power spectrum of the microwave received in a predetermined time range.

The impedance measuring unit 45 calculates the impedance from the reflected wave based on the square wave.

FIG. 3 is a diagram for explaining the processing of the reflected wave synthesis unit 44 and the impedance measurement unit 45, and FIG. 3A shows an example of a power spectrum showing the relationship between the frequency of the microwave irradiated to the DPF 20 and the signal strength. , (B) show an example of a square wave generated from a reflected wave, and (c) show an example of an impedance obtained from a square wave.

As shown in FIG. 3A, the reference frequency f and microwaves having a frequency that is an integral multiple of the reference frequency f are applied to the DPF 20. The signal at the reference frequency f is larger, and the higher the frequency of the microwave, the smaller the signal.

When the reflected wave is inverse Fourier transformed, the square wave shown in FIG. 3B is calculated. The square wave deforms according to the amount of PM deposited (detailed later).

Impedance analysis of the square wave shown in FIG. 3B gives a graph of impedance shown in FIG. 3C. Various known methods can be used for impedance analysis.

Returning to the description of FIG. The impedance measuring unit 45 can observe the change in impedance according to the distance from the antenna 30 by calculating the square wave. Since the distance from the predetermined measurement point on the first end surface 21 to the antenna 30 is known in advance, the impedance measuring unit 45 determines the reflected wave reflected at the measurement point on the first end surface 21 among all the reflected waves. Only can be taken out. Then, the impedance measuring unit 45 can exclude the influence of the unintended reflected wave inside the housing 10 by calculating the change in impedance from the reflected wave reflected at the measurement point on the first end surface 21. ..

The PM deposition amount calculation unit 46 calculates the impedance change amount, which is the difference between the impedance measured by the impedance measurement unit 45 and the impedance calculated from the reflected wave of the DPF 20 in which PM is not deposited, and the calculated impedance. The amount of PM deposited on the DPF 20 is calculated based on the amount of change.

The PM deposition amount calculation unit 46 holds the impedance (hereinafter, referred to as initial impedance) when PM is not deposited. As for the initial impedance, the sine wave generation unit 41 generates a reference sine wave, and the sweep unit 42 generates a microwave whose frequency is swept by an integral multiple of the reference sine wave and irradiates the DPF 20 on which PM is not deposited. The receiving unit 43 receives the reflected wave reflected by the undeposited DPF 20, the reflected wave combining unit 44 synthesizes the reflected wave received by the receiving unit 43 to calculate a square wave, and the impedance measuring unit 45 calculates the square wave. It is obtained by calculating the impedance from the wave.

Then, the PM deposition amount calculation unit 46 calculates the difference between the impedance measured by the impedance measurement unit 45 and the initial impedance as the impedance change amount.

Further, the PM accumulation amount calculation unit 46 calculates the accumulation amount of PM deposited on the DPF 20 (hereinafter referred to as PM accumulation amount) based on the impedance change amount. The PM deposit amount calculation unit 46 holds information indicating the relationship between the impedance change amount and the PM deposit amount. The amount of impedance change and the amount of PM deposition are in a proportional relationship (linear distribution), and the larger the impedance, the larger the amount of PM deposition. The PM deposition amount calculation unit 46 stores the relational expression between the impedance change amount and the PM accumulation amount in advance, and calculates the PM accumulation amount on the surface of the DPF 20 from the impedance change amount by calculating using the relational expression. calculate.

The PM deposition location calculation unit 47 calculates the deposition location where PM is deposited on the surface of the DPF 20 based on the square wave generated by the reflected wave synthesis unit 44.

FIG. 4 is a graph showing the relationship between the PM deposit amount or the deposit location and the square wave, (a) and (b) show the relationship between the PM deposit amount and the waveform, and (c) shows the PM deposit position. The relationship between the distance from the antenna 30 and the waveform is shown. The rectangular wave s1 in FIGS. 4A to 4C is an ideal square wave generated based on the reflected wave of the DPF 20 when PM is not deposited.

The shape of the square wave received by the receiving unit 43 differs depending on the state of the PM deposition distribution in the DPF 20. As shown in the square waves r1 and r2 in FIG. 4A, when PM is deposited, the rise of the square wave becomes slow (the rise becomes gentle). Further, when PM is deposited, the peak voltage of the square wave increases or decreases as shown in the square waves r1 and r2 of FIG. 4 (a). For example, when the impedance of the deposited PM is larger than the impedance of the DPF 20 in the initial state, the peak voltage of the square wave increases. Further, for example, when the impedance of the deposited PM is smaller than the impedance of the DPF 20 in the initial state, the peak voltage of the square wave decreases.

Further, as PM is deposited on the surface of the DPF 20, the distance from the antenna 30 at the PM deposit position becomes shorter. Therefore, as shown in the square wave r3 of FIG. 4B, the rise of the square wave is advanced.

Further, if the distance between the antenna 30 and the DPF 20 is different, the phase shift of the square wave occurs. Further, when the distance from the antenna 30 at the PM deposition position becomes long, the rise of the square wave is delayed as shown in the square wave r4 of FIG. 4 (c). In reality, the waveform changes schematically shown in FIGS. 4 (a) to 4 (c) occur in a complex manner.

Returning to the description of FIG. Further, the PM deposition location calculation unit 47 creates a model in advance, and in a state where PM is not deposited on the DPF 20, each measurement point on the first end surface 21 for each frequency to be irradiated by the method already described. The impedance is calculated from the reflected wave from and is held as a reference value. The PM deposit location calculation unit 47 can specify each measurement point by the difference in the distance from the antenna 30. Further, since the transmission path of the irradiation wave and the reflected wave is different due to the non-uniform shape inside the housing 10, the PM deposit location calculation unit 47 has the same transmission path even if the linear distance from the antenna 30 is the same. The measurement point can be specified from the difference between the above. At this time, by sweeping and irradiating a plurality of frequencies, it becomes easier to identify the measurement location.

The PM deposit distribution estimation unit 48 estimates the PM deposit distribution in the DPF 20 based on the deposit amount calculated by the PM deposit amount calculation unit 46 and the deposit location calculated by the PM deposit location calculation unit 47.

The amount of deposit inside the DPF20 cannot be measured directly. However, the shape of the DPF 20 is uniform, and as described above, the amount of deposits deposited on the surface of the DPF 20 and the position thereof can be calculated. Therefore, the PM deposition distribution estimation unit 48 can estimate the PM deposition distribution inside the DPF 20, that is, the entire DPF 20 from the deposition distribution on the surface of the DPF 20.

It should be noted that the configuration of the arithmetic unit 40 shown in FIG. 2 has described the main configuration in explaining the features of the present embodiment, and does not exclude, for example, the configuration provided in a general information processing apparatus. The components of the calculation unit 40 may be further classified into more components according to the processing content, or one component may execute the processing of a plurality of components.

FIG. 5 is a flowchart showing the mechanism by which the particulate matter measuring device 1 calculates the PM deposition distribution.

First, the sine wave generation unit 41 generates a sine wave (reference sine wave) having a reference frequency f (step S1). Then, the sweep unit 42 sweeps the reference frequency f to an integral multiple (step S2). Further, the sweep unit 42 irradiates the DPF 20 with a sine wave having a frequency that is an integral multiple of the reference frequency f and the reference frequency f via the directional coupler 35 (step S2).

Next, the receiving unit 43 receives the reflected wave reflected by the DPF 20 from the microwave radiated from the antenna 30 to the DPF 20 via the antenna 30 and the directional coupler 35 (step S3).

Next, the reflected wave synthesizing unit 44 generates a square wave by synthesizing the reflected wave and performing an inverse Fourier transform (step S4). The impedance measuring unit 45 analyzes the square wave generated in step S4 for impedance and measures the impedance calculated from the reflected wave (step S5).

The PM deposition amount calculation unit 46 calculates the difference between the impedance calculated in step S5 and the initial impedance as the impedance change amount, and calculates the PM deposit amount in the DPF 20 based on the impedance change amount (step S6). Further, the PM deposition location calculation unit 47 calculates the PM deposition location on the surface of the DPF 20 based on the amount of impedance change (step S6). The calculation of the PM deposition amount and the calculation of the PM deposition location may be performed in order (in no particular order) or at the same time.

Next, the PM deposition distribution estimation unit 48 estimates the total PM deposition distribution in the DPF 20 based on the PM deposition amount and deposition location calculated in step S6 (step S7).

The calculation unit 40 determines whether or not an instruction to end the process has been input (step S8). The instruction to end the process may be input to the calculation unit 40 from an input device (not shown) or the like, or at the same time when the internal combustion engine is stopped, the control unit (not shown) that controls the internal combustion engine calculates. It may be input to the unit 40.

If the instruction to end the process is not input (NO in step S8), the calculation unit 40 returns the process to step S1. When the instruction to end the process is input (YES in step S8), the calculation unit 40 ends the series of processes. That is, the calculation unit 40 continuously performs the processing shown in FIG. By continuously measuring the change in impedance in this way, the transition of the PM deposition amount in the DPF 20 can be measured. As a result, the PM deposition distribution can be estimated accurately.

According to this embodiment, since the PM deposition amount is calculated using the reflected wave, the PM deposition amount and the PM deposition distribution can be obtained even when a filter formed of a conductor is used.

For example, in the method using the microwave transmission characteristics, the amount of PM deposited cannot be calculated in the case of a conductor such as silicon carbide, which is difficult to transmit microwaves, that is, DPF20 manufactured of a substance having a high dielectric constant. ..

On the other hand, in the present embodiment, since the reflected wave from the DPF 20 is used, the amount of PM deposited can be estimated accurately even if the DPF 20 is composed of a conductor that reflects microwaves, that is, a substance having a high dielectric constant. be able to. In particular, since silicon carbide is excellent in thermal conductivity, it is possible to achieve both thermal conductivity and highly accurate PM deposition distribution estimation by using DPF20 composed of silicon carbide.

Further, according to the present embodiment, since the PM deposit amount is calculated using the reflected wave, only one antenna 30 is required, and the PM deposit amount can be measured with a simple configuration.

FIG. 6 is a cross-sectional view showing an outline of the conventional particulate matter measuring device 100. In the particulate matter measuring device 100, the transmitting antenna 130a is arranged on the first end surface 21 side of the DPF 20, and the receiving antenna 130b is arranged on the second end surface 22 side. That is, the microwave transmitted from the antenna 130a and transmitted through the DPF 20 is received by the antenna 130b, and the arithmetic unit 140 analyzes the received microwave to estimate the amount of PM deposited.

However, in the particulate matter measuring device 100, since the PM deposition amount is obtained from the microwave transmission characteristics, two antennas 130a and 130b are required before and after the DPF 20, and the microwave transmission characteristics are taken into consideration. The antennas 130a and 130b must be placed in appropriate positions.

Further, in the particulate matter measuring device 100, in order to measure the bias of PM deposition in the DPF 20, the directivity of the antennas 130a and 130b is increased, and then the antennas 130a and 130b are made movable or a plurality of antennas are used. 130a and 130b must be installed.

On the other hand, in the present embodiment, since the PM deposition amount is obtained based on the impedance change amount calculated from the reflected wave, only one antenna 30 is required, and there are no restrictions on the arrangement and directivity of the antennas. Further, in the present embodiment, the PM deposition distribution of the entire DPF 20 can be estimated by one irradiation of microwaves without spatially dividing the lateral region.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present invention. ..

1: Particulate matter measuring device 10: Housing 11: First surface 12: Second surface 13: First opening 14: Second opening 20: DPF (diesel particulate filter)
21: 1st end surface 22: 2nd end surface 30: Antenna 35: Directional coupler 40: Calculation unit 41: Sine wave generation unit 42: Sweep unit 43: Reception unit 44: Reflected wave synthesis unit 45: Impedance measurement unit 46: PM accumulation amount calculation unit 47: PM accumulation location calculation unit 48: PM accumulation distribution estimation unit 100: Particulate matter measuring device 130a, 130b: Antenna 140: Arithmetic device

Claims (6)

A substantially cylindrical DPF that collects particulate matter contained in exhaust gas,
A substantially cylindrical housing in which both end faces for accommodating the DPF are covered, and a housing having openings on each of the first and second surfaces, which are both end faces, and a housing.
An antenna provided inside the housing, which is arranged between the first surface and the first end surface which is an end surface facing the first surface of the DPF.
A sine wave generator that generates a reference sine wave, which is a sine wave with a reference frequency,
A sweeping unit that generates a microwave obtained by sweeping the frequency of the reference sine wave by an integral multiple and irradiates the DPF with the microwave via the antenna.
A receiving unit that receives the reflected wave reflected by the DPF via the antenna, and
A reflected wave synthesizer that synthesizes the received reflected waves to calculate a square wave, and
An impedance measuring unit that calculates impedance from the reflected wave based on the square wave,
The amount of impedance change, which is the difference between the calculated impedance and the impedance calculated from the reflected wave in the state where the particulate matter is not deposited on the DPF, is calculated, and the DPF is based on the amount of the impedance change. A deposition amount calculation unit that calculates the deposition amount of the deposited particulate matter, and
A particulate matter measuring device characterized by being equipped with. The particulate matter measuring apparatus according to claim 1, further comprising a depositing place calculation unit for calculating a depositing place where the particulate matter is deposited on the surface of the DPF based on the square wave. It is characterized by providing a sedimentation distribution estimation unit that estimates the deposition distribution of the particulate matter in the DPF based on the sedimentation amount calculated by the sedimentation amount calculation unit and the sedimentation location calculated by the sedimentation site calculation unit. The particulate matter measuring device according to claim 2. Any of claims 1 to 3, wherein the sine wave generator calculates the frequency and amplitude of the reference sine wave based on the natural frequency of the DPF and the shape and capacitance of the housing. The particulate matter measuring device according to item 1. A substantially rod-shaped DPF that collects particulate matter contained in exhaust gas,
A substantially tubular housing in which both end faces for accommodating the DPF are covered, and a housing having openings on each of the first and second surfaces, which are both end faces, and a housing.
An antenna provided inside the housing, which is provided between the first surface and the first end surface which is an end surface facing the first surface of the DPF.
The particulate matter measuring device provided with the above is a particulate matter measuring method for calculating the accumulated amount of the particulate matter.
Steps to generate a reference sine wave, which is a reference frequency sine wave,
A step of generating a microwave obtained by sweeping the frequency of the reference sine wave by an integral multiple,
The step of irradiating the DPF with the microwave through the antenna,
The step of receiving the reflected wave reflected by the DPF through the antenna, and
The step of synthesizing the received reflected waves to calculate a square wave,
Impedance is calculated from the reflected wave based on the square wave, and the impedance change which is the difference between the calculated impedance and the impedance calculated from the reflected wave in the state where the particulate matter is not deposited on the DPF. Steps to calculate the amount and
A step of calculating the amount of the particulate matter deposited on the DPF based on the amount of impedance change, and
A method for measuring particulate matter, which comprises. A substantially rod-shaped DPF that collects particulate matter contained in exhaust gas,
A substantially tubular housing in which both end faces for accommodating the DPF are covered, and a housing having openings on each of the first and second surfaces, which are both end faces, and a housing.
An antenna provided inside the housing, which is provided between the first surface and the first end surface which is an end surface facing the first surface of the DPF.
It is a particulate matter measurement program that controls a particulate matter measuring device equipped with
Computer,
A sine wave generator that generates a reference sine wave, which is a sine wave with a reference frequency.
A sweeping unit that generates a microwave obtained by sweeping the frequency of the reference sine wave by an integral multiple and irradiates the DPF with the microwave via the antenna.
A receiver that receives the reflected wave reflected by the DPF via the antenna.
A reflected wave synthesizer that synthesizes the received reflected wave to calculate a square wave,
Impedance is calculated from the reflected wave based on the square wave, and the impedance change which is the difference between the calculated impedance and the impedance calculated from the reflected wave in the state where the particulate matter is not deposited on the DPF. Impedance measuring unit that calculates the amount,
A deposit amount calculation unit that calculates the deposit amount of particulate matter deposited on the DPF based on the impedance change amount.
Particulate matter measurement program characterized by functioning as.

Images