WO2020149065A1

WO2020149065A1 - Pm sensor

Info

Publication number: WO2020149065A1
Application number: PCT/JP2019/048738
Authority: WO
Inventors: 俊輔石黒; 熊田　辰己; 耕治加藤; 健太中嶋; 尚敬石山
Original assignee: 株式会社デンソー
Priority date: 2019-01-18
Filing date: 2019-12-12
Publication date: 2020-07-23
Also published as: JP2020118453A

Abstract

A PM sensor is provided with a storage control unit (S100) for causing particle concentration data to be stored sequentially in a storage unit for each predetermined period on the basis of a sensor signal corresponding to the intensity of scattered light scattered by impingement on particulate matter, a moving average calculation unit (S202) for sequentially calculating an average value for each predetermined period of the particle concentration data as a moving average while shifting the period thereof, a signal output unit (S204) for outputting a concentration signal indicating a particle concentration specified on the basis of the moving average, and a refreshing unit (S116) for refreshing the particle concentration data stored in the storage unit when a blower goes from an operation-stopped state to a starting state, the moving average calculation unit excluding refreshed particle concentration data, and calculating the moving average using the particle concentration data stored in the storage unit after refreshing.

Description

PM sensor

Cross-reference to related application

This application is based on Japanese Patent Application No. 2019-7075 filed on January 18, 2019, the description of which is incorporated herein by reference.

The present disclosure relates to a PM sensor that detects the particle concentration of particulate matter contained in air.

▽Vehicle air conditioner controls the temperature of the air taken into the air conditioning unit from inside the vehicle or outside the vehicle, and blows out the temperature-controlled air into the vehicle interior. The temperature control of the air is performed by a heater core or an evaporator in the air conditioning unit, as described in Patent Document 1 below, for example.

JP, 2008-24032, A

The present inventors are studying to add a function of measuring the concentration of particles floating in the air, such as PM2.5, to an air conditioner for a vehicle. The PM sensor detects the suspended particles in the air by receiving the scattered light when the light emitted from the light emitting element of the light emitting unit hits the suspended particles by the light receiving element of the light receiving unit. If such a PM sensor is provided in a vehicle air conditioner and a part of the air drawn into the air conditioning unit flows through the PM sensor, the particle concentration in the air drawn into the air conditioning unit can be measured. Is possible.
In the PM sensor under consideration, in order to separate scattered light received by the light receiving element and ambient light from the surroundings, the gain of the light receiving portion becomes 0 at low frequencies, and the gain increases as the frequency increases. There is. Specifically, the light receiving unit of the PM sensor has a high-pass filter that removes low-frequency components, and outputs a sensor signal representing 0 at low frequencies. This PM sensor measures the particle concentration in the air flowing through the PM sensor at a certain flow velocity or higher. The particle concentration data indicating the particle concentration specified by the sensor signal output from the light receiving unit is sequentially stored in the buffer by the control unit.

On the other hand, the particle concentration measured by the PM sensor varies greatly, so we are considering using moving averages to identify the particle concentration. Here, the moving average is a value obtained by shifting an interval from an average value of certain constant intervals in time series data.

The control unit of the PM sensor stores the particle concentration in a buffer such as a memory at predetermined time intervals, and in the particle concentration data stored in the buffer, obtains an average value for each fixed period while shifting the period. Memory is a non-transitional tangible storage medium.

However, in the configuration described above, the particle concentration data representing 0 is sequentially stored in the buffer while the blower is off. For this reason, the rising of the moving average becomes gentle immediately after the blower that takes in air to the air conditioning unit is turned on. Therefore, there is a problem that the response is poor and the particle concentration cannot be accurately specified.

The present disclosure has an object of providing excellent responsiveness and enabling accurate identification of particle concentration even immediately after the blower is turned on.

According to one aspect of the present disclosure, a PM sensor that detects the particle concentration of a particulate matter contained in the air flowing in a case by the operation of a blower emits light to the air, and the PM sensor emits the light. Light is received by the scattered light scattered by the particulate matter, the sensor signal according to the intensity of the scattered light is output, and a low-frequency component of the sensor signal is removed. Based on the particle concentration data indicating the particle concentration of the particulate matter specified based on the storage controller, the storage controller sequentially stores the data in the storage unit at predetermined intervals, and the predetermined particle concentration data sequentially stored in the storage unit by the storage controller. A moving average calculation unit that sequentially calculates the average value for each period as a moving average while shifting the period, and specifies the particle concentration of the particulate matter based on the moving average calculated by the moving average calculation unit, and the specified particulate matter The signal output unit that outputs a concentration signal indicating the particle concentration of the blower, the operation determination unit that determines the operation state of the blower, and the operation determination unit determines that the storage unit stores the blower from the stopped state to the started state. And a refresh unit that refreshes the stored particle concentration data.

Then, the moving average calculation unit excludes the particle concentration data refreshed by the refresh unit, and calculates the moving average using the particle concentration data stored in the storage unit after being refreshed by the refresh unit.

According to the above-described configuration, the refresh unit refreshes the particle concentration data stored in the storage unit when the operation determination unit determines that the blower has changed from the operation stopped state to the startup state, and the moving average calculation unit, The particle concentration data of the particulate matter refreshed by the refresh section is excluded, and the moving average is calculated using the particle concentration data stored in the storage section after being refreshed by the refresh section, so immediately after the blower is turned on. However, the responsiveness is excellent and the particle concentration can be accurately specified.

Note that the reference numerals in parentheses attached to the respective constituent elements and the like indicate an example of a correspondence relationship between the constituent elements and the like and specific constituent elements and the like described in the embodiments described later.

It is the figure which showed typically the schematic structure of the vehicle air conditioner provided with the PM sensor which concerns on 1st Embodiment. It is a figure showing composition of a PM sensor. 3 is a flowchart of a control unit of the PM sensor according to the first embodiment. It is a figure showing the value of the buffer when there is no refresh. It is a figure showing the value of the buffer at the time of refreshing. It is a flow chart of a control part of a PM sensor. It is a flow chart of a control part of a PM sensor concerning a 2nd embodiment. It is a flow chart of a control part of a PM sensor concerning a 3rd embodiment. It is a figure showing composition of a PM sensor. It is the figure which showed the frequency characteristic of PM sensor. It is a block diagram of a PM sensor. It is a figure for demonstrating the calculation method of the moving average of particle concentration. It is a figure for demonstrating the rising of the moving average immediately after a blower turns on from OFF.

Before describing the PM sensor according to the present embodiment, the PM sensor 50 under consideration by the present inventors and a method for identifying the particle concentration will be described.

The configuration of the PM sensor under consideration by the present inventors is shown in FIG. The PM sensor 50 detects the floating particles in the air by receiving the scattered light when the light emitted from the light emitting element 511 of the light emitting section 51 hits the floating particles by the light receiving element 521 of the light receiving section 52. If such a PM sensor 50 is provided in a vehicle air conditioner and a part of the air drawn into the air conditioning unit flows through the PM sensor 50, the particle concentration in the air drawn into the air conditioning unit can be measured. It becomes possible to do.

In the PM sensor 50 under consideration, the scattered light received by the light receiving element 521 is separated from the ambient light from the surroundings. Therefore, as shown in FIG. 10, the gain of the light receiving unit 52 becomes 0 when the frequency becomes 0 Hertz, The gain is increased as the frequency is increased.

Specifically, as shown in FIG. 11, the light receiving unit 52 of the PM sensor 50 includes a light receiving element 521 that receives light and a high-pass filter 524 that removes low-frequency components included in the signal output from the light receiving element 521. And are equipped with. A control unit 525 that performs various controls is connected to the light receiving unit 52.

A sensor signal indicating 0 is output to the control unit 525 when the blower that takes in air to the air conditioning unit is turned off and the flow velocity of the air flowing in the PM sensor becomes 0 m/sec. Further, when the blower that takes in air to the air conditioning unit is turned on and the flow velocity of the air flowing in the PM sensor increases, a sensor signal corresponding to the intensity of scattered light is output.

On the other hand, since the particle concentration measured by the PM sensor varies greatly, the inventors are considering using a moving average to specify the particle concentration. Here, the moving average is a value obtained by shifting an interval from an average value of certain constant intervals in time series data.

Specifically, the control unit 525 stores the particle concentration in a buffer such as a memory at fixed time intervals, and in the particle concentration data stored in the buffer, obtains an average value for each fixed period while shifting the period. ..

For example, as shown in FIG. 12, at time a seconds, the average particle concentration in the period A to X is calculated as a moving average, and at time a+1 second, the average particle concentration in the period B to Y is calculated as a moving average. At time a+2 seconds, the average of the particle concentrations during the period C to Z is calculated as the moving average. As described above, by specifying the particle concentration at each time using the moving average, it becomes possible to absorb the variation in particle concentration and specify the particle concentration more accurately.

However, as described above, in the configuration in which the particle concentration data representing 0 is sequentially stored in the buffer while the blower is off, as shown in FIG. As indicated by A, the rising of the moving average becomes gradual. Therefore, the response is poor and the particle concentration cannot be specified accurately.

Above, the PM sensor 50 under study by the present inventors and the method for specifying the particle concentration using the moving average have been described. The PM sensor shown below solves such a point. Hereinafter, embodiments will be described with reference to the drawings. In each of the following embodiments, the same or equivalent parts are designated by the same reference numerals in the drawings.

(First embodiment)
The PM sensor according to the first embodiment will be described with reference to FIGS. 1 to 6. As shown in FIG. 1, the PM sensor 50 is arranged in the vehicle air conditioner 1 mounted on the vehicle. The PM sensor 50 detects the concentration of dust contained in the air flowing in the air conditioning case 21 of the vehicle air conditioner 1, that is, the concentration of particles of the particulate matter, by the operation of the blower 23.

The vehicle air conditioner 1 includes an air conditioning unit 2 and an air conditioning control device 40. The air conditioning unit 2 is a vehicle air conditioning unit that is installed in the vehicle compartment and performs air conditioning in the vehicle interior. For example, the air conditioning unit 2 is installed in an instrument panel arranged on the front side of the vehicle in the vehicle interior.

As shown in FIG. 1, the air conditioning unit 2 includes an air conditioning case 21, an inside/outside air switching door 22, a blower 23, an evaporator 26, a heater core 27, an air mix door 28, an air filter 30,

blowout opening doors

254, 255, 256 and the like. have.

The air conditioning case 21 is made of a resin that has some elasticity and is also excellent in strength. Examples of the resin forming the air conditioning case 21 include polypropylene. The air-conditioning case 21 forms the outer shell of the air-conditioning unit 2, and inside the air-conditioning case 21, an air passage, that is, a ventilation passage 24, through which air blown into the vehicle compartment is formed. In addition, the air conditioning case 21 has an inside air introduction port 241 for introducing inside air into the ventilation passage 24 from a predetermined location in the vehicle compartment on the upstream side in the air flow direction of the ventilation passage 24, and introduces outside air into the ventilation passage 24 from outside the vehicle. And an outside air introduction port 242 for. Here, the inside air is the air inside the vehicle compartment, and the outside air is the air outside the vehicle compartment.

Further, the air conditioning case 21 has a plurality of

blowout openings

251, 252, 253 on the downstream side of the air passage 24 in the air flow direction for blowing air from the air passage 24 to the front seat area in the vehicle interior. .. The plurality of

blowout openings

251, 252, 253 include a face blowout opening 251, a foot blowout opening 252, and a defroster blowout opening 253.

The face blowout opening 251 blows air-conditioning air toward the upper half of the occupant seated in the front seat. The foot blowout opening 252 blows out the conditioned air toward the feet of the occupant. The defroster blowout opening 253 blows out the conditioned air toward the windshield of the vehicle.

Inside the air conditioning case 21, an inside/outside air switching door 22, a blower 23, an evaporator 26, a heater core 27, an air mix door 28, etc. are provided.

The inside/outside air switching door 22 is for continuously adjusting the opening area of the inside air inlet 241 and the opening area of the outside air inlet 242. The inside/outside air switching door 22 is driven by an actuator such as a servo motor (not shown). The inside/outside air switching door 22 rotates so that the opening of one of the inside air inlet 241 and the outside air inlet 242 closes the other inlet. As a result, the inside/outside air switching door 22 can adjust the ratio between the air volume of the inside air introduced into the ventilation passage 24 and the air volume of the outside air.

As the intake mode to the ventilation passage 24, there are an inside air mode for introducing the inside air inside the vehicle and an outside air mode for introducing outside air outside the vehicle. For example, in the inside air mode in which the inside air is exclusively introduced into the ventilation passage 24, the inside/outside air switching door 22 is positioned at an operating position where the inside air introduction port 241 is opened and the outside air introduction port 242 is closed. On the contrary, in the outside air mode in which the outside air is exclusively introduced into the ventilation passage 24, the inside/outside air switching door 22 is positioned at an operating position where the inside air introduction port 241 is closed and the outside air introduction port 242 is opened.

The blower 23 is a centrifugal blower that blows air, and has a centrifugal fan 231 arranged in the ventilation passage 24 and a motor (not shown) that rotationally drives the centrifugal fan 231. When the centrifugal fan 231 of the blower 23 is rotationally driven, an air flow is formed in the ventilation passage 24. Thereby, the air introduced into the ventilation passage 24 from the inside air introduction port 241 or the outside air introduction port 242 flows through the ventilation passage 24 and at least the face blowout opening 251, the foot blowout opening 252, and the defroster blowout opening 253. Blow out from one. In the ventilation passage 24, on the downstream side of the centrifugal fan 231 in the air flow direction, air roughly flows in the direction indicated by an arrow Ar.

An air introduction path 211 is formed at the end of the air conditioning case 21 where the centrifugal fan 231 is arranged. The air introduction path 211 is formed as a space in which air flows from the outside of the air conditioning case 21 to the inside of the air conditioning case 21.

The face outlet opening door 254 is provided in the face outlet opening 251, and the opening area of the face outlet opening 251 is adjusted. The foot outlet opening door 255 is provided in the foot outlet opening 252, and adjusts the opening area of the foot outlet opening 252. The defroster outlet opening door 256 is provided in the defroster outlet opening 253, and adjusts the opening area of the defroster outlet opening 253.

The evaporator 26 is a heat exchanger for cooling the air flowing through the ventilation passage 24. The evaporator 26 exchanges heat between the air passing through the evaporator 26 and the refrigerant, thereby cooling the air and evaporating the refrigerant.

The heater core 27 is a heat exchanger for heating the air flowing through the ventilation passage 24. The heater core 27 exchanges heat between the engine cooling water and the air passing through the heater core 27, for example, and heats the air with the heat of the engine cooling water. The heater core 27 is arranged downstream of the evaporator 26 in the air flow direction.

An air mix door 28 is provided between the evaporator 26 and the heater core 27 of the air conditioning unit 2. The air mix door 28 adjusts the ratio of the air volume that passes through the evaporator 26 and bypasses the heater core 27 and the air volume that passes through the evaporator 26 and then passes through the heater core 27.

The air filter 30 is arranged between the blower 23 and the evaporator 26 in the ventilation path 24 of the air conditioning case 21. In other words, the air filter 30 is arranged downstream of the blower 23 in the air flow direction and upstream of the evaporator 26 in the air flow direction.

The air filter 30 captures dust and the like contained in the air passing through the air filter 30 to some extent. Therefore, the air blown from the blower 23 flows into the evaporator 26 after dust and the like in the air are removed to some extent by the air filter 30.

Since this air filter 30 is provided in the ventilation passage 24 of the air conditioning case 21, the air conditioning control device 40 can operate the air conditioning unit 2 so as to reduce the dust concentration in the vehicle interior. In such an operation, the air conditioning control device 40 operates the blower 23 after setting the air conditioning unit 2 to the inside air mode, for example. The larger the amount of air blown by the blower 23, the higher the dust removing capability of the air conditioning unit 2 for removing dust in the vehicle interior.

Next, the PM sensor 50 will be described with reference to FIG. The PM sensor 50 is arranged in the ventilation path 24, through which the air blown into the vehicle interior of the vehicle flows, upstream of the blower 23 in the air flow direction and upstream in the air flow direction with respect to the air filter 30. Therefore, the PM sensor 50 detects the concentration of dust contained in the air before passing through the air filter 30.

As shown in FIG. 2, the PM sensor 50 detects the dust concentration, which is the concentration of suspended particles contained in the air at a predetermined sensing location Are, and outputs a detection signal indicating the detected dust concentration to the air conditioning controller 40. .. The dust concentration is also called dust concentration, and more specifically, it is the mass concentration of dust contained in the air, and the unit of dust concentration is, for example, “μg/m ³ ”.

The PM sensor 50 of this embodiment is an optical dust sensor configured to detect the dust concentration by the light scattering method. The PM sensor 50 includes a light emitting portion 51 having a light emitting element 511 that emits light, a light receiving portion 52 that receives the light emitted by the light emitting element 511, and a sensor case 53 that houses the light emitting portion 51 and the light receiving portion 52. ing. The light emitting element 511 is composed of, for example, a light emitting diode. Part of the air flowing through the air introduction passage 211 formed in the air conditioning case 21 flows inside the sensor case 53 of the PM sensor 50. The PM sensor 50 detects the concentration of dust contained in the air flowing inside the sensor case 53 by receiving the scattered light, which is the light emitted from the light emitting unit 51 hit by the particulate matter and scattered by the light receiving unit 52. ..

The block configuration of the light receiving section 52 of the PM sensor 50 is the same as that shown in FIG. That is, the light receiving unit 52 of the PM sensor 50 includes a light receiving element 521 that receives light, and a high pass filter 524 that removes low frequency components included in the signal output from the light receiving element 521. The light receiving element 521 is composed of, for example, a photodiode. A current corresponding to the amount of received light flows through the light receiving element 521. A control unit 525 that performs various controls is connected to the light receiving unit 52.

When the blower 23 that takes in air to the air conditioning unit 2 is turned off and the flow velocity of the air flowing in the PM sensor 50 becomes 0 m/sec, the control unit 525 receives a signal indicating that the sensor output=0. A high pass filter 524 is arranged between the element 521 and the control unit 525.

As shown in FIG. 10, the PM sensor 50 is configured so that the gain becomes 0 when the frequency of the sensor signal becomes 0 hertz. The gain increases as the flow velocity of the air flowing in the sensor case 53 increases, that is, as the frequency increases.

Next, the air conditioning control device 40 will be described. The air conditioning control device 40 shown in FIG. 1 is a control device that controls the air conditioning unit 2. Specifically, the air conditioning control device 40 is an electronic control device including a storage unit configured by a non-transitional physical storage medium such as a semiconductor memory and a processor. Semiconductor memory is a non-transitional tangible storage medium. The air conditioning control device 40 executes a computer program stored in its storage unit. By executing this computer program, the method corresponding to the computer program is executed. That is, the air conditioning control device 40 executes various control processes such as the processes of FIGS. 5 to 6 described later according to the computer program.

Further, the air conditioning control device 40 controls the operation of each actuator by outputting a control signal to each actuator included in the air conditioning unit 2. In short, the air conditioning control device 40 performs various air conditioning controls in the air conditioning unit 2. For example, the blower 23, the inside/outside air switching door 22, the air mix door 28, the face outlet opening door 254, the foot outlet opening door 255, and the defroster outlet opening door 256 described above are drive-controlled by the air conditioning controller 40. ..

Further, as shown in FIG. 1, the air conditioning control device 40 is electrically connected to, for example, sensors such as the PM sensor 50 and actuators such as doors, as well as an operating device 44 and a display device 46.

The operation device 44 is an operation unit operated by an occupant when adjusting the air volume, temperature, etc. of the conditioned air blown from the air conditioning unit 2. The operation device 44 is arranged, for example, on an instrument panel of a vehicle. The operation device 44 can set, for example, the air volume of the conditioned air, the target room temperature in the passenger compartment, and the outlet of the conditioned air. In addition, the operation device 44 can also set an automatic air conditioning mode in which air volume adjustment of air conditioning air, temperature adjustment of air conditioning air, and selection of inside air circulation or outside air introduction are automatically performed. The operation device 44 outputs information indicating these settings, that is, operation information indicating an occupant operation performed on the operation device 44 to the air conditioning control device 40.

Next, the processing of the control unit 525 will be described with reference to FIGS. 3 to 6. First, the processing shown in FIG. 3 will be described. When the power supply to the control unit 525 is started, the control unit 525 carries out the processing shown in FIG.

First, the control unit 525 identifies the sensor output value in S100. Specifically, the process of specifying the sensor output value based on the sensor signal output from the light receiving unit 52 and storing the specified sensor output value in the memory as a buffer is repeatedly performed for a certain period. As a result, the sensor output value is sequentially stored in the predetermined buffer area. A memory is a tangible transitional storage medium.

Here, when the blower 23 is turned on, the sensor output value specified based on the sensor signal output from the light receiving unit 52 is sequentially stored in the memory as a buffer. However, when the blower 23 is turned off and the flow velocity of the air flowing in the PM sensor 50 becomes 0 m/sec, the sensor output value is set to 0 and sequentially stored in the memory as a buffer.

Next, in S102, the control unit 525 refers to the sensor output value stored in the memory to determine whether or not the sensor output value=0 is continuously stored in the memory for a certain number (X times) or more. judge.

Here, if the sensor output value=0 is not stored in the memory for a certain number (X times) or more in succession with reference to the sensor output value stored in the memory, the control unit 525 determines in S104 that the blower is Recognizing that 23 is turned on, the process returns to S100.

By repeatedly performing such processing, the sensor output value specified based on the sensor signal output from the light receiving unit 52 is sequentially stored in the memory as a buffer.

When the blower 23 is turned off and the sensor output value stored in the memory is referred to and the sensor output value=0 is continuously stored in the memory for a certain number (X times) or more, the control unit 525 , S106, it is recognized that the blower 23 is off.

Next, the control unit 525 identifies the sensor output value in S108. Specifically, the process of specifying the sensor output value based on the sensor signal output from the light receiving unit 52 and storing the specified sensor output value in the memory as a buffer is repeatedly performed for a certain period. As a result, the sensor output value is sequentially stored in the predetermined buffer area. However, since the blower 23 is off here, the sensor output value is specified as 0, and the sensor output value=0 is sequentially stored in the memory.

Next, in S110, the control unit 525 refers to the sensor output value stored in the memory to determine whether the density change rate R, which is the change rate of the density of dust per unit time, is equal to or greater than the threshold value R _noise . To judge. Assuming that the dust concentration at a certain time point is C _{T =Nt} and the dust concentration after a certain time t has passed from a certain time point is C _{T =N} , the concentration change ratio R is R=(C _T=N − It can be expressed as C _{T =Nt} )/t. In addition, the threshold value R _noise is a constant that determines whether or not the density change ratio R is determined as noise.

When the density change of dust per unit time is small and the density change ratio R is less than the threshold value R _noise , the control unit 525 recognizes in S112 that the blower 23 is off, and returns to S108. By repeating such processing, the sensor output value is sequentially stored in the memory as 0.

When the dust concentration suddenly increases and the concentration change ratio R becomes _{equal to} or higher than the threshold value R _noise , the control unit 525 recognizes that the blower 23 is turned on in S114.

Next, the control unit 525 determines in S115 whether or not the time from the operation stop state of the blower 23 to the start state is equal to or more than a threshold value.

Here, when the time from the operation stop state to the start state of the blower 23 becomes the threshold value or more, the control unit 525 refreshes the particle concentration data sequentially stored in the memory as the buffer in S116. .. Specifically, the predetermined specific code is stored in the memory, and the process returns to S100.

FIG. 4 shows the particle concentration data stored in the memory when refresh is not performed. As shown in the figure, after the sensor output value=0 is continuously stored, the sensor output values A to D specified based on the sensor signal output from the light receiving unit 52 are sequentially stored.

FIG. 5 shows the particle concentration data stored in the memory when refresh is performed. The particle concentration data is refreshed at the refresh time Tref. The hyphen "-" in the figure represents a specific code that means that the refresh has been performed. As shown in the figure, when the sensor output value=0 is continuously stored and then the sensor output values A to B are sequentially stored, the blower 23 is turned on based on the sensor output values A to B in S114. A specific code is stored, which means that it has been recognized that it has been refreshed. Specifically, the continuous sensor output value=0 and the sensor output values A to B are replaced with the specific code. After that, the sensor output values C to D are sequentially stored.

Note that the control unit 525 performs a moving average calculation process that excludes the refreshed particle concentration data and calculates a moving average. This moving average calculation process will be described later.

In S115, when the time from the operation stop state to the start state of the blower 23 is less than the threshold value, the control unit 525 determines the particle concentration stored in the memory in S118. The data is corrected to a value larger than the sensor output value=0. For example, the particle concentration data stored in the memory is corrected using the sensor output value before the blower 23 is in the operation stopped state and the sensor output value in which the variation amount is equal to or less than the predetermined threshold value. When it is determined that the vehicle window is open based on the vehicle window opening signal and the intake mode to the ventilation passage 24 is determined to be the outside air mode, the concentration of particles around the vehicle is determined based on the WEB information and the like. May be estimated. Then, the particle concentration data stored in the memory may be corrected with this particle concentration. After correcting the particle concentration data in this way, the control unit 525 returns to S100.

Next, this moving average calculation process will be described with reference to FIG. The control unit 525 periodically executes the processing shown in FIG. 6 in parallel with the processing shown in FIG.

First, the control unit 525 reads the particle concentration data from the memory as a buffer in S200.

Next, the control unit 525 calculates a moving average in S202. As described above, the moving average is obtained by shifting the intervals of the average value for each certain interval in the time series data. The control unit 525 stores the particle concentration in a buffer such as a memory at regular time intervals, and in the particle concentration data stored in the buffer, obtains an average value for each constant period while shifting the period. Here, the average value of the particle concentration data read from the memory as the buffer in a certain section is calculated.

At this time, if there is refreshed particle concentration data in S116, the control unit 525 excludes the refreshed particle concentration data and calculates the average value of the particle concentration data in a certain section. For example, when there is refreshed particle concentration data and particle concentration data stored in the buffer after the refresh is executed, the concentration data stored in the buffer after being refreshed is used to average the particle concentration data over a certain section. Calculate the value.

Next, in S204, the control unit 525 identifies the particle concentration based on the average value of the particle concentration data calculated in S202 in a certain section, and outputs a signal indicating the particle concentration. Specifically, a pulse signal with a duty ratio is output according to the particle concentration, and this processing is repeatedly performed.

In S202, when the average value of a certain section of the particle concentration data is calculated without excluding the refreshed particle concentration data, as shown in A in FIG. The moving average rises slowly. Therefore, the response is poor and the particle concentration cannot be specified accurately.

On the other hand, in S202, when the refreshed particle concentration data is excluded to calculate the average value of the particle concentration data in a certain section, the rising of the moving average becomes steeper even immediately after the blower is turned on. .. Therefore, the responsiveness is good, and the particle concentration can be specified accurately.

As described above, the PM sensor of this embodiment includes the light emitting unit (51) that irradiates air with light. Further, a light receiving unit (52) for receiving scattered light which is emitted by the light emitting unit and scattered by hitting the particulate matter, outputs a sensor signal according to the intensity of the scattered light, and removes a low frequency component of the sensor signal. I have it. Further, a storage control unit (S100) is provided for sequentially storing, in the storage unit, particle concentration data indicating the particle concentration of the particulate matter specified based on the sensor signal output from the light receiving unit. .. In addition, the storage control unit includes a moving average calculation unit (S202) that sequentially calculates an average value of the particle concentration data of the particulate matter for each predetermined period sequentially stored in the storage unit as a moving average while shifting the period. In addition, a signal output unit (S204) is provided that specifies the particle concentration of the particulate matter based on the moving average calculated by the moving average calculation unit and outputs a concentration signal indicating the particle concentration of the specified particulate matter. .. Further, the operation determining unit (S102, S202, S110) for determining the operation state of the blower is provided. In addition, the operation determination unit includes a refresh unit (S116) that refreshes the particle concentration data of the particulate matter stored in the storage unit when it is determined that the blower has changed from the operation stop state to the start state. Further, the moving average calculation unit excludes the particle concentration data of the particulate matter refreshed by the refreshing unit, and calculates the moving average using the particle concentration data stored in the storage unit after being refreshed by the refreshing unit.

According to the above configuration, the refresh unit refreshes the particle concentration data of the particulate matter stored in the storage unit when the operation determination unit determines that the blower has changed from the operation stopped state to the startup state. Further, the moving average calculation unit excludes the particle concentration data of the particulate matter refreshed by the refreshing unit. Since the moving average calculation unit calculates the moving average using the particle concentration data stored in the storage unit after being refreshed by the refresh unit, it has excellent responsiveness and high accuracy even immediately after the blower is turned on. The particle concentration can be specified.

In addition, the light receiving section includes a light receiving element (521) through which a current corresponding to the intensity of scattered light hitting the particulate matter flows, and a high pass filter (524) for removing low frequency components included in the signal output from the light receiving element. And are equipped with. Then, when the blower stops operating, a sensor signal representing 0 is output.

In this way, it is possible to configure a light receiving unit that outputs a sensor signal that represents 0 at a low frequency by using the high-pass filter 524 that removes the low frequency component included in the signal output from the light receiving element.

Further, the operation determination unit determines that the blower is in a stopped state when the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit is 0 continuously for the reference number of times or more. ..

As described above, when the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit is 0 for the reference number of times or more, it can be determined that the blower is in the stopped state. ..

In addition, the operation determination unit determines that the concentration change rate of the particle concentration of the particulate matter per unit time is equal to or higher than a predetermined noise determination level based on the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit. If it becomes, it is determined that the blower is in operation.

In this way, when the concentration change rate of the particle concentration of the particulate matter per unit time becomes equal to or higher than the predetermined noise determination level based on the particle concentration data of the particulate matter sequentially stored in the storage section by the storage control section. It can be determined that the blower is in the operating state.

Also, the PM sensor includes a time determination unit (S115) that determines whether or not the time from the operation stop state of the blower to the start state is equal to or greater than a threshold value. Further, when the time determination unit determines that the time from the operation stop state to the start state of the blower is less than the threshold value, the particle concentration data of the particulate matter stored in the storage unit is corrected to a value larger than 0. The correction unit (S118) for

As described above, when the correction unit determines that the time from the operation stop state to the start state of the blower is less than the threshold value by the time determination unit, the particle concentration data of the particulate matter stored in the storage unit is It is corrected to a value greater than 0. Therefore, it is possible to specify the particle concentration more accurately.

(Second embodiment)
The PM sensor according to the second embodiment will be described with reference to FIG. 7. The configuration of the PM sensor 50 of this embodiment is the same as that of the first embodiment. The configuration of the PM sensor 50 of this embodiment is different from that of the first embodiment in the processing of the control unit 525.

FIG. 7 shows a flowchart of the control unit 525 of this embodiment. The control unit 525 of the present embodiment is different in that the determination of S202 is performed instead of S102 of FIG.

In S202, the control unit 525 of the first embodiment refers to the sensor output value stored in the memory, and determines whether the sensor output value=0 is continuously stored in the memory for a certain number (X times) or more. Determine whether or not. Then, it was recognized that the blower 23 was turned off in the case of a positive determination, and was recognized that the blower 23 was turned on in the case of a negative determination.

On the other hand, in S202, the control unit 525 of this embodiment refers to the sensor output value stored in the memory, and the density change rate R, which is the change rate of the density of dust per unit time, is equal to or less than the threshold value R _noise. Or not. Then, in the case of a positive determination, it is recognized that the blower 23 is off, and in the case of a negative determination, it is recognized that the blower 23 is on. In this way, the determination in S202 may be performed instead of S102 in FIG.

In this embodiment, the same effect as that of the configuration common to the first embodiment can be obtained in the same manner as the first embodiment.

In addition, the operation determination unit, when the concentration change rate of the particle concentration of the particulate matter per unit time becomes less than or equal to a predetermined value based on the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit. , It is determined that the blower is stopped.

In this way, when the concentration change rate of the particle concentration of the particulate matter per unit time becomes less than or equal to the predetermined value based on the particle concentration data of the particulate matter sequentially stored in the storage section by the storage control section, the blower It can be determined that it is in a stopped state.

(Third Embodiment)
The PM sensor according to the third embodiment will be described with reference to FIG. The configuration of the PM sensor 50 of this embodiment is the same as that of the first embodiment. The control unit 525 of the PM sensor 50 of the present embodiment is different in that when the determination of S102 of FIG. 3 is affirmative, the determination of S302 of FIG. 7 is further performed.

As shown in FIG. 8, in S102, the control unit 525 refers to the sensor output value stored in the memory and the sensor output value=0 is continuously stored in the memory for a certain number (X times) or more. It is determined whether or not there is. When the determination in S102 is affirmative, the concentration change rate R, which is the change rate of the dust concentration per unit time, is referred to in S302 by referring to the sensor output value stored in the memory, and is equal to or less than the threshold value R _noise. Or not. When the determination in S302 is affirmative, it is recognized that the blower 23 is off, and when it is negative, it is recognized that the blower 23 is on.

In this way, when the determination in S102 is affirmative, it is possible to more accurately recognize whether or not the blower 23 is off by performing the determination in S302.

Further, the operation determination unit determines that the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit becomes 0 continuously for the reference number of times or more, and the particle concentration of the particulate matter per unit time. When the concentration change rate is less than or equal to the predetermined value, it is determined that the blower is in a stopped state.

As described above, when the particle concentration data of the particulate matter becomes 0 continuously for the reference number of times or more and the concentration change rate of the particle concentration of the particulate matter per unit time becomes less than the predetermined value, the blower is It can be determined that it is in a stopped state.
(Other embodiments)

(1) In each of the above-described embodiments, when it is recognized in S106 that the blower 23 is off, and when it is recognized in S114 that the blower 23 is on, it is sequentially stored in the buffer in S116. The particle concentration data was refreshed. On the other hand, if it is determined that the blower 23 is turned off in S106 and then the time until the blower 23 is turned on in S114 is less than the threshold value, the particle concentration data is not refreshed. You may Then, the value of a certain time before the blower 23 becomes inoperative may be stored in the buffer.

(2) In each of the above embodiments, in S102, the operation determination unit determines whether or not the blower is in a stopped state, and in S202, the operation determination unit is sequentially stored in the storage unit by the storage control unit. Based on the particle concentration data of the particulate matter, it was determined whether or not the blower was stopped. On the other hand, the operation state of the blower may be determined based on the blower control signal sent from the air conditioning controller (40) that controls the operation of the blower.

It should be noted that the present disclosure is not limited to the above-described embodiment, and can be modified as appropriate. Further, the above embodiments are not unrelated to each other, and can be appropriately combined unless a combination is obviously impossible. In addition, in each of the above-described embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential unless explicitly stated as being essential and in principle considered to be essential. Yes. Further, in each of the above-mentioned embodiments, when numerical values such as the number of components of the embodiment, numerical values, amounts, ranges, etc. are mentioned, it is clearly limited to a particular number when explicitly stated as being essential. The number is not limited to the specific number, except in the case of being. Further, in each of the above-mentioned embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, etc., unless specifically stated or in principle limited to a specific material, shape, positional relationship, etc. However, the material, shape, positional relationship, etc. are not limited.

(Summary)
According to the first aspect shown in part or all of each of the above-described embodiments, the PM sensor includes a light emitting unit that irradiates air with light. Further, the light emitting unit is provided with a light receiving unit that receives scattered light scattered by the particulate matter hitting the particulate matter, outputs a sensor signal according to the intensity of the scattered light, and removes low-frequency components of the sensor signal. .. In addition, the storage control unit is provided that sequentially stores the particle concentration data indicating the particle concentration of the particulate matter specified based on the sensor signal output from the light receiving unit in the storage unit for each predetermined period. Further, the storage control unit includes a moving average calculation unit that sequentially calculates an average value of the particle concentration data of the particulate matter for each predetermined period sequentially stored in the storage unit as a moving average while shifting the period. Further, it is provided with a signal output unit that specifies the particle concentration of the particulate matter based on the moving average calculated by the moving average calculation unit and outputs a concentration signal indicating the particle concentration of the specified particulate matter. Further, it is provided with an operation determination unit that determines the operation state of the blower. Further, when the operation determination unit determines that the blower has changed from the operation stop state to the start state, the refresh unit is provided to refresh the particle concentration data of the particulate matter stored in the storage unit. Then, the moving average calculation unit excludes the particle concentration data of the particulate matter refreshed by the refreshing unit, and calculates the moving average using the particle concentration data stored in the storage unit after being refreshed by the refreshing unit.

Further, according to the second aspect, the light receiving section removes the light receiving element in which a current corresponding to the intensity of the scattered light hitting the particulate matter flows, and the low frequency component contained in the signal output from the light receiving element. And a high pass filter (524). Then, when the blower stops operating, a sensor signal representing 0 is output.

In this way, it is possible to configure a light receiving unit that outputs a sensor signal that represents 0 at low frequencies by using a high-pass filter that removes low frequency components included in the signal output from the light receiving element.

Further, according to a third aspect, the operation determination unit is configured such that, when the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit is equal to or greater than the reference number of times and is continuously 0. Is determined to be in a stopped state.

Further, according to the fourth aspect, the operation determination unit is configured to determine the concentration change rate of the particle concentration of the particulate matter per unit time based on the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit. Is less than or equal to a predetermined value, it is determined that the blower is in a stopped state.

Further, according to a fifth aspect, the operation determination unit determines that the particle concentration data of the particulate matter is 0 continuously for the reference number of times or more, and the concentration change rate of the particle concentration of the particulate matter per unit time. Is less than or equal to a predetermined value, it is determined that the blower is in a stopped state.

As described above, when the particle concentration data of the particulate matter becomes 0 continuously for the reference number of times or more and the concentration change rate of the particle concentration of the particulate matter per unit time becomes less than the predetermined value, the blower is It can be determined that it is in a stopped state.

Further, according to a sixth aspect, the operation determination unit, based on the particle concentration data of the particulate matter sequentially stored in the storage unit by the storage control unit, the concentration change rate of the particle concentration of the particulate matter per unit time. Is above a predetermined noise determination level, it is determined that the blower is in an operating state.

According to the seventh aspect, the operation determination unit determines the operation state of the blower based on the blower control signal sent from the air conditioning control device that controls the operation of the blower.

In this way, it is also possible to determine the operating state of the blower based on the blower control signal sent from the air conditioning control device that controls the operation of the blower.

Further, according to the eighth aspect, the PM sensor includes a time determination unit that determines whether or not the time from the operation stop state of the blower to the start state is a threshold value or more. When the time determination unit determines that the time from the operation stop state to the start state of the blower is less than the threshold value, the particle concentration data of the particulate matter stored in the storage unit is corrected to a value greater than 0. The correction unit is provided.

Note that S100 corresponds to the storage control unit, S202 corresponds to the moving average calculation unit, and S204 corresponds to the signal output unit. Further, S102, S202, and S110 correspond to the operation determination unit, S116 corresponds to the refresh unit, S115 corresponds to the time determination unit, and S118 corresponds to the correction unit.

Claims

A PM sensor for detecting the particle concentration of particulate matter contained in the air flowing in the case by the operation of the blower (23),
A light emitting unit (51) for irradiating the air with light,
A light receiving unit (52) that receives scattered light that is emitted by the light emitting unit and is scattered by hitting the particulate matter, outputs a sensor signal according to the intensity of the scattered light, and removes low-frequency components of the sensor signal. When,
A storage control unit (S100) for sequentially storing, in a storage unit, particle concentration data indicating a particle concentration of the particulate matter specified based on the sensor signal output from the light receiving unit, every predetermined period;
A moving average calculation unit (S202) that sequentially calculates an average value of the particle concentration data sequentially stored in the storage unit by the storage control unit as a moving average while shifting the period.
A signal output unit (S204) that specifies the particle concentration of the particulate matter based on the moving average calculated by the moving average calculation unit, and outputs a concentration signal indicating the particle concentration of the specified particulate matter,
An operation determination unit (S102, S202, S110) for determining the operation state of the blower,
A refreshing unit (S116) for refreshing the particle concentration data stored in the storage unit when the operation determining unit determines that the blower has changed from an operation stop state to a start state,
The moving average calculating unit excludes the particle concentration data refreshed by the refreshing unit, and calculates the moving average using the particle concentration data stored in the storage unit after being refreshed by the refreshing unit. PM sensor.
The light receiving unit,
A light receiving element (521) through which an electric current flows according to the intensity of the scattered light hitting the particulate matter;
A high-pass filter (524) for removing low frequency components included in the signal output from the light receiving element,
The PM sensor according to claim 1, which outputs the sensor signal indicating 0 when the blower stops operating.
The operation determination unit determines that the blower is in a stopped state when the particle concentration data sequentially stored in the storage unit by the storage control unit is 0 for a predetermined number of times or more. Item 2. The PM sensor according to Item 2.
The operation determination unit, when the concentration change ratio of the particle concentration of the particulate matter per unit time is less than or equal to a predetermined value based on the particle concentration data sequentially stored in the storage unit by the storage control unit, The PM sensor according to claim 2, wherein it is determined that the blower is in a stopped state.
In the operation determination unit, the particle concentration data sequentially stored in the storage unit by the storage control unit becomes 0 continuously for a reference number of times or more, and is sequentially stored in the storage unit by the storage control unit. The PM sensor according to claim 2, wherein when the concentration change rate of the particle concentration of the particulate matter per unit time is less than or equal to a predetermined value based on the particle concentration data, it is determined that the blower is in a stopped state.
The operation determination unit, based on the particle concentration data sequentially stored in the storage unit by the storage control unit, the concentration change rate of the particle concentration of the particulate matter per unit time is equal to or higher than a predetermined noise determination level. The PM sensor according to claim 2, wherein the blower determines that the blower is in an operating state.
The PM sensor according to claim 1, wherein the operation determination unit determines the operation state of the blower based on a control signal of the blower sent from an air conditioning controller (40) that controls the operation of the blower.
A time determination unit (S115) for determining whether or not the time from the operation stop state to the start state of the blower is a threshold value or more;
Correction for correcting the particle concentration data stored in the storage unit to a value greater than 0 when the time determination unit determines that the time from the operation stop state to the start state of the blower is less than the threshold value The PM sensor according to claim 1, further comprising a section (S118).