The present application claims priority to Korean Patent Application No. 10-2021-0096011, filed Jul. 21, 2021, the entire contents of which is incorporated herein for all purposes by this reference.
The present disclosure relates to a particulate matter sensing device and a method for controlling driving of the same, and more particularly, to a particulate matter sensing device that detects a harmful substance in a vehicle and removes the detected harmful substance, and a method for controlling driving of the particulate matter sensing device.
As social hygiene concerns increase due to COVID-19 and the expansion of shared vehicles, a need for hygiene management in vehicles has emerged. Although techniques for removing and preventing harmful substances in vehicles have been actively developed, research and application of sensing technology are still insufficient.
Korean Patent Registration No. 10-1853104 discloses a technique in which when light output from a light source is scattered by floating fine particles, the scattered light is received and the amount of particles is measured. In Korean Patent Registration No. 10-1853104, accuracy and precision are improved using a variable gain amplification circuit and a background correction circuit. Meanwhile, to measure ultra-fine particles and low-concentration particles, a beam size of a light source needs to be small and a micro-signal has to be measured by a receiving unit. Such an optical sensor system is limited in application to a vehicle due to a need for expensive parts.
Therefore, there is a need for a device for a vehicle, which is capable of providing information about harmful substances to vehicle users and removing the harmful substances.
The matters described as the background art are merely for improving the understanding of the background of the present disclosure, and should not be accepted as acknowledging that they correspond to the prior art known to those of ordinary skill in the art.
The present disclosure is proposed to solve these problems and aims to provide a particulate matter sensing technique for selectively sensing fine particles floating in a vehicle in real time.
In particular, the present disclosure aims to provide a particulate matter sensing technique for sensing a small amount of fine particles and collecting and selectively removing the sensed fine particles.
The present disclosure also aims to implement a particulate matter sensing device to estimate a particulate matter to be removed based on an output signal detected by the particulate matter sensing device and to share estimated particulate matter information with a vehicle user.
A particulate matter sensing device according to an embodiment of the present disclosure to achieve the foregoing aims includes an inlet through which air is introduced, a particle classifying unit classifying particles included in air introduced through the inlet, a corona discharging unit electrifying the particles passing through the particle classifying unit, and a sensing unit collecting the particles electrified by the corona discharging unit.
The sensing unit may include an electrode having a plurality of intervals to collect the particles electrified by the sensing unit, and a control unit determining whether fine particles are detected, based on a result of monitoring an output signal change of the electrode.
The particulate matter sensing device may further include a heater increasing a temperature of a side of the sensing unit.
The particulate matter sensing device may further include a heater installed under the electrode to increase a temperature of a side of the electrode, in which the control unit operates the heater according to the output signal change of the electrode.
The control unit may previously store reaction temperature information of fine particles matched according to types of the fine particles, and the control unit may determine information of detected fine particles, by comparing a temperature at which the output signal change of the electrode occurs when operating the heater with the previously stored reaction temperature information.
Thus, when the control unit operates the heater, the control unit may drive the heater at the preset first voltage to monitor the output signal change of the electrode, and drive the heater at the preset second voltage to remove the particles remaining in the sensing unit.
The particle classifying unit may be a virtual impactor including a major flow unit and a minor flow unit.
The sensing unit may include a plurality of insulating protrusions extending in a side longitudinal direction on the substrate, an interdigitated electrode (IDE) electrode applied to be arranged alternately in parallel on a sidewall part of the insulating protrusions, and a heater installed to heat the insulating protrusions.
The inlet may be connected to an inside of a vehicle to introduce air in the inside of the vehicle, the sensing unit may be connected to an outlet for discharging the air to an outside, and a fan may be installed in a discharging path connecting the sensing unit with the outlet.
The particulate matter sensing device may further include a substrate on which the particle classifying unit, the corona discharging unit, and the sensing unit are installed, a housing installed on the substrate, the housing on which a flow path connecting the inlet with the outlet is partitioned, and a cover covering a side of the housing, in which the particulate matter sensing device may be modularized by the housing and the cover.
A method for controlling driving of a particulate matter sensing device according to a preferred implementation example of the present disclosure includes a particle classifying operation of classifying fine particles of air introduced through an inlet, by a particle classifying unit, a particle electrifying operation of electrifying fine particles, by a corona discharging unit, a signal generating operation of generating an output signal by collecting the electrified fine particles, by a sensing unit including an interdigitated electrode (IDE) electrode, and a sensing operation of detecting the fine particles based on a change of the output signal, by a control unit.
The sensing operation may include a heater operating operation of operating a heater to heat a side of the sensing unit, when determining that the fine particles of a reference amount or more are collected between electrodes, by the control unit.
The control unit may previously store reaction temperature information of fine particles matched according to types of the fine particles, and the sensing operation may further include, after the heater operating operation, determining information of detected fine particles, by comparing a temperature at which the change of the output signal of the electrode occurs when operating the heater with the previously stored reaction temperature information, by the control unit.
The heater driving operation may include a first heater driving operation of driving the heater at the preset first voltage, by the control unit and a second heater driving operation of removing the particles remaining in the sensing unit by driving the heater to the preset second voltage after an elapse of a specific time.
With the particulate matter sensing device and the method for controlling driving of the same according to the present disclosure, a sensor capable of detecting the fine particles floating in the vehicle in real time and selectively may be provided.
In particular, according to the present disclosure, by using the corona discharging unit and the nanogap sensing unit, a small amount of fine particles may be effectively sensed.
Moreover, according to the present disclosure, bacteria and super-fine dust may be selective removed based on a heating temperature of the heater formed in the sensing unit, and an attenuation signal output from the sensing unit may be analyzed, thus estimating information about the sensed particulate matter.
Therefore, according to a preferred implementation example of the present disclosure, particles sensed by the sensing unit may be removed immediately after heater driving, enabling measurement and removal of fine particles at the same time.
Hereinafter, a particulate matter sensing device and a method for controlling driving of the same according to various embodiments of the present disclosure will be described in detail with reference to the attached drawings.
A particulate matter sensing device according to the present disclosure may have a modularized structure that may be installed in a vehicle and may have a structure connected to an indoor of the vehicle to introduce the air inside the vehicle and then discharge the air again. Preferably, the particulate matter sensing device may have a structure in which a corona discharging unit, a sensing unit, etc., are installed on a single substrate and an internal flow path is formed to allow the air including a particulate matter to flow therein.
The particulate matter sensing device according to the present disclosure may provide a sensor structure and an operating algorithm for simultaneously measuring bacteria and fine dust floating in the air inside the vehicle through one sensing unit. In this regard, the operating algorithm of a sensor may be based on a principle for measuring an electrical signal change occurring due to sequential removal of particles. Most bacteria are dissipated within several seconds at a temperature of 130° C. or higher, and ultra-fine dust may be removed within several seconds at a temperature of 500° C. or higher. Thus, by using a difference between temperatures at which two particles, i.e., bacteria and ultra-fine dust are removed, a temperature near an electrode where the fine particles are collected is sequentially increased, enabling selective and sequential removal of particles. When the operating algorithm of the particulate matter sensing device is implemented, a scheme of measuring electrical characteristics, e.g., a change of current may be used.
In this regard,
As shown in
The air entering the particulate matter sensing device 100 after passing through the inlet 110 may be classified by the particle classifying unit 120 according to a particle size, and classified fine particles may move to a side of the corona discharging unit 130. The fine particles moved to the corona discharging unit 130 may be electrified by the corona discharging unit 130, and the electrified fine particles may move to a side of the sensing unit 140. The fine particles moved to the sensing unit 140 may be collected around the electrode of the sensing unit 140, and the collected particles may be removed by driving of a heater 144 (shown in
The particle classifying unit 120, the corona discharging unit 130, and the sensing unit 140 may be installed on a substrate S, and the particulate matter sensing device 100 may be integrated into a housing 160 during the manufacturing process. A flow path connecting the inlet 110 with the outlet 150 is partitioned, and a cover 180 covering the housing 160 on the substrate S.
Hereinbelow, referring to
For example, the particle classifying unit 120 may be a virtual impactor including a major flow unit 121 and a minor flow unit 122. The virtual impactor is widely used in sampling of particles with the advantages of high performance and real-time classification.
The fine particles introduced through an inlet of the virtual impactor may be accelerated while passing through a flow path with a cross section called a spray nozzle which gradually narrows. Major flow may be formed through a flow path bent at a right angle of 90 degrees, and minor flow may be formed through a flow path formed to go in a straight line. In this case, particles with high inertia may go in a straight line to move to a side of the minor flow unit 122, and particles with low inertia may mostly move to the major flow unit 121 bent 90 degrees where flow is concentrated. Based on such a principle, fine particles may be classified according to particle sizes through the virtual impactor. A classification particle diameter of the virtual impactor may be determined by a cross-sectional area and a flow rate of the spray nozzle, such that the particulate matter sensing device 100 according to the present disclosure may properly select a particle diameter of a fine particle to be detected and removed by adjusting the cross-sectional area and the flow rate of the nozzle.
For example, to improve sensing accuracy for each particle size, the fine particles may be classified according to sizes into ultra-fine particles having a size of 2.5 μm or less before cation attachment and fine particles having a size greater than 2.5 μm. By using a flow speed difference between the major flow unit 121 and the minor flow unit 122 of a flow path designed for a particle size desired to be measured, classification by particle size may be possible based on an inertia difference according to particle mass.
As shown in
As shown in
The corona discharging unit 130 may include a corona discharging electrode installed on the insulating substrate S. The corona discharging unit 130 may be a component for attaching cations to fine particles included in the introduced air. When high voltage is applied to the corona discharging unit 130 through an electrode exposed to the outside of the housing 160 of the corona discharging unit 130, fine particles in the air moving on the corona discharging unit 130 may be electrified.
In this regard, in
The sensing unit 140 may be installed in a downstream side of the corona discharging unit 130, and is a component for collecting fine particles electrified by the corona discharging unit 130. The sensing unit 140 of the particulate matter sensing device 100 according to a preferred embodiment of the present disclosure may have a structure in which the heater 144 and a nano gap interdigitated electrode (IDE) electrode are integrated, and may be manufactured through various MEMS (micro-electromechanical system) processes.
In this regard,
An embodiment of a method for manufacturing the sensing unit 140 having such a shape will be described with reference to
As shown in
Thereafter, by using a deposition process having good directionality, thin film deposition may be carried out such that metal may be deposited on one wall and a top of a convex-concave structure in an inclined state of the substrate. In this regard,
By performing the deposition process as shown in
Meanwhile, a subsequent process may be performed to deposit metal on a sidewall in an opposite direction to the metal-deposited sidewall as shown in
Thereafter, as shown in
Meanwhile, a method for manufacturing an electrode part may be merely an example, and the sensing unit 140 may be manufactured using another manufacturing method. For example, a heater may be previously formed by a photolithography process by using an electron beam (E-beam) lithography process, and an insulating film such as SiO2, Si3N4, etc., may be formed on a heater electrode upper end, after which a nanogap IDE may be formed by using the E-beam lithography process.
Moreover, a suspended photoresist (PR) may be formed on a substrate where the heater and the insulating film are formed through PR patterning in a way to use carbon-MEMS (C-MEMS), and the diameter of the suspended PR may be reduced to a nanoscale using PR carbonization. Thereafter, metal may be deposited using the suspended PR as a shadow mask, and then the carbonized PR may be removed to form a nano gap electrode pattern.
Meanwhile, the control unit 170 may be connected to the IDE electrode 143, and the control unit 170 may be configured to monitor an electrical output signal change of the electrode and control driving of the heater 144 under the electrode. For example, the sensing unit 140 may be configured to sense a fine particle/bacteria concentration change by monitoring a resistance/impedance change of the electrode.
The control unit 170 may determine whether fine particles are detected, based on a result of monitoring the output signal change of the IDE electrode 143, and drive the heater 144 according to a certain condition to remove the collected fine particles, e.g., bacteria and ultra-fine dust. In a preferred implementation example of the present disclosure, the control unit 170 may be configured to operate the heater 144 when it is determined that fine particles of a reference amount of more are collected between electrodes, according to the output signal changes of the electrode.
In this regard, the control unit 170 may previously store reaction temperature information of fine particles matched according to types of the fine particles, and may determine information of the detected fine particles by comparing a temperature at which the output signal change of the electrode occurs in an operation of the heater 144 with the previously stored reaction temperature information. The reaction temperature information of the fine particles may be specific temperature information regarding a temperature at which fine particles generally existing in the inside of the vehicle may be removed, and the reaction temperature information may be stored separately for the fine particles. The control unit 170 may analyze an output signal from the sensing unit 140 and estimate information about fine particles collected and removed in the sensing unit 140 based on temperature information regarding a temperature at which bacteria are dissipated, temperature information regarding a temperature at which ultra-fine dust is removed, or the like. As described above, most bacteria are dissipated within several seconds at a temperature of 130° C. or higher, and ultra-fine dust may be removed within several seconds at a temperature of 500° C. or higher, such that such temperature information may be previously stored as the reaction temperature information in the control unit 170, and may be matched to temperature information at a time instant where an actual output signal change is detected, thereby estimating a removal target.
To this end, when the control unit 170 operates the heater 144, the control unit 170 may drive the heater 144 at a first voltage for driving the heater 144 for increasing the temperature of the sensing unit 140 to preset first reaction temperature information or higher and at a second voltage for increasing the temperature of the sensing unit 140 to preset second reaction temperature information or higher. Thus, when the control unit 170 operates the heater 144, the control unit 170 may drive the heater at the preset first voltage to monitor the output signal change of the electrode, determine whether bacteria are dissipated, and drive the heater 144 at the preset second voltage to remove the particles remaining in the sensing unit 140.
As described above, the inlet 110 may be connected to the inside of the vehicle to introduce air inside the vehicle, and the sensing unit 140 may be connected to the outlet 150 for discharging the air to the outside in a downstream side thereof. A fan may be installed in a discharging path connecting the sensing unit 140 with the outlet 150, and according to driving of the fan, air flow from the inlet 110 to the outlet 150 may be formed.
In relation to the method for controlling driving of the particulate matter sensing device according to an embodiment of the present disclosure,
A detailed operation of the method for controlling driving of the particulate matter sensing device according to a preferred embodiment of the present disclosure will be described with reference to the flowchart of
In an initial stage, as shown in
Referring to
Thereafter, particles classified as having sizes to be detected among the classified particles may move to the corona discharging unit side, and cations may be attached to the moved particles by the corona discharging unit, thereby electrifying the particles, in operation S102. In the particle electrifying operation, current and temperature maintain the state as shown in
The electrified particles may move to the sensing unit and may be collected on the IDE electrode of the sensing unit as shown in
An operation of driving the heater by the control unit separately from the notification regarding the sensing may be performed in operations S106 and S107.
In this regard, whether the amount of collection exceeds a reference may be determined by a detected output signal change, for example, by setting a reference current value for driving the heater. On the other hand, by regarding a time instant at which the increase degree of increase of current changes due to completion of collection of sufficient fine particles as a heater driving time, driving of the heater may be controlled based on a result of monitoring the output signal change.
Meanwhile, in relation to a heater driving scheme, by considering a temperature at which bacteria and fine particles are removable, heater driving may be controlled to be performed through two stages.
For example, the heater driving operation may include first heater driving operation S106 of dissipating the bacteria by driving the heater at the preset first voltage and second heater driving operation S107 of removing the particles remaining in the sensing unit by driving the heater to the preset second voltage after an elapse of a specific time.
In this regard, in the first heater driving operation according to operation S106, the bacteria, which are organic matters, are dissipated and thus become carbides, according to heater driving, and in this case, as the bacteria are attached or detached, the current path is reduced, thus reducing the current. Moreover, when the dissipated bacteria are not attached or detached, the total resistance is affected by an electrical conductivity difference between the bacteria before and after dissipation, causing a current change. That is, regardless of whether the bacteria are attached or detached, the current change occurs, and by sensing the current change, whether the bacteria are sensed may be determined.
Such a current change is shown in
Meanwhile, by further increasing the temperature of the heater through second heater driving operation S107, an operation of controlling all of the ultra-fine particles may be performed. This operation is an operation of substantially initializing the sensing unit and the particulate matter sensing device, and through this operation, as shown in
While the present disclosure has been shown and described in relation to specific embodiments thereof, it would be obvious to those of ordinary skill in the art that the present disclosure can be variously improved and changed without departing from the spirit of the present disclosure provided by the following claims.
Number | Date | Country | Kind |
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10-2021-0096011 | Jul 2021 | KR | national |