WO2022163074A1

WO2022163074A1 - Vehicle-mounted exhaust gas analysis device and exhaust gas analysis method

Info

Publication number: WO2022163074A1
Application number: PCT/JP2021/042012
Authority: WO
Inventors: 謙次近藤; 伸宜奥井
Original assignee: 株式会社堀場製作所
Priority date: 2021-01-27
Filing date: 2021-11-16
Publication date: 2022-08-04
Also published as: JPWO2022163074A1

Abstract

To make it possible to accurately analyze particulate matter included in exhaust gas emitted from stop-start vehicles and hybrid vehicles, including plug-in types, this invention is made to comprise a recirculation path L2 that branches from a branching point L1a provided between an analyzer X that is provided in a sample flow path L1 through which exhaust gas from an engine E flows and a diluter MIX and joins with the diluter MIX, a pump P provided in the recirculation path L2, an additional flow path L3 that is connected to the recirculation path L2 and leads to the atmosphere, a filter F3 provided in the additional flow path L3, an opening and closing mechanism V1 provided in the additional flow path L3, an engine information acquisition unit 21 for acquiring on/off information for the engine E, an engine state determination unit 22 for determining whether the engine E is on or off, and an opening and closing control unit 23 for closing the opening and closing mechanism V1 if a determination is made that the engine E is on and opening the opening and closing mechanism V1 if a determination is made that the engine E is off.

Description

On-vehicle exhaust gas analyzer and exhaust gas analysis method

The present invention relates to a vehicle-mounted exhaust gas analyzer and an exhaust gas analysis method.

As a conventional vehicle-mounted exhaust gas analyzer, as shown in Patent Document 1, a reflux passage is provided to return part of the exhaust gas flowing through the sampling passage from the downstream side to the upstream side. Some have a so-called reflux dilution mechanism that returns the exhaust gas that has flowed into the reflux passage to the sampling passage as a dilution gas.

When measuring particulate matter contained in engine exhaust gas using such an on-vehicle exhaust gas analyzer, if the test vehicle is an idling stop vehicle or a hybrid vehicle, even if the engine is stopped during idling stop or electric drive In spite of this, sampling is continued, and particulate matter in the atmosphere is led to the analyzer and measured, resulting in loss of measurement accuracy.

On the other hand, as a method of stopping sampling when the engine is stopped, for example, it is possible to stop the sampling pump of the analyzer. Otherwise, the measurement accuracy immediately after the engine is started is impaired.

Japanese Patent Application Publication No. 2014-526679

Therefore, the present invention has been made to solve the above-mentioned problems at once, and the main purpose is to enable accurate analysis of particulate matter contained in exhaust gas emitted from idling stop vehicles and hybrid vehicles. This is an issue.

That is, the vehicle-mounted exhaust gas analyzer according to the present invention includes a sampling channel through which exhaust gas from an engine flows, an analyzer connected to the sampling channel for analyzing the exhaust gas, and an upstream of the analyzer in the sampling channel. a diluter provided in the sampling channel, a return path that branches from a branch point set between the analyzer and the diluter in the sampling flow path and joins the diluter, and is provided in the return path, a pump that guides part of the exhaust gas from the branch point to the diluter; an additional flow path that is connected to the return flow path or the sampling flow path and through which additional gas from which particulate matter has been removed flows; an opening/closing mechanism provided in a flow path; an engine information acquisition unit that acquires ON/OFF information that is information relating to ON/OFF of the engine; and whether the engine is in the ON state or the OFF state based on the ON/OFF information. an engine state determination unit for determining whether the engine is in the ON state, the opening/closing mechanism is closed when the engine state determination unit determines that the engine is in the ON state, and the engine state determination unit determines that the engine is in the OFF state and an opening/closing control unit that opens the opening/closing mechanism when the determination is made.

According to the vehicle-mounted exhaust gas analyzer configured in this manner, when the engine state determination unit determines that the engine is in the OFF state, the opening/closing control unit opens the opening/closing mechanism for the additional flow path, so that particulate matter The additional gas from which the gas has been removed can be led from the additional flow path to the analyzer via the return flow path or the sampling flow path.
As a result, when the engine is switched from the ON state to the OFF state, particulate matter is prevented from being measured by the analyzer without stopping equipment downstream of the diluter, such as the sampling pump of the analyzer. As a result, it is possible to accurately analyze particulate matter contained in exhaust gases emitted from idling stop vehicles and hybrid vehicles.

In order to remove particulate matter from the additional gas with a simple configuration, it is preferable that the additional flow path is provided with an additional flow path filter that traps particulate matter.

If the engine is switched from ON to OFF and the opening/closing mechanism is opened, if the additional gas introduced into the additional flow path flows back into the tail pipe of the test vehicle, the concentration of the particulate matter remaining in the tail pipe will decrease. This leads to measurement errors when the engine is subsequently turned on.
Therefore, in a state where the opening/closing control section opens the opening/closing mechanism, it is preferable that the total flow rate of the additional gas flowing through the additional flow path is guided to the analyzer.
In this case, even if the engine is switched from the ON state to the OFF state and the opening/closing mechanism is opened, the additional gas introduced into the additional flow path will not flow back to the tail pipe of the test vehicle, and measurement accuracy can be ensured. .

As a specific embodiment for reliably preventing backflow, the analysis gas flow rate, which is the flow rate of the gas introduced into the analyzer, is controlled to a first flow rate in a state where the opening/closing control unit closes the opening/closing mechanism. and an additional flow rate, which is the flow rate of the additional gas flowing through the additional flow path, is controlled to the first flow rate when the opening/closing control unit opens the opening/closing mechanism. .

Further, in order to more reliably prevent atmospheric particulate matter from being led to the analyzer when the engine is stopped, the additional flow path flowing through the additional flow path is maintained in a state in which the opening/closing control section opens the opening/closing mechanism. A portion of the gas preferably flows back through the sampling channel from the diluter.

In order to further improve the measurement accuracy, it is desirable to guide the exhaust gas remaining in the tail pipe or the sampling flow path to the analyzer immediately after the engine is switched from the ON state to the OFF state.
Therefore, when the engine is switched from the ON state to the OFF state, the opening/closing control section is configured to open the opening/closing mechanism after a predetermined first waiting time has elapsed from the time of the switching. is preferred.
In this case, the introduction of additional gas to the analyzer can be stopped until the exhaust gas remaining in the tail pipe or sampling flow path is guided to the analyzer, thereby further improving the measurement accuracy.

If the opening/closing mechanism of the additional flow path is closed immediately after the engine is switched from OFF to ON, air inside the tail pipe, for example, will be led to the analyzer, resulting in measurement errors due to particulate matter contained in the air. to invite
Therefore, in order to reduce such a measurement error, when the engine is switched from the OFF state to the ON state, after a predetermined second waiting time has elapsed from the time of the switching, the opening/closing control unit controls the opening/closing It is preferably arranged to close the mechanism.

As a more specific configuration of the present invention, the analyzer analyzes particulate matter in the exhaust gas, and the return passage is provided with a return passage filter that captures the particulate matter. I can list what I have.

It is preferable that the return path filter is provided upstream of the pump in the return path.
With such a configuration, it is possible to reduce the flow of particulate matter into the pump, and prevent pump failure.

It is preferable that the additional flow path is connected between the pump and the return path filter in the return path.
With such a configuration, at the time of exhaust gas analysis, the diluent gas in which particulate matter is captured from the exhaust gas flows through the connection point of the additional flow path, and contamination of the additional flow path can be reduced. .

Further, an exhaust gas analysis method according to the present invention includes a sampling channel through which exhaust gas from an engine flows; an analyzer connected to the sampling channel for analyzing the exhaust gas; a diluter provided; a return path branched from a branch point set downstream of the diluter in the sampling flow path and connected to the diluter; and a pump for guiding a part of the exhaust gas to the diluter, and an exhaust gas analysis method using a vehicle-mounted exhaust gas analyzer, wherein an additional flow path through which an additional gas from which particulate matter has been removed flows is defined as the return flow path. Alternatively, the method is characterized in that an opening/closing mechanism connected to the sampling channel and provided in the additional channel is closed when the engine is in an ON state and opened when the engine is in an OFF state.
With such an exhaust gas analysis method, it is possible to obtain the same effects as those of the vehicle-mounted exhaust gas analyzer described above.

According to the present invention configured in this manner, it is possible to accurately analyze particulate matter contained in exhaust gases emitted from idling stop vehicles and hybrid vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing how the vehicle-mounted exhaust gas analyzer of the present embodiment is used. The schematic diagram which shows the structure of the vehicle-mounted exhaust-gas analyzer of the same embodiment. FIG. 2 is a schematic diagram showing the principle of the analyzer of the same embodiment; 4 is a flowchart for explaining the operation of the vehicle-mounted exhaust gas analyzer of the embodiment; FIG. 4 is a schematic diagram for explaining the flow rate of gas flowing through the vehicle-mounted exhaust gas analyzer of the same embodiment. The schematic diagram which shows the structure of the vehicle-mounted exhaust-gas analyzer of other embodiment. The schematic diagram which shows the structure of the vehicle-mounted exhaust-gas analyzer of other embodiment. The schematic diagram which shows the structure of the vehicle-mounted exhaust-gas analyzer of other embodiment. The schematic diagram which shows the structure of the vehicle-mounted exhaust-gas analyzer of other embodiment.

DESCRIPTION OF SYMBOLS 100... Vehicle-mounted exhaust gas analyzer 1... Exhaust gas sampling apparatus L1... Sampling flow path L2... Recirculation path X... Analyzer 10... Dilution mechanism MIX... Diluter P... - Pump F1... First filter 11... Flow controller L3... Additional channel V1... Opening/closing mechanism 20... Control device

An embodiment of a vehicle-mounted exhaust gas analyzer according to the present invention will be described below with reference to the drawings.

The vehicle-mounted exhaust gas analyzer 100 of the present embodiment is, as shown in FIG. 1, mounted on a test vehicle VH such as an idling stop vehicle or a hybrid vehicle including a plug-in system.

Specifically, as shown in FIG. 2, the vehicle-mounted exhaust gas analyzer 100 includes an exhaust gas sampling device 1 that samples the exhaust gas emitted from the engine E, and an analyzer X that analyzes the sampled exhaust gas.

The exhaust gas sampling device 1 samples the exhaust gas from the engine E when the engine E is ON (driving state), and stops sampling the exhaust gas when the engine E is OFF (stopped state). Exhaust gas is intermittently sampled. Specifically, the exhaust gas sampling device 1 has an exhaust gas sampling flow path L1 provided with a sampling probe (not shown) at one end thereof. A part or all of the flue gas is sampled. A part of the sampling flow path L1 here is configured by a heating tube unit called a hot hose, and is configured to guide the sampled exhaust gas to the analyzer X while heating or maintaining it at a predetermined temperature. .

The analyzer X is connected to the other end of the sampling flow path L1 and analyzes the particulate matter contained in the exhaust gas. is X.

As an example of the particle counting mechanism, as shown in Fig. 3, one called a condensation nucleus counter (CPC) can be mentioned. This CPC is led to a heating section A1 containing an organic gas such as isopropyl alcohol or butanol, and then cooled in a condensation section A2 so that the organic gas is condensed and attached to the particulate matter in the exhaust gas to grow into a large diameter. , the grown particulate matter is discharged from the slit A3, and the emitted particles are counted by the laser beam R. A critical orifice type constant flow rate means (not shown) is provided downstream of the CPC as a flow rate controller, and a constant flow rate of gas flows through the CPC.

When using such a particle number counter X, it is necessary to dilute the exhaust gas before introducing it to the particle number counter in order to prevent the particulate matter contained in the exhaust gas from aggregating. Note that even in the analyzer X that analyzes components other than the particulate matter contained in the exhaust gas, it may be necessary to dilute the exhaust gas for various reasons.

Therefore, as shown in FIG. 2, the exhaust gas sampling device 1 of this embodiment further includes a dilution mechanism 10 that dilutes the sampled exhaust gas.

The dilution mechanism 10 samples a portion of the exhaust gas flowing through the sampling flow path L1, removes particulate matter (measurement target) contained in the exhaust gas to obtain a diluted gas, and then returns the diluted gas to the sampling flow path L1. , so-called reflux type.

Specifically, the dilution mechanism 10 branches from a branch point L1a set on the sampling flow path L1, merges with a confluence point L1b set on the sampling flow path L1, and dilutes the exhaust gas flowing through the sampling flow path L1. It has a reflux channel L2 that returns a part of the sampling channel L1 from the downstream side to the upstream side. In this embodiment, a diluter MIX is provided at the junction L1b, and a branch point L1a is set between the diluter MIX and the analyzer X. FIG.

The return path L2 is provided with a pump P for circulating the fluid flowing through the return path L2. In order to prevent this, a first return path filter F1 (hereinafter also referred to as first filter F1) that captures particulate matter contained in the exhaust gas may be provided.

Further, downstream of the pump P in the return path L2, that is, between the pump P and the diluter MIX, a flow rate control for controlling the flow rate of the diluent gas flowing from the return path L2 into the diluent MIX is provided. A vessel 11 is provided. The flow controller 11 here is a venturi as a constant flow means, but a mass flow controller, a flow control valve, or the like, for example, may be used.

Furthermore, downstream of the pump P in the return path L2, that is, between the pump P and the diluter MIX, in order to prevent the diluent gas flowing into the diluter MIX from containing particulate matter such as dust from the pump, A second return path filter F2 (hereinafter also referred to as a second filter F2) that traps particulate matter may be provided. The second filter F2 here is provided between the pump P and the flow rate controller 11, but may be provided between the flow rate adjustment device 11 and the diluter MIX.

In addition, a dehumidifier 12 for reducing the humidity of the diluent gas flowing into the diluter MIX may be provided downstream of the pump P in the return path L2, that is, between the pump P and the diluter MIX. . The dehumidifier 12 here is provided between the pump P and the second filter F2. , or may be provided upstream of the pump P.

The vehicle-mounted exhaust gas analyzer 100 of the present embodiment is connected to the upstream of the pump P in the return path L2, the additional flow path L3 through which the additional gas from which the particulate matter has been removed flows, and the additional flow path L3. In this embodiment, the control device 20 for controlling the opening/closing mechanism V1 to open or close is further provided. It should be noted that the "additional gas from which particulate matter has been removed" here is not limited to gas from which particulate matter has been completely (all) removed, and is not limited to gas in which particulate matter is at least less than that in the atmosphere. It is a concept that includes the gas that has been discharged.

In this embodiment, the additional flow path L3 is connected to the upstream side (negative pressure side) of the pump P in the return flow path L2 at the other end. is provided with a return path filter F3 (hereinafter also referred to as a third filter F3) that captures particulate matter contained in the atmosphere. The third filter F3 here is provided upstream of the opening/closing mechanism V1, but may be provided downstream of the opening/closing mechanism V1.

Further, the additional flow path L3 is provided with a flow rate adjustment valve V2 as a flow controller for adjusting the additional flow rate, which is the flow rate of the atmosphere. becomes a constant flow rate. As this flow rate controller, a mass flow controller, a plurality of venturis connected in parallel in a switchable manner, or the like may be used.

The opening/closing mechanism V1 switches between an open state in which the atmosphere after particulate matter has been removed by the third filter F3 is supplied as additional gas from the additional flow path L3 to the return flow path L2, and a closed state in which the supply is stopped. , which is an opening/closing valve such as a solenoid valve that is operated by a control signal from the control device 20 here.

The control device 20 physically includes a CPU, an internal memory, an input/output interface, etc., and the CPU and other components work together based on the gas supply program stored in the internal memory. Accordingly, as shown in FIG. 2, at least the functions of an engine information acquisition section 21, an engine state determination section 22, and an opening/closing control section 23 are exhibited.

In the following, the specific operation of the control device 20 will be described with reference to FIGS.

First, when exhaust gas analysis of the engine E is started, the engine information acquisition unit 21 acquires ON/OFF information, which is information regarding ON/OFF of the engine (S1). This ON/OFF information is information indicating whether the engine E is in the ON state or the OFF state. In this embodiment, for example, the engine state itself (ON state or OFF state) output from the OBD is indicated. is a signal. Other ON/OFF information includes the engine speed output from the OBD, the number of engine rotation signal pulses, the fuel injection amount, etc., and the exhaust gas flow rate, which can be obtained separately from the information from the OBD. Concentrations of various components and the like can be mentioned.

Next, the engine state determination unit 22 determines whether the engine is ON or OFF based on the ON/OFF information acquired by the engine information acquisition unit 21 (S2). Specifically, the engine state determination unit 22 determines that the engine is in the ON state when the engine speed, which is the ON/OFF information, is greater than a predetermined value (for example, zero), and determines that the engine speed is the predetermined value. If it is less than or equal to (for example, zero), it is determined that the engine is in the OFF state. The ON state is the engine state of the test vehicle VH when the engine is driven, and the OFF state is the engine state of the test vehicle VH when idling is stopped or when the test vehicle is electrically driven.

In this embodiment, the opening/closing control section 23 is configured to control the opening/closing mechanism based on the determination result of the engine state determination section 22. Specifically, the engine state determination section 22 turns on the engine. If it is determined that the engine is in the OFF state, the opening/closing mechanism V1 is closed (S3), and if the engine state determination unit 22 determines that the engine is in the OFF state, the opening/closing mechanism V1 is opened (S4).

More specifically, when the engine is switched from the ON state to the OFF state, the opening/closing control unit 23 determines whether the engine state is changed from the ON state to the OFF state at the time of the switching, that is, when the engine state determination unit 22 determines the engine state. The opening/closing mechanism V1 is opened after a predetermined first standby time has elapsed from the point of time when switching to .
This first standby time is the time required for the exhaust gas remaining in the tail pipe of the test vehicle VH or the sampling flow path L1 to be guided to the analyzer X when the engine E is switched from the ON state to the OFF state, or set longer than the time.

Further, when the engine is switched from the OFF state to the ON state, the opening/closing control unit 23 is operated at the time when the engine state is switched, that is, at the time when the engine state determination unit 22 switches from the OFF state to the ON state. The opening/closing mechanism V1 is closed after a predetermined second waiting time has passed since the closing.
This second standby time is the time required for the exhaust gas from the engine E to reach the branch point L1a set on the sampling flow path L1 at the time when the engine E is switched from the OFF state to the ON state, or the time is set shorter than

After that, the control device 20 determines whether or not to end the analysis based on, for example, whether an analysis end signal has been input (S5), and if the analysis is to be continued, returns to S2 to determine the engine state again.

[Closed State of Opening/Closing Mechanism V1]
Next, gas flow when it is determined that the engine is ON and the opening/closing control unit 23 closes the opening/closing mechanism V1 will be described.

As described above, since the flow rate controller is provided downstream of the analyzer X and the return path L2, the flow is led to the analyzer X as shown in FIG. 5(a) when the opening/closing mechanism V1 is closed. A first flow rate A (hereinafter referred to as analysis gas flow rate A) that is the flow rate of the analysis gas, and a second flow rate B (hereinafter referred to as supply flow rate B) that is the flow rate of the gas supplied to the diluter MIX from the return path L2. is a constant flow rate. Note that the supply flow rate B at the time of exhaust gas analysis is the supply flow rate of the diluent gas supplied from the reflux path L2 to the diluter MIX.

Here, as shown in FIG. 5A, the third flow rate C (hereinafter referred to as mixed gas flow rate C), which is the flow rate of the mixed gas composed of the exhaust gas and the dilution gas flowing from the diluter to the branch point L1a, is It is the total flow rate of the gas flow rate A and the supply flow rate B. Since the analysis gas flow rate A and the supply flow rate B are constant as described above, the mixed gas flow rate C is also controlled at a constant flow rate.
A fourth flow rate D (hereinafter referred to as sampling flow rate D), which is the flow rate of the gas sampled from one end of the sampling flow path L1, is the flow rate of the difference between the mixed gas flow rate C and the supply flow rate B. FIG. Since the mixed gas flow rate C and the supply flow rate B are constant, the sampling flow rate D is also controlled to be constant.

For a more specific explanation, consider a case where the analysis gas flow rate A is set to 1 and the diluent gas flow rate B is set to 4, for example, as shown in FIG. 5(a). In this case, the mixed gas flow rate C is 5, which is the sum of the analysis gas flow rate A and the diluent gas flow rate B, and the sampling flow rate D is 1, which is the mixed gas flow rate C minus the diluent gas flow rate B. As a result, the exhaust gas sampled from one end of the sampling flow path L1 is diluted five times by the dilution gas and is led to the analyzer X.

[Open state of opening/closing mechanism V1]
Next, gas flow when it is determined that the engine is in the OFF state and the opening/closing control unit 23 opens the opening/closing mechanism V1 will be described.

As described above, the flow rate controller is provided not only in the downstream of the analyzer X and the return path L2, but also in the additional flow path L3. In addition to the analysis gas flow rate A and the supply flow rate B, a fifth flow rate (hereinafter referred to as The additional flow rate E) also becomes a constant flow rate.

In this embodiment, the flow rate control valve V2, which is a flow rate controller provided in the additional flow path L3, controls the additional flow rate E to be equal to or higher than the analysis gas flow rate A guided to the analyzer X when the engine E is ON. , and is controlled to a first flow rate equal to the analysis gas flow rate A in this embodiment. In addition, in this embodiment, since the air is drawn by the pump P, the additional flow rate E is smaller than the supply flow rate B.

In order to explain more specifically, as shown in FIG. 5B, as in the case of the exhaust gas analysis described above, when the analytical gas flow rate A is set to 1 and the supply flow rate B is set to 4, the additional flow rate E is set to the analytical gas Consider the case where the flow rate is set to 1, which is equal to A.

In this case, the sixth flow rate (hereinafter referred to as the branch flow rate F), which is the flow rate of the gas branched from the branch point L1a of the sampling flow path L1 to the return flow path L2, is 3, which is obtained by subtracting the additional flow rate E from the supply flow rate B. . As a result, the mixed gas flow rate C becomes 4, which is the sum of the analysis gas flow rate A and the branch flow rate F. As a result, the total flow rate (additional flow rate E) of the additional gas (atmosphere) flowing through the additional flow path L3 is guided to the analyzer X, and flows backward from the return flow path L2 toward the test vehicle VH via the diluter MIX. The reverse flow rate G is substantially zero.

In this case, the mixed gas flowing through the return path L2 is composed only of the atmosphere introduced from the additional flow path L3 into the return path L2. Additional gas not included (atmosphere) will be introduced. Note that the gas substantially free of particulate matter here means not only a gas that does not contain any particulate matter, but also a gas containing an extremely small amount of particulate matter that does not affect the measurement results of the analyzer X. It is a concept that also includes gases containing substances.

According to the vehicle-mounted exhaust gas analyzer 100 according to the present embodiment configured as described above, when the engine state determination unit 22 determines that the engine is in the OFF state, the opening/closing control unit 23 switches the additional flow path L3. Since the opening/closing mechanism V1 is opened, the air introduced into the additional flow channel L3 is guided to the analyzer X through the return flow channel L2 in a state where particulate matter is removed by the additional flow channel filter F3.
As a result, when the engine is switched from the ON state to the OFF state, the particulate matter is measured by the analyzer X without stopping the equipment downstream of the diluter MIX, such as the sampling pump of the analyzer X. As a result, it is possible to accurately analyze particulate matter contained in exhaust gases emitted from idling stop vehicles and hybrid vehicles.

Here, when the engine E is switched from the ON state to the OFF state and the opening/closing mechanism V1 is opened, if the atmosphere introduced into the additional flow path L3 flows back into the tail pipe of the test vehicle VH, the tail pipe The concentration of the remaining particulate matter is diluted, which leads to measurement errors when the engine E is subsequently turned on.
On the other hand, in the configuration of the present embodiment, when the opening/closing mechanism V1 is opened by the opening/closing control unit 23, the total flow rate of the atmosphere flowing through the additional flow path L3 is guided to the analyzer X, so that the engine E Even if the ON state is switched to the OFF state and the opening/closing mechanism is opened, the atmosphere introduced into the additional flow path L3 does not flow back to the tail pipe of the test vehicle VH, and the measurement accuracy can be ensured.

Furthermore, when the engine E is switched from the ON state to the OFF state, the opening/closing control unit 23 opens the opening/closing mechanism V1 after the predetermined first waiting time has elapsed from the point of time when the engine E is switched from the ON state to the OFF state. The introduction of air into analyzer X can be stopped until exhaust gas remaining in the tail pipe or sampling flow path is led to analyzer X immediately after switching to the OFF state, further improving measurement accuracy. I can plan.

On the other hand, if the opening/closing mechanism V1 of the additional flow path L3 is closed immediately after the engine is switched from the OFF state to the ON state, for example, the atmosphere in the tail pipe is led to the analyzer X, and particles contained in the atmosphere Induce measurement errors due to substances such as
On the other hand, in the configuration of the present embodiment, when the engine E is switched from the OFF state to the ON state, the opening/closing control unit 23 switches the opening/closing control unit 23 after the predetermined second waiting time has elapsed from the switching time. Since it is configured to close the mechanism V1, the measurement error mentioned above can be reduced.

Moreover, since the additional flow path L3 is connected between the pump P and the first filter F1 in the return flow path L2, particulate matter from the exhaust gas is present at the connection point of the additional flow path L3 during the analysis of the exhaust gas. The captured diluent gas flows, and contamination of the additional flow path L3 can be reduced.

In addition, since the dehumidifier 12 is provided downstream of the pump P in the return path L2, the calibration gas and the purge gas can be dried and flowed, thereby suppressing condensation of moisture contained in these gases. can do.

The present invention is not limited to the above embodiments.

For example, in the above embodiment, the connection point of the additional flow path L3 was between the first filter F1 and the pump P in the above embodiment, but as shown in FIG. It may be between the first filter F1.
Further, as shown in FIG. 6B, the connection point of the additional channel L3 is between the diluter MIX and the branch point L1a in the sampling channel L1 (this is a concept including the diluter MIX and the branch point L1a). may be connected to the additional flow path L3.
Furthermore, as shown in FIG. 7, if a pumping means B is provided in the additional flow path L3, the connection point of the additional flow path L3 may be downstream of the pump P in the return flow path L2.
In addition, as shown in FIG. 8(a), if the pressure-feeding means B is provided in the additional flow path L3, the connection point of the additional flow path L3 can be the upstream side of the diluter MIX in the sampling flow path L1. Alternatively, it may be between the branch point L1a and the analyzer X as shown in FIG. 8(b).

In addition, the vehicle-mounted exhaust gas analyzer 100 according to the present invention does not necessarily require the venturi as the flow controller 11, the second filter F2, the dehumidifier 12, and the flow control valve V2 as the flow controller. Instead, as shown in FIG. 9, one, a plurality, or all of them may be omitted. In this case, the first filter F1 may be provided upstream or downstream of the pump P in the return path L2.

Further, in the above-described embodiment, by providing the third filter F3, which is an additional flow path filter, in the additional flow path L3, the gas from which particulate matter has been removed from the atmosphere is flowed into the additional flow path L3 as an additional gas. For example, a gas from which particulate matter has been removed in advance from a gas source such as a gas cylinder may be supplied as the additional gas to the additional gas flow path L3. In this case, the third filter F is unnecessary.

Furthermore, in the vehicle-mounted exhaust gas analyzer 100 according to the present invention, in the above-described embodiment, the total flow rate of the air flowing through the additional flow path L3 is introduced to the analyzer X in a state where the opening/closing control unit 23 opens the opening/closing mechanism V1. However, when the opening/closing control unit 23 opens the opening/closing mechanism V1, part of the air flowing through the additional flow path L3 flows backward from the diluter MIX through the sampling flow path L1 toward the test vehicle VH. may be configured to
With this, it is possible to more reliably prevent atmospheric particulate matter from being led to the analyzer X when the engine E is stopped, and by controlling the backflow flow rate to a small flow rate, measurement errors can be minimized. can be suppressed.

In addition, the analyzer X is not limited to the CPC for measuring the number of particles of particulate matter contained in the exhaust gas, and may be one that measures the amount of particulate matter (PM).
Also, the analyzer X may analyze various components contained in the exhaust gas, such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOX), and hydrocarbons (HC). However, an analyzer for analyzing these components may be provided separately from the analyzer X of the above embodiment. In this case, if an exhaust gas cleaning device such as a scrubber is provided instead of the first filter F1 or the second filter F2 of the above embodiment, the exhaust gas introduced into the recirculation path L2 is supplied to the diluter MIX as a dilution gas. can do.

In addition, it goes without saying that the present invention is not limited to the above-described embodiments, and that various modifications are possible without departing from the spirit of the present invention.

According to the present invention configured in this manner, it is possible to accurately analyze particulate matter contained in exhaust gases emitted from hybrid vehicles including idling stop vehicles and plug-in type vehicles.

Claims

a sampling channel through which exhaust gas from the engine flows;
an analyzer connected to the sampling channel for analyzing the exhaust gas;
a diluter provided upstream of the analyzer in the sampling channel;
a return path branching from a branch point set between the analyzer and the diluter in the sampling path and joining the diluter;
a pump provided in the return path for guiding a portion of the exhaust gas from the branch point to the diluter;
an additional channel connected to the return channel or the sampling channel and through which an additional gas from which particulate matter has been removed flows;
an opening/closing mechanism provided in the additional channel;
an engine information acquisition unit that acquires ON/OFF information that is information relating to ON/OFF of the engine;
an engine state determination unit that determines whether the engine is in an ON state or an OFF state based on the ON/OFF information;
The opening/closing mechanism is closed when the engine state determination unit determines that the engine is in the ON state, and the opening/closing mechanism is closed when the engine state determination unit determines that the engine is in the OFF state. An in-vehicle exhaust gas analyzer, comprising an opening/closing control unit for opening.
The vehicle-mounted exhaust gas analyzer according to claim 1, wherein the additional channel is provided with an additional channel filter for trapping particulate matter.
3. The vehicle-mounted exhaust gas analyzer according to claim 1 or 2, wherein in a state in which the opening/closing control section opens the opening/closing mechanism, the total flow rate of the additional gas flowing through the additional flow path is guided to the analyzer.
In a state in which the opening/closing control unit closes the opening/closing mechanism, an analysis gas flow rate, which is a flow rate of the gas introduced into the analyzer, is controlled to a first flow rate,
4. Any one of claims 1 to 3, wherein an additional flow rate, which is a flow rate of the additional gas flowing through the additional flow path, is controlled to the first flow rate in a state in which the opening/closing control section opens the opening/closing mechanism. 1. The vehicle-mounted exhaust gas analyzer according to 1 above.
3. The vehicle-mounted exhaust gas analysis according to claim 1, wherein part of the additional gas flowing through the additional flow path flows backward from the diluter through the sampling flow path when the opening/closing control section opens the opening/closing mechanism. Device.
The opening/closing control section is configured to open the opening/closing mechanism after a predetermined first waiting time has elapsed from the point in time when the engine is switched from the ON state to the OFF state. 6. The vehicle-mounted exhaust gas analyzer according to any one of 1 to 5.
The opening/closing control unit is configured to close the opening/closing mechanism when the engine is switched from the OFF state to the ON state after a predetermined second waiting time has elapsed from the time of the switching. 7. The vehicle-mounted exhaust gas analyzer according to any one of 1 to 6.
The analyzer analyzes particulate matter in the exhaust gas,
8. The vehicle-mounted exhaust gas analyzer according to claim 1, wherein said return path is provided with a return path filter for trapping particulate matter.
The vehicle-mounted exhaust gas analyzer according to claim 8, wherein the return path filter is provided upstream of the pump in the return path.
The vehicle-mounted exhaust gas analyzer according to claim 9, wherein the additional flow path is connected between the pump and the return path filter in the return path.
a sampling channel through which exhaust gas from an engine flows; an analyzer connected to the sampling channel for analyzing the exhaust gas; a diluter provided upstream of the analyzer in the sampling channel; a reflux path branched from a branch point set downstream of the diluter and connected to the diluter; and a reflux path provided in the reflux path to guide part of the exhaust gas from the branch point to the diluter. An exhaust gas analysis method using an in-vehicle exhaust gas analyzer comprising a pump,
connecting an additional channel through which an additional gas from which particulate matter has been removed flows to the reflux channel or the sampling channel;
An exhaust gas analyzing method, wherein an opening/closing mechanism provided in the additional flow path is closed when the engine is in an ON state and is opened when the engine is in an OFF state.