JP2003035636A - Method and apparatus for analyzing particulate matter in engine exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for analyzing a particulate matter in an engine exhaust gas whereby a minute amount of the particulate matter in the engine exhaust gas can be highly accurately measured by particle size. SOLUTION: The exhaust gas G flowing in an exhaust pipe 5 connected to an engine 4 is diluted in a dilution pipe 6 by a dilution air A, and the particulate matter 21 included in the diluted exhaust gas is trapped by particle size by a plurality of particulate matter-trapping members 16a-16b. Each component of SOF, sulfate and soot in the particulate matter trapped by particle size by the plurality of the trapping members 16a-16b is analyzed, so that each component in the particulate matter included in the exhaust gas is analyzed by particle size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to particulate matter (particulate matter, hereinafter referred to as PM) contained in gas discharged from, for example, a diesel engine.
Analysis method and device.

[0002]

2. Description of the Related Art As a method of measuring PM contained in exhaust gas of a diesel engine, high temperature exhaust gas discharged from a diesel engine is diluted with clean air, and the diluted exhaust gas is sucked in a fixed volume to capture PM with a filter. A filter weight method is generally known in which the filter is collected, weighed with a precision balance or the like, and quantitatively analyzed based on the weight difference from the filter before PM collection.

However, in the above-described filter weight method, the water adsorbed on the filter has a great influence as a measurement error, so that a constant temperature / constant humidity treatment is required to keep the water content in the filter constant before and after the collection. Also, low concentration PM
When measuring the exhaust gas of, for example, 0.1 mg of PM collected on a 200 mg filter needs to be accurately weighed, and the measurement error of the weight of the filter itself greatly affects the measurement error of the PM weight. There is such a problem.

On the other hand, as disclosed in Japanese Examined Patent Publication No. 7-58264, a method of heating the filter trapping PM stepwise in a heating furnace to oxidize PM and measure it with a gas analyzer There is.

However, most of PM is an inorganic carbon called soot (hereinafter referred to as soot) and SOF (Soluble Organic Fr).
A hydrocarbon called "action" (hereinafter referred to as SOF) and a sulfate hydrate called "sulfate" (hereinafter referred to as "SOF")
It is difficult to separate the high-boiling point SOF and reduce the sulfate in an oxidizing atmosphere by the method described in the above publication, and therefore, the soot occupying most of PM, It was difficult to separate SOF and sulfate individually and measure their concentration or weight.

As a solution to the above-mentioned drawbacks of the prior art, the applicant of the present application has filed a patent application for "Analysis method and apparatus for particulate matter in engine exhaust gas" on March 29, 2000. (Japanese Patent Application No. 2000-92283). The content of the invention of this patent application is that a filter that collects PM contained in engine exhaust gas is provided in a heating furnace, and first, the filter is heated at a predetermined temperature while flowing an inert gas into the heating furnace to remove PM in PM. The SOF and the sulfate are vaporized, and the vaporized SOF is oxidized to CO ₂ , while the vaporized sulfate is reduced to SO ₂ , and the CO ₂ and SO ₂
It was analyzed by gas analysis unit, then, the heating furnace and heating the filter while feeding oxygen into oxidized remaining PM on the filter to generate CO _2, the CO ₂ gas analyzer It is to analyze.

According to the above-described method and apparatus for analyzing particulate matter in engine exhaust gas, SOF, sulfate and soot in PM contained in engine exhaust gas can be individually and easily separated with a small amount even if they are minute amounts. SPM, sulfate, and soot, which can be measured well, and which cannot be measured by the conventional filter weight method or the method described in Japanese Patent Publication No. 7-58264 mentioned at the beginning, account for most of PM. It is possible to separately measure the concentration or weight of each, and it is also possible to accurately measure low-concentration PM.

[0008]

The particle size of PM in the engine exhaust gas varies depending on various conditions such as the temperature in the engine cylinder, the degree of compression of air, and the amount of light oil dropped. On the other hand, in recent exhaust gas measurement of low-emission vehicles, it is required to measure PM with high accuracy in a very low concentration range. In this case, the amount of SOF, sulfate, and soot for each particle size of PM is required. It is also required to ask.

However, conventionally, as a filter for collecting PM, only one filter which can collect 95% or more of 0.3 μm in diameter is used, and the filter is classified by particle size. It was not possible to determine the amount of SOF, sulphate and soot in PM.

The present invention has been made with the above matters in mind, and its object is to trace a minute amount of PM in engine exhaust gas.
It is an object of the present invention to provide a method and an apparatus for analyzing PM in engine exhaust gas, which can measure each component with high accuracy by particle size.

[0011]

In order to achieve the above object, the method for analyzing PM in engine exhaust gas according to the present invention comprises:
The exhaust gas flowing through the exhaust pipe connected to the engine is diluted with the dilution air in the dilution pipe, and the particulate matter contained in the diluted exhaust gas is collected by a plurality of particulate matter collecting members according to the particle size. A particulate matter contained in the exhaust gas for each particle size by analyzing each component of SOF, sulfate and soot in the particulate matter collected by the plurality of particulate matter collection members according to the particle size It is characterized in that each of the above components is analyzed.

Further, PM in engine exhaust gas of the present invention
The analyzer described above introduces the gas sampling means for collecting and diluting the exhaust gas flowing through the exhaust pipe connected to the engine, and introducing the diluted exhaust gas in this gas sampling means, and also the particulate matter contained in the diluted exhaust gas Particle-size-specific particulate matter collection means having a plurality of particulate matter collection members that are collected according to diameter, and SO in the particulate matter collected by the particle size by the plurality of particulate matter collection members
The present invention is characterized by comprising a particulate matter analysis means for analyzing each of the components in the particulate matter contained in the exhaust gas for each particle size by analyzing each component of F, sulfate and soot.

As a method for analyzing each component of SOF, sulfate and soot in PM collected by the plurality of PM collecting members according to particle size, for example, the PM collecting members are individually heated in a heating furnace. First, the PM trapping member is heated at a predetermined temperature while flowing an inert gas into the heating furnace to vaporize the SOF and the sulfate in the PM, and the vaporized SOF is oxidized to CO ₂ while being vaporized. The sulfate is reduced to SO ₂ and the CO ₂ and S
O ₂ is analyzed by the gas analyzer, and then the PM trapping member is heated while flowing oxygen into the heating furnace to oxidize the soot remaining on the PM trapping member to generate CO ₂ ,
A method of analyzing ₂ in the gas analysis unit can be adopted.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below with reference to the drawings. 1 to 4 show a first embodiment of the present invention. First, FIG. 1 schematically shows one configuration example of an analyzer used in a method for analyzing PM in engine exhaust gas of the present invention (hereinafter, simply referred to as an analysis method). It has a gas sampling means 1 for sampling and diluting, and a plurality of PM collecting members for introducing the exhaust gas diluted in the gas sampling means 1 and collecting PM contained in the diluted exhaust gas for each particle size. PM collecting means 2 and the P
A PM analysis means 3 for analyzing PM collected by the M collection member is provided.

First, the gas sampling means 1 and the PM collecting means 2 are constructed, for example, as follows.
That is, in FIG. 1, reference numeral 4 denotes a diesel engine mounted in an automobile, for example. An exhaust pipe 5 is connected to the engine 4, and a downstream end 5a thereof is connected to a diluting pipe line (also referred to as a diluting tunnel) 6. This dilution line 6
Is used to dilute the entire amount of the engine exhaust gas G discharged into the exhaust pipe 5 and introduced into the diluting pipe line 6 with clean air A, and to keep the flowing gas at a constant flow rate. The air introduction part 6a provided with the filter 7
Are formed, and CFV (Cr
An initial flow venturi) 8 and a suction pump 9 are provided so that the exhaust gas G from the engine 4 can flow at a constant flow rate.

Reference numeral 10 is a sample gas introduction flow passage connected to the dilution pipe 6 at a point slightly upstream of the CFV 8, and its probe 10a is inserted and connected in the dilution pipe 6. A part of the exhaust gas G diluted with the air A in the dilution pipe 6 is introduced as the sample gas S. The downstream side of the sample gas introduction flow channel 10 is branched into two flow channels 11 and 12,
12 is provided with filter devices 13 and 14 as particle size-specific PM collecting means 2 for collecting PM contained in the sample gas S by particle size, and one flow path 11 is used for collecting PM. Of the sample gas S, and the other channel 12 is a bypass channel for flowing the sample gas S when PM is not collected. Note that the filter devices 13 and 14 have the same configuration (this configuration will be described later), and among these filter devices 13 and 14, one 13 is a measurement filter device and the other 14 is a dummy filter device. Is.

The filter devices 13 and 14 are constructed, for example, as shown in FIG. That is, in this figure, reference numeral 15 denotes a filter case, in which a plurality (for example, four) of filters 16a to 16d (collectively referred to as filters 16) are arranged in series at appropriate intervals. Case body 17 that can be stored
And a cover body 18 which is detachably connectable to the case body 17, and flanges 17a, 18a are provided on the side of the case body 17 and the cover body 18 which are separated and joined.
Is provided, and gas circulation holes 19 and 20 are formed on the opposite sides of the case body 17 and the cover body 18, respectively.

In the case body 17, PM is
Filters 16a to 16d are provided as PM collecting members for collecting 21 according to their particle size. The filters 16a to 16d are made of a material having a small amount of impurities, for example, quartz, and the coarseness of the mesh in them is, for example, the filter 16a is the coarsest, and the filters 16b and 16c are finer in this order and the filter 16d is the finest. And the coarsest filter 16a is located at the most upstream position of the case body 17 (on the side where the sample gas S flows).
The filters 16b and 16c are arranged on the downstream side in this order, and the finest filter 16d is provided on the most downstream side (the side on which the sample gas S flows out).

The filter devices 13 and 14 having the above structure
The cover body 17 is located on the upstream side, and the case body 16 is
The sample gas flow path 11 and the bypass
It is arranged in each of the pass channels 12. Therefore, Sun
Flow into the filter device 13 provided in the pull gas flow path 11.
The entered sample gas S is filtered by the filters 16a to 16d. In order
The next pass, but the coarseness of each filter 16a-16d
Therefore, PM21 in the sample gas S has a large particle size.
The filters are sequentially collected from the filters 16a to 16d.

The coarseness of the mesh in the filters 16a to 16d is appropriately set depending on how much particles of PM21 are collected. In addition, the filter 16
It is needless to say that the number of sheets installed is not limited to 4 and may be set to an appropriate number of 2 or more.

Referring again to FIG. 1, reference numeral 22 denotes a three-way solenoid valve as a flow path switching means provided on the downstream side of the sample gas flow path 11 and the bypass flow path 12, the downstream side of which is connected to the gas flow path 23. In the gas flow path 23, a suction pump, such as a roots blower pump 24, whose suction capacity can be changed by controlling the number of revolutions, and a flow meter with high measurement accuracy,
For example, a venturi meter 25 is provided in this order.

Next, the structure of the PM analysis means 3 is shown in FIG.
Describing with reference to FIG. 3, 31 is a heating furnace for heating the filter 16 that traps PM21 contained in the engine exhaust gas.
Equipped with 2. The heating state of the heating heater 32 is controlled by a temperature adjusting mechanism (not shown), so that the temperature in the heating furnace 31 is set to an arbitrary predetermined temperature.

Reference numeral 33 is a gas supply portion for selectively supplying an inert gas (for example, nitrogen gas) or oxygen to the heating furnace 31, and is a flow rate control device such as a mass flow controller having functions of flow rate measurement and flow rate control. A nitrogen gas supply passage 36 and an oxygen supply passage 37, which are provided with 34 and 35, respectively,
The three-way solenoid valve 39 is connected to the downstream side of these supply paths 36 and 37 and the connection flow path 38 to the heating furnace 31, respectively.

Reference numeral 40 denotes a gas flow path through which gas generated in the heating furnace 31 flows, and its downstream side is branched into two mutually parallel gas flow paths 41 and 42. Then, on the downstream side of these gas flow paths 41, 42, the oxidation / reduction processing unit 43 is provided.
And the gas analysis unit 44 is provided in series in this order.

More specifically, one of the gas flow paths 41 has
A flow meter 45 such as a mass flow meter, an oxidation catalyst such as CuO, for example, is provided, and an oxidation treatment section 43A and a CO ₂ analyzer 44A, which are connected to an oxygen supply path 46 for supplying oxygen, are provided in this order. Then, in the other gas flow path 42, a flow meter 47 similar to the flow meter 45,
For example, a reduction processing unit 43B provided with a reduction catalyst such as carbon and an SO ₂ analyzer 44B are provided in this order. The CO ₂ analyzer 44A and SO ₂ analyzer 44B used here are, for example, a non-dispersive infrared gas analyzer (ND).
IR gas analyzer). That is, the oxidation / reduction processing unit 4
3, the oxidation processing unit 43A and the reduction processing unit 43B are arranged in parallel with each other, and in the gas analysis unit 44, the CO ₂ analyzer 44A and the SO ₂ analyzer 44B are arranged in parallel with each other. .

Although not shown, the gas flow paths 38,
The parts up to the gas analysis part 44 (including the oxidation processing part 43A and the reduction processing part 43B) of 40 and the gas flow paths 41, 42 are configured so that they can be heated and kept at a proper temperature by a heater, for example. There is. This is to prevent changes in the components contained in the gas generated in the heating furnace 31 and to ensure that the oxidation and reduction processes are performed.

Reference numeral 48 indicates that the calculation is performed on the basis of signals (flow rate signal Q, concentration signal C, etc.) from various parts of the apparatus,
An arithmetic control unit that sends a control signal to each unit of the device based on the arithmetic result, and is composed of, for example, a personal computer.

Next, the analysis method of the present invention will be described with reference to FIG.
It will be explained with reference to also. FIG. 4 shows changes with time in the atmosphere in the heating furnace 31 and the heating temperature of the filter 16, and the output state in each atmosphere. Code a,
c is a CO ₂ concentration output, and b is an SO ₂ concentration output.

First, the procedure for collecting PM using the gas sampling means 1 and the PM collecting means 2 shown in FIG. 1 will be described. The filter devices 13 and 14 incorporating a plurality of filters 16a to 16d are used as flow paths. Attach to 11 and 12. The exhaust gas G emitted from the engine 4 is
After passing through the exhaust pipe 5, it enters the diluting pipe 6, and is diluted with the clean air A. The diluted exhaust gas G is sampled at a constant flow rate, enters the sample gas introduction flow path 10 as the sample gas S, is guided to the sample gas flow path 11, and passes through the filter device 13. In this filter device 13, a plurality of filters 16a to 16d having different mesh roughness are sequentially arranged in series from the coarse mesh to the fine mesh, so that the PM21 contained in the sample gas S is
The filters having the largest diameter are collected by the filters 16a to 16d in order.

When the predetermined sampling is completed, the filter device 13 is opened and the filters 16a to 16d are taken out.

The PM 21 collected by the filters 16a to 16d is analyzed by the PM analysis means 3 as follows. For example, the filter 16a that collects PM21 having the largest particles is housed in the heating furnace 31 whose inside is heated to 1000 ° C. in advance. Then, the solenoid valve 39 of the gas supply unit 33 is operated to connect the nitrogen gas supply passage 36 to the heating furnace 31, and the flow rate control device 34
Nitrogen gas is supplied into the heating furnace 31 via. The flow rate of the nitrogen gas at this time is measured by the flow rate control device 34, and the result is sent to the personal computer 48 as a flow rate signal Q.

In the heating furnace 31, the filter 16a is heated at 1000 ° C. in a nitrogen gas atmosphere, so that the SOF and the sulfate in the PM 21 trapped in the filter 16a are gasified, and these are gasified together with the nitrogen gas. It flows out into the gas flow path 40.

The gas (containing gasified SOF, sulfate and other generated gas) flowing out to the gas flow passage 40 flows through the gas flow passages 41 and 42 in a divided state. Then, the gas flowing through one of the gas flow paths 41 passes through the flow meter 45, and the oxidation / reduction processing unit 43A of the oxidation / reduction processing unit 43
Flow into. Oxygen is supplied to the oxidation treatment section 43A, and SOF of the gasified SOF and the sulfate is oxidized by the oxidation catalyst and oxygen, and CO
₂ and H ₂ O, and gas analyzer 4 together with other gases
No. 4 is sent to the CO ₂ analyzer 44A, and the CO ₂ concentration is measured. In addition, the gas flowing through the other gas flow path 42 passes through the flow meter 47 and the reduction processing unit 43B of the oxidation / reduction processing unit 43.
Of the gasified SOF and sulfate, the sulfate is reduced by the reduction catalyst, and SO
It becomes ₂ and is sent to the SO ₂ analyzer 44B of the gas analysis unit 44 together with other gas, and the SO ₂ concentration is measured.

Then, the gas analyzer 44 outputs CO ₂ concentration and SO ₂ concentration signals having the shapes shown by reference characters a and b in FIG. 4, for example.
8 is input. Since a signal indicating the flow rate of nitrogen gas is input to the personal computer 48, the nitrogen gas flow rate and C
Based on the O ₂ concentration and the SO ₂ concentration, the filter 15
a The weights of the SOF and the sulfate in the PM21 collected in the above are obtained respectively.

Next, the solenoid valve 39 of the gas supply unit 33.
The oxygen supply path 37 is communicated with the heating furnace 31, and oxygen is supplied into the heating furnace 31 via the flow rate control device 35. The flow rate of oxygen at this time is measured by the flow control device 35, and the result is sent to the personal computer 48 as a flow signal Q.
Sent as.

In the heating furnace 31, the filter 16a is heated at 1000 ° C. in an oxygen atmosphere, so that the soot remaining in the filter 16a burns (oxidizes), and CO ₂ and CO (which are almost trace amounts). )
Are generated, and these flow out to the gas flow path 40 together with oxygen.

The gas flowing out to the gas flow passage 40 (containing CO ₂ and CO generated by the combustion and other generated gas) branches into the gas flow passages 41 and 42.
Then, the gas flowing through one of the gas flow paths 41 is the flow meter 4
After that, it flows into the oxidation / reduction processing section 43A of the oxidation / reduction processing section 43. Since oxygen is supplied to the oxidation treatment section 43A, CO contained in the gas is oxidized to form C
It becomes O ₂ , is mixed with CO _{2 in} the gas, and is sent to the CO ₂ analyzer 44A of the gas analysis unit 44 together with other gas,
The CO ₂ concentration is measured. In addition, the gas flowing through the other gas flow path 42 passes through the flow meter 47 and is passed through the oxidation / reduction processing unit 43.
Of the SO ₂ analyzer 44B of the gas analyzer 44 without any treatment.
Sent to and discarded without measuring the concentration.

Then, from the gas analysis section 44, as shown in FIG.
At, a signal representing the CO ₂ concentration having a shape as indicated by the symbol c is output and input to the personal computer 48. Since the signal indicating the oxygen flow rate is input to the personal computer 48, the weight of the soot in the PM 21 collected by the filter 16a is obtained based on the oxygen flow rate and the CO ₂ concentration.

In this embodiment, the filter 16
Since the exhaust gas G from the engine 4 is diluted when the PM 21 is collected by a, the exhaust gas G is calculated by taking the dilution rate into consideration and performing a calculation based on the weights of the soot, SOF, and sulfate. SO in
The weights of F, sulfate and soot can be obtained.

PM2 in the other filters 16b to 16d
The quantitative analysis of No. 1 may be sequentially performed similarly to the quantitative analysis of PM21 in the filter 16a. In this way, the filter 16 that collects PM21 having different particle diameters
By quantitatively analyzing a to 16d by the PM analysis means 3, the PM 21 contained in a small amount in the exhaust gas G can be quantitatively analyzed with high accuracy according to its particle size.

The present invention can be implemented by being modified in various ways. For example, in order to collect PM21 according to its particle size, a plurality of filters 16a to 16d having different coarseness of meshes are used. PM collection means 5 according to particle size as shown in 5
You may use 0.

That is, in FIG. 5 showing the second embodiment, 51 is, for example, an elongated housing, and a gas introducing portion 52 is formed on one end side thereof and a gas outlet portion 53 is formed on the other end side thereof. The flow passages 54a to 54 are provided between the gas introduction part 52 and the gas discharge part 53 inside the housing 51.
A plurality of spaces 55a to 55d are formed via e. The spaces 55a to 55d have the same shape and the same size,
The PM trapping members 56a to 56 of the same shape made of a quartz plate having an inner diameter smaller than the inner diameters of the spaces 55a to 55d and having an appropriate thickness.
d (generally denoted by 56) is provided. The inner diameters of the flow paths 54a to 54e are the spaces 55a to 55e.
The flow path 54a on the most upstream side, which is smaller than the maximum diameter of d
Is the largest, and the channels 54b, 54c, and 54d become thinner in this order, and the most downstream channel 54e becomes the thinnest.

Channels 54a to 54 in the housing 51
The dimensions of e, the spaces 55a to 55d, and the like are PM2 to be collected.
It is needless to say that it is appropriately set depending on how the particle size of 1 is divided and collected.

When the exhaust gas G containing PM21 is sucked into the PM trapping device 50 for each particle size having the above-described structure at a constant flow rate, the exhaust gas G is allowed to flow into the spaces 55a to 55d.
It passes while avoiding the collection members 56a to 56d, and also passes through the flow paths 54a to 54e. In this case, the velocity of the exhaust gas G in the flow channels 54a to 54e is the same as that of the flow channel 54a.
a is the slowest, and is the flow path 54b, 54c, 54
It becomes faster in the order of d and 54e. Therefore, of the PM21 contained in the exhaust gas G entering the uppermost space 55a,
The large diameter particles are collected by the PM collecting member 56a due to the low flow velocity. Hereinafter, each PM collection member 56b-56
The diameter of the PM 21 collected in d becomes small, and the PM 21 having the smallest diameter is collected in the PM collecting member 56d.

As described above, the PM collecting members 56b to 56d, which have collected the PM 21 according to the particle size, are sequentially arranged in FIG.
By applying the PM analysis means 3 shown in FIG.
Quantitative analysis by particle size of M21 can be performed.

By the way, the gas sampling means 1 shown in FIG. 1 dilutes all the exhaust gas G from the engine 4,
After that, although a part of this diluted exhaust gas is sampled as the sample gas S, the present invention collects a part of the exhaust gas G from the engine 4 and then dilutes all the collected exhaust gas to obtain the sample gas S. It can also be applied to the gas sampling means of the partial sampling total amount dilution method in which all of the diluted exhaust gas is the sample gas S.

FIG. 6 schematically shows an example of the structure of the gas sampling means 60 of the partial sampling total dilution type. In the third embodiment, 61 is the engine 4
An exhaust pipe 62 connected to is a probe inserted into and connected to the exhaust pipe 61 for collecting and introducing a part of the exhaust gas G flowing through the exhaust pipe 61. Reference numeral 63 is a diluting pipe, and the downstream side of the probe 62 is inserted and connected, and the diluting air introducing pipe 64 for introducing the diluting air A is connected to the upstream side thereof. The downstream side of the dilution pipe 63 is connected to the sample gas introduction flow passage 65 so that all the exhaust gas diluted in the dilution pipe 63 flows into the sample gas introduction flow passage 65. .

By the way, in the embodiment shown in FIG. 3, the gas passage 40 provided on the downstream side of the heating furnace 31 is divided into two gas passages 41 and 42, and one of the gas passages 41 is provided with an oxidation treatment section. 43A and CO ₂ analyzer 44A are provided, and the reduction processing section 43B and SO ₂ analyzer 44B are provided in the other gas flow path 42. Therefore, the gas generated in the heating furnace 31 becomes ½ each, and The output signal obtained at this time is inevitably small. A configuration that solves this point will be described as a fourth embodiment with reference to FIG.

In FIG. 7, reference numeral 71 denotes a flow meter provided in the gas flow passage 40 on the downstream side of the heating furnace 2, which is similar to the flow meters 45 and 47 in the first embodiment. Then, in the oxidation / reduction processing unit 43 provided on the downstream side of the flow meter 71, an oxidation / reduction catalyst containing platinum (Pt) as a main component is provided and an oxygen supply passage 46 is connected. Further, the gas analysis section 44 provided on the downstream side of the oxidation / reduction processing section 43 includes a CO ₂ analyzer 44A and an SO ₂ analyzer.
_Two analyzers 44B are arranged in series.

The PM analysis method using the gas analyzer shown in FIG. 7 will be described. First, the exhaust gas G from the engine 4 is sampled at a constant flow rate using the gas sampling means 1 shown in FIG. The PM 21 in the exhaust gas G is collected by the filters 16a to 16d.

Then, for example, the filter 16a in which the PM 21 is collected is housed in the heating furnace 31 whose inside is heated to 1000 ° C. in advance. And first,
The electromagnetic valve 39 of the gas supply unit 33 is operated to connect the nitrogen gas supply passage 36 to the heating furnace 31, and nitrogen gas is supplied into the heating furnace 31 via the flow rate control device 34. The flow rate of the nitrogen gas at this time is measured by the flow rate control device 34,
The result is sent to the personal computer 48 as a flow rate signal Q.

In the heating furnace 31, the filter 16a is heated at 1000 ° C. in a nitrogen gas atmosphere, so that the S in the PM collected by the filter 16a is heated.
The OF and the sulphate are gasified, and these gas and the other generated gas and the nitrogen gas flow out to the gas passage 40.

The gas (containing the gasified SOF and sulfate) flowing out to the gas flow path 40 flows into the oxidation / reduction processing section 43 via the flow meter 71. Since oxygen is supplied to the oxidation / reduction processing unit 43, SOF of gasified SOF and sulfate is oxidized by the oxidation / reduction catalyst and oxygen to become CO ₂ and H ₂ O, while The sulfate is reduced to SO ₂ by the oxidation / reduction catalyst. These CO
₂ , H ₂ O and SO ₂ are in that state,
Sent to 4.

The concentration of CO _{2 in} the gas flowing into the gas analyzer 44 is first measured by the CO ₂ analyzer 44A, and then S ₂ is measured by the SO ₂ analyzer 44B.
The O ₂ concentration is measured, the CO ₂ concentration and SO ₂ concentration signals are output from the gas analysis unit 44, and these are output to the personal computer 48.
Entered in. Since a signal indicating the flow rate of nitrogen gas is input to the personal computer 48, this nitrogen gas flow rate and CO
_The filter 16a is based on the ₂ concentration and the SO ₂ concentration.
The weights of SOF and sulfate in the PM collected in are obtained.

Next, the solenoid valve 39 of the gas supply unit 33.
Is switched to connect the oxygen supply path 47 to the heating furnace 31, and oxygen is supplied into the heating furnace 31 via the flow rate control device 35. The flow rate of oxygen at this time is measured by the flow control device 35, and the result is sent to the personal computer 48 as a flow signal.

In the heating furnace 31, the filter 16a is heated at 1000 ° C. in an oxygen atmosphere, so that the soot remaining in the filter 16a burns (oxidizes), and CO ₂ and CO (which are almost trace amounts). )
Are generated, and these flow out to the gas flow path 40 together with oxygen.

The gas (including CO ₂ and CO produced by the combustion) flowing out to the gas flow path 54 is
It flows into the oxidation / reduction processing unit 44 via the flow meter 71. Since oxygen is supplied to the oxidation / reduction processing unit 44, CO contained in the gas is oxidized to generate CO ₂
And sent to the CO ₂ analyzer 44A of the gas analysis unit 44 together with the CO _{2 in the} gas, and the CO ₂ concentration is measured.
This density signal is input to the personal computer 48. And C
The gas leaving the O ₂ analyzer 44A is sent to the SO ₂ analyzer 44B, but is discarded without measuring the concentration.

Since a signal indicating the flow rate of oxygen is input to the personal computer 48, the oxygen gas flow rate and the C
Based on the O ₂ concentration, the P collected in the filter 16a
The weight of soot in M is determined. Needless to say, the other filters 16b to 16d are also sequentially analyzed by the above procedure.

As described above, also according to the fourth embodiment, the SOF, the sulfate and the soot in the PM 21 contained in the exhaust gas G of the engine 4 can be individually separated and simply and accurately measured according to the particle size. it can.

In addition, in the above-mentioned fourth embodiment
The gas generated in the heating furnace 31 in half
In addition, in the gas analysis unit 44, they are arranged in series.
CO ₂Analyzer 44A and SO₂Analyzer 44B sequentially
Since it is designed to pass through, CO₂And SO₂Concentration of
A large signal can be obtained. Also, the overall structure of the device
There is also an advantage that the composition is simple.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, as the heating furnace 31, a high frequency heating furnace or an infrared image furnace may be used. Then, as the inert gas supplied to the heating furnace 31, other than nitrogen gas, an appropriate gas such as argon gas may be used.

Further, in a nitrogen gas atmosphere, particulate matter
It occurs when the material collecting members 16 and 56 are heated at a predetermined temperature.
The gasified SOF is oxidized by the oxidation treatment section 43A or
-When oxidized in the reduction processing unit 43, CO₂With
To H₂O occurs, but this H ₂O is CO₂And SO₂of
May interfere with the measurement. Therefore, the gas analysis section
Or remove it before feeding it to
CO provided in the gas analysis unit 44₂44A analyzer
SO₂As the analyzer 44B, it can compensate the influence of interference components.
A gas analyzer having such a configuration may be used.

Further, as the gas analyzer provided in the gas analysis unit 44, a gas analyzer (FTIR gas analyzer) using a Fourier transform infrared spectrophotometer may be provided.
This FTIR gas analyzer is capable of simultaneously measuring the concentrations of CO ₂ and SO ₂ by itself,
Since NO _x, etc. can also be measured, SO contained in PM
Not only F, sulfate and soot but also the concentrations of other components can be measured all at once. A mass spectrometer (mass spectrometer) may be used as the gas analyzer provided in the gas analyzer 44. Even in this mass spectrometer, CO ₂ , SO ₂ , N
It is possible to simultaneously measure O _{x and the} like. Therefore, when these FTIR gas analyzers or mass spectrometers are provided in the gas analyzer 44, the configuration of the entire device is simplified.

[0064]

As described above, according to the present invention, a very small amount of PM in engine exhaust gas can be measured with high accuracy by particle size, and SO in each particle size range can be measured.
F, sulfate and soot can be measured easily and accurately. In particular, when the PM analysis means described above is used, SOF, sulfate, and soot, which account for most of PM that cannot be measured by the conventional filter weight method or the method disclosed in the above-mentioned publication, are individually separated. The concentration or weight can be measured separately.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a gas analyzer used in an analysis method of the present invention.

FIG. 2 is a vertical sectional view schematically showing an example of a particulate matter collecting means.

FIG. 3 is a diagram schematically showing an example of a particulate matter analysis means.

FIG. 4 is a diagram for explaining the operation of the present invention.

FIG. 5 is a vertical cross-sectional view schematically showing another example of the particulate matter collecting means.

FIG. 6 is a diagram schematically showing another example of gas sampling means.

FIG. 7 is a diagram schematically showing another example of the particulate matter analysis means.

[Explanation of Codes] 1 ... Gas sampling means, 2 ... Particle size-specific particulate matter collection means, 3 ... Particulate matter analysis means, 4 ... Engine, 5 ... Exhaust pipe, 6 ... Diluting pipeline, 13, 14 ... Particle collecting means by particle size, 16, 16a to 16d ... Particulate collecting member, 21 ... Particulate material, 50 ... Particle collecting means by particle size, 56a to 56d ... Particulate material collecting Collection member, 60 ... Gas sampling means, 61 ... Exhaust pipe, 63 ... Dilution pipe line,
A ... Diluting air, G ... Exhaust gas.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G052 AA02 AB06 AB08 AD04 AD24                       AD52 BA22 EB11 FD01 GA11                       HA15 HC28                 2G059 AA01 BB01 CC04 CC06 DD04                       DD12 DD16 EE01 HH01

Claims (2)

[Claims] 1. An exhaust gas flowing through an exhaust pipe connected to an engine is diluted with a diluting air in a diluting pipe, and a plurality of particulate substances contained in the diluted exhaust gas are collected according to a particle size. SO in the particulate matter collected by the member and collected by the plurality of particulate matter collecting members according to the particle size.
Particulate matter in engine exhaust gas, characterized in that by analyzing each component of F, sulphate and soot, the respective components in the particulate matter contained in the exhaust gas are analyzed for each particle size. Analysis method. 2. A gas sampling means for collecting and diluting exhaust gas flowing through an exhaust pipe connected to an engine, and introducing the exhaust gas diluted by the gas sampling means, and for particulate matter contained in the diluted exhaust gas. Particle-size-specific particulate matter collection means having a plurality of particulate matter collection members that are collected according to diameter, and SO in the particulate matter collected by the particle size by the plurality of particulate matter collection members
An engine exhaust gas, comprising particulate matter analysis means for analyzing each of the components of F, sulfate and soot by analyzing each component of the particulate matter contained in the exhaust gas for each particle size. Analytical device for particulate matter.