WO2007119872A1

WO2007119872A1 - Exhaust gas analyzer

Info

Publication number: WO2007119872A1
Application number: PCT/JP2007/058479
Authority: WO
Inventors: Tokio Okano; Katsutoshi Goto; Masahiro Yamakage; Tomoyasu Iwase; Yoshihiro Deguchi; Shinya Ishii; Satoshi Tsuzuki; Eiji Kato
Original assignee: Toyota Jidosha Kabushiki Kaisha; Mitsubishi Heavy Industries, Ltd.
Priority date: 2006-04-14
Filing date: 2007-04-12
Publication date: 2007-10-25
Also published as: JP2007285826A

Abstract

An exhaust gas analyzer that applies a laser beam to exhaust gas discharged from an internal combustion engine, receives the laser beam passed through the exhaust gas, and measures and analyzes, based on the received laser beam, the concentration and temperature of components contained in the exhausted gas. The gas analyzer has a sensor base (20) installed in a route where the exhaust gas flows and having an exhaust gas passage hole where the exhaust gas passes. The sensor base has an optical fiber (25) for emitting the laser beam, a detector (27) for receiving the laser beam, a sensor hole (23) for guiding the laser beam emitted from an irradiation section to the exhaust gas passage hole, and a sensor hole (24) for guiding the laser beam, having passed through the exhaust gas, to the detector (27). At least a portion of the sensor holes (23, 24) is filled with a glass body (40) which is a light transmitting member.

Description

Technical description

The present invention relates to an analyzer for exhaust gas discharged from an internal combustion engine such as an automobile, and more particularly, based on the light intensity of laser light that is irradiated with laser light to the exhaust gas in a path through which the exhaust gas flows and that has passed through the exhaust gas. The present invention relates to an exhaust gas analyzer that measures and analyzes the concentration and temperature of gas components in exhaust gas. Background art

Conventionally, this type of exhaust gas analyzer is an in-vehicle type equipped with an NDIR (non-dispersive infrared spectroscopy) type gas analyzer for continuously measuring the HC concentration in the exhaust gas flowing through the exhaust pipe connected to the engine. There is an HC measuring device. In this measuring device, the gas analyzer of the NDIR gas analyzer supplies the sample gas into the cell, irradiates the cell with an infrared light source, and rotates the optical tipper at a predetermined cycle. When the gas is supplied to the cell, an AC signal is output from the detector as an AC signal and a comparison signal corresponding to the concentrations of HC and H ₂ 0. From these signals, HC and H in which it is possible to obtain a concentration of ₂ 0 (e.g., see Patent Document 1).

In addition, as another device for analyzing exhaust gas, the exhaust gas is irradiated with laser light, the laser light transmitted through the exhaust gas is received, the light intensity is measured, and the light intensity attenuated by passing through the exhaust gas is measured from the exhaust gas. There are exhaust gas analyzers that measure the concentration and temperature of certain components. In such an exhaust gas analyzer, the light intensity of the laser beam is measured with a configuration as shown in FIG. That is, a light passage hole 72 through which the laser light R can pass is formed in the sensor base 71 that fixes the light receiving element 70. A light passage window 73 that prevents the ingress of exhaust gas and transmits laser light is inserted into the light passage hole 7 2 with a heat-resistant gasket 7 4 interposed therebetween, and a gasket 7 5 is sandwiched on the light passage window 73. The fixing ring 7 6 is screwed in. The entrance and exit surfaces of this light passage window 73 are usually stray light. In order to prevent interference light, it is not formed in parallel, but one surface is formed in a wedge shape having an inclined surface slightly inclined with respect to the central axis.

In addition, a fixing jig 7 9 made of stainless steel or the like is stacked on the upper part of the sensor base 7 1 with a ceramic base 7 7 and a heat insulating ring 7 8 interposed therebetween, and the light receiving element 70 is fixed to the fixing jig 7 9. It is the composition which becomes. With such a configuration, it is possible to receive laser light while preventing leakage of exhaust gas from the mounting portion of the sensor base 71 of the light receiving element. In addition, the configuration of the irradiation part such as the attachment part of the optical fiber that irradiates the laser beam is almost the same, and the laser beam can be irradiated by preventing the leakage of the exhaust gas. Yes.

Patent Literature 1

[Patent Document 1] Japanese Patent Laid-Open No. 2 0 0 4 1 1 7 2 5 9

By the way, the exhaust gas analyzer having the above structure is an analyzer for directly analyzing exhaust gas discharged from an internal combustion engine such as a vehicle engine in a pipe or a flow path, and fixes a light receiving element to a measurement cell attached to the pipe. In this case, the light transmission hole formed from the light receiving element mounting surface toward the flow path provided in the measurement cell becomes an invalid space for measurement, which causes a decrease in measurement accuracy. Specifically, due to the influence of temperature and the like, the oxygen concentration present in the invalid space cannot be accurately corrected, and the measurement accuracy is reduced.

In addition, in the other exhaust gas analyzers described above, it is necessary to correct the influence of gas such as air existing in the invalid space in the light passage hole, and the calculation time for calculating the concentration of the exhaust gas component becomes great. Yes. Furthermore, when the light passage window 73 is fixed, one surface of the light passage window is an inclined surface and a torsional force acts on the gaskets 74, 75 to prevent exhaust gas leakage. Heat-resistant gasket 7 4 is easily damaged, and if the gasket is damaged, gas leaks and measurement accuracy decreases. When the above-mentioned irradiating part and the light-receiving part are assembled to the sensor base 71, it is difficult to position the light passage window 73 that allows the laser light to pass through without passing through the waste gas, and breakage occurs due to misalignment. It is easy to do, and if it breaks, there is a risk of gas leakage. The present invention has been made in view of such problems, and an object of the present invention is to provide an exhaust gas analyzer that can improve the measurement accuracy of a gas to be analyzed and can shorten the analysis time. There is. In addition, it is easy to attach an irradiating unit that emits laser light into the exhaust gas and to attach a light receiving unit that measures the light intensity of the laser light that has passed through the exhaust gas, preventing damage to the gasket and leaking the exhaust gas. It is an object of the present invention to provide an exhaust gas analyzer that can prevent the above.

In order to achieve the object, an exhaust gas analyzer according to the present invention irradiates exhaust gas emitted from an internal combustion engine with laser light, receives laser light transmitted through the exhaust gas, and is based on the received I-light. An exhaust gas analyzer that measures and analyzes the concentration and temperature of components contained in the exhaust gas, the apparatus comprising: an irradiation unit that emits laser light; a light receiving unit that receives laser light; and the irradiation unit A light passage hole that guides the laser light emitted from the light path to a path through which the exhaust gas flows, and a light passage hole that guides the laser light that has passed through the exhaust gas to the light receiving portion. It is characterized in that at least a part of is filled with a translucent member.

The exhaust gas analyzer of the present invention configured as described above has a light passage path through which a laser beam that measures the component concentration and temperature of exhaust gas passes by filling at least a part of the light passage hole with a translucent member. Since the volume of the gas staying in the exhaust gas can be reduced, the measurement accuracy of the concentration and temperature of the components in the exhaust gas can be increased. In addition, when measuring the light intensity of the laser light that has passed through the exhaust gas and calculating the concentration and temperature of the gas to be analyzed, the influence of the gas present in the passage through which the laser light passes can be reduced, so the correction calculation The calculation time can be shortened and exhaust gas analysis can be completed in a short time.

In a conventional exhaust gas analyzer, for example, when a light receiving element or an optical fiber is assembled to a sensor base constituting a sensor unit, the light path is filled with air. If measurement is performed in such a state, nitrogen and oxygen in the air that is filled are also measured together with the measurement of the components in the exhaust gas, so it is necessary to correct the gas that is filled during measurement. . If this gas correction is not performed, nitrogen and oxygen will be added in addition to the exhaust gas components, and the measurement accuracy will deteriorate. In the exhaust gas analyzer of the present invention, since at least a part of the light passage hole through which the laser beam passes is filled with a translucent member, the influence of gas such as air existing in the light passage hole is reduced. Can do. Further, as a preferable specific aspect of the exhaust gas analyzer according to the present invention, the irradiation unit and the light receiving unit are fixed to a sensor base having an exhaust gas passage hole that is supported in the path and through which the exhaust gas passes. The light passage hole communicates the exhaust gas passage hole with the irradiation unit and the light receiving unit. According to this configuration, the sensor-based exhaust gas passage hole is made to correspond to the exhaust gas flow path, and the irradiation unit and the light receiving unit can be fixed to the light passage hole communicating with the exhaust gas passage hole. The sensor base can be easily installed in the path through which the current flows.

The translucent member further includes a gas facing surface close to the exhaust gas passage hole, and an element extending from the gas facing surface along the light passage hole and close to the irradiation unit or the light receiving unit. And the translucent member fills the passage path of the laser beam. The translucent material constituting the translucent member is preferably made of optical glass or sapphire.

Since the exhaust gas analyzer configured in this way is provided with the gas facing surface of the translucent member close to the exhaust gas passage hole through which the exhaust gas flows, the exhaust gas does not stay in the light passage hole and changes from moment to moment. The state of exhaust gas to be measured can be measured in real time. The translucent member is extended along the light passage hole, and the element facing surface is close to the irradiation part and the light receiving part and fills the passage path of the laser light in the light passage hole. It is possible to eliminate gas such as air present in the sensor and to correct the received light intensity, thereby improving measurement accuracy and shortening the calculation time of component concentration. Further, by forming the translucent member with optical glass or sapphire, attenuation during transmission of laser light can be reduced, and high-accuracy measurement is possible.

As another aspect of the exhaust gas analyzer according to the present invention, laser light is emitted to exhaust gas discharged from an internal combustion engine, laser light transmitted through the exhaust gas is received, and the received laser light is converted into light. An exhaust gas analyzer that measures and analyzes the concentration and temperature of components contained in the exhaust gas based on the above is equipped with a sensor base that is mounted in a path through which the exhaust gas flows and has an exhaust gas passage hole through which the exhaust gas passes. The sensor base is fixed to the sensor base with a pedestal interposed, and an irradiation unit that emits laser light and a light receiving unit that receives laser light, and the laser light emitted from the irradiation unit passes through the exhaust gas. A light passage hole for guiding light to the hole, a light passage hole for guiding laser light transmitted through the exhaust gas to the light receiving portion, and A translucent member that closes the overhole in an airtight state, and the pedestal includes a cylindrical portion that is inserted into the light passage hole and presses the translucent member against the sensor base. It is a feature.

Furthermore, as another preferable specific aspect of the exhaust gas analyzer according to the present invention, the translucent member is opposed to the light passage hole with a heat resistant gasket interposed therebetween, and the light passage hole is sealed in an airtight state. It is characterized by. The pedestal is preferably formed of ceramics. In the exhaust gas analyzer configured in this manner, when the irradiation unit for irradiating the sensor base with the laser beam and the light receiving unit for receiving the laser beam are attached, the cylindrical portion of the pedestal is inserted into the light passage hole, Since the light passage window formed from the optical member is pressed against the sensor base and sealed in an airtight state, the torsional force does not act on the packing of the gasket and the like, and the damage of the gasket and the like can be prevented. In particular, when using a heat-resistant gasket formed of mica or the like, it is easy to crack when a torsional force is applied, but in the present invention, it is pressed by the cylindrical portion of the pedestal to ensure airtightness. It is possible to prevent exhaust gas from leaking. It is preferable to form the pedestal from ceramics because it can block the high heat of the exhaust gas.

The exhaust gas analyzer of the present invention removes the effect of light absorption by the staying gas by reducing the volume of the gas staying inside the light passage hole through which the laser beam used for exhaust gas analysis passes, and the components contained in the exhaust gas Can be measured with high accuracy. In addition, the mounting structure of the optical fiber that irradiates the laser light into the exhaust gas and the mounting structure of the light receiving element that measures the light intensity of the laser light that has passed through the exhaust gas can be simplified. As well as damage to parts such as these can be prevented, cost reduction and maintenance can be improved, and gas leakage can be prevented. Brief Description of Drawings

FIG. 1 is a configuration diagram of a main part of an embodiment in which an exhaust gas analyzer according to the present invention is mounted on a vehicle.

FIG. 2 is a configuration diagram of a main part of another embodiment in which the exhaust gas analyzer according to the present invention is mounted on an engine bench.

Fig. 3 shows an exhaust gas analyzer that includes a perspective view of the essential parts of one sensor unit in an exploded state. FIG.

4A is a front view of the sensor unit of FIG. 3, FIG. 4B is a cross-sectional view of the sensor base portion of FIG. 4A taken along the line A-A, and FIG. 4C is a B-B line of the sensor base portion of FIG. It is sectional drawing.

5A is a cross-sectional view showing the main part of the light passage hole along the line C-C in FIG. 4A, and FIG. 5B is a perspective view showing the exploded state of the main part of the force S (a). .

FIG. 6 is a block diagram showing the main configuration of the laser oscillation / light reception controller and the overall configuration of the exhaust gas analyzer including the signal analyzer.

FIG. 7 is a cross-sectional view showing a main part of a light passage hole portion in a conventional exhaust gas analyzer. In the drawing, 1 is an automobile, 1 A is an engine bench, 2 is an engine (internal combustion engine),

3: Exhaust manifold (exhaust path), 4: Exhaust pipe (exhaust path), 5: First catalytic device (exhaust path), 6: Second catalytic device (exhaust path), 7: Muffler (exhaust path), 8 : Exhaust pipe (exhaust path), 10: Exhaust gas analyzer, 1 1 to 14: Sensor part, 20: Sensor base, 2 1: Exhaust gas passage hole, 2 3: Sensor hole (irradiation light passage hole), 24: Sensor hole (transmitted light passage hole), 25, 25 A to 25 C: Optical fiber (irradiation part), 26, 26 A to 26C: Collimator lens (irradiation part), 27 , 2 7 A to 2 7 C: Detector (light receiving part), 3 0, 3 1: Mirror, 3 5: Light passage slit,

40: Glass body (translucent member), 40a: Incident surface (gas facing surface), 40b: Outgoing surface (element facing surface), 41, 42: Gasket, 43: Base, 4 3 a: cylindrical part, 50: laser oscillation 'light receiving controller, 5 2: demultiplexer, 5 3 A to 5 3 C: demultiplexer,

54 A to 54 C, 5 5 A to 5 5 C: multiplexer, 5 7 A to 5 7 C: differential photodetector,

60: Personal computer (analyzer), R: Laser light.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment in which an exhaust gas analyzer according to the present invention is used as an exhaust gas analyzer from an internal combustion engine (engine) of an automobile will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a main part in which the exhaust gas analyzer according to the present embodiment is mounted on an automobile. Fig. 3 is a main part configuration diagram in a state where the exhaust gas analyzer of Fig. 1 is mounted on an engine bench, Fig. 3 is a perspective view showing the sensor unit and its vicinity in an exploded state, and Fig. 4 is a detailed diagram of the sensor unit. FIG. 5 is a block diagram showing the main configuration of the laser oscillation 'light receiving controller and the overall configuration of the exhaust gas analyzer including the signal analyzer.

1 to 3, the exhaust gas analyzer of the present embodiment is an apparatus that analyzes exhaust gas discharged from an engine (internal combustion engine) 2 installed in an automobile 1. In addition, as shown in FIG. 2, it is a device for analyzing exhaust gas of the engine 2 installed on the engine bench 1A. The exhaust gas discharged from each cylinder of the engine 2 is merged in the exhaust manifold 3 and introduced into the first catalyst device 5 through the exhaust pipe 4, and then into the second catalyst device 6, and then through the muffler 7. Released from the exhaust pipe 8 into the atmosphere. The exhaust path is composed of exhaust manifold 3, exhaust pipe 4, first catalyst device 5, second catalyst device 6, muffler 7, and exhaust pipe 8. Exhaust gas discharged from engine 2 is divided into two catalyst devices 5, Purify with 6, muffle with muffler 7, depressurize and release into the atmosphere. The muffler may have two main mufflers and sub mufflers.

The plurality of members constituting the exhaust path are connected by bolts or the like with the flange portions facing each other. For example, the first and second catalytic devices 5 and 6 have an exhaust pipe connected to the upstream and downstream sides of the large-diameter main body, and flanges F and F are fixed to the ends of the exhaust pipe by welding or the like. Has been. The exhaust pipe 7 is connected to the upstream and downstream sides of the large-diameter main body, and the flanges F and F are fixed to the ends of these exhaust pipes. The exhaust pipe 8 at the end is fixed directly to the muffler 7 by welding or the like. In this way, the plurality of members constituting the exhaust path are connected by the flange portion F, and the cross-sectional shape through which the exhaust gas passes is formed in a circular shape having a diameter d. The exhaust gas analyzer 10 of the present embodiment includes a plurality of (four in the illustrated example) sensor units 11 to 14 installed at a plurality of locations in the exhaust path. The first sensor unit 1 1 is installed between the exhaust pipe 4 on the engine side upstream from the first catalyst device 5, and the second sensor unit 1 2 is installed downstream of the first catalyst device 5. The third sensor unit 13 is installed on the downstream side of the second catalyst device 6. The fourth sensor unit 14 is installed in the exhaust pipe 8 downstream of the muffler 7. Sensor section 1 4 is exhaust pipe Even if it is installed in the middle of the pipe 8, it may be installed in the opening at the end of the exhaust pipe. Further, another sensor unit may be installed in the exhaust pipe for each cylinder before joining in the exhaust manifold 3 on the upstream side of the first sensor unit 11.

The exhaust pipe 4, the first catalyst device 5, the second catalyst device 6, and the muffler 7 are connected by tightening the flange portions F and F with bolts, and the sensor portion is disposed between the members constituting the exhaust path. 1 1, 1 2, 1 3 are installed in a state of being sandwiched between flanges F, F. The flange portions F and F are formed at both ends of a member constituting the exhaust path, and the joint surfaces of the flange portions intersect each other at right angles to the center line of the exhaust path. As a result, the sensor parts 1 1 to 1 3 are installed so as to cross the exhaust path between the flange parts F and F. The fourth sensor section 14 performs analysis immediately before the exhaust gas is released into the atmosphere. Even if it is installed in the middle of the exhaust pipe 8 protruding from the muffler 7, it is sandwiched between the flange sections F and F. Good. The number of sensor units can be set arbitrarily.

Each of the sensor units 11 to 14 has the same configuration, and one sensor unit 11 will be described with reference to FIGS. The sensor unit 1 1 has a sensor base 2 0 formed of a rectangular thin plate material. This sensor base has an exhaust gas passage hole 2 1 having a diameter d 1 substantially the same as the inner diameter d of the circular cross section of the exhaust pipe unit at the center. The exhaust gas passes through the exhaust gas passage hole. The exhaust gas passage hole 21 constitutes an exhaust gas introduction path. The thickness of the plate-shaped sensor base 20 is preferably as thin as possible within a range in which the laser light emitting part and the light receiving part can be fixed.

Specifically, the thickness of the sensor base 20 is preferably about 5 to 20 mm, for example. If it exceeds 2 O mm, the exhaust gas flow tends to be turbulent and pressure loss that cannot be ignored is likely to occur. If it is thinner than 5 mm, the mounting and fixing of the measurement laser beam irradiation part and the light receiving part become complicated. The diameter d 1 of the exhaust gas passage hole 21 is preferably the same as the inner diameter d of the circular cross section of the exhaust pipe part. For example, if the inner diameter d of the circular cross section of the exhaust pipe part is 30 mm, If the diameter dl of the passage hole 21 is about 30 ± 1 to 2 mm, an error is allowed. As the plate material constituting the sensor base 20, a metal plate material or a ceramic plate material is used, but the material is not particularly limited.

The sensor base 20 is fixed in a state where it is sandwiched between the flanges F and F. Gaskets 22 and 22 are sandwiched between F and F and the sensor base 20, and are fixed by a port, a nut, etc. not shown. The gasket 22 is formed of an appropriate material and has an exhaust gas passage hole having the same diameter as the inner diameter of the exhaust pipe portion. With this configuration, even when the exhaust path is connected with the sensor base 20 sandwiched between the flange portions F and F, the exhaust gas does not leak in the middle, and the increase in the length of the exhaust path is small. FIG. 3 shows a gasket 2 2, between a flange portion F welded to the downstream end of the exhaust pipe 4 and a flange portion F welded to the end of the exhaust pipe portion 5 a on the upstream side of the catalyst device 5. 2 shows a configuration in which the sensor base 20 is fixed with the 2 2 in between.

The sensor base 20 is formed with two sensor holes 2 3 and 2 4 that penetrate the center of the plate thickness from the end surface toward the exhaust gas passage hole. The sensor hole 23 is opened toward the exhaust gas passage hole 21 and constitutes an irradiation light passage hole formed so that the irradiated laser light can reach the light receiving part through the exhaust gas passage hole 21. The sensor hole 2 4 opens toward the exhaust gas passage hole 21 and constitutes a transmitted light passage hole formed so that the laser beam can reach the light receiving part. The sensor holes 2 3 and 2 4 Is open perpendicular to the direction in which the exhaust gas flows.

The sensor unit 1 1 has an optical fiber 25 and a collimator lens 26 fixed to the sensor hole 23 as an irradiation unit for irradiating laser light. A detector 27 is fixed to the sensor hole 24 as a light receiving portion for receiving the transmitted laser beam. In other words, the sensor unit 11 reflects the laser beam irradiated from the irradiation side optical fiber 25 so as to cross the exhaust path, is reflected by the two mirrors 30 and 3 1, passes through the exhaust gas, and is attenuated. The detector 27 receives the light, and the mirror reflects the irradiated laser light and guides it to the detector.

As shown in detail in FIG. 4, the two mirrors 30 and 31 are attached outside the circular exhaust gas passage hole 21 at the center of the sensor base 20 at opposite positions sandwiching the exhaust gas passage hole, respectively. Two mirrors are arranged so that their reflecting surfaces are parallel to each other, and are fixed up and down so as to reflect the laser beam for measurement. In other words, the mirrors 30 and 3 1 are arranged in parallel on the outer periphery of the exhaust gas passage hole 21 so as to face each other with the exhaust gas passage hole interposed therebetween. The mirrors 30 and 31 are flat on the outer periphery of the exhaust gas passage hole 21. It is detachably fixed in the two insertion grooves 3 2 and 3 3 formed in the row, and irradiated from the optical fiber 25 and collimator lens 26 to the exhaust gas passage hole 21. It has a function to make the laser beam reach the detector 27. The mirrors 30 and 31 are formed in a rectangular substrate having a thickness of several millimeters. A thin film of gold or platinum is formed on one surface of the substrate as a reflective surface, and M is used as a protective layer on the surface. Thin films of g F ₂ and S 1 0 ₂ are formed. Note that the protective film may not be formed.

The insertion grooves 3 2 and 3 3 formed on the outer periphery of the exhaust gas passage hole 21 of the sensor base 20 are set to a size that allows the mirrors 30 and 31 to be loosely inserted. The insertion grooves 3 2, 33 may penetrate the sensor base 20 and be open on both sides, or may be open on one side and closed on the other side. The mirrors 30 and 3 1 are fixed in the insertion grooves 3 2 and 3 3 through the spacers by the mounting screws 3 4. If the mirror is damaged by heat shock, etc., it can be removed by loosening the mounting screws 3 4 and fixed with a new mirror. When the mirror is dirty, it can be removed from the sensor base 20 and cleaned.

Since the mirrors 30 and 3 1 are fixed with a spacer (not shown) sandwiched by mounting screws 3 4, the mirrors are prevented from vibrating due to engine vibrations and vibrations in the exhaust pipe and other exhaust paths. is doing. A spacer is sandwiched to absorb the difference in thermal expansion between the mirror and the mounting screw, and functions as a cushioning material. As the spacer, those having excellent environmental resistance and elastic deformation are preferable. For example, mica, carbon and copper are preferred. In this way, the mirror is fixed stably without being vibrated even at a high temperature of about 800 ° C. by being fixed with the mounting screw through the spacer.

The mirrors 30 and 31 are manufactured by coating a reflective material on the surface of a base material such as quartz, sapphire, or ceramic. As the coating material, it is preferable to select a material having high reflectivity suitable for the laser wavelength, such as gold or titanium oxide. Also, excellent transparency and heat resistance such as S i 0 ₂ as a coating to protect the anti Ysaÿe, it is preferable to form the excellent environmental resistance to the uppermost surface. Using a mirror with excellent heat resistance and high reflectivity enables accurate measurement. When titanium oxide is used as a reflector, titanium oxide alone has excellent environmental resistance and is effective as a photocatalyst for preventing contamination, so it is not necessary to form a protective film, and measurement should be performed as it is. Is preferred.

A light passage hole is formed between the inner peripheral surface of the exhaust gas passage hole 21 and the insertion grooves 3 2 and 3 3 for fixing the mirror so that the laser beam for measurement can reach the mirror. As the light passing hole, a penetrating slit, a penetrating light passing hole and the like are formed. In this embodiment, light passage slits 35 and 35 having a width of about several millimeters penetrate from the inner peripheral surface of the exhaust gas passage hole 21 to the insertion grooves 3 2 and 3 3 in the direction orthogonal to the exhaust path. The light transmission slit is formed so as to penetrate the inner peripheral surface of the exhaust gas passage hole 21 and the mirrors 30 and 31. With this configuration, when an infrared laser beam for measurement is irradiated from the optical fiber 25, which is the irradiation section, into the exhaust gas passage hole 21 through the sensor hole 23, the upper mirror 3 passes through the upper light passage slit 35. 1 and reflected downward by the upper mirror, then reaches the lower mirror 30 through the lower light passage slit 35, reflected upward by the lower mirror, and repeatedly reflected up and down Light is received by the detector 27 fixed upward through the sensor hole 24.

Mounting holes 3 6 and 3 6 are formed in the sensor base 20 in the horizontal direction adjacent to the mirrors 30 and 3 1, and heaters 3 7 and 3 7 are fixed to these mounting holes by fixing screws. . The heaters 3 7 and 3 7 prevent the condensation of the mirror. For example, even if water vapor in the exhaust gas adheres to the mirror surface, the mirror is heated by energizing the heater to vaporize the moisture, and the water vapor is reflected in the mirror. Prevents adhesion to the surface. The heating temperature of Mira 30 and 31 is preferably equal to or higher than the dew point of moisture. By preventing dew condensation on the mirror, the reflectance is improved and attenuation due to reflection of the laser beam is prevented.

Here, details of the light passage hole will be described with reference to FIG. The sensor hole 23 constituting the irradiation light passage hole and the sensor hole 24 constituting the transmitted light passage hole are formed by stepped holes having different diameters. That is, in the sensor holes 2 3 and 24, a through hole with a small diameter communicates with the exhaust gas passage hole 21, and a through hole with a large diameter communicates with the outside of the sensor base 20. Sensor holes 2 3 and 2 4 have a small diameter on the exhaust gas passage hole 2 1 side so that the flow of the exhaust gas is less disturbed and the exhaust gas is constantly exchanged and does not stagnate. Has been. When the thickness of the sensor base 20 is about 15 to 20 mm, the diameter of the small diameter part of the sensor hole is preferably about 6 to 8 mm. The sensor holes 2 3 and 2 4 have a large diameter on the outer peripheral side of the sensor base 20. Therefore, it is easy to mount the irradiation part such as the optical fiber 25 and the collimator lens 26 and the light receiving part such as the detector 27 and the like.

The sensor holes 2 3 and 2 4 constituting the light passage hole are different from each other only in the irradiation part and the light receiving part to be fixed. Therefore, the configuration of one sensor hole 2 4 for fixing the detector 27 as the light receiving part is described in detail. explain. The sensor hole 24 constitutes a light passage path through which the laser light passes, and at least a part of the light passage hole is filled with a stepped columnar glass body 40 formed of optical glass as a translucent material. Yes. In other words, a mica-based heat-resistant gasket 41 is disposed in the middle of the sensor hole 24, and the glass body 40 is inserted into the large-diameter portion of the sensor hole 24 so as to come into contact with the gasket 41. The interior space is filled. With this configuration, the closed internal space of the sensor hole 24 is not filled with gas such as air.

The glass body 40 has a lower entrance surface 40 a and an upper exit surface 40 b in FIG. 5 polished, and the outer peripheral surface is formed on a satin surface to prevent fringes. Note that the entrance surface 40 a and the exit surface 40 b are not formed parallel to each other, and one surface is inclined by about 1 degree with respect to the central axis. In this embodiment, the exit surface 40 b is an inclined surface. The glass body 40 filling the sensor hole 24 of the light receiving section has a lower incident surface 40 a as a gas facing surface and an upper emitting surface 40 b as an element facing surface facing the detector 27. . The glass body 40 that fills the sensor hole 23 of the irradiating portion has an incident surface and an output surface that are opposite to each other, the lower element facing surface is the incident surface, and the upper gas facing surface is the emitting surface.

As described above, since the small diameter portion communicating with the exhaust gas passage hole 21 of the sensor holes 2 3 and 2 4 is set to have a small depth, the glass body 40 inserted from the large diameter portion does not pass the exhaust gas. Located near the hole 21, the incident surface 40 a of the glass body is close to the exhaust gas passage hole 21. As a result, the exhaust gas stays in the small diameter part of the sensor hole and does not change, and even if the state of the exhaust gas changes, the exhaust gas in the sensor hole also changes and changes momentarily. Can be measured accurately. Further, the exit surface 40 b of the glass body 40 is close to, preferably in contact with, the detector 27, and fills the laser beam passage path of the sensor hole 24. With this configuration, the passage path of the laser light passing through the sensor hole 24 is a glass made of a translucent member. The laser light that is filled with the glass body 40 and passes through the sensor hole passes through the glass body through almost no space. In the sensor hole 23 which is the other light passage hole, the laser light emitted from the optical fiber and the collimator lens does not pass through the space but passes through the glass body filling the passage path.

A copper gasket 42 is externally fitted as a gasket to the middle step 40 c of the glass body 40. The intermediate step and the incident surface 40a are formed in a parallel state. A pedestal 4 3 for fixing the glass body 40 to the sensor base 20 is fixed to the installation surface outside the sensor hole 24, and a cylindrical portion extending from the pedestal into the sensor hole 24 4 3 a is formed in a body-like manner, and this cylindrical portion 4 3 a is in contact with the copper gasket 4 2. The length of the cylindrical part 4 3 a and the position of the stepped part of the glass body 40 are determined by the copper gasket 4 when the base 4 3 is fixed with a set screw 4 5 so that it is in close contact with the installation surface of the sensor base 20. 2 adheres to and presses the step portion of the glass body 40, and the heat-resistant gasket 41 adheres to the step portion of the glass body 40 and sensor hole 24, and exhaust gas cannot enter the sensor hole 24. Is set to The two gaskets 4 1 and 4 2 are installed in parallel by forming the incident surface 40 a and the intermediate step 4 O c in parallel, and the exit surface 40 b to be an inclined surface of about 1 degree. The airtight state can be stabilized, and the gasket can be prevented from being damaged.

An annular heat insulating ring 46 made of a heat insulating material such as ceramic is disposed on the surface of the base 43, and a support ring 47 for fixing the detector 27 is fixed to the surface of the heat insulating ring. The support ring is formed of a metal plate material such as stainless steel, and is fixed to the sensor base 20 with a set screw 48 that penetrates the base 43 and the heat insulation ring 46. A plurality of screw holes are formed on the circumference of the support ring 47, and the detector 27, which is a light receiving element, is fixed by these screw holes. Further, an optical fiber 25 and a collimator lens 26 are fixed to the support ring fixed to the other sensor hole 23 (not shown) as an irradiating portion. In this way, the detector 27 is fixed to the sensor base 20 with the heat insulating ring 46 interposed therebetween, so the high heat of the exhaust gas is not directly transmitted to the detector 26, improving reliability and durability. Can be made.

Gas that allows the measurement laser light to pass through the sensor holes 2 3 and 2 4 of the sensor base 20 constituting the plurality of sensor sections 1 1 to 1 3 (1 4) while preventing leakage of exhaust gas. An operation of incorporating various parts such as a lath body will be described. First, a mica-based heat-resistant gasket 41 is inserted from the large diameter open ends of the sensor holes 2 3 and 2 4. Thereafter, a glass body 40 made of a translucent material is inserted into the sensor hole and brought into contact with the gasket 41. Next, the copper gasket 42 is fitted on the small diameter portion of the glass body 40, and the cylindrical portion 4 3 a of the base 43 is inserted into the outer periphery of the small diameter portion of the glass body in the sensor holes 2 3 and 24. In this state, when the base 4 3 is fixed to the sensor base 20 with the set screw 4 5, the cylindrical part 4 3 a presses the copper gasket 4 2, and the glass body 40 presses the mica-based gasket 4 1, Laser light can be guided by preventing exhaust gas from entering sensor holes 2 3 and 2 4.

Thus, a sensor hole 23 that is a light passage hole that guides the measurement laser light to the exhaust gas passage hole, and a sensor that is a light passage hole that guides the transmitted laser light of the laser light irradiated into the exhaust gas to the detector 27. When fixing the glass body 40 through which the exhaust gas does not leak and allows laser light to pass through the hole 24, the heat-resistant gasket 41, which is weak against impact and easily broken, is not subject to torsional force, and only the pressing force is applied. Since it acts and is kept airtight, damage and destruction are reliably prevented and the airtight state is stabilized. In addition, since the number of parts is small and the assembly is easy, the work time can be shortened. The incident surface where the stepped part 40c and the heat-resistant gasket 41 are in contact with each other. And the glass body 40 can be positioned easily.

After fixing the glass body 40 to prevent the exhaust gas from leaking into the sensor holes 2 3 and 2 4 of the sensor base 20, the heat insulating ring 4 6 and the support ring 4 7 are sandwiched between the base 4 3 of the irradiation unit. The optical fiber 25 and the collimator lens 26 are fixed using set screws 48 to form the irradiation section. In the same way, fix the detector 2 7 to the pedestal 4 3 of the light receiving part using the set screw 4 8. Of course, the irradiation unit for irradiating the exhaust gas with the laser beam and the light receiving unit for receiving the laser beam transmitted through the exhaust gas may be disposed upside down. Further, the sensor unit 11 shown in FIG. 3 may be rotated 90 degrees to irradiate the laser beam in the horizontal direction.

In the sensor base 20 configured as described above, in the laser beam irradiation part and the laser light receiving part, the sensor hole 23 that guides the laser light to the exhaust gas passage hole 21, and the laser that has passed through the exhaust gas The sensor hole 2 4 that guides the light to the detector 2 7 is a laser beam. Most of the space in the passage through which is passed is filled with the glass body 40, and the volume of the space is set to almost zero. For this reason, when assembling the detector 27, almost no air enters the sensor hole 24, and the gas existing in this space can be ignored. Further, when the optical fiber 25 or the collimator lens 26 is attached to the sensor hole 23, almost no air enters the sensor hole 23, and the gas existing in this space can be ignored.

If the inner space of the sensor holes 2 3 and 2 4 is not filled with the glass body 40 as a translucent member, the space between the glass body 40 and the detector 27 or the glass body 40 and the optical fiber 25 For example, when oxygen is measured as an exhaust gas component, the oxygen component in the exhaust gas is about 1% because of the combustion exhaust gas, but the amount of oxygen in this space is 13%. Due to the large amount, the light intensity of the transmitted laser light needs to be greatly corrected. Similar corrections are required for other exhaust gas components. However, in this embodiment, since there is almost no air in the space, it is not necessary to correct the gas existing in the path of the laser beam, the calculation time can be shortened, and the exhaust gas can be analyzed in real time. It becomes possible.

In this way, the optical fiber 25 fixed to the sensor base 20 and the collimator lens 26 and the detector 27 are connected to the laser oscillation / light receiving controller 50 and emitted from the laser oscillation / light receiving controller 50. The infrared laser beam is irradiated into the exhaust gas passage hole 21 of the sensor base 20 through the optical fiber 25, and the infrared laser beam that has passed through the exhaust gas is received by the detector 27 on the light receiving side, and the signal line 2 It is configured to be input to laser oscillation / light receiving controller 50 through 8. The intensity of light emitted from the optical fiber 25, the intensity of light received through the exhaust gas and received by the detector 27, and the like are supplied to a personal computer 60 as an analyzer. As described above, the exhaust gas analyzer 10 includes a plurality of sensor units 11 to 14, a laser oscillation / light reception controller 50, and a personal computer 60. Here, the laser oscillation 'light receiving controller 50 will be described with reference to FIG. Laser oscillation 'Reception controller 50 is an irradiation device that irradiates infrared laser beams of multiple wavelengths. Multiple laser diodes LD 1 to LD 5 are connected to a plurality of signal generators such as a function generator (not shown). Supply frequency signal, Laser diodes LD 1 to LD: LD 5 emits infrared laser beams having a plurality of wavelengths corresponding to the respective frequencies. Laser oscillation · Signals of multiple frequencies output from the signal generator of the light receiving controller 50 are supplied to the laser diodes LD i to LD 5 to emit light, for example, LD 1 has a wavelength of about 1300 to 1330 nm, LD 2 is set to generate infrared light in the wavelength band in which the wavelength band where the peak wavelength of the component gas to be detected exists, such as 1330-1360 nm. The

The wavelength of the infrared laser beam that passes through the exhaust gas is set according to the component of the exhaust gas to be detected. Carbon monoxide (CO), carbon dioxide (C0 ₂ ), ammonia (NH ₃ ), methane (CH ₄ ), When detecting water (H ₂ 0), use infrared laser light of 5 wavelengths. For example, a suitable wavelength for detecting ammonia is 1 530 nm, a suitable wavelength for detecting carbon monoxide is 1 560 nm, and a suitable wavelength for detecting carbon dioxide is 1 570 nm It is. The wavelength suitable for detecting methane is 1680 nm, and the wavelength suitable for detecting water is 1 350 nm. Furthermore, when detecting the concentration of other exhaust gas components, infrared laser beams with different wavelengths are used according to the number of exhaust gas components. The gas concentration may be detected at different wavelengths even for the same component, and may be selected from different wavelengths.

Infrared laser light emitted from each of the laser diodes LD 1 to LD 5 is guided to the demultiplexer 52 by the optical fiber 51, and is demultiplexed by the demultiplexer 52 according to the number of sensors. It is demultiplexed. In FIG. 6, the laser beams emitted from the laser diodes LD 1 to LD 5 in accordance with the three sensor units 11 to 13 are demultiplexed into three. The laser light demultiplexed by the demultiplexers 52 is divided into signal light and measurement light by demultiplexers 53Α, 53Β, 53C .... The duplexers 53 A are for the sensor unit 11, the duplexers 5 3 B are for the sensor unit 12, and the duplexers 53 C are for the sensor unit 1 ′ 3. The signal light divided by the five demultiplexers 53 A ... for the sensor unit 1 1 is multiplexed by the multiplexer 5 4 A through the optical fiber, and the combined signal light in multiple wavelength bands is the optical fiber 56. The light is guided to the differential photodetector 57 A through A. On the other hand, the measurement light divided by the five demultiplexers 53 A ... is multiplexed by the multiplexer 55 A through the optical fiber, and then by the optical fiber 25 A The light is guided to the irradiation part of the sensor part 11.

The infrared laser beam demultiplexed by the demultiplexers 5 2... Is divided into signal light and measurement light by the five demultiplexers 5 3 B for the sensor unit 12. The signal light is multiplexed. At 54 B, signal light is obtained by combining a plurality of wavelength bands, and is guided to the differential photodetector 5 7 B through the optical fiber 56 B. The measurement light divided by the five demultiplexers 5 3 B,... Is multiplexed by the multiplexer 5 5 B and guided to the irradiation part of the sensor unit 12 by the optical fiber 25 B. Furthermore, the infrared laser light demultiplexed by the demultiplexers 5 2... Is divided into signal light and measurement light by the five demultiplexers 5 3 C for the sensor unit 13. The signal light is multiplexed. The signal 54C becomes signal light in multiple wavelengths and is guided to the differential photodetector 57 C through the optical fiber 56 C. The measurement light divided by the five demultiplexers 5 3 C ... is multiplexed by the multiplexer 55 C and guided to the irradiation area of the sensor unit 13 by the optical fiber 25 C.

In FIG. 6, three sensor units 1 1 to 1 3 are shown. However, when more sensor units 1 4... Are installed, the demultiplexer 5 2 demultiplexes them into more laser beams. The separated laser light is demultiplexed into measurement light and signal light by more demultiplexers 53, and then the signal laser light is combined by a combiner 54, then a differential photodetector. The light is guided to 5 7... And the measurement laser light is multiplexed by a multiplexer 5 5... And then guided to more sensor sections 14.

The exhaust gas analyzer 10 is configured to reflect the infrared laser light for measurement by mirrors 30 and 31 to increase the transmission distance in the exhaust gas, and is repeatedly reflected by the mirrors 30 and 31. The measured laser beam is received by a detector. Sensor unit 1 1 to 1 3 Photodetector 2 7 A, 2 7 B, 2 7 C connected to photo detector 2 7 A, 5 7 B Differential laser detector 5 7 A, 5 7 B , 5 7 C are connected via signal lines 2 8 A, 2 8 B, 2 8 C. The signal light combined by the multiplexers 54A, 54B, 54C passes through the optical fibers 5 6 A, 5 6 B, 5 6 C, and the differential photodetectors 5 7 A, 5 7 B, 5 7 C Is guided to.

The three differential photodetectors 5 7 A, 5 7 B, and 5 7 C are configured to take the difference between the transmitted laser light that has been attenuated by passing through the exhaust gas and the signal laser light that has not passed through the exhaust gas. It has become. The signal laser beam is input to a photodiode and converted to an electrical signal. An electrical signal corresponding to the difference between the signal light and the measurement light calculated by a differential photodetector For example, the signal is amplified by a preamplifier (not shown) and input to a personal computer 60 as an analysis device via an AZD converter. The personal computer 60 analyzes the exhaust gas by calculating the concentration of the components contained in the exhaust gas, the temperature and pressure of the exhaust gas from the input signal.

In the exhaust gas analyzer 10 of the present embodiment, the laser light emitted from the optical fiber 25 and the collimator lens 26 is irradiated into the exhaust gas passage hole 21 through which the exhaust gas flows through the sensor hole 23. Reflected downward by the upper mirror 30, then reflected upward by the lower mirror 3 1, repeatedly reflected and entered the sensor hole 2 4 from the lower mirror 3 1, and received by the detector 2 7 The At this time, the sensor holes 2 3 and 24 are filled with a glass body 40 made of a translucent material, and the volume of gas existing in the sensor holes 2 3 and 2 4 is zero or very small. . Since the laser beam in the sensor hole passes through the glass body 40 and hardly passes through the ineffective space, the transmitted laser beam intensity measured by the detector 27 is compared with the gas existing in the middle. This eliminates the need for correction, shortens the time required to calculate the concentration of components in the exhaust gas, and increases the measurement accuracy. In addition, by filling at least a part of the sensor hole with the translucent member, the influence of the gas existing in the space can be reduced, and the measurement accuracy can be improved.

As described above, the exhaust gas analyzer 10 of the present invention transmits, for example, infrared laser light into the exhaust gas, based on the intensity of incident light and the intensity of transmitted light after passing through the exhaust gas. The concentration of these components is calculated and the exhaust gas is analyzed. That is, the concentration C of the exhaust gas component is calculated from the following formula (1).

C =-1 n (I / Io) / k ... (1)

In this equation (1), I is the transmitted light intensity, I o is the incident light intensity, k is the absorptance, and L is the transmission distance. Therefore, the concentration C of the exhaust gas component is calculated based on the ratio of the transmitted light intensity (I) to the incident light intensity (I o), which is the signal light, and the signal intensity (I / I o). The transmitted light intensity I is output through the detector 2 7 (2 7 A, 2 7 B, 2 7 C), and the incident light intensity I o is transmitted through the optical fibers 5 6 A, 5 6 B, 5 6 C. It is output from a photoelectric converter such as a photodiode in the differential photodetectors 5 7 A, 5 7 B, 5 7 C. In this embodiment, the incident light intensity I o is not transmitted through the exhaust gas. High signal light intensity is used.

The operation of the exhaust gas analyzer 10 of the present embodiment configured as described above will be described below. The exhaust gas analyzer 10 is operated while the engine is operating. The exhaust gas discharged from the engine 2 is merged in the exhaust manifold 3 as an exhaust path, introduced into the first catalyst device 5 through the exhaust pipe 4, and further introduced into the second catalyst device 6, and then exhausted through the muffler 7. Released from the pipe 8 into the atmosphere. Then, the exhaust gas passes through the exhaust gas passage hole 21 formed in the sensor base 20 of the sensor units 11 to 14 installed in the exhaust path. When measuring the concentration of a specific component of the exhaust gas, the laser light is irradiated into the exhaust gas passage hole 21 and the light intensity of the laser light transmitted through the exhaust gas is measured.

That is, by operating the signal generator of the laser oscillation / light receiving controller 50 to supply a signal to each of the laser diodes LD 1 to LD 5, each laser diode LD 1 to: an infrared laser beam having a predetermined wavelength from the LD 5 To emit light. The infrared laser light emitted from each of the laser diodes LD 1 to LD 5 reaches the duplexer 52− through the optical fibers 51, and is demultiplexed according to the number of sensor units. After that, the demultiplexed infrared laser light is demultiplexed into measurement light and signal light by the demultiplexers 53 A-, 53 Β, 53 C.

One sensor unit 1 1 will be described in detail. The signal light demultiplexed by the five demultiplexers 53 合 is multiplexed by the multiplexer 54 A to become a signal laser beam, and the differential optical detector 57A Is guided to. The measurement light demultiplexed by the five demultiplexers 53 A is multiplexed by the multiplexer 55 A to become measurement laser light, which is guided to the irradiation part of the sensor unit 11 through the optical fiber 25A. The Similarly, the other sensor units 12, 1 and 3 are demultiplexed by the demultiplexers 5 2… and then demultiplexed into signal light and measurement light by demultiplexers 53 B-, 53 C… 54 B and 54 C are combined, the signal light is guided to differential optical detectors 57 B and 57 C, and combined by multiplexers 55 B and 55 C. 1 3 Guided to light.

Then, the infrared laser light for measurement irradiated from the optical fibers 25 (25A, 25B, 25C) of the sensor units 11 to 13 is exhausted through the sensor hole 23 which is an irradiation light passage hole. Irradiated into the exhaust gas passage hole 21 passing therethrough. The infrared laser beam crosses the exhaust gas passage hole 2 1 內 that is the exhaust path, and passes through the light passage slit 35 to mirror 3 It reaches 0, is reflected downward by the upper mirror 30, then passes through the light passage slit 35, reaches the mirror 31 and is reflected upward by the lower mirror 31, and repeats reflections in the exhaust gas. Finally, the transmission distance increases, and the light is received by the detector 2 7 (27 A, 27 B, 27 C) through the sensor hole 24. In other words, the infrared laser light for measurement passes through the exhaust gas and is attenuated, and the attenuated transmitted light is received by the detector that is the light receiving unit, and the light intensity of the transmitted light (measurement light) is measured.

The infrared laser light for measurement that has attenuated through the exhaust gas and reached the light receiving section is output as an electrical signal by the detectors 2 7 A, 2 7 B, 2 7 C, and the signal lines 2 8 (2 8 A, 2 8 B, 28 C) and supplied to the differential photodetectors 5 7 A, 5 7 B, 5 7 C. On the other hand, the signal laser light is supplied to the differential optical detectors 5 7 A, 5 7 B, and 5 7 C. In the differential optical detector, transmitted light (measurement light) and signal light are transmitted for each of a plurality of wavelength components. The absorption spectrum in which the peak wavelength of the specific gas component in the transmitted light is detected is detected. In this way, the output from the differential photodetector is input to the personal computer 60 which is an analyzer. The personal computer 60 calculates and measures the concentration, temperature, and pressure of the components of the exhaust gas based on the peak wavelength of each frequency band of the input absorption spectrum. In particular, the exhaust gas analyzer 10 of the present embodiment is capable of measuring from exhaust gas at about 80 ° C immediately after exhaust from the engine 2 to exhaust gas at about 100 ° C at the end of the exhaust path. Even cold exhaust gas can be measured.

As described above, the exhaust gas analyzer 10 of the present embodiment includes the sensor hole 23, which is a light passage hole that constitutes a laser light irradiation unit irradiated into the exhaust gas, and the laser light transmitted through the exhaust gas. The sensor hole 24, which is a light passage hole that constitutes a light receiving portion that receives light, is filled with a glass body 40 made of a translucent material, and there is no invalid space, so it exists in this space 內Measurement accuracy can be increased without correction for gas. In addition, since correction is not required, the calculation time for the gas concentration and temperature of the components can be shortened, and the exhaust gas can be analyzed in real time.

In addition, when fixing the glass body 40 as a light passage window that closes the sensor holes 2 3 and 2 4 in an airtight state, the heat-resistant gasket 41 inserted between the glass body 40 and the sensor hole has a pedestal. 4 3 Since the cylindrical part 4 3 a has a pressing force and no torsional force, It is possible to prevent the heat-resistant gasket from being destroyed or damaged. As a result, assembly becomes easy, leakage of exhaust gas can be prevented, and accuracy of exhaust gas analysis can be improved. As mentioned above, although one embodiment of the present invention has been described in detail, the present invention is not limited to the above-described embodiment, and is within the scope not departing from the spirit of the present invention described in the claims. Various design changes can be made. For example, an example of using a heat-resistant mica-based gasket and a metal copper gasket as a gasket for preventing leakage of exhaust gas from the light passage hole has been shown, but the material and quantity can be set as appropriate. A metal gasket may be arranged on the exhaust gas passage hole side.

An artificial sapphire may be used instead of the optical glass as a material constituting the translucent member filling at least a part of the light passage hole. In the above-described embodiment, the laser light emitted from the irradiation unit is repeatedly reflected by two mirrors to increase the transmission distance in the exhaust gas. However, the laser beam is transmitted through the exhaust gas without using a mirror. The laser beam may be configured to be directly received by the light receiving element. Industrial applicability

As an application example of the present invention, this exhaust gas analyzer can be used to analyze exhaust gas from a combustion apparatus such as a boiler. It can be applied to applications. In addition to exhaust gas analysis of gasoline engines, exhaust gas analysis of diesel engines can be performed, and it can also be applied to exhaust gas analysis applications of other internal combustion engines.

Claims

The scope of the claims

1. Irradiate the exhaust gas discharged from the internal combustion engine with laser light, receive the laser light transmitted through the exhaust gas, and measure the concentration and temperature of the components contained in the exhaust gas based on the received laser light An exhaust gas analyzer for analyzing

The apparatus includes an irradiation unit that emits laser light, a light receiving unit that receives laser light, a light passage hole that guides laser light emitted from the irradiation unit to a path through which the exhaust gas flows, and exhaust gas. A light passage hole for guiding the transmitted laser light to the light receiving unit,

An exhaust gas analyzer characterized in that at least a part of the light passage hole is filled with a translucent member.

2. The irradiation unit and the light receiving unit are fixed to a sensor base that is supported in the path and has an exhaust gas passage hole through which exhaust gas passes;

2. The exhaust gas analyzer according to claim 1, wherein the light passage hole communicates the exhaust gas passage hole with the irradiation unit and the light receiving unit.

3. The translucent member includes a gas facing surface close to the exhaust gas passage hole, and an element facing surface extending from the gas facing surface along the light passage hole and close to the irradiation unit and the Z or light receiving unit. The exhaust gas analyzer according to claim 1 or 2, wherein the translucent member fills a laser beam passage path.

4. The exhaust gas analyzer according to any one of claims 1 to 3, wherein the translucent member is made of optical glass or sapphire.

5. Irradiate the exhaust gas discharged from the internal combustion engine with laser light, receive the laser light transmitted through the exhaust gas, and measure the concentration and temperature of the components contained in the exhaust gas based on the received laser light An exhaust gas analyzer for analyzing

The apparatus includes a sensor base having an exhaust gas passage hole that is mounted in a path through which exhaust gas flows and through which exhaust gas passes.

The sensor base is fixed with the pedestal sandwiched between the sensor base and an irradiation unit that emits laser light, a light receiving unit that receives the laser light, and guides the laser light emitted from the irradiation unit to the exhaust gas passage hole. And the laser beam that has passed through the exhaust gas. A light passage hole for guiding light to the light receiving portion, and a translucent member for sealing the light passage hole in an airtight state,

The exhaust gas analyzer according to claim 1, wherein the pedestal includes a cylindrical portion that is inserted into the light passage hole and presses the translucent member against the sensor base.

6. The exhaust gas analyzer according to claim 5, wherein the translucent member is in contact with the light passage hole with a heat-resistant gasket interposed therebetween, and closes the light passage hole in an airtight state.

7. The exhaust gas analyzer according to claim 5 or 6, wherein the base is made of ceramics.