JP2017173211A - Measurement device and measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement device and measurement method, which allow for reducing the amount of heat transferred to a sensor of the measurement device for measuring temperature and concentration of a measurement target at a relatively high temperature, and prolonging life of the sensor.SOLUTION: A measurement device is configured to have a heat transfer reduction mechanism disposed between a measurement target and a sensor for detecting a physical quantities indicative of condition of the measurement target, the heat transfer reduction mechanism being configured to reduce radiant heat transferred from the measurement target to the sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measuring apparatus and a measuring method that can suppress heat from being transferred to a measuring apparatus due to radiation, convection, or the like from a measuring object such as a combustion chamber of an internal combustion engine.

  In a measuring device that measures the combustion state in a cylinder (cylinder) of an internal combustion engine, there are many relatively high portions such as a combustion chamber that is a measurement target. Even if a gap is provided, heat may be transferred from the measurement object to the measuring device due to radiation, convection, or the like, and the sensor portion of the measuring device may become hot and be damaged.

  In this connection, in an optical sensor for measuring temperature and pressure in a combustion engine, the temperature at which an optical fiber (waveguide means) arranged in front of the optical sensor is surrounded by a metal such as copper or other thermally conductive metal. Provide a descent means to radiate the heat of the optical fiber, or provide a spacer formed of a hollow tube that transmits the beam emitted from the optical fiber, and from the high temperature side end where the measurement object is located to the low temperature side where the sensor is located An optical sensor that reduces heat to the end has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 5628044

  However, with a hollow tube, the amount of heat transfer due to heat convection and heat conduction can be reduced, but heat transfer due to radiant heat (radiant heat) cannot be reduced, and there is a large amount of radiant heat at high temperatures. There is a problem that it is not possible to sufficiently prevent heat from reaching the sensor.

  An object of the present invention is to provide a measuring device and a measuring method capable of reducing the amount of heat transferred to a sensor of a measuring device that measures the temperature, concentration, etc. of a relatively high temperature measuring object, and extending the life of the sensor. There is.

  In order to achieve the above object, a measuring apparatus of the present invention reduces the radiant heat transmitted from the measuring object to the sensor between the measuring object and a sensor that detects a physical quantity indicating the state of the measuring object. A measuring apparatus is provided with a heat quantity reduction mechanism.

  As for this sensor, it refers to the receiving part when measuring by receiving infrared rays or electromagnetic waves, etc., but for measuring the temperature and the concentration of the gas component, the terahertz wave is transmitted to the measurement object, When the reflected wave or the scattered wave is received and measured, the transmitter includes not only the receiver but also the transmitter.

  According to this configuration, by providing a heat transfer amount reduction mechanism that reduces radiant heat, it is possible to prevent failure due to sensor heat by measuring the temperature of internal combustion engines and other parts that are relatively hot and the concentration of gas inside. You will be able to do it.

  Further, in the measurement apparatus, the heat transfer amount reducing mechanism includes a heat absorption part that absorbs radiant heat, a heat reflection part that reflects radiant heat, a space part that excludes an air layer, and And a heat dissipating part that dissipates heat absorbed by the heat absorbing part.

  More specifically, in the measurement apparatus, the heat transfer amount reduction mechanism is configured by a cylindrical body, and a space in which the glass layer and a rare gas are filled in the cylindrical body in order from the front to the rear. Or a vacuum space and a glass layer.

  According to this configuration, by providing a glass layer, this glass layer can be used as a heat absorption part, a coating layer can be provided on the surface of the glass layer, and a heat reflection part can be provided on the upper surface thereof. The space between the glass layers can be made a space portion, and the heat absorption portion, the heat reflection portion, the space portion excluding the air layer, the heat radiation portion, and the like can be easily provided in a compact manner.

  Further, in the above measurement device, when the measurement device is configured to measure a physical quantity indicating the state inside the combustion chamber of the internal combustion engine, the exhaust manifold, or the exhaust pipe, the temperature of the internal combustion engine becomes high. The state of the internal combustion engine can be accurately measured while protecting the sensor in the combustion chamber, the exhaust manifold, or the exhaust pipe.

  And the measuring method of the present invention for achieving the above object is a measuring method for detecting a physical quantity indicating a state of a measuring object, between the measuring object and a sensor for detecting a physical quantity indicating the state of the measuring object. The method is characterized in that the radiant heat transmitted from the measurement object to the sensor is reduced by a heat transfer amount reduction mechanism provided. According to this method, the heat transfer amount reducing mechanism for reducing the radiant heat can be used to measure the temperature of the relatively high temperature portion of the internal combustion engine or the like, the internal gas concentration, and the like while preventing the failure of the sensor. become.

  According to the measuring apparatus and the measuring method of the present invention, the amount of heat transmitted to the sensor of the measuring apparatus that measures the temperature and concentration of a relatively high temperature measurement target can be reduced, and the life of the sensor can be extended.

It is a figure showing typically composition of a measuring device of a 1st embodiment concerning the present invention. It is a figure which shows typically the structure of the measuring apparatus of 2nd Embodiment which concerns on this invention. It is a figure which shows typically the structure of the measuring apparatus of 3rd Embodiment which concerns on this invention. It is a figure which shows typically the arrangement | positioning of a glass layer and a coating layer, and the mode of incidence | injection of electromagnetic waves, permeation | transmission, and reflection. It is a figure which shows typically the mode of arrangement | positioning of a glass layer, a coating layer, and a dielectric multilayer film, and the incidence | injection and reflection of electromagnetic waves. It is a figure which shows typically the relationship of arrangement | positioning with the transmission part in the 1st Embodiment which concerns on this invention, a receiving part, and the combustion chamber of a measuring object. It is a figure which shows typically the relationship of arrangement | positioning with the transmission part in a comparative example without a heat-transfer amount reduction mechanism, a receiving part, and the combustion chamber of a measuring object. It is a figure which shows typically the movement of the radiant heat from a combustion chamber to the transmission part and receiving part in the comparative example of FIG. The prediction result when there is an air layer between the transmitter and the combustion chamber, and between the receiver and the combustion chamber, the experimental result when there is an air layer, and the prediction result when there is no air layer. It is a figure which shows the relationship between the value of ratio of temperature and signal intensity shown typically.

  Hereinafter, a measuring device and a measuring method according to embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, the inside of the combustion chamber of the internal combustion engine is taken as an example of the measurement object, and the physical quantity to be measured is taken as an example of the temperature and the concentration of the gas component. However, the present invention is not limited to these examples. For example, the present invention is not limited to these. For example, the measurement of the temperature and the concentration of gas components in the exhaust manifold of an internal combustion engine, the interior of an exhaust pipe, etc. The present invention can also be applied to a measuring device such as a radiation thermometer that measures temperature in a non-contact manner.

  Note that the sensor here refers to the receiving unit when measuring by receiving electromagnetic waves or the like, but as shown in FIG. 6, the temperature and the concentration of gas components are measured from the transmitting unit 10. The electromagnetic wave Wm such as a terahertz wave (0.02 THz (terahertz) to 30 THz) is transmitted to the combustion chamber 3, and the reflected wave or the scattered wave is received by the receiving unit 30, and the temperature and gas inside the combustion chamber 3 are received. In the case where the concentration of the component is measured, not only the receiver 30 but also the transmitter 10 is included in the sensor here.

  As shown in FIG. 7, in the prior art, when measuring the state of the combustion chamber 3 of the internal combustion engine, the transmitter 10 and the receiver 30 of the measuring device with an air layer sandwiched at a position away from the combustion chamber 3. And a measurement signal (electromagnetic wave: terahertz wave in this case) that has passed through the inside of the combustion chamber 3 reaches the receiving unit 30, and the measurement signal is analyzed to analyze the physical and chemical inside the combustion chamber 3. The target situation. In this case, as shown in FIG. 8, the radiant heat H emitted from the combustion chamber 3 reaches the transmitter 10 and the receiver 30, and the transmitter 10 and the receiver 30 may be destroyed by heat.

  On the other hand, in the present invention, as shown in FIG. 6, the measuring apparatus 1 according to the first embodiment of the present invention includes the combustion chamber (measurement target) 3 of the internal combustion engine and the state of the combustion chamber 3. A heat transfer amount reduction mechanism 20 that reduces the radiant heat H transmitted from the combustion chamber 3 to the transmission unit 10 with the transmission unit (sensor) 10 that transmits a terahertz wave to detect a physical quantity such as a temperature and a gas component. It is set as the structure which has provided. Further, a heat transfer amount reducing mechanism 20 that reduces the radiant heat H transmitted from the combustion chamber 3 to the receiving unit 30 is provided between the receiving unit (sensor) 30 that receives the terahertz wave. In addition, since the heat transfer amount reduction mechanism 20 provided in the transmission part 10 and the reception part 30 can use the same thing, below, although demonstrated with the heat transfer amount reduction mechanism 20 provided in the reception part 30, a transmission part The heat transfer amount reduction mechanism 20 provided in 10 can also exhibit the same effect with the same configuration.

  In the present invention, the transmitter 30 and the receiver 30 as shown in FIG. 6 face each other, and the receiver 30 receives the measurement signal that has passed through the inside of the combustion chamber 3 to be measured from the transmitter 10. Not only the measuring apparatus 1 but also the transmitting direction of the transmitting unit 10 and the receiving direction of the receiving unit 30 cross each other, and the receiving unit 30 detects scattered waves generated by the measurement signal colliding with the substance inside the measurement target. It can also be applied to a measuring device for receiving, and a measuring device for receiving the reflected signal of the measurement signal transmitted from the transmitting unit 10 to the measurement object by the receiving unit 30 when the transmitting unit 10 and the receiving unit 30 are on the same side. .

  As shown in FIG. 1, the heat transfer amount reduction mechanism 20 of the measuring apparatus 1 according to the first embodiment is configured by a cylindrical body having a cylinder 21, and the cylindrical body 21 has a cylindrical body 21. The glass layers 22 and the space portions 23 are alternately provided in this order from the front on the combustion chamber 3 side to the rear on the reception unit 30 side, and the glass layer 22 is provided immediately before the sensor substrate 31 of the reception unit 30. The structure is provided.

  Heat absorption by mixing a heat-absorbing substance such as graphite or soot that resembles a black body into the glass layer 22 provided between the combustion chamber 3 and the sensor substrate 31 of the receiving unit 30. The heat absorbing material absorbs electromagnetic waves that are radiant heat H (for example, infrared rays: about 1 μm to 1 mm in wavelength) Whi, heat is stored in the glass layer 22, and the radiant heat H The electromagnetic wave Whi can be prevented from reaching. With this configuration, the heat transfer amount reduction mechanism 20 is provided with a heat absorbing portion 22 that absorbs the radiant heat H.

  Further, as shown in FIG. 1, the foremost coat layer 22a is provided on the most combustion chamber 3 side of the glass layer 22, and a coating for reflecting the electromagnetic wave Whi which is radiant heat H is applied to the surface of the foremost coat layer 22a. Provide. Further, as shown in FIGS. 1 and 4, the front surface 22 bf of the coating layer 22 b in front of the glass layer 22 in the middle or rear of the cylinder 21, and the coating layer 22 b and the glass layer 22 behind the glass layer 22. A coating for reflecting the electromagnetic wave Whi of the radiant heat H is provided on the boundary surface 22s.

  When this measuring device 1 is used for measuring the combustion chamber 3, as shown in FIG. 1, a through-hole 3b serving as a window communicating with the combustion chamber 3 is provided in the peripheral wall 3a surrounding the combustion chamber 3, thereby measuring the measuring device. 1 is inserted into the through-hole 3b so that the combustion gas is in contact therewith. That is, the cylinder 21 is inserted into the through hole 3 b opened in the wall surface 3 a of the combustion chamber 3, and the glass layer 22 on the combustion chamber 3 side comes into contact with the combustion gas in the combustion chamber 3. Note that the front surface of the glass layer 22 in contact with the combustion gas is exposed to a particularly high temperature substance such as the combustion gas, and the coat layer 22a due to heating may be damaged. The coat layer 22a may not be provided.

  Further, as shown in FIG. 5, the boundary surface 22s where the glass layer 22 and the coating layer 22b are in contact with each other is made to be a mirror surface so that the electromagnetic wave Whi can be easily reflected and the coating layer 22b can be easily formed. For example, the surface roughness is preferably 10 μm or less in terms of JIS arithmetic average roughness (centerline average roughness) Ra.

  As one of the structures for reflecting the electromagnetic wave Whi, there is a coating for reflecting or absorbing radiant heat (infrared wavelength). This coating can produce special transmittance / reflectance wavelength characteristics by appropriately selecting a plurality of materials and film thicknesses having different refractive indexes. In other words, by using this coating, a specific wavelength can be used as the center wavelength of the design, and only a longer wavelength side than that wavelength can be transmitted or reflected, or only a specific wavelength can be transmitted. The structure can be made. Also, a gold thin film coat can be used as the heat reflecting portion.

  As shown in FIG. 4, the reflected coating reflects the electromagnetic wave Whr that is a part of the electromagnetic wave Whi that becomes the radiant heat H, and prevents the electromagnetic wave Whi from reaching the sensor substrate 31 of the receiving unit 30. Necessary electromagnetic waves Wm such as terahertz waves of the signal for use can be passed through and reach the sensor substrate 31. Thus, by providing the coating on the surface of the coating layers 22 a and 22 b on the surface of the glass layer 22, it is possible to configure a heat reflecting portion that reflects the radiant heat H to the heat transfer amount reducing mechanism 20.

  When a part of the electromagnetic wave Wm having a terahertz wave (0.02 THz (terahertz) to 30 THz: about 0.01 m to 15 mm in wavelength) is used for measurement, the frequency band of the reflected electromagnetic wave Whr is measured by this measurement. Frequency band excluding the terahertz wave electromagnetic wave Wm for use. The selection of the frequency band of the reflected electromagnetic wave Whr and the frequency band of the transmitted electromagnetic wave Wm is controlled by the thickness of the glass layer 22, the material of the coating layers 22a and 22b, the thickness and the coating configuration that reflects or absorbs radiant heat, and the like. can do.

  And the space part 23 is provided between this glass layer 22 and the glass layer 22, and in this space part 23, rare gas type gas Ga, such as argon (Ar) which is hard to absorb electromagnetic waves W etc., is enclosed, Vacuum is used to dilute the air volume and eliminate the air layer. With this configuration, the electromagnetic wave Wm irradiated to the combustion chamber 3 by the air layer is attenuated, and the measurement signal received by the receiving unit 30 is prevented from becoming weak. Thereby, the attenuation of the measurement signal can be reduced, so that the signal intensity reaching the sensor substrate 31 can be maintained high, and the detection accuracy is prevented from being lowered. In addition, when it is set as a vacuum, the heat transfer by the convection in the space part 23 can be prevented with the exclusion of this air layer.

  Furthermore, the heat transfer amount reducing mechanism 20 is configured by providing a heat dissipating part that dissipates heat absorbed by the glass layer 22 that is a heat absorbing part around the glass layer 22. In the measuring apparatus 1 according to the first embodiment shown in FIG. 1, the heat radiating part radiates heat to the outside using a fin-shaped heat radiating plate 24 provided around the cylindrical body 21. In addition, in the measuring apparatus 1A of the second embodiment shown in FIG. 2, the heat radiating section uses a heat pipe 25 provided inside the cylindrical body 21 to move heat to the low temperature portion of the cylinder 21, Move heat to the outside.

  Further, in the measuring apparatus 1B of the third embodiment shown in FIG. 3, a flow path 26 is formed inside the cylinder 21 so that the rare gas Ga circulates in the space 23, and an inlet side flow is formed in the flow path 26. The path 26a and the outlet side flow path 26b are connected to each other, and the rare gas Ga is introduced from the inlet side flow path 26a through the flow path 26 into the space 23 to cool the glass layer 22. Thereafter, the rare gas Ga heated by the heat of the glass layer 22 is led out from the outlet side channel 26b to the outside of the space portion 23 through the channel 26, and is rarely discharged outside by a cooling device (not shown) or the like. The gas Ga is cooled. Then, the noble gas Ga, which has been cooled and whose temperature has been lowered, is again put into the channel 26 from the inlet-side channel 26a and circulated. Instead of the rare gas Ga, it is also possible to use polyethylene that melts due to temperature rise and has fluidity.

  With the configuration including the heat radiating portions 24, 25, and 26, the glass layer 22, which is a heat absorbing portion that has absorbed the radiant heat H, can be cooled to dissipate the heat of the glass layer 22, so heat accumulates in the glass layer 22. Thus, the temperature can be prevented from rising, and the heat of the glass layer 22 can be prevented from being transferred to the sensor substrate 31.

  That is, in the measuring devices 1, 1 </ b> A, 1 </ b> B, the heat transfer amount reduction mechanisms 20, 20 </ b> A, 20 </ b> B are configured by a cylindrical body, and a glass layer is sequentially formed from the front to the rear inside the cylindrical body 21 forming the cylindrical body. 22, a space 23 filled with a rare gas Ga or a vacuum space 23, and a glass layer 22. In FIG. 1 to FIG. 3, there are three glass layers 22, and there are two space portions 23 therebetween.

  According to this configuration, by providing the glass layer 22, the glass layer 22 can be used as a heat absorption part, or the coat layers 22a and 22b can be provided on the surface of the glass layer 22, and the heat reflection part ( Coating), and the space 23 can be formed between the front glass layer 22 and the rear glass layer 22, so that the heat absorbing portion 22 and the heat reflecting portion can be easily provided. The space part 23 excluding the 22bf, 22s air layer, the heat radiation parts 24, 25, 26, etc. can be provided in a compact manner.

  That is, these prevent the radiant heat H from reaching the receiving unit 30 in the measuring devices 1, 1 </ b> A, and 1 </ b> B that sense a relatively high temperature measuring object such as the inside of the combustion chamber 3 of the internal combustion engine. It is possible to provide a mechanism that can protect the unit 10 and the receiving unit 30 from heat and can improve the detection accuracy without reducing the measurement signal reaching the receiving unit 30.

  Further, in these measuring devices 1, 1A, 1B, inside the combustion chamber 3 of the internal combustion engine, inside the exhaust manifold (not shown) of the internal combustion engine, or inside the exhaust pipe (not shown) of the internal combustion engine. When the physical quantity such as the temperature indicating the state or the concentration of the gas component is measured, the sensor substrate 31 is used to indicate the state of the combustion chamber 3 of the internal combustion engine, the exhaust manifold, and the exhaust pipe. While protecting, the state of the internal combustion engine can be accurately measured.

  Next, a measurement method in the embodiment of the present invention will be described. This measuring method is a measuring method for detecting a physical quantity such as a temperature indicating the state of the combustion chamber (measuring object) 3 and a concentration of a gas component, and a receiving unit for detecting the physical quantity indicating the state of the combustion chamber 3 and the combustion chamber 3. This is a method characterized in that the radiant heat H transmitted from the combustion chamber 3 to the receiving unit 30 is reduced by the heat transfer amount reducing mechanisms 20, 20 </ b> A, 20 </ b> B provided between the (sensor) 30.

  Further, in this measurement method, the heat absorption unit 22 that absorbs the radiant heat H provided in the heat transfer amount reduction mechanism 20, 20 </ b> A, 20 </ b> B absorbs the radiant heat H and prevents the radiant heat H from being transmitted to the receiver 30. Or the heat reflecting portions 22bf and 22s that reflect the radiant heat H to prevent the radiant heat H from being transmitted to the receiving portion 30 by reflecting the radiant heat H, It is avoided that the electromagnetic wave Wm irradiated to the combustion chamber 3 is attenuated and the measurement signal received by the receiving unit 30 is weakened. Further, the heat absorbed by the heat absorbing unit 22 is radiated by the heat radiating units 24, 25, and 26, the temperature of the heat absorbing unit 22 is prevented from rising, and the heat absorbed by the heat absorbing unit 22 is transferred to the receiver 30. Or prevent it from being transmitted.

  According to the measuring apparatus 1, 1A, 1B and the measuring method of the embodiment of the present invention having the above-described configuration, the heat transfer amount reducing mechanisms 20, 20A, 20B that reduce the radiant heat H are used to relatively increase the temperature of an internal combustion engine or the like. It becomes possible to measure the temperature of the portion to become and the internal gas concentration while preventing the transmitter 10 and the receiver 30 from being damaged by heat.

  That is, as shown in FIGS. 7 and 8, there is an air layer because a gap is provided between the measurement target (detection target) such as the combustion chamber 3 and the transmission unit 10 and the reception unit 30. The radiation (radiation) or convection in the air layer causes the radiant heat H or convection heat to be transmitted to the transmitting unit 10 and the receiving unit 30, or the measurement signal is reduced by the air layer until it reaches the receiving unit 30. Although not shown, the radiant heat H applied to the sensor of the receiver 30 is reduced as compared with a case where a protective cover for protecting the receiver 30 from heat is provided in front of the receiver 30 and the detection signal becomes weak. In addition, by eliminating the air layer, the measurement signal input to the receiving unit 30 can be maintained in a strong state, and the measurement accuracy (detection accuracy) can be improved. Therefore, the state of the measurement target such as the combustion chamber 3 of the internal combustion engine can be detected more accurately. Furthermore, it is possible to extend the life of the receiving unit 30 by reducing the heat applied to the receiving unit 30.

  Note that, as shown in FIG. 9, the signal strength is attenuated due to the presence of a gap (air layer) between the sensor and the combustion chamber. In FIG. 9, the horizontal axis indicates the temperature, and the vertical axis indicates the ratio of the signal intensity to the reference state. 9A shows a prediction result (calculated value) when there is a gap between the receiving unit 30 and the measurement target, and FIG. 9B shows a case where there is a gap between the receiving unit 30 and the measurement target. An experimental result is shown and C of Drawing 9 shows a prediction result (calculated value) when there is no gap between receiving part 30 and a measuring object. There is a large difference in the signal strength ratio value between the prediction result A with a gap and the prediction result C without a gap at the same distance, in order to suppress the effect of making it difficult to detect the value of the signal strength ratio in the air layer. It is understood that it is necessary to prevent the gap, that is, the air layer from being present.

1, 1A, 1B Measuring device 3 Combustion chamber (measuring object)
3a Combustion chamber peripheral wall 3b Through hole 10 Transmitter (sensor)
20 Heat transfer reduction mechanism 21 Cylinder 22 Glass layer (heat absorption part)
22a Frontmost coat layer (heat reflection part)
22b Coat layer 22bf Surface of coat layer (heat reflection part)
22s Boundary surface 23 between coat layer and glass layer 24 Space 24 Heat sink (heat sink)
25 Heat pipe (heat dissipation part)
26 Flow path (heat dissipation part)
26a Inlet side flow path (heat dissipation part)
26b Outlet side flow path (heat radiation part)
30 Receiver (sensor)
31 Sensor board (sensor)
Ga Noble gas H Radiant heat W Electromagnetic wave Whi Electromagnetic wave Wr greatly involved in radiant heat Reflected electromagnetic wave Wm Electromagnetic wave for measurement

Claims (8)

  A measurement apparatus comprising a heat transfer amount reduction mechanism for reducing radiant heat transmitted from the measurement object to the sensor between the measurement object and a sensor that detects a physical quantity indicating the state of the measurement object.   The measuring apparatus according to claim 1, wherein the heat transfer amount reduction mechanism includes a heat absorption unit that absorbs radiant heat.   The measuring apparatus according to claim 1, wherein the heat transfer amount reducing mechanism includes a heat reflecting portion that reflects radiant heat.   The measurement apparatus according to claim 1, wherein the heat transfer amount reduction mechanism includes a space portion from which an air layer is excluded.   The measuring apparatus according to claim 2, wherein the heat transfer amount reducing mechanism includes a heat radiating unit that radiates heat absorbed by the heat absorbing unit.   The heat transfer amount reducing mechanism is configured by a cylindrical body, and a glass layer, a space portion filled with a rare gas or a vacuum space portion, and a glass layer are provided in this cylindrical body in order from the front to the rear. The measuring apparatus of any one of Claims 1-5.   The measuring apparatus according to claim 1, wherein a physical quantity indicating a state inside a combustion chamber of an internal combustion engine, an exhaust manifold, or an exhaust pipe is measured.   In a measurement method for detecting a physical quantity indicating a state of a measurement target, the measurement target is transmitted from the measurement target to the sensor by a heat transfer amount reduction mechanism provided between the measurement target and a sensor for detecting a physical quantity indicating the state of the measurement target. A measurement method characterized by reducing radiant heat.

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