JP2011232257A - Method for measuring concentration of particulate matter in gas and engine system equipped with apparatus for measuring concentration of particulate matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring a concentration of particulate matter in gas and an engine system equipped with an apparatus for measuring a concentration of particulate matter.SOLUTION: An engine system 200A equipped with an apparatus for measuring a concentration of particulate matter comprises: a diesel engine 100; an exhaust pipe 202 which exhausts exhaust gas 201 coming from the diesel engine 100; and a particulate matter concentration measurement apparatus (hereinafter referred to as "concentration measurement apparatus") 10 which measures a concentration of particulate matter (PM), etc. in the exhaust gas 201 inside the exhaust pipe 202. During the operation of the diesel engine, the amount of PM actually exhausted in accordance with the changes in fuel injection pressure and supercharging pressure can be checked online by constantly measuring the accurate concentration of PM.

Description

  The present invention relates to a particulate matter concentration measuring method in exhaust gas that can stably measure the particulate matter concentration in a gas and an engine system equipped with a particulate matter concentration measuring device.

  Conventionally, for example, it is known to measure the concentration of a dust component in a fuel gas (for example, gasified gas) by Mie scattered light by laser irradiation (see Patent Documents 1 and 2).

JP 2005-24249 A JP 2005-24250 A

By the way, the laser device is required to perform continuous measurement over a long period of time, and extending its life is a problem. In particular, there is a problem of a decrease in light emission efficiency of Mie scattered light due to a decrease in laser output or an optical axis shift. In particular, the Mie scattered light method directly calculates the concentration based on the scattered light intensity, and thus has a problem that it is easily affected by fluctuations on the measuring device side.
Therefore, the advent of a gas component measurement technique that enables stable measurement over a long period of time is eagerly desired.

  In particular, in the case of troubles caused by carbon-derived particulate matter (PM (Particulate Matter)) in the exhaust gas of the ship's engine during navigation, the amount of particulate matter and its components are determined during navigation. Since it is impossible to analyze and it takes a long time for the analysis results to come out, and a lot of loss is incurred during the period until the implementation of the countermeasures, it is necessary to develop a simple and quick measuring device. It has been.

  In view of the above problems, the present invention provides a particulate matter concentration measuring method and a particulate matter concentration measuring apparatus in a gas capable of measuring particulate matter in a gas that is stable over a long period of time and has high measurement accuracy. It is an object to provide an engine system including

A first invention of the present invention for solving the above-mentioned problems is a laser device for irradiating a gas to be measured with laser light, and a first photodetector for measuring Mie scattered light generated by the laser light irradiation. And a particulate matter concentration measuring device comprising a second photodetector for measuring the Raman scattered light generated by the laser light irradiation, and the first photodetector detects the Mie scattered light in advance. The signal intensity (M ₀ ) of the particulate matter is measured, and the signal intensity (R ₀ ) of the Raman scattered light of the reference gas present in the gas to be measured is measured by the second photodetector, Each time the concentration of the substance is measured, the detection signal intensity (M ₁ ) of the particulate matter of Mie scattered light is measured by the _first photodetector, and the reference gas existing in the measurement region is measured by the second photodetector. signal intensity of the Raman scattered light (R ₁₎ is measured, resulting et al And R ₀ / a R ₁ a calibration constant (K), the particulate matter concentration detection signal intensity of the particulate matter measurement time of Mie scattered light (M _1), the calibration factor (K = R ₀ / R ₁ ) To calculate the true particulate matter concentration (M ₂ ).

  According to a second invention, in the first invention, the reference gas is a gas contained in the gas to be measured, and there is a particulate matter concentration measuring method in the gas.

  According to a third aspect of the present invention, there is provided the particulate matter concentration measuring method in the gas according to the first aspect, wherein the reference gas is nitrogen.

  A fourth invention is the particulate matter concentration measurement method in gas according to the first or second invention, wherein the gas to be measured is exhaust gas from a diesel engine.

5th invention is a diesel engine, the exhaust pipe which discharges | emits the exhaust gas from the said diesel engine, the laser apparatus which irradiates a laser beam to the exhaust gas in the said exhaust pipe, and the Mie scattered light which generate | occur | produces by irradiation of the said laser beam And a second photodetector for measuring Raman scattered light generated by the irradiation of the laser light, and Mie scattering by the first photodetector in advance. The signal intensity (M ₀ ) of the particulate matter of light is measured, and the signal intensity (R ₀ ) of the Raman scattered light of the reference gas existing in the gas to be measured is measured by the second photodetector, Each time the particulate matter concentration is measured, the detection signal intensity (M ₁ ) of the particulate matter of Mie scattered light is measured by the _first photodetector, and the reference existing in the measurement region by the second photodetector. Raman scattering light of gas (nitrogen) Measuring the signal strength (= R _1), the resulting R ₀ / a R ₁ a calibration constant (K), the detection signal intensity of the particulate matter in the particulate matter concentration measuring time of Mie scattered light (M ₁ ) Is multiplied by the calibration factor (K = R ₀ / R ₁ ) to calculate the true particulate matter concentration (M ₂ ). If the true particulate matter concentration exceeds the threshold, the engine control is performed. An engine system having a particulate matter concentration measuring device characterized in that it is provided.

  A sixth invention is an engine system comprising a particulate matter concentration measuring device according to the fifth invention, wherein the engine control is control for advancing fuel injection timing.

  According to a seventh aspect of the present invention, in the fifth aspect of the invention, the engine control includes a particulate matter concentration measuring device, wherein the engine control is control for increasing a fuel injection pressure.

  An eighth invention is an engine system comprising a particulate matter concentration measuring device according to the fifth invention, wherein the engine control is control for increasing a supercharging pressure of a turbocharger.

  A ninth aspect of the invention is the engine equipped with the particulate matter concentration measuring device according to the fifth aspect of the invention, wherein the engine control is control for reducing an opening degree of an EGR valve of an exhaust gas recirculation (EGR) device. In the system.

  A tenth aspect of the invention is the particulate matter concentration measuring apparatus according to any one of the fifth to ninth aspects, further comprising controlling the exhaust gas to pass through a removal filter for removing the particulate matter in the exhaust gas. The engine system with

  An eleventh aspect of the invention is an engine system including the particulate matter concentration measuring device according to any one of the fifth to tenth aspects of the invention, which further generates an alarm.

According to the present invention, every time measurement is performed, calibration is performed using the calibration coefficient K with reference to the nitrogen concentration of the initial Raman scattered light, so that the concentration of the particulate matter whose concentration is calibrated (M ₂ ) Can be promptly requested.

  Further, by applying to measurement of particulate matter in exhaust gas from diesel engines, it is possible to appropriately take measures to suppress particulate matter.

FIG. 1 is an explanatory view schematically showing a diesel engine. FIG. 2 is an explanatory diagram schematically showing one cylinder. FIG. 3A is a schematic diagram of an engine system including the particulate matter concentration measuring apparatus according to the present invention. FIG. 3-2 is a schematic view of an engine system including the particulate matter concentration measuring device according to the present invention. FIG. 3-3 is a schematic diagram of an engine system including the particulate matter concentration measuring device according to the present invention. FIG. 4 is a schematic view of an apparatus for measuring the concentration of particulate matter in gas. FIG. 5A is a relationship diagram between the initial Mie scattered light time and the signal intensity. FIG. 5B is a relationship diagram between the wavelength of the initial Raman scattered light measurement and the signal intensity. FIG. 6A is a relationship diagram between the time of Mie scattered light at the time of calibration and the signal intensity. FIG. 6B is a relationship diagram between the wavelength of Raman scattered light measurement during calibration and the signal intensity. FIG. 6-3 is an overlay of measurement results of Mie scattered light. FIG. 7 is a chart of Raman scattering light measurement results of diesel engine exhaust gas. FIG. 8 is a correlation diagram between the Raman scattering signal intensity and the laser output. FIG. 9 is a flowchart for measuring the fine particles in the gas and implementing the countermeasure.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

FIG. 1 is an explanatory view schematically showing a diesel engine. FIG. 2 is an explanatory diagram schematically showing one cylinder.
As shown in FIG. 1, the diesel engine 100 of the present embodiment includes one or more (9 in this embodiment) cylinders 120, a supercharger 111, an air cooler 112, and an exhaust collecting pipe 113. Including. First, a basic configuration of one cylinder 120 will be described with reference to FIG. In the following, a reciprocating type is described as an example of the cylinder 120, but the cylinder 120 may be a rotary type. As shown in FIG. 2, the cylinder 120 includes a cylinder 121, a piston 122, a crankshaft 123, a crank chamber 123a, a connecting rod 124, a cylinder head 125, a combustion chamber 125a, an intake port 126a, and an intake air. A valve 126, an exhaust port 127a, an exhaust valve 127, an injector 128, and an oil pan 129 are included.

  The cylinder 121 is a cylindrical member. The piston 122 is provided in the hollow portion of the cylinder 121. The piston 122 is provided so as to be movable in the central axis direction of the cylinder 121. The crankshaft 123 is provided in the crank chamber 123a so that it can rotate. The crank chamber 123 a is provided on one side of the cylinder 121 in the central axis direction. The crankshaft 123 converts the reciprocating motion of the piston 122 into rotational motion. The connecting rod 124 connects the piston 122 and the crankshaft 123.

  The cylinder head 125 is provided on the other side of the cylinder 121 in the central axis direction (the side opposite to the crank chamber 123a). The combustion chamber 125 a is a space surrounded by the piston 122 and the cylinder head 125.

  The intake port 126a and the exhaust port 127a communicate the outside of the cylinder 120 and the combustion chamber 125a. The intake valve 126 is provided in the intake port 126a. The intake valve 126 adjusts the flow of air between the outside of the cylinder 120 and the combustion chamber 125a via the intake port 126a. The exhaust valve 127 is provided in the exhaust port 127a. The exhaust valve 127 adjusts the flow of air between the outside of the cylinder 120 and the combustion chamber 125a via the exhaust port 127a.

  The fuel injection pump 132 pressurizes the emulsion fuel and guides the emulsion fuel to the injector 128. The injector 128 is provided with, for example, a jet port protruding from the combustion chamber 125a. The fuel injection pump 132 guides the emulsion fuel guided from the fuel supply device 130 to the combustion chamber 125a. Emulsion fuel is a mixture of water and fuel such as light oil and heavy oil. The fuel injection pump 132 may be provided with a jet port protruding from the intake port 126a. The oil pan 129 is provided in the crank chamber 123a. Oil pan 129 stores lubricating oil 131.

  The cylinder 120 configured as described above repeatedly performs one cycle of intake, compression, expansion, and exhaust. Thereby, in the cylinder 120, the piston 122 reciprocates and the crankshaft 123 rotates. The cylinder 120 may perform one cycle with four strokes, or may perform one cycle with two strokes.

Returning to the description of the diesel engine 100.
The supercharger 111 pressurizes air. The supercharger 111 is a so-called turbocharger that pressurizes air by obtaining energy of exhaust gas discharged from the exhaust port 127a shown in FIG. The supercharger 111 may be a so-called supercharger that obtains the rotational force of the crankshaft 123 and pressurizes the air. The air cooler 112 cools the air guided from the supercharger 111. The exhaust collecting pipe 113 communicates with the exhaust port 127a of each cylinder 120. In the present embodiment, the exhaust gas discharged from the exhaust port 127 a of each cylinder 120 is guided to the supercharger 111 through the exhaust collecting pipe 113.

  Here, the crankshaft 123 shown in FIG. 1 is a member common to each cylinder 120. With the above configuration, when each cylinder 120 is operated, the diesel engine 100 rotates the crankshaft 123. In the present embodiment, the diesel engine 100 has been described as including the supercharger 111, but the diesel engine 100 may not include the supercharger 111. That is, the diesel engine 100 may be a naturally aspirated internal combustion engine. In this case, the diesel engine 100 may not include the air cooler 112.

  Next, an engine system including a particulate matter concentration measuring method and a particulate matter concentration measuring device in gas will be described in detail.

FIGS. 3-1 to 3-3 show schematic views of an engine system including a particulate matter concentration measuring apparatus that implements the particulate matter concentration measuring method in gas according to the present invention.
As shown in FIGS. 3-1 to 3-3, an engine system 200A-C including a particulate matter concentration measuring device includes a diesel engine 100 and an exhaust pipe 202 that discharges exhaust gas 201 from the diesel engine 100. And a particulate matter concentration measuring device (hereinafter referred to as a “concentration measuring device”) 10 for measuring the concentration of particulate matter (particulate matter (PM), etc.) of the exhaust gas 201 in the exhaust pipe 202. is there.

  First, the engine 100 in the diesel engine system 200A shown in FIG. 3A includes a supercharger 111 for supercharging intake air. The supercharger 111 is interposed in the exhaust pipe 202. A turbine 111 a and a compressor 111 b interposed in the intake pipe 203 are included. Reference numeral 220 denotes a common rail fuel injection system (CRS) of an electromagnetic high pressure injection system, and 221 denotes a throttle valve.

  The engine 100 in the diesel engine system 200B shown in FIG. 3-2 further includes an exhaust gas recirculation device (hereinafter referred to as “exhaust gas recirculation device”) connecting the exhaust pipe 202 upstream of the turbine 111a and the intake pipe 203 downstream of the compressor 111b. EGR passage 210 (referred to as “EGR”). An EGR valve 211 is interposed in the EGR passage 210. The EGR rate is adjusted by controlling the opening degree of the EGR valve 211. Reference numeral 212 denotes an EGR cooler.

  Further, in the engine 100 in the diesel engine system 200C shown in FIG. 3C, a diesel particulate filter (hereinafter referred to as DPF) 230 is further interposed in the exhaust pipe 202. Normally, the exhaust gas bypasses the DPF 230 and is exhausted. 201 is exhausted to the outside.

FIG. 4 is a schematic diagram of the concentration measuring apparatus 10 according to the present embodiment.
As shown in FIG. 4, the concentration measuring device 10 measures the laser device 13 that irradiates the exhaust gas 201 that is the gas to be measured with the laser light 11 and the Mie scattered light 30 that is generated by the irradiation of the laser light 11. And a second light detector 18 for measuring the Raman scattered light 15 generated by the irradiation of the laser light 11, and the first light detection in advance (at the initial measurement). The signal intensity (= M ₀ ) of the particulate matter of the Mie scattered light 30 is measured by the instrument 31 and the Raman scattered light of the reference gas (for example, nitrogen) present in the gas to be measured is measured by the second photodetector 18. When the signal intensity (= R ₀ ) is measured and the particulate matter concentration is measured, the detection signal intensity (= M ₁ ) of the particulate matter of Mie scattered light is measured by the _first photodetector. , In the measurement area by the second photodetector The reference gas signal intensity of the Raman scattered light (nitrogen) (= R ₁₎ is measured, the resulting R ₀ / R ₁ and calibration constant (K), the particulate matter concentration during measurement of Mie scattered light The true particulate matter concentration (M ₂ ) is calculated by multiplying the detection signal intensity (M ₁ ) of the particulate matter by a calibration coefficient (K = R ₀ / R ₁ ).
Here, in FIG. 4, reference numeral 21 denotes a reflection mirror that reflects the laser beam 11 from the laser device 13, 22 denotes a condenser lens that collects the laser beam 11, and 23 denotes a data processing means (CPU).

Here, the laser beam 11 from the laser device 13 is reflected to the exhaust pipe 202 side through the reflecting mirror 21, condensed by the condenser lens 22 as a condenser, and then sent into the exhaust pipe 202. The laser beam 11 is incident on the measurement region 14 to irradiate the exhaust gas 201 introduced into the exhaust pipe 202.
In this embodiment, laser light is directly introduced into the exhaust pipe 202. However, a sample line branched from the exhaust pipe may be provided and introduced into this sample line.

Further, the Raman scattered light 15 scattered from the center of the measurement region 14 is spectrally separated by the spectroscopic unit 16 via an optical group (not shown) such as a polarizer, a condenser lens, and a filter, for example, and the spectroscopic unit 16 The intensity of light of each wavelength is measured by the ICCD camera 17 connected to the.
The measurement data from the ICCD camera 17 is sent to a data processing means (CPU) 23 where the measurement data is processed.

Next, a method for measuring the particulate matter concentration using the concentration measuring apparatus 10 will be described.
FIGS. 5A and 5B show the measurement results at the initial stage, and the chart of FIG. 5A is a relationship diagram between the time of Mie scattered light and the signal intensity. The chart in FIG. 5-2 is a relationship diagram between the wavelength of Raman scattered light measurement and the signal intensity.
The chart in FIG. 6A is a relationship diagram between time of Mie scattered light and signal intensity. The chart in FIG. 6B is a relationship diagram between the wavelength of Raman scattered light measurement and the signal intensity. FIG. 6-3 is an overlay of the measurement results of the Mie scattered light in FIGS. 5-1 and 6-1.
FIG. 7 is a chart of Raman scattering light measurement results of diesel engine exhaust gas. As shown in FIG. 7, carbon dioxide (CO ₂ ), oxygen (O ₂ ), nitrogen (N ₂ ), and water (H ₂ O) are confirmed.

First, an initial value is obtained in advance using the concentration measuring apparatus 10.
Here, in this embodiment, nitrogen (N ₂ ) gas contained in a large amount in the exhaust gas is used as the reference gas.

Here, as the initial value setting, as shown in the chart of FIG. 5A, the signal intensity (= M ₀ ) of the particulate matter of the Mie scattered light 30 is obtained by the first photodetector 31.
Further, as shown in the chart of FIG. 5B, the signal intensity (= R ₀ ) of the Raman scattered light 15 of the concentration calibration gas (N _{2 in} this example) existing in the measurement region 14 by the second photodetector 18. ) The laser output and the signal intensity of the Raman scattered light are in a proportional relationship as shown in FIG.

That is, each time the particulate matter concentration is measured, the first photodetector 31 measures the detection signal intensity (M ₁ ) of the particulate matter of the Mie scattered light 30 (chart in FIG. 6A) and the second The signal intensity (R ₁ ) of the Raman scattered light 15 of the reference gas (N ₂ ) existing in the measurement region 14 is measured by the photodetector 18 (chart in FIG. 6-2).
As shown in FIG. 6-3, “R ₀ / R ₁ ” obtained from R ₀ obtained in the initial stage and R ₁ actually measured at the time of concentration measurement is set as a calibration constant (K). . Then, the true particulate matter concentration (M ₂ ) is calculated by multiplying the measured signal intensity (M ₁ ) of the particulate matter of the Mie scattered light 30 by the calibration coefficient (K = R ₀ / R ₁ ). To do.

As a result, the true concentration of particulate matter (M ₂ ) whose concentration has been calibrated is quickly calibrated by using the calibration coefficient K with reference to the nitrogen concentration of the initial Raman scattered light 15 as a reference. Can be requested.
At this time, nitrogen used as the reference gas is not introduced from the outside, but is the gas itself contained in the exhaust gas, so that the measurement accuracy is improved.

In order to measure the scattering of the particulate matter (dust), the laser beam 11 is irradiated to the particulate matter in the measurement region 14 through the windows 27-1 and 27-2, and the Mie scattering is performed. Scattered light 30 is introduced into the first photodetector 31 through the window 32a.
Similarly, nitrogen also scatters at a nearby wavelength, and the Raman scattered light 15 passes through the windows 27-1 and 27-2 and is measured by the second photodetector 18.
In this way, light of the same property is measured through the same optical component, so that the calibration accuracy is high.

In contrast, when an output meter is installed outside the window, the calibration accuracy is low because the situation due to the dirt on the window (the transmittance of the excitation light window and the transmittance of the scattered light window) is not considered. It will be a thing.
In addition, when an output meter is installed in the measurement area in the window, contamination of the incident light of the laser light is taken into account and the transmittance of the excitation light window is taken into account, but the transmittance of the scattered light is taken into consideration. As a result, the calibration accuracy is similarly low. Since the output meter is a precision part, if it is installed in the measurement site, it will be greatly affected by dirt, and it may be difficult to measure the output with high accuracy.

  In the present embodiment, diesel engine exhaust gas is used as an example of the gas to be measured. However, the present invention is not limited to this. For example, biomass gas may be used as a generated gas discharged from industrial equipment and used for gasification, for example. Gasified coal, coal gasified gas, and the like can be mentioned, but the present invention can also be applied to gasifiers used for other purposes and exhaust gas from gas engines.

Below, each structural member of the particulate-material density | concentration measuring apparatus in the gas using a laser apparatus is demonstrated.
First, the laser device 13 having the function of outputting the laser beam 11 and irradiating the exhaust gas 201 will be described. The laser device 13 outputs laser light 11 by laser oscillation, and the desired wavelength of the laser light 11 can be used depending on the laser used.
In the present invention, it is preferable to use one having a wavelength of visible light (400 nm to 700 nm). Here, the one of 532 nm is used.

Note that the power meter 26 provided in the exhaust pipe 202 is provided in the traveling direction of the laser beam 11 output from the laser device 13 and is a computing device that can accurately measure the output of the laser beam 11. is there. This numerical value is fed back to adjust the output of the laser device 13.
Thereby, the position detection accuracy of the laser beam is improved, and the optical axis can be corrected quickly. However, it is not suitable for poor environments.

  The reflecting mirror 21 is a mirror that reflects the traveling direction of the output laser beam 11 toward the exhaust pipe 202 where the exhaust gas 201 exists by reflection. By adjusting the angle of the mirror 21, measurement at an arbitrary position in the measurement region 14 is possible.

  The laser light 11 for measurement and the Raman scattered light 15 from the exhaust gas 201 enter and exit from the first window 27-1 and the second window 27-2.

  The second window 27-2 is a quartz glass window for preventing the exhaust gas 201 from flowing out. The reason why it is made of quartz glass is to allow the laser beam 11 to pass through the window. This window is doubled so that gas does not leak even if one piece of quartz glass is broken.

  Further, an electromagnetic valve (not shown) is provided in the path of the laser beam 11 and is normally closed. This is because if the second window 27-2 on the exhaust pipe 202 side is exposed to the exhaust gas 201 over a long period of time, the second window 27-2 is contaminated by impurities in the gas. This is because measurement with a laser becomes difficult due to contamination. The solenoid valve is opened during measurement.

  In addition, the second window 27-2 is directly installed in the exhaust pipe 202. However, the present invention is not limited to this, and a measurement chamber is provided in a line partially branched in the exhaust pipe, and measurement in the measurement chamber is performed. You may make it measure by irradiating the exhaust gas which exists in an area | region with a laser beam. However, the exhaust gas does not need to stay in this place, and can be measured even when the gas is flowing (moving) without stagnation.

  Next, the first photodetector 31 having a function of separating the Mie scattered light 30 from the particulate matter in the exhaust gas 201 and taking it out as measurement data will be described. The first photodetector 31 receives the Mie scattered light 30 from the particulate matter that is a solid component in the exhaust gas 201 by the light receiving unit 32 including the light receiving window 32a, and after the light is introduced by the optical fiber 33, the first photodetector 31 performs spectroscopy. The first detector 31 has a function of taking out as measurement data.

  Further, the second photodetector 18 having the spectroscopic unit 16 having a function of separating the Raman scattered light 15 from the exhaust gas 201 and extracting it as measurement data will be described. Here, the Raman scattered light 15 scattered from the central portion of the measurement region 14 forms an angle from the laser light 11 and passes through the second window 27-2 and the first window 27-1, and the spectroscopic unit. Enter 16.

  The polarizer (not shown) provided in the spectroscopic unit 16 is a polarizing means that transmits only the scattered light having a specific polarization plane without changing the traveling direction. The scattered light transmitted by the polarizer is After being condensed by a condenser lens (not shown), only scattered light having a specific wavelength is transmitted by a filter (not shown). In this embodiment, a filter that transmits light in the region of 570 to 700 nm is used.

  The Raman scattered light 15 in a specific wavelength region is spectrally separated by the spectroscopic unit 16 and the intensity of the light is measured by the ICCD camera 17 connected thereto. The ICCD camera 17 is a photomultiplier device, and here, the intensity of light of each wavelength spectrally separated by the spectroscopic unit 16 is measured.

  As a result of measuring the particulate matter concentration using the concentration measuring apparatus 10 shown in FIG. 4 as described above, if the true particulate matter concentration at the time of measurement exceeds a predetermined threshold, a control device (not shown) Thus, various engine controls are performed to reduce the particulate matter concentration.

Here, the following control methods can be exemplified as engine control for reducing the particulate matter concentration.
In the diesel engine system 200A shown in FIG. 3A, as the first engine control, the fuel injection timing of an electromagnetic high-pressure injection system (for example, CRS (common rail fuel injection system) 130) is advanced to reduce the particulate matter concentration. I am doing so.

  As the second engine control, the fuel injection pressure of an electromagnetic high-pressure injection system (for example, CRS (common rail fuel injection system)) 220 is increased to reduce the particulate matter concentration.

  As the third engine control, the supercharging pressure of the supercharger 111 is increased to reduce the particulate matter concentration.

  In the diesel engine system 200B shown in FIG. 3B, in addition to the first to third engine controls described above, as the fourth engine control, the opening degree of the EGR valve 212 of the exhaust gas recirculation (EGR) device is set. Aperture and particulate matter concentration are reduced.

  In addition, when the first to fourth engine controls are not performed, if the particulate matter concentration reducing effect is not exhibited, the exhaust gas 201 is controlled to pass through the DPF 230 that removes the particulate matter in the exhaust gas 201. It is intended to prevent discharge to the outside.

  Furthermore, when the particulate matter concentration exceeds a predetermined threshold, an alarm may be issued from a control device (not shown) to stop the engine.

  Here, the control means is constituted by a microcomputer or the like. The control means is composed of a RAM, a ROM, etc., and is provided with a storage unit (not shown) in which programs and data are stored. The data stored in the storage unit checks the concentration of particulate matter in the exhaust gas from the engine, determines whether or not a predetermined threshold is exceeded, and controls to suppress particulate matter emission. .

  Next, the control of an example of the particulate matter concentration measurement by the control means and the emission suppression countermeasure will be described. FIG. 9 is an example of a flowchart for measuring the fine particles in the gas and implementing the countermeasure.

  First, the control means measures the discharge concentration of the particulate matter (PM) from the concentration measuring device 10 (step ST1).

  Next, it is determined whether or not the measured density exceeds a predetermined allowable value (threshold value) (step ST2).

If it is determined that the measured PM concentration does not exceed the allowable value (step ST2: Yes), this control is terminated, and the concentration measurement of the particulate matter is continued.
On the other hand, when it is determined that the allowable value is exceeded (step ST2: No), the oxygen concentration and the carbon dioxide concentration in the exhaust pipe 202 are measured (step ST3).

  Based on the measurement result in step ST3, the oxygen excess rate is calculated (step ST4).

Next, it is determined whether the calculated oxygen excess rate is less than a predetermined allowable value (threshold value) (step ST5).
If it is determined that the value is below the allowable value (step ST5: No), the exhaust turbine nozzle is throttled to increase the intake pressure (step ST6).

Thereafter, the oxygen (O ₂ ) concentration and the carbon dioxide (CO ₂ ) concentration in the exhaust pipe 202 are measured again (step ST3).

On the other hand, when it is determined that the oxygen excess rate is not below the allowable value (step ST5: Yes), the oxygen (O ₂ ) concentration and the carbon dioxide (CO ₂ ) concentration of the intake air are measured (step ST7).
Based on the measurement result in step ST7, the intake oxygen concentration is calculated (step ST8).

Next, it is determined whether the calculated intake oxygen excess rate is less than a predetermined allowable value (threshold) (step ST9).
If it is determined that the value is below the allowable value (step ST9: No), the opening of the EGR valve is throttled (step ST10).

Thereafter, the oxygen (O ₂ ) concentration and the carbon dioxide (CO ₂ ) concentration in the intake air are measured again (step ST7).

  On the other hand, when it is determined that the intake oxygen excess rate is not lower than the allowable value (step ST9: Yes), the concentration of the particulate matter is again measured using the concentration measuring device 10 (step ST11).

Next, it is determined whether or not the measured density exceeds a predetermined allowable value (threshold value) (step ST12).
If it is determined that the measured PM concentration does not exceed the allowable value (step ST12: Yes), this control is terminated, and the concentration measurement of the particulate matter is continued.

On the other hand, when it is determined that the allowable value is exceeded (step ST12: No), control for increasing the fuel injection pressure is executed (step ST13).
Thereafter, the concentration of the particulate matter is measured again using the concentration measuring device 10 (step ST11).

In this way, by measuring the concentration of particulate matter accurately while the diesel engine is operating, how much particulate matter (PM) is actually discharged according to changes in fuel injection pressure and supercharging pressure. You can check online.
In addition, as shown in FIG. 7, the Raman scattering analysis can simultaneously detect N ₂ , CO ₂ , O ₂ , and H ₂ O, so that the O ₂ and CO ₂ concentrations can be traced in real time. For this measurement, the composition of the introduced gas can be confirmed in real time by installing a laser measuring meter including the laser device 13 and the second photodetector 18 also in the intake pipe.

  As described above, according to the engine system equipped with the particulate matter concentration measuring method and the particulate matter concentration measuring apparatus according to the present invention, the particulate component in the gas is stable and accurate over a long period of time. (Dust) can be measured. Furthermore, since the concentration of the particulate matter can be accurately measured during engine operation, control for normal operation of the engine can be performed.

DESCRIPTION OF SYMBOLS 10 Concentration measuring device 11 Laser beam 13 Laser device 14 Measurement area | region 15 Raman scattered light 16 Spectrometer 18 2nd photodetector (Raman scattered light detector)
30 Mie scattered light 31 1st photodetector (Mie scattered light detector)
DESCRIPTION OF SYMBOLS 100 Diesel engine 120 Cylinder 200A-200C Engine system provided with concentration measuring device 201 Exhaust gas 202 Exhaust pipe

Claims (11)

A laser device for irradiating a gas to be measured with laser light;
A first photodetector for measuring Mie scattered light generated by the laser light irradiation;
Using a particulate matter concentration measuring device comprising a second photodetector for measuring Raman scattered light generated by the laser light irradiation,
The signal intensity (M ₀ ) of the particulate matter of Mie scattered light is previously measured by the first photodetector, and the Raman scattered light signal of the reference gas existing in the gas to be measured is measured by the second photodetector. Measure the intensity (R ₀ )
Each time the particulate matter concentration is measured, the detection signal intensity (M ₁ ) of the particulate matter of Mie scattered light is measured by the _first photodetector, and the reference existing in the measurement region by the second photodetector. Measure the signal intensity (R ₁ ) of the Raman scattered light of the gas,
The resulting R ₀ / R ₁ and calibration constant (K), the particulate matter concentration detection signal intensity of the particulate matter measurement time of Mie scattered light (M _1), the calibration factor (K = R ₀ / Multiplying R ₁ ) to calculate the true particulate matter concentration (M ₂ ), a particulate matter concentration measurement method in gas. In claim 1,
The method for measuring the concentration of particulate matter in a gas, wherein the reference gas is a gas contained in the gas to be measured. In claim 1,
The method for measuring the concentration of particulate matter in a gas, wherein the reference gas is nitrogen. In claim 1 or 2,
The method for measuring particulate matter concentration in a gas, wherein the gas to be measured is exhaust gas from a diesel engine. A diesel engine,
An exhaust pipe for discharging exhaust gas from the diesel engine;
A laser device for irradiating the exhaust gas in the exhaust pipe with laser light;
A first photodetector for measuring Mie scattered light generated by the laser light irradiation;
A second photodetector for measuring the Raman scattered light generated by the laser light irradiation,
The signal intensity (M ₀ ) of the particulate matter of Mie scattered light is previously measured by the first photodetector, and the Raman scattered light signal of the reference gas existing in the gas to be measured is measured by the second photodetector. Measure the intensity (R ₀ )
Each time the particulate matter concentration is measured, the detection signal intensity (M ₁ ) of the particulate matter of Mie scattered light is measured by the _first photodetector, and the reference existing in the measurement region by the second photodetector. Measure the signal intensity (= R ₁ ) of Raman scattered light of gas (nitrogen),
The resulting R ₀ / R ₁ and calibration constant (K), the particulate matter concentration detection signal intensity of the particulate matter measurement time of Mie scattered light (M _1), the calibration factor (K = R ₀ / R ₁ ) to calculate the true particulate matter concentration (M ₂ )
An engine system equipped with a particulate matter concentration measuring device, characterized in that engine control is performed when the true particulate matter concentration exceeds a threshold value. In claim 5,
An engine system comprising a particulate matter concentration measuring device, wherein the engine control is control for advancing fuel injection timing. In claim 5,
An engine system comprising a particulate matter concentration measuring device, wherein the engine control is control for increasing a fuel injection pressure. In claim 5,
An engine system comprising a particulate matter concentration measuring device, wherein the engine control is control for increasing a supercharging pressure of a turbocharger. In claim 5,
An engine system provided with a particulate matter concentration measuring device, wherein the engine control is control for reducing an opening of an EGR valve of an exhaust gas recirculation (EGR) device. In any one of Claims 5 thru | or 9,
Furthermore, the engine system provided with the particulate matter concentration measuring apparatus characterized by performing control which makes exhaust gas pass through the removal filter which removes the particulate matter in waste gas. In any one of Claims 5 to 10,
Furthermore, the engine system provided with the particulate matter concentration measuring device characterized by issuing an alarm.

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