JPH056527Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a measuring device for measuring exhaust smoke concentration of automobiles, especially diesel cars, in real time. This invention relates to an automobile exhaust smoke concentration measurement device that is used by being directly connected to the exhaust stack of a vehicle.

[Prior Art] Conventionally, as a method for measuring the concentration of automobile exhaust smoke in real time, a hole is drilled in the middle of the exhaust pipe, and a projector and a light receiver are attached to both sides of the hole.
The end of line system (Line System) or the End of Line System (Line System) is adopted, or the end of line system (Line System) is used.

However, in the former method, the surface of the glass or lens in the optical system is significantly contaminated, and the indicated value for the same concentration tends to change over time. In addition, in the latter method, since the exhaust gas is once released into the outside air, it is immediately diffused and diluted into the outside air, and it is strongly affected by turbulence in the outside air, making it difficult to expect stable measurements. In addition,
Due to the small diameter of the exhaust pipe, it is difficult to expect high-sensitivity measurements using the light transmission method, even at high concentrations.

Among these problems, to deal with contamination of the glass or lens surface in an optical system, we use an air curtain or sheath air that is formed by pumping clean air from the outside, and use a reference light using a prism. Alternatively, this can be dealt with by a self-compensation system using a transceiver with two built-in emitters and receivers.

Therefore, the Lambert
It is necessary to increase the optical path length L of the measurement beam in Beer's law (I=Io e ^-kcL , where I: transmitted light intensity, Io: incident light intensity, K: absorption coefficient).

It is also important that problems such as pressure loss, particle deposition, flow turbulence, and vortex flow do not occur at the inlet and outlet of the exhaust gas in the measurement duct.

[Problem to be solved by the invention] The technical problem of the invention is that in a measurement duct that is directly connected to an automobile exhaust stack, there is a disturbance caused by the release of exhaust gas to the outside air, or a disturbance caused by the exhaust gas of the measurement duct. The above-mentioned optical path length L has been increased to enable high-accuracy, high-sensitivity real-time measurement while avoiding the effects of flow turbulence and vortex generation at the introduction and exit sections, and allows for flexible optical path length. By changing to , you can easily expand the measurement range while
An object of the present invention is to provide an automobile exhaust smoke concentration measuring device with improved accuracy.

[Means for Solving the Problems] In order to solve the above problems, the automobile exhaust smoke concentration measuring device of the present invention connects the connecting tube directly connected to the automobile exhaust stack and the exhaust passage connected to the exhaust system in a straight line. A beam for measuring exhaust smoke concentration is connected to both ends of a cylindrical measuring duct, and projected into the measuring duct along the axial direction of the duct. A guide vane is provided at the connecting tube portion of the measuring duct and the connecting portion with the exhaust passage to prevent the exhaust gas from straying, thereby ensuring a smooth introduction and exit portion of the exhaust gas. The length of the optical path expanding portion in the duct can be adjusted by expanding and contracting the fitting cylinder portion, and the measurement beam is projected onto both ends of this optical path expanding portion to attenuate the light transmitted through the exhaust gas. We have adopted a technical means of installing a light-transmission type duct concentration meter that measures exhaust smoke concentration in real time.

[Operation] Exhaust gas is introduced into the measuring duct through the connecting tube directly connected to the exhaust stack of the automobile, and the light-transmitting duct concentration meter installed at both ends of the measuring duct expands the optical path. When measuring smoke concentration, it is possible to increase the optical path length according to Beer-Lambert law during the flow of exhaust gas, so it is possible to measure smoke concentration without being affected by external disturbances.
Real-time measurement with high precision and high sensitivity becomes possible.

In addition, a guide vane is provided at the connection section of the measurement duct and the connection section with the exhaust passage to form a smooth introduction/exit section for the exhaust gas, and the length of the optical path expansion section of the duct can be adjusted by expanding and contracting the fitting section. Since it is adjustable, the above-mentioned optical path length L can be adjusted without being affected by flow turbulence or vortex generation at the exhaust gas introduction/output part of the measurement duct.
Automotive exhaust smoke concentration measurement enables high-accuracy, high-sensitivity real-time measurement by increasing the diameter, and by freely changing the optical path length, the measurement range can be easily expanded while improving accuracy. You can get the equipment.

[Example] FIG. 1 shows an example of the automobile exhaust smoke concentration measuring device of the present invention.

This automobile exhaust smoke concentration measuring device is configured to directly connect to the exhaust stack 2 of the automobile 1 to measure the automobile exhaust smoke concentration without using a dilution cylinder. A connecting cylinder part 4 connected to the exhaust pipe 2 of the automobile 1 is provided at one end of the cylindrical measuring duct 3, and the measuring duct 3
At the other end, an exhaust passage 5 connected to an exhaust system is provided.

The measurement duct 3 is configured to project a beam for measuring exhaust smoke concentration into the exhaust gas introduced there through the connecting tube portion 4, and the beam stably flows through the exhaust gas over a necessary optical path length. At both ends of the linear cylindrical optical path enlarging portion 6 having the required effective optical path length,
A connecting tube portion 4 to the automobile exhaust stack 2 and an exhaust passage 5 connected to an exhaust system are connected in a branched manner. A light transmitting type dust densitometer projector projects a measuring beam onto both ends of the linear optical path expansion portion 6 of the duct 3 in the axial direction of the duct 3, that is, in the direction of the flow of exhaust gas in the duct. 8 and a light receiver 9 are arranged.

In addition, the connecting cylinder portion 4 in the measurement duct 3
Guide vanes 13 and 14 are provided at the connection between the exhaust passage 5 and the emitter 8 and the receiver 9 to prevent the exhaust gas from straying into the emitter 8 and the receiver 9, and to guide the exhaust gas in and out in a rectified state. Forms a smooth gas inlet and outlet. Furthermore, the measurement duct 3 has a length of the optical path expansion portion 6 that is inserted into the cylindrical portion 7.
It is constructed so that it can be adjusted arbitrarily by expanding and contracting.

On the other hand, the exhaust passage 5 is connected to an exhaust system including a duct collector constituted by a filter, etc., and a blower, and the exhaust gas is sent as it is into the dilution wind cylinder, or Particles are collected by a filter, the mass concentration of which is checked intermittently, and then released to the atmosphere via a blower.

The light transmission type dust densitometer mentioned above has a controller 1.
0, and it is possible to measure the exhaust smoke concentration in real time from the amount of attenuation of light transmitted through the exhaust gas. The configuration is not limited to the above, but it is possible, for example, to arrange a projector/receiver at one end of the optical path expanding section 6 and a reflector at the other end, or to arrange a transceiver having a projector and a receiver at both ends of the optical path expanding section 6. You can select the equipment to be used and its arrangement as appropriate.

The light emitter 8 and light receiver 9 constituting the light transmission type duct densitometer are supplied with air from the outside through an air supply path 11 in order to prevent the amount of light emitted and the amount of light received from being attenuated due to particles adhering to the glass or lens surface of the optical system. By pumping the introduced clean air for purging between the exhaust gas circulation part of the duct 3 and the emitter/receiver, clean sheathed air is applied between the measurement duct 3 and the vicinity of the optical system is filled. The flow path for supplying clean air is opened.

In the automobile exhaust smoke concentration measuring device having the above configuration, exhaust gas is introduced into the measuring duct 3 through the connecting tube portion 4 directly connected to the exhaust stack 2 of the automobile 1, and the optical path enlarged portion 6 in the measuring duct is When measuring the exhaust smoke concentration using a light transmission type dust concentration meter, the optical path length can be set long in the uniform flow of exhaust gas, so it is possible to measure the concentration of exhaust smoke with high accuracy and without being affected by external disturbances. Highly sensitive real-time measurement becomes possible.

Further, guide vanes 13 and 14 are provided at the connecting portion of the measuring duct 3 with the connecting cylinder portion 4 and the exhaust passage 5.
to form a smooth introduction and exit part for exhaust gas,
The length of the optical path expanding portion 6 in the duct 3 can be adjusted by expanding and contracting the fitting tube portion 7.
Real-time measurement with high precision and high sensitivity is possible by increasing the optical path length L while avoiding the effects of flow disturbances and eddy currents at the exhaust gas inlet and outlet part of the measurement duct 3. Furthermore, by freely changing the optical path length, it is now possible to perform highly accurate continuous measurements over a wide range of concentrations, from low to high concentrations, which was previously unattainable, expanding the measurement range and increasing accuracy. A device for measuring the concentration of automobile exhaust smoke can be obtained.

[Effects of the invention] According to the measurement device of the invention detailed above, the measurement duct is directly connected to the exhaust stack of the automobile, and the required effective optical path length can be secured in the measurement duct. As a result, it is possible to perform high-precision, high-precision real-time measurement extremely simply and without the influence of turbulence caused by outside air.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Automobile, 2...Exhaust tube, 4...Connection cylinder part, 5...Exhaust passage, 3...Measurement duct, 6...
...Optical path enlargement part, 7... Fitting cylinder part, 8... Emitter, 9... Light receiver.

Claims (1)

[Scope of utility model registration request] A connecting tube that directly connects to the automobile exhaust stack and an exhaust passage that connects to the exhaust system are connected to both ends of a linear cylindrical measuring duct. An optical path expansion part is provided that allows the beam for measuring exhaust smoke concentration projected along the exhaust gas to pass through the exhaust gas over the required optical path length,
A guide vane is provided at the connection tube part of the measurement duct and the connection part with the exhaust passage to prevent the exhaust gas from straying, to form a smooth introduction and exit part for the exhaust gas, and the optical path expansion part of the duct is ,
Its length can be adjusted by expanding and contracting the fitting cylinder part,
A light transmission type dust concentration meter is installed at both ends of this optical path expansion part to measure the exhaust smoke concentration in real time from the amount of attenuation of the light transmitted through the exhaust gas by projecting the measurement beam. Vehicle exhaust smoke concentration measuring device.