JPS5926277Y2 - Oil mist concentration detection device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a concentration detection device for a mixture of atomized liquid fuel and air, that is, a so-called oil mist.

This type of oil mist is a mixture with air that is obtained by atomizing liquid fuel using ultrasonic waves. It is important to always maintain the ratio between the liquid fuel and the amount of air, the so-called air-fuel ratio, at a predetermined value.

This air-fuel ratio can be easily determined by detecting the concentration of oil mist. Conventionally, in order to detect the concentration of oil mist flowing inside the conveying pipe, a
A set of light-emitting and light-receiving elements are arranged facing each other, and the amount of diffuse reflection of a constant amount of light from the light-emitting elements by the oil mist is checked as a change in the amount of light received by the light-receiving element. The detection result of this oil mist concentration is fed back to the atomization device to control the air-fuel ratio, thereby making it useful for complete combustion.

A conventional example of this type of oil mist concentration detection device is shown in FIGS. 1 and 2.

In each of these figures, reference numeral 1 denotes a conveying pipe through which the oil mist passes in a certain direction shown by arrow A, that is, from left to right in the conventional example in FIG. 1, and from bottom to top in the conventional example in FIG.
2 and 3 are l pairs of protective tubes each provided inside the tube wall;
4 and 5 are translucent window plates that close the tube ends of each protection tube, and 6 and 7 are a pair of light emitting and light receiving elements arranged to face each other inside each protection tube. The radiation light B is irradiated onto the oil mist flowing inside the conveying pipe 1, and the light receiving element 7 is obtained through the oil mist.
The target concentration of oil mist is detected from the amount of light received.

However, according to each of these conventional examples, in the conventional example shown in FIG. Since the window plate 4.5 covering the light emitting and light receiving elements 6, 7 is perpendicular to the flow direction A, and the protective films 2, 3 are also in a protruding position, the oil is irradiated with synchrotron radiation B. Turbulent flow is generated in the mist, and the stagnation accompanying this turbulent flow tends to cause oil mist to adhere to and aggregate on each window plate 4, 5. In addition, in the conventional example shown in FIG. Although none of the members protruding into the conveying pipe 1 causes turbulence in the oil mist flowing inside the pipe, oil mist particles or a film adhering to the inner wall surface of the conveying pipe 1 gradually develop. Since these are done on the entire surface of the inner wall, the particles or coatings are continuous and accumulate due to their surface tension, which obstructs light emission and light reception in each conventional example and reduces detection accuracy. There were drawbacks.

In view of these conventional circumstances, this invention aims to improve these shortcomings by ensuring that the configuration of the detection unit, especially the amount of oil mist adhering to the window plate surface, is always maintained in a nearly constant state. This is what I did.

Hereinafter, one embodiment of the oil mist concentration detection device according to this invention will be described in detail with reference to FIG.

In this FIG. 3, the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts, and in the embodiment shown in FIG. A pair of protective tubes 8 are placed at predetermined positions on each inner wall surface.
. , 11, and a set of light-emitting and light-receiving elements 6, 7 is housed in each protective tube 8, 9 and arranged facing each other in the same manner as described above.

Therefore, in this embodiment, as in the conventional example described above, the oil mist is irradiated with the radiation light B from the light emitting element 6, and the light is received by the light receiving element 7 to detect the oil mist concentration. However, in this embodiment, since the protective tubes 8 and 9 protrude from the inner wall surfaces 1a and 1a of the conveying tube 1, the window plates 10 and 11 are contaminated by particles or coatings that adhere to the inner wall surfaces. never be done.

These particles or coatings are formed independently on each of the window panels 10, 11 in the same way as on the inner wall surfaces 1a, la, but the particles or coatings accumulated due to the surface tension are Since the oil mist is independent, some of it is pushed upwards by the flow of oil mist in the A direction.
Particularly, as the particles or coatings grow in the downwardly extending surplus portions 10a and 11a, the gravity increases, and the particles or coating gradually become the surplus portions 10a.

11a, and as a result, on the surface of each window pane 10, 11, the layer of particles or coating becomes thinner and more uniform as it goes upward, and this state never changes. , Therefore, the detection accuracy can be kept constant at all times.

As described in detail above, according to this invention, each tube end of a pair of protection tubes is made to protrude from the inner wall surface of the conveying tube, and there is a surplus portion downwardly with respect to each of these tube ends. With an extremely simple configuration that only requires a translucent window plate,
The detection accuracy of the oil mist concentration can be sufficiently improved, and the oil mist air-fuel ratio can be reliably controlled.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing a conventional oil mist concentration detecting device, and FIG. 3 is a cross-sectional view showing the structure of an embodiment of the oil mist concentration detecting device according to the present invention. 1... Conveyance tube, 1a, 1a... Inner wall surface, 6 and 7... Light emitting and light receiving element, 8, 9
... Protection tube, 10.11 ... Translucent window plate, 10a, lla ... Surplus part.

Claims (1)

[Scope of utility model registration request] A pair of protection tubes is provided at a predetermined position on each opposing inner wall surface of a conveying tube through which oil mist passes from below to above, with each tube end protruding from the inner wall surface, and each of these tube ends is The oil mist concentration is characterized in that it is closed by a translucent window plate with a surplus portion extending downward, and a pair of light emitting and light receiving elements are housed in each protection tube and arranged facing each other. Detection device.