JPS6155312A - Detector for flame figure in combustion chamber of reciprocating internal-combustion engine - Google Patents

Abstract

PURPOSE:To externally detect a flame figure in a combustion chamber by air- tightly providing a seeing through window through which a flame figure is transmitted in the combustion chamber on the side of a penetrated hole and fixing an optical fiber on a side opposite to the combustion chamber on the above side. CONSTITUTION:A penetrated hole to externally propagate a flame figure generated in a combustion chamber 2 is formed on the partition wall 3 of the combustion chamber 2 of a reciprocating internal-combustion engine 1. A seeing through window 11 to pass the flame figure is air-tightly provided on the inside of the combustion chamber 2 on the side of a penetrated hole 4. An optical fiber 19A into which the flame figure passing through the seeing through window 11 is fed is fixed on the outside of the combustion chamber 2 on the side of the penetrated hole 4. The seeing through window 11 is formed into condensing lens type, and its focus serves as the plane of incidence for the light fiber. In addition, this plane is at least arranged farther from the outside of the partition wall located near by the combustion chamber. The flame figure in the combustion chamber can be therefore externally detected.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a reciprocating internal combustion engine combustion system that detects the combustion state by transmitting light energy (hereinafter referred to as a flame image) generated by combustion in the combustion chamber of the internal combustion engine to the outside. This invention relates to a chamber flame image detection device.

[Prior art]

Details of the combustion status of fuel gas inside a high-temperature, high-pressure combustion chamber, such as the combustion chamber of a reciprocating internal combustion engine such as a gasoline or diesel engine, such as fuel flow status, ignition timing, flame propagation status, and exhaust gas There are many aspects of the flow that are unclear.

Since these factors are greatly involved in combustion efficiency, those involved have been conducting vigorous research on them, and the phenomenon has been elucidated to some extent. However, most of these are results from tests using models or experimental model engines, and there are still many unknowns about the details of actual engines. This is because the combustion chamber of a reciprocating internal combustion engine or the like has extremely adverse environmental conditions due to the presence of high temperature and high pressure gas, and these adverse conditions impede various measurements.

Recently, some types of optical fibers or long quartz glass rods that are being used for various data transmission and visual inspection of the inside of the human body in medicine have excellent light transmittance and high pressure resistance, and can withstand a certain degree of high temperature. It not only withstands a lot of heat, but is also extremely resistant to various types of external noise, and has excellent properties such as being highly flexible when it comes to small diameters.

Therefore, if these light propagation materials (hereinafter referred to as optical fibers) are installed near the partition wall of the combustion chamber, and the flame image generated during combustion in the combustion chamber is made to enter the optical fiber by some means and transmitted to the outside, Not only can phenomena within the combustion chamber be clarified, even if only partially, but the state of the flame image can also be detected.

This is because flame images have brightness at high temperatures or emit high levels of infrared rays, so the existence of the flame image or its occurrence can be easily transmitted to the outside through an optical fiber.

On the other hand, although it is very convenient to use optical fibers as a means of transmitting such information, optical fibers are made of extremely fragile materials.Usually, to compensate for this drawback, the surroundings of optical fibers are It is often covered with a resin coating or the like to ensure strength and flexibility.

However, this resin coating cannot be applied because there is a risk of damage due to combustion or the influence of high-pressure gas in high-temperature areas such as inside the combustion chamber. When installing an optical fiber nearby, it must be inserted without any resin coatings, etc., or it must be installed in a location where these coatings will not be damaged, which poses problems such as requiring special measures. .

[Summary of the invention]

This invention has been made in consideration of the above points, and in order to detect the combustion situation by propagating the flame image of the reciprocating internal combustion engine to the outside, a through hole is formed in the partition wall of the reciprocating internal combustion engine. A see-through window is provided on the combustion chamber side of the partition wall, and an optical fiber is installed on the outside side of the partition wall to allow the flame image that has passed through the see-through window to enter and propagate to the light receiving element, so that the flame image inside the combustion chamber can be detected from the outside. This is what I did. The present invention will be explained below with reference to the drawings.

[Embodiments of the invention]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, in which a combustion condition detection device is attached to a reciprocating internal combustion engine. In this figure, 1 indicates a part of a reciprocating internal combustion engine. 2 is the combustion chamber.

Reference numeral 3 denotes a partition wall of the combustion chamber 2, 4 a through hole formed in the partition wall 3, and 5 an overall detection device provided in the through hole 4 for detecting the combustion status of the combustion chamber 2.

FIG. 2 is a side sectional view showing an enlarged main part of FIG. 1, in which the same reference numerals as in FIG. 1 indicate the same parts, and 6 is a water jacket for cooling the partition wall 3. In the detection device 5, reference numeral 11 denotes a see-through window, and the one shown is a lens, which transmits the flame image in the combustion chamber 2 and collects the light, so it is made of a heat-resistant and pressure-resistant material, e.g. It is made of artificial sapphire. 12 is the transparent window 11
It is attached to the bulkhead 3 by screwing with the mounting bracket equipped with. Reference numeral 13 denotes a bonding agent that airtightly fixes the transparent window 11 to the mounting fitting 12, and is heat resistant and airtight. Reference numeral 14 designates the entire light receiving device that receives the flame image and propagates it to the outside, the details of which are shown in FIG.

That is, FIG. 3 shows an enlarged view of the light-receiving device 14 of FIG. 2, and 15 is a metal cylindrical holding fitting having a tapered surface 16 on the tip side. 17 is a fixed member;
It is fixed to the tip of the holding fitting 15 by welding or the like. A protective tube 18 is fixed to the base of the holding fitting 15 by welding or the like.

Reference numeral 19 denotes an optical fiber, and those covered with resin or cladding have an optical fiber strand at the center.

The optical fiber 19 is attached to the holding fitting 15. The main part of the part covered with the protective tube 18 etc. is further covered with two protective sheaths 20 and 21 on the front and back, which is particularly important for small diameter optical fibers 19 etc. during manufacturing. This is to prevent damage due to slight stress.

This optical fiber 19 is inserted so as to pass through the center of the holding fitting 15, and the optical fiber 19 (the optical fiber wire for the one covered with a cladding) is exposed at the tip part, and this is inserted into the fixing member 17. Positioned and heat resistant fixing material 2
2, it is airtightly fixed. Further, a heat-resistant filler 23 is filled between the outer periphery of the optical fiber 19 and the inner surface of the holding fitting 15, and furthermore, the optical fiber 19 within the protection tube 18 is fixed with a heat-resistant fixing material 22. Reference numeral 24 denotes a light incident surface located behind the transparent window 11. Reference numeral 25 indicates the light exit side, and reference numeral 26 indicates a mounting bracket to which the holding bracket 15 is attached, which is airtightly attached to the partition wall 3 by screwing using a special tool or the like.

The mounting bracket 26 is provided with a mounting hole 27 that passes through the mounting bracket 26 and has a center line concentric with the center line of the holding bracket 15 to be attached, and a smooth tapered surface 28 is formed in this mounting hole 27. Furthermore, the outer side of the mounting hole 27 is a screw hole 29. Reference numeral 30 designates a mounting screw, which has a stepped portion 32 in which the rear end of the holding fitting 15 comes into contact with a central through-hole 31, and a threaded portion 33 that is screwed into the threaded hole 29 of the mounting fitting 26.

Referring again to FIG. 2, 34 is a connector for the optical fiber 19, 35 is an adapter for connecting the connectors 34 and 34, and 36 is a light receiving element. Note that 19A is an optical fiber for extension for setting the light receiving element 36 at a position where it is not affected by the heat of the reciprocating internal combustion engine 1, and a plurality of optical fibers can be connected in series via the connector 34.

Next, the operations in FIGS. 2 and 3 will be explained.

After the flame image in the combustion chamber 2 enters and passes through the viewing window 11,
The light is incident on the entrance surface 24 of the optical fiber 19 . The flame image that entered the optical fiber 19 is transferred to an intermediate adapter 35. The light propagates to the optical fiber 19A via the connector 34 and the like, is received by the light receiving element 36, and is converted into an electrical output.

In the embodiment shown in FIG. 2, a water jacket 6 is installed inside the partition wall 3, so that even if the entrance surface 24 of the optical fiber 19 is inside the outer partition wall 3, it is not exposed to the combustion chamber 2. Another feature of this embodiment is that the thermal load on the optical fiber 19 is reduced because it is located outside the partition wall 3 which is in a high temperature state in the immediate vicinity.

FIG. 4 is an enlarged side sectional view of main parts showing another embodiment of the present invention, in which the same reference numerals as in FIGS. 1 to 3 indicate the same configuration;
Reference numeral 1 denotes a mounting bracket to which the see-through window 11 and the light-receiving device 14 are integrally attached, and a through-hole portion 42 is formed between the see-through window 11 and the light-receiving device 14. And this through hole 4
2 is hermetically sealed by the see-through window 11 and the light receiving device 14, and the space of the through hole 42 is evacuated or filled with inert gas to prevent heat and rust. 43 is the partition wall 3
A female thread 43a is formed in the through hole formed in the mounting bracket 41.
It is sealed by. In addition, the entrance surface 2 of the optical fiber 19
4 is set at least outwardly from the outer surface 3a of the partition wall 3 to prevent the optical fiber 19 from being damaged by high temperatures. The point based on the concept of installing the device outward from 3 is the same as the embodiment shown in FIG.

In addition, the incident angle θ is the maximum incident angle with respect to the incident surface 24 of the optical fiber 19, and the angle line is set so that the long line is inside the effective incident diameter d of the perspective window 11.
The effective incident diameter d of the optical fiber 19 is set so that it is at least on the outside of the maximum incident angle line of the incident surface of the optical fiber 19 to prevent infrared scattered light from entering due to heating of the mounting bracket 41 itself, as described later. That's what I do.

In this way, if the viewing window 11 and the optical fiber 19 are fixed together in advance with the mounting bracket 41, and then the mounting bracket 41 is hermetically fixed to the through hole 43 of the partition wall 3 by fitting, the focal point of the viewing window 11 can be fixed. Adjustment, vacuum maintenance of the through hole 42, and filling of inert gas 1 assembly work can be easily performed.

In the embodiment shown in Fig. 4, when the temperature level of the flame image detected by the optical fiber 19 is low, that is, when the flame image is infrared rays with a long wavelength, the object itself near the mounting bracket 41 becomes hot. When the optical fiber 19 focuses the infrared rays generated by this, the so-called combustion level S/N ratio decreases due to disturbance, which poses a problem. Objects that may emit high-level infrared radiation at high temperatures in the range on the extension of the maximum incident angle θ determined according to the number NA (in Figure 4, the mounting bracket 41
), so that only the light incident on the optical fiber 19 through the viewing window 11 is focused in a limited manner. Moreover, when artificial sapphire is used for the transparent window 11, even if the transparent window 11 becomes high in temperature, the level of infrared rays emitted by the transparent window 11 itself is significantly lower than that of metal, etc., and is expected to have a significant effect in eliminating the effects of external disturbances. can.

By adopting the method shown in FIG. 4, many of the problems associated with the optical fiber 19, which has various difficulties in propagating the flame image to the outside, can be solved by projecting directly into the high-temperature part of the combustion chamber 2 and making the flame image incident thereon. Ru. In other words, the combustion of the reciprocating internal combustion engine reaches a high temperature that adversely affects the optical fiber 19 during a very limited period of the combustion period, and only during this period is the heat-resistant material made of quartz etc. In order to protect the excellent optical fiber 19 from high temperatures, it is sufficient to cover it with artificial sapphire or the like. Furthermore, artificial sapphire not only has better heat resistance and hardness than quartz, but also has excellent transparency to light, especially in the infrared region.

Regarding the method of fixing the optical fiber 19 inside the light receiving device 14, it is not necessary to keep it airtight by filling the outside of the transparent window 11 with inert gas, or the heat load inside the light receiving device 14 is reduced. If the size is not large, a simpler method may be used, for example, fixing the optical fiber 19 with a normal sealant or the like to determine the position relative to the viewing window 11.Furthermore, the optical fiber 19 may be made to enter the optical fiber 19. If the level of the flame image is high and there is no need to provide the viewing window 11 with a light condensing function, this may be a flat window.

〔Effect of the invention〕

As explained above, this invention forms a through hole in the partition wall of the combustion chamber of a reciprocating internal combustion engine through which a flame image generated in the combustion chamber propagates, and a see-through window that transmits the flame image is placed on the side of the combustion chamber on the side of the through hole. Since the optical fiber through which the flame image transmitted through the transparent window enters is fixed to the side of the through hole opposite to the combustion chamber, the flame image in the combustion chamber can be sufficiently focused.

In addition, in this invention, a mounting bracket having a through-hole part through which a flame image propagates is attached to the through-hole, and a see-through window through which the flame image passes is airtightly provided on the combustion chamber side in the through-hole part. Since the optical fiber through which the flame image enters is tightly sealed on the opposite side of the combustion chamber, the mounting bracket can be constructed separately from the partition wall, so the space inside the mounting bracket can be evacuated or filled with inert gas. Therefore, a heat insulating effect and a rust prevention effect can be obtained inside the through hole. Furthermore, since the see-through window is made of artificial sapphire, the heat resistance of the see-through window is improved and infrared rays can be transmitted better. Furthermore, since the viewing window is formed in the shape of a condensing lens and its focal point is the incident surface of the optical fiber,
The light focusing function of the flame image has been improved, and the effective entrance outer diameter of the viewing window is set to be at least on the outer side of the maximum angle of incidence line of the optical fiber entrance plane, which reduces disturbances in the combustion level in the combustion chamber. can be eliminated and accurately grasped. Furthermore, since the entrance surface of the optical fiber is set at least outwardly from the outer surface of the partition wall near and outside the combustion chamber, damage to the optical fiber due to high temperatures can be prevented. Further, since a plurality of optical fibers are connected in series using a connector, there is an advantage that the light receiving element can be set at a position where it is not affected by the heat of the reciprocating internal combustion engine.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing one embodiment of the present invention, Fig. 2 is a side sectional view showing an enlarged main part of Fig. 1, and Fig. 3 shows details of the light receiving device portion of Fig. 2. FIG. 4 is an enlarged side sectional view of main parts showing another embodiment of the present invention. In the figure, 1 is a reciprocating internal combustion engine, 2 is a combustion chamber, 3 is a partition wall, and 4
1 is a through hole, 5 is a detection device, 6 is a water jacket, 11 is a see-through window, 12 is a mounting bracket, 13 is an adhesive, 14 is a light receiving device, 15 is a holding bracket, 19.19A is an optical fiber, and 24 is an incident surface , 26 is a mounting bracket, 27 is a mounting hole, 30 is a mounting screw, 33 is a threaded portion, 41 is a mounting bracket, 42 is a through hole portion, 4
3 is a through hole. Figure 1 Figure 2

Claims (10)

[Claims] (1) A through hole is formed in the partition wall of the combustion chamber of a reciprocating internal combustion engine through which the flame image generated in the combustion chamber is propagated to the outside, and a see-through window that transmits the flame image is provided on the side of the combustion chamber on the side of the through hole. A flame image detection device for a combustion chamber of a reciprocating internal combustion engine, characterized in that an optical fiber that is airtightly provided and that allows the flame image transmitted through the transparent window to enter is fixed to a side of the through hole opposite to the combustion chamber. (2) The reciprocating internal combustion engine combustion chamber according to claim (1), wherein the viewing window is formed in the shape of a condensing lens, and the focal point of the viewing window is the entrance surface of the optical fiber. flame image detection device. (3) A reciprocating internal combustion engine according to claim (1), characterized in that the effective entrance diameter of the viewing window is set to be at least further outward than on the maximum angle of incidence line of the entrance surface of the optical fiber. Flame image detection device for engine combustion chamber. (4) A flame image of a reciprocating internal combustion engine combustion chamber according to claim (1), characterized in that the entrance surface of the optical fiber is set outward from at least the outer surface of a partition wall located near the combustion chamber. Detection device. (5) A through-hole is formed in the partition wall of the combustion chamber of the reciprocating internal combustion engine, and a mounting bracket having a through-hole portion for propagating the flame image generated in the combustion chamber to the outside is attached to the through-hole. A see-through window that allows the flame image to pass through the through-hole is airtightly provided on the side of the combustion chamber, and an optical fiber that allows the flame image that has passed through the see-through window to enter is provided on a side of the through-hole that is opposite to the combustion chamber. A flame in a combustion chamber of a reciprocating internal combustion engine, characterized in that the space between the transparent window and the part in which the optical fiber is hermetically sealed is evacuated or filled with an inert gas. Image detection device. (6) A flame image detection device for a combustion chamber of a reciprocating internal combustion engine according to claim (5), wherein the transparent window is made of artificial sapphire. (7) The reciprocating internal combustion engine combustion chamber according to claim (5), wherein the viewing window is formed in the shape of a condensing lens, and the focal point of the viewing window is the entrance surface of the optical fiber. flame image detection device. (8) Reciprocating internal combustion according to claim (5), characterized in that the effective entrance diameter of the viewing window is set to be at least further outward than on the maximum angle of incidence line of the entrance surface of the optical fiber. Flame image detection device for engine combustion chamber. (9) A flame image of a combustion chamber of a reciprocating internal combustion engine according to claim (5), characterized in that the entrance surface of the optical fiber is set outward from at least the outer surface of a partition wall located close to the combustion chamber. Detection device. (10) A flame image detection device for a combustion chamber of a reciprocating internal combustion engine according to claim (5), wherein a plurality of optical fibers are connected in series via connectors.