JPH02138833A - Fire position detector within engine combustion chamber - Google Patents

Abstract

PURPOSE:To achieve a highly precise engine control by arranging a convex lens on a wall part that it can forms an image of a fire caused within a combustion chamber at a proper position other than the combustion chamber corresponding to a position where the fire exists on a wall part to detect the position at which the fire exists within the combustion chamber with the lens. CONSTITUTION:When a fire occurs within a combustion chamber 8, an image of the fire is formed at a proper position on a semi-transparent rod 3 outside the combustion chamber 8 according to a distance between a convex lens 2 and a position where the fire exists within the combustion chamber 8 and a focal length of the convex lens 2 and the image of the fire caused within the combustion chamber 8 is taken out of the combustion chamber. Then, positions P'0-P'7 of the image of the fire formed outside the combustion chamber 8 correspond to positions P0-P7 where the fire exists actually within the combustion chamber 8. As the rod 3 is so arranged to generate scattered light at the position where an image of the fire is formed when it is done, the scattered light therefrom is detected with a photo diode 13 of a highly directive one-dimensional photodiode array 4 and a high level of a light reception signal S3 is outputted to a measuring device 5. This enables detection of a fire existing at the position P3 within the combustion chamber 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting the position of flame generated within the combustion chamber of an engine such as an automobile.

[Prior Art] Conventionally, there is a device shown in FIG. 12 that detects combustion light (flame) generated within the combustion chamber of an engine such as an automobile. In this device, a wide-angle spherical lens 100 with no directivity is provided on the wall surface of a combustion chamber, and a photodiode 101 for detecting the presence or absence of light is placed behind this spherical lens 100. The signal is displayed and output by the measuring instrument 102.

The area where such a device detects light is the area shown by diagonal lines in FIG. be done.

Conventionally, a combustion light processing device (Japanese Patent Laid-Open No. 62-21427
No. 2 Publication), as well as a device that measures the emission period of combustion light in the combustion chamber using a combustion light detection device as described above, predicts the combustion speed, and uses it as a criterion for intake air heating control (Utility Model No. 62-15
No. 4264) and the like have been proposed.

[Problems to be Solved by the Invention] By the way, with conventional dual combustion light detection devices, it is possible to detect whether or not light is emitted within the combustion chamber;
It is impossible to detect the location of the light emission, that is, the location of the flame that is the source of the combustion light.

In the combustion chamber of an engine, a flame body generated by ignition near the spark plug usually propagates from the ignition point toward the wall surface of the combustion chamber. Detecting the state of flame propagation, that is, the position of the flame, is extremely important for understanding the combustion state of the engine and for performing more detailed engine control (knocking control, etc.). It is desired to realize a device that detects the position of flame generated within a combustion chamber.

The present invention is an attempt to solve the following two problems.It is possible to detect the position of the flame within the combustion chamber, thereby making it possible to control the combustion state in detail and to realize fine-grained engine control. , an object of the present invention is to provide a flame position detection device within an engine combustion chamber.

[Means for Solving the Problems] Therefore, the flame position detection device in the engine combustion chamber of the present invention detects the image of the flame generated in the combustion chamber of the engine at an appropriate position outside the combustion chamber corresponding to the position of the flame. A convex lens capable of forming an image at a position is provided on the wall of the combustion chamber, and the position of the image of the flame "imaged outside the combustion chamber" by this convex lens is taken as the location of the flame within the combustion chamber. It is characterized by providing a detection means for detection.

[Function] In the flame position detection device in the engine combustion chamber of the present invention described above, the convex lens focuses the image of the light source at an appropriate position on the opposite side of the light source according to the distance between the convex lens and the light source and the focal length. The image of the flame generated inside the combustion chamber is taken out to the outside of the combustion chamber by a convex lens provided on the wall of the combustion chamber. The position of the flame image formed outside the combustion chamber corresponds to the position of the flame inside the combustion chamber, so by detecting the flame image position with the detection means, the flame position inside the combustion chamber can be detected. It becomes possible.

[Implementation example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a flame position detecting device in an engine combustion chamber as an embodiment of the present invention. FIG. 1 is a schematic configuration diagram thereof, and FIG. A diagram showing the existence position in correspondence with the cylinder pressure and heat release rate,
3 to 5 are timing charts of photodetection signals of the photo diode for explaining specific usage examples thereof.

In the device of this embodiment, as shown in FIG. 1, a convex lens 2 is fitted into an opening 1a of an appropriate diameter formed in a wall 1 of a combustion chamber 8 of an automobile engine. This convex lens 2
can form an image of the flame generated within the combustion chamber 8 at an appropriate position outside the combustion chamber 8 depending on the position of the flame, and the optical axis of the convex lens 2 is horizontal and , is arranged on the optical axis so as to be located at the ignition point of the spark plug 6 in the combustion chamber 8 (see the chain line in FIG. 1) or near the ignition point (see the solid line in FIG. 1). Further, the convex lens 2 is disposed on the wall 1 which is preferably farthest from the spark plug 6.

Note that the convex lens 2 is made of a heat-resistant material so as to be able to withstand the high heat associated with combustion within the combustion chamber 8. In addition, in FIG. 1, the opening 1a and the convex lens 2 are connected to the spark plug 6.
It is shown enlarged compared to the size of , but in reality, it is formed to a size that does not cause problems in terms of strength and allows the flame image to be captured reliably.

A semitransparent rod 3 and a mask 7 are arranged on the optical axis of the convex lens 2 outside the combustion chamber 8 .

The semi-transparent rod (semi-transparent medium) 3 is aligned with the optical axis T of the convex lens 2.
, l are arranged in a range where an image of the flame in the combustion chamber 8 can be formed, and when the image of the flame in the combustion chamber 8 is formed and the light is concentrated, the light is converted into scattered light at that part. Such a translucent rod 3 is made of, for example, ceramic fiber or
It is made of a transparent material with many fatigue fracture surfaces and aluminum foil.

The mask 7 is placed near the convex lens 2, and partially covers the vicinity of the center of the convex lens 2 to ensure spatial resolution in the direction along the optical axis.

Further, along the translucent rod 3, a highly directional one-dimensional photodiode array 4 consisting of eight photodiodes 10 to 17 is arranged. Each photodiode 10~
17 is a position P, as shown in FIG. '〜P
7' to face the translucent rod 3, and scattered light accompanying the formation of the flame image at the portion of the translucent rod 3 (positions P.' to P7') facing each of the photodiodes 10 to 17. Detects whether or not a photo-diode light reception signal S is generated. This is output as ~S7.

Here, each position P. ' to P7' are the combustion chamber 8, respectively.
Position P within. - This corresponds to the position where an image of the flame is formed by the action of the convex lens 2 when a flame is present at P7. In addition, position P. is the ignition position of the spark plug 6, position P7 is the position on the wall 1 side of the combustion chamber 8, and each position P□
~P6 is position P. This is a position equally divided between P7 and P7.

Furthermore, a measuring instrument 5 is connected to the highly directional one-dimensional fort diode array 4, and each photodiode 10
Photodiode light reception signal S from ~17. -87 is output to the measuring instrument 5, and in this measuring instrument 5, it is the photodiode light reception signal S. -87, photodiodes 10 to 17 receiving scattered light from the translucent rod 3
is identified, and the location of the flame within the combustion chamber 8 (po-p7
) is detected. That is, the photodiode light reception signal S from the photodiomids 10 to 17 at each position PI, ' to P7'. ~ If S7 is at High level, the position P on the translucent rod 3, respectively. An image of the flame is formed at a position P in the combustion chamber 8 from ' to P7'. - It is determined that flame exists at P7.

The position of the flame image formed by the convex lens 2 on the translucent rod 3 outside the combustion chamber 8 from these highly directional one-dimensional photodiode array 4 and the measuring instrument 5 is determined as the position of the flame within the combustion chamber 8. A detection means is configured to detect as follows.

The flame position detection device in the engine combustion chamber according to the first embodiment of the present invention is constructed as described above, and operates as follows.

When a flame is generated in the combustion chamber 8, the convex lens 2
The combustion chamber 8
An image of the flame is formed at an appropriate position on the outer translucent rod 3, and an image of the flame generated within the combustion chamber 8 is taken out of the combustion chamber 8.

Position P of the flame image formed outside the combustion chamber 8. '～P7'
is the actual position P of the flame within the combustion chamber 8. -P
7.

For example, when a flame exists at a position P3 in the combustion chamber 8, an image of the flame at this position P3 is formed at a position P3' on the translucent rod 3 by the action of the convex lens 2. When a flame image is formed, the semitransparent rod 3 emits scattered light at the imaging position, so the scattered light from the semitransparent rod 3 is detected by the photodiode 13 of the highly directional one-dimensional photodiode array 4. , a high-level photodiode light reception signal S3 is output to the measuring device 5. As a result, it is detected that a flame image has been formed at position P3' on the translucent rod 3, that is, that the flame is present at position P3 within the combustion chamber 8.

A position P in the combustion chamber 8 other than position P3. -P2. P4～P
Even if there is a flame at point 7, the position P is determined by the highly directional one-dimensional photodiode array 4 and the measuring device 5 in the same manner as described above. -P2. P4 to P7 are detected.

When the position of the flame generated in the combustion chamber 8 is detected by the apparatus of this embodiment, the position of the flame generated in the combustion chamber 8 is detected as shown in FIG. 2, for example. In FIG. 2, the position of the flame is shown in accordance with the crank angle, and is also shown in correspondence with the in-cylinder pressure and heat generation rate within the combustion chamber 8. As is clear from FIG. 2, the flame propagates from the plug 6 side toward the wall 1 side of the combustion chamber 8 in response to the rise in cylinder pressure and temperature.

Next, a specific usage example of the apparatus of this embodiment will be explained with reference to FIGS. 3 to 5.

■ Sensing the flame propagation period As shown in FIG. The period of flame propagation can be detected by using a timer to set the time period between the rising and falling times of the light reception signal S7 from the photodiode 17 on the part 1 side.

■ Sensing of the combustion period As shown in FIG. 3, the light reception signal S from the photodiode 10. By counting with a timer the period from the rising time of S7 to the falling time of the light reception signal S7 from the photodiode 17 located closest to the wall 1 of the combustion chamber 8,
The combustion period within the combustion chamber 8 can be detected.

■ Measuring the width of the flame zone (a) If multiple consecutive photodiodes among photodiodes 10 to 17 are outputting Hjgh-level light reception signals at the same time, the flame position detected by the photodiodes at both ends of each photodiode will be The width of the flame zone can be roughly determined from the distance, but in this case, each photodiode 10~
The error range depends on the arrangement interval of 17, that is, the sensing resolution.

For example, in FIG. 3, photodiodes 10 to 1
The light reception signal S from 2. -82 is continuously and almost simultaneously at High level, so the position P in the combustion chamber 8. -There is a flame band extending over P2, and its width is approximately P.

It can be determined that it is P2.

(b) Also: Regarding the light reception signals of the two photodiodes at both ends, the rise time of the light reception signal on the flame front end side (wall 1 side) and the rise time of the light reception signal on the flame rear end side (spark plug 6 side) The opening times at these times are determined by sensing the falling times.

On the other hand, the flame is activated based on the time difference between the rise time (or fall time) of the light reception signal from the photodiodes at both ends and the rise time (or fall time) of the light reception signal from the photodiodes adjacent to the photodiodes at both ends. Find the propagation speed. Then, the time interval mentioned above −
The width of the flame zone determined in item (a) may be corrected based on the monthly time and flame propagation speed.

For example, in FIG. 3, the rise time of the light reception signal S2 and the light reception signal S. By sensing the fall time of
In addition to finding these time opening times Δt□, the light reception signal S is also obtained. and the time difference Δt2 between the falling time of the light receiving signal S2 and the falling time of the light reception signal S2, and the distance P between the positions corresponding to the photodiodes 10 and 11. P and flame propagation velocity P, P, /
Find Δt2. Then, the time opening time Δt□ and the flame propagation speed P. Width P of the flame zone obtained in item (a) from P1/Δt2. P2, PoP2+(PoP1/Δ
t2)' Δt1.

This allows the width of the flame band to be measured with higher accuracy.

■Identification of bregnition As shown in Figure 4, if any of the light reception signals 5o-87 of photodiodes 10 to 17 is detected to be at a high level before the ignition signal is generated, ignition is detected. It can be determined that this has occurred.

■Identification of knocking due to self-ignition Normally, flame propagation within the combustion chamber 8 progresses from the spark plug 6 side toward the wall 1 side, so the photodiode 1
Light reception signal S of 0 to 1,7. ~S7 will start up in order, but if knocking occurs due to self-ignition, for example,
As shown in FIG. 5, the received light signal S. Discontinuity is observed at the rise of -87. By detecting this, knocking due to self-ignition is determined.

As described above, according to the flame position detection device of the first embodiment of the present invention, it is possible to detect the position of the flame within the combustion chamber 8, and the position of the flame within the combustion chamber 8 is determined based on the detected position of the flame. 8, for example, the flame propagation period, the combustion period, the width of the flame band, etc. can be measured. Therefore, the device of this embodiment can be effectively used in a test device for testing the operating state of an engine.

Furthermore, based on the detected position of the flame, it is possible to determine knocking due to ignition or self-ignition, as shown in Figure 4.5, and by controlling the ignition timing etc. based on the determination result, This enables fine-grained engine control.

Note that in the apparatus of this embodiment, the flame image is at position P. '～P7
The photodiodes 10 to 17 check whether the image is focused on
The position of the flame is detected by detecting the flame position, and it has nothing to do with the light reception level (light intensity). Therefore, unless the convex lens 2 is particularly dirty and cannot receive light completely, some dirt on the convex lens 2 will affect the position detection result. It will not affect you.

Next, a flame position detection device in an engine combustion chamber as a second embodiment of the present invention will be explained with reference to FIG. 6. FIG. 6 is a schematic configuration diagram thereof, and this second embodiment is also similar to the first embodiment. In this second embodiment, the position P of the translucent rod 3 is as shown in FIG. A bundle of optical fibers 20-27 is disposed between '-P,' and each photodiode 10-17, respectively.

In other words, each position P of the translucent rod 3. When scattered light is generated due to the formation of the flame image at ' to P7', the light becomes
The light is received by optical fibers 20-27 and guided to photodiodes 10-17, respectively.

With such a configuration, the device of the second embodiment of the present invention can obtain the same effects as the above-mentioned first embodiment, and in this second embodiment, the optical fibers 20 to 27 have high directivity. Therefore, the emission position of the scattered light, that is, the position of the flame, can be detected more accurately than when the scattered light from the translucent rod 3 is directly received by the photodiodes 10 to 17 as in the first embodiment. become able to. Further, by using the optical fibers 20 to 27, the installation positions of the photodiodes 10 to 17 can be freely set.

Further, a flame position detecting device in an engine combustion chamber as a third embodiment of the present invention will be explained with reference to FIG. 7. FIG. 7 is a schematic configuration diagram thereof. As such, the translucent rod 3 in the devices of the first and second embodiments is omitted. That is, in the third embodiment, the flame imaging position P. Spherical lenses 30 to 37 are arranged at positions P' to P7', respectively. When the flame image is formed at points ' to P7', the light is transmitted to each spherical lens 30.
37 to guide each photodiode 10 to 17 in the highly directional one-dimensional photodiode array 4.

With such a configuration, the device of the third embodiment of the present invention can provide the same effects as the above-described first embodiment.

A flame position detection device in an engine combustion chamber as a fourth embodiment of the present invention will be explained with reference to FIGS. 8 to 11. FIG. 8 is a schematic configuration diagram thereof, FIG. 9 is a plan view of its photodiode array, Figures 10 and 11 are graphs showing examples of photodiode outputs to explain their effects.

In this fourth embodiment, as shown in FIG. 8, the temperature within the combustion chamber 8 is 1 iP. A position P where an image of the flame is formed by the convex lens 2 when there is a flame in the position P. 9, an annular photodiode array 4A as shown in FIG. 9 is arranged perpendicular to the optical axis of the convex lens 2. As shown in FIG.

The annular photodiode array 4A is composed of eight annular photodiodes 40 to 47, as shown in FIG. 9, and the photodiode 40 is located at position P. It is arranged on the optical axis of the convex lens 2 at .

In this embodiment, the flame exists in the combustion chamber 8 at a position P. In order to detect the spread position of the flame image at ', annular photodiodes 41 to 47 are sequentially arranged around the outer periphery of the photodiode 40.

Each of the annular photodiodes 41 to 47 is arranged at a position P due to the action of the convex lens 2 when a flame is generated at a position P1 to P7 in the combustion chamber 8. This corresponds to the position of the outermost circumference of the flame image projected at . When the outermost peripheral position of the flame image projected by the convex lens 2 reaches each of the annular photodiodes 40 to 47, it becomes High.
H level light reception signal S. -87 is output to the measuring device 5.

In the measuring instrument 5, a light reception signal S is received. The position of the flame within the combustion chamber 8 is determined by detecting the spread position of the flame image on the annular photodiode array 4A based on the output distribution of -87. That is, when a flame exists on the spark plug side in the combustion chamber 8, the light reception signal S is generated. As shown in FIG. 10, the output distribution of -87 is concentrated near the central photodiode 40, while when the flame is present on the wall 1 side in the combustion chamber 8, the light reception signal S is generated. The output distribution of -87 is spread throughout the photodiodes 40 to 47, as shown in FIG.

In this manner, the apparatus according to the fourth embodiment of the present invention also makes it possible to detect the position of the flame within the combustion chamber 8 using the annular photodiode array 4A and the measuring device 5. In addition to obtaining the same effect as the example,
In this fourth embodiment, there is no need to arrange the translucent rod 3 etc. along the optical axis direction of the convex lens 2, and the position P is not required. Since it is only necessary to arrange the annular photodiode array 4A at ', the length of the device in the optical axis direction can be shortened, which is advantageous when mounting it in an automobile where space is limited.

In any of the second to fourth embodiments described above, specific uses of the present device as explained in the first embodiment (sensing the flame propagation period, sensing the combustion period, measuring the width of the flame zone) , ignition, knocking due to self-ignition, etc.).

In addition, in any of the two embodiments, eight photodiodes are used to detect P in the combustion chamber 8.

Although the presence or absence of flame is detected at the eight points ~P7, the number of Fol-diodes can be set arbitrarily, and by increasing the number, the detection accuracy of the flame position can be improved.

Further, in the above embodiment, the case where the flame position in the engine combustion chamber of an automobile is detected is described, but the present invention is not limited to this, and the present invention can be applied to detecting the flame position in the combustion chamber of various other engines. In this case, the same method as described above can be applied, and the same effect as described above can be obtained.

=19- [Effects of the Invention] As detailed above, according to the flame position detection device in the engine combustion chamber of the present invention, the image of the flame generated in the combustion chamber of the engine can be detected according to the position of the flame. A convex lens capable of forming an image at an appropriate position outside the combustion chamber is provided on the wall of the combustion chamber, and the position of the image of the flame formed outside the combustion chamber by this convex lens is determined by the position of the flame within the combustion chamber. With an extremely simple configuration that includes a detection means that detects as It is also possible to identify knocking caused by ignition or self-ignition, and by controlling ignition timing etc. based on the determination results, fine-grained engine control can be realized.

[Brief explanation of the drawing]

1 to 5 show a flame position detection device in an engine combustion chamber as a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram thereof, and FIG. A diagram showing the existence position in correspondence with the cylinder pressure and heat release rate,
3 to 5 are timing charts of photodiode light reception signals for explaining specific usage examples thereof, and FIG. 6 is a flame position detection device in an engine combustion chamber as a second embodiment of the present invention. FIG. 7 is a schematic diagram showing a flame position detection device in an engine combustion chamber as a third embodiment of the present invention, and FIGS. 8 to 11 are diagrams showing an engine combustion chamber as a fourth embodiment of the present invention. Fig. 8 is a schematic diagram of the indoor flame position detection device, Fig. 9 is a plan view of its photo 1 to diode array, and Fig. 10 and 11 are photos for explaining its operation. 1 to 12 are graphs showing examples of diode output, and FIG. 12 is a schematic configuration diagram showing a conventional combustion light detection device. 1--Wall of combustion chamber, 1a-opening, 2--convex lens, 3-semi-transparent rod, 4-highly directional one-dimensional photodiode array (detection means), 4A-annular photodiode array (detection means), 5-measuring instrument (detection means), 6
... Spark plug, 7-mask, 8... Combustion chamber, 10
~17...-photodiode, 20-27--optical fiber, 30-37--spherical lens, 40-47--annular photodiode, L...-optical axis.

Claims (1)

[Claims] A convex lens is provided on the wall of the combustion chamber that can form an image of the flame generated within the combustion chamber of the engine at an appropriate position outside the combustion chamber depending on the location of the flame, and the convex lens allows the image of the flame to be focused outside the combustion chamber. A flame position detection device in an engine combustion chamber, characterized in that a detection means is provided for detecting the position of the flame image formed in the combustion chamber as the position of the flame in the combustion chamber.