JP3439938B2 - In-cylinder observation device for internal combustion engines - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-cylinder observation device for an internal combustion engine.

[0002]

2. Description of the Related Art As a technique for directly visualizing the inside of an internal combustion engine, (1) a glass cylinder is used for visualization, (2) a visualization window is attached to the top of the piston to visualize it from the bottom, and (3) a head. A visualization window is attached to the wall of the side combustion chamber to visualize from the top. For more details,
As an example of the above (2), for example, Japanese Utility Model Publication No. 63-3390.
In the publication, a visualization window is provided on the top surface of the piston so that it can be visualized from the bottom through a mirror.

[0003]

However, when visualization is performed using these techniques, there is a problem that the internal combustion engine must be remodeled significantly. Further, in recent years, direct injection of fuel into a cylinder has also been performed in an internal combustion engine for gasoline, so that the piston has a shape having a cavity on the top surface of the piston. Therefore, it is not possible to visualize the behavior of the air-fuel mixture in the cavity or the state of combustion immediately after ignition in the glass cylinder of (1) described above, which is a side view. Furthermore, the visualization window cannot be formed in a cavity shape and attached by the visualization from the bottom of (2). In addition, in the visualization from the top of (3) above, a large visualization window must be attached in order to secure the visualization range and the amount of light, and to achieve mixture behavior and combustion behavior that match the actual combustion chamber shape. It could not be observed.

Therefore, an object of the present invention is to provide an in-cylinder observing device for an internal combustion engine, which can observe the behavior in the cylinder easily and accurately.

[0005]

According to the first aspect of the invention, a light emitting portion supplies light for imaging into a cylinder of an internal combustion engine, and a position facing the cylinder.
The arranged image pickup device, the said said cylinder
The inside of the cylinder is imaged through a visualization window interposed between the image pickup devices . The behavior inside the cylinder of the internal combustion engine is observed with this image pickup device.

As described above, since the device such as forming the observation window on the cylinder head is simply added, the number of modifications can be reduced. Further, since it is not necessary to machine the piston top surface, it can be applied to an internal combustion engine having a cavity on the piston top surface. Further, since it has a light emitting portion, it is possible to observe without a flame.

According to the second aspect of the invention, the degree of mixture formation near the spark gap of the spark plug is observed from the image data obtained by the image pickup device immediately before ignition.
According to the invention described in claim 3, the behavior of the fuel spray is observed from the image data by the image pickup device after a predetermined period after the fuel injection.

As described above, according to the second and third aspects of the invention, the degree of mixture formation and the behavior of fuel spray can be easily observed. According to the invention of claim 4, at least one of the ignition timing and the injection timing is controlled based on the observation result of the degree of mixture formation.

According to the fifth aspect of the invention, at least one of the ignition timing and the injection timing is controlled based on the observation result of the behavior of the fuel spray. As described above, according to the inventions of claims 4 and 5, the observation result of the degree of mixture formation and the behavior of the fuel spray can be reflected in the ignition timing and the injection timing.

That is, for example, in the intake pipe injection, the state of the air-fuel mixture sucked into the cylinder of the internal combustion engine, and in the direct cylinder injection, the state of the spray injected into the cylinder, the ignition timing and the injection It becomes possible to perform optimum ignition and optimum combustion by reflecting the timing.

According to the sixth aspect of the invention, the visualization window, the light emitting portion, and the image pickup element are incorporated in the spark plug. Therefore, the attachment to the internal combustion engine becomes easy. Further, according to the invention described in claim 7, since the visualization window has the concave portion on the cylinder side, the viewing angle of the image pickup device can be widened and the viewing field can be secured.

[0012]

DETAILED DESCRIPTION OF THE INVENTION

(First Embodiment) The first embodiment of the present invention will be described below.
Embodiments will be described with reference to the drawings.

FIG. 1 shows a longitudinal sectional view of an engine 1 in which an in-cylinder observation device for an internal combustion engine according to this embodiment is incorporated.
A direct injection gasoline engine is used as the engine 1.

In FIG. 1, a cylinder head 3 is provided on a cylinder block 2 and a cylinder 4 is provided.
A piston 5 is arranged inside. A piston ring 6 is provided on the outer peripheral portion of the piston 5. Piston 5
A cavity 7 is formed on the top surface of the.

An intake valve 8 and an exhaust valve 9 are mounted on the cylinder head 3, and the intake port 10 and the exhaust port 11 are opened and closed by the valves 8 and 9. That is, the intake valve 8 and the exhaust valve 9 are urged by the valve springs 12 and 13 in the direction of closing the ports 10 and 11, and the urging force of the valve springs 12 and 13 is increased by the valve drive mechanism (not shown) as the engine is driven. On the contrary, the ports 10 and 11 are opened at a predetermined timing.

A fuel injection valve 14 is provided on the cylinder head 3.
Is mounted, and its tip is located in the cylinder 4. High-pressure gasoline pressurized by a pressure pump (not shown) is supplied to the fuel injection valve 14, and the gasoline is injected from the fuel injection valve 14 toward the cavity 7.

Further, the cylinder head 3 has an ignition plug 15
Is attached, and the lower end of the spark plug 15 is attached to the cylinder 4.
It is exposed inside. Then, a high voltage is applied between the ground electrode 16 and the center electrode 17 provided at the lower end of the ignition plug 15 at a predetermined timing to ignite by sparks.

FIG. 2 shows a partial sectional view of the spark plug 15. As shown in FIG. 2, an in-cylinder observation device 18 is incorporated in the spark plug 15. In-cylinder observation device 18
3, includes a visualization window 19, an image pickup element 20, and an optical fiber 21, and these members are housed in a cylindrical case 22 as shown in FIG.

As shown in FIG. 2, a visualization window 19 is arranged at the lower end opening in the cylindrical case 22 so as to face the cylinder 4, and the visualization window 19 is made of a transparent material.
A columnar image pickup device 20 is arranged on the visualization window 19. A microminiature CCD camera is used for the image pickup device 20. The image pickup element 20 is not limited to the CCD camera, and other photoelectric conversion elements may be used, and an element sensitive to an electron beam, a laser beam, or the like other than visible light may be used.

In this way, the visualization window 1 is attached to the spark plug 15.
9 and the image pickup device 20 is arranged near the combustion chamber, and the vicinity of the spark gap of the spark plug 15 (near the gap between the ground electrode 16 and the center electrode 17) is the image pickup region of the image pickup device 20.

Image pickup device 2 in the aforementioned cylindrical case 22
The end of the optical fiber 21 is arranged above the optical fiber 0, and the light source 23 is connected to the other end of the optical fiber 21. A strobe device is used as the light source 23, and strobe light is emitted to the optical fiber 21 when a drive signal (light emission command) is input. In addition, as the light source 23, xenon light, laser light, or the like may be used.

Then, the strobe light emitted from the light source 23 propagates inside the optical fiber 21 and is emitted from the tip of the optical fiber 21 in the spark plug 15, passes through the outer peripheral portion of the image pickup element 20, and enters from the visualization window 19 to the combustion chamber. Is emitted.

At this time, as shown in FIG. 4, the cross-sectional area of the image pickup device 20 is made smaller than the area of the front end face of the optical fiber 21 so that the center of the front end face of the optical fiber 21 and the center of the image pickup device 20 coincide with each other. Arrange to do. In this case, the strobe light reaches the visualization window 19 through the periphery of the image sensor 20, so that the loss of the light amount is small and uniform light can be supplied into the cylinder 4.

As described above, in the present embodiment, the light emitting section uses the optical fiber 21 for guiding the light from the light source 23 installed at another place. Here, further referring to the visualization window, as shown in FIG. 5A, when the visualization window 30 having the concave end surface 30a on the cylinder 4 side is used as the visualization window, the visualization window 30 has a function of a concave lens. It will be. Then, due to this concave lens function, the image pickup device 2
As the viewing angle of 0 expands, the light from the tip surface (light emitting portion) of the optical fiber 21 diffuses into the cylinder 4.
If you do not need to expand the viewing angle or diffuse the light,
As shown in (b), the visualization window 31 in which the end surface 31a on the cylinder 4 side is planar may be used. Further, as shown in FIG. 5C, the end surface 32a on the cylinder 4 side is used as a visualization window.
If the visualization window 32 having a convex shape is used, the visualization window 32
Has the function of a convex lens. In this way, the light can be concentrated on one point.

Returning to the description of FIG. 2, the image pickup device 20 is connected to a microcomputer (hereinafter, referred to as a microcomputer) 25 by a cable 24, and image data from the image pickup device 20 is taken in by the microcomputer 25. or,
The microcomputer 25 is connected to the light source 23, and a drive signal is output from the microcomputer 25 to the light source 23.

Next, the operation of the in-cylinder observation device for an internal combustion engine configured as above will be described. First, the outline of the compression and explosion strokes in the direct injection gasoline engine of FIG. 1 will be described.

In the compression stroke, the piston 5 in the cylinder 4 moves upward. Then, fuel is injected from the fuel injection valve 14 at a predetermined injection timing. At this time, the fuel is injected toward the cavity 7. More specifically, FIG.
When the piston 5 is viewed from above, it is injected toward the side wall 7a of the cavity 7, and the atomized fuel thereof extends along the side wall 7a and the side wall 7b of the cavity 7 to reach the ignition position by the ignition plug 15.

At this time, as shown in FIG. 6 (a), the sprayed fuel from the fuel injection valve 14 extends narrowly along the side wall 7a of the cavity 7 and further along the side wall 7b at the ignition position by the ignition plug 15. When it has reached, the fuel spray state is good. Further, in the state shown in FIG. 6B, the atomized fuel from the fuel injection valve 14 extends thickly along the side walls 7a and 7b of the cavity 7, and the atomized state of the fuel is poor. Further, in the state shown in FIG. 6C, the sprayed fuel from the fuel injection valve 14 does not go along the side wall 7b of the cavity 7 but the side wall 7b.
Since there is no atomized fuel at the ignition position, the atomized state of the fuel is poor.

When a predetermined ignition timing comes after the fuel is injected, a high voltage is applied between the ground electrode 16 and the center electrode 17 of the spark plug 15, and spark ignition is performed.

In such a process, the microcomputer 25 of FIG. 2 outputs a drive signal to the light source 23 immediately before ignition, and the light source 23 emits strobe light in response to this drive signal. This light is transmitted to the spark plug 15 by the optical fiber 21, is irradiated from the tip end surface of the optical fiber 21, and is emitted from the visualization window 19 to the combustion chamber in the cylinder 4. With this light, the vicinity of the spark gap of the spark plug 15 is imaged by the image sensor 20. The image data obtained in this way is sent to the microcomputer 25, and the microcomputer 25 performs image processing to analyze the spray state. That is, image processing is performed in the microcomputer 25, and the degree of mixture formation near the spark gap of the spark plug 15, that is,
A mixture distribution is observed. The result is displayed on a display device (not shown).

As for the strobe emission timing,
It is determined by the engine speed, engine load, injection mode (whether intake pipe injection or direct cylinder injection), fuel injection pressure, and the like. The signal for that is taken in by the microcomputer 25.

As described above, the present embodiment has the following features. (B) The visualization window 19, the image pickup device 20, and the tip of the optical fiber 21 connected to the light source 23 are incorporated in the spark plug 15 of the direct injection gasoline engine 1, and the inside of the cylinder of the internal combustion engine is determined by the image data from the image pickup device 20. Therefore, the behavior of the air-fuel mixture in the cavity 7 can be easily and accurately observed. That is,
Since the observation window 19 is only formed in the cylinder head portion, the modification is less necessary and the top surface of the piston 5 does not need to be machined, which is suitable for the direct injection engine having the cavity 7. Further, since it has the optical fiber 21 connected to the light source 23, it is possible to observe without a flame. (B) The degree of air-fuel mixture formation in the vicinity of the spark gap of the spark plug 15 can be easily observed from the image data obtained by the image pickup device 20 immediately before ignition. (C) Since the visualization window 19, the light emitting portion (21) and the image pickup device 20 are incorporated in the ignition plug 15, the attachment to the engine 1 becomes easy. (D) Since the visualization window 30 shown in FIG. 5 (a) has the concave portion 30a on the cylinder side, the viewing angle of the image pickup device 20 can be widened and an observation viewing field can be secured. Further, the strobe light introduced by the optical fiber 21 can be diffused to the cylinder 4 to visualize the entire inside of the cylinder. (Second Embodiment) Next, the second embodiment will be described with reference to the first embodiment.
The difference from the above embodiment will be mainly described.

FIG. 7 shows a perspective view of the piston head portion in this embodiment. In the first embodiment shown in FIG. 2, the in-cylinder observation device 18 is provided inside the ignition plug 15, but in the present embodiment, as shown in FIG. The in-cylinder observation device 40 is arranged at another place, specifically, near the ignition plug 15.
In this way, the inside of the cylinder 4 can be observed. (Third Embodiment) Next, the third embodiment will be described with reference to the first embodiment.
The difference from the above embodiment will be mainly described.

FIG. 8 shows a perspective view of the piston head portion in this embodiment. In the first embodiment shown in FIG. 2, the in-cylinder observation device 18 is provided inside the ignition plug 15 so that the inside of the cylinder 4 can be seen from directly above the cylinder 4.
In the present embodiment, as shown in FIG. 8, an in-cylinder observation device 45 is arranged on the engine side.

In this way, the inside of the cylinder 4 can be observed by disposing the in-cylinder observation device 45 at a position completely different from the ignition plug 15. (Fourth Embodiment) Next, the fourth embodiment will be described with reference to the second embodiment.
The difference from the above embodiment will be mainly described.

FIG. 9 shows an in-cylinder observation device according to this embodiment. As shown in FIG. 9, the vicinity of the spark gap of the spark plug 15 is set as an image pickup area of the image pickup device 20, and the microcomputer 25 drives the light source (strobe device) 23 to emit light at an arbitrary time and the microcomputer 25 makes an image pickup device at an arbitrary time. Image data of 20 is taken in, and at least one of the ignition signal and the injection signal is controlled according to the state in the cylinder 4 at that time.

That is, the image data in the vicinity of the spark gap of the spark plug 15 immediately before ignition is taken into the microcomputer 25, and the microcomputer 25 performs image processing to determine the degree of mixture formation near the spark gap. Then, the microcomputer 25 controls the ignition signal and / or the injection signal in accordance with the determination result (observation result) so that ignition and combustion can be performed in the vicinity of the spark gap portion at the optimum air-fuel mixture degree. More specifically, referring to FIG. 11, the microcomputer 2
5 determines the air-fuel ratio before ignition, during ignition, and after ignition in the vicinity of the spark gap in the cylinder 4 based on the image data. For example, if the microcomputer 25 determines that it is in the state shown in FIG. As shown in FIG. 11B, the ignition timing,
At least one of the injection timing as shown in FIG. 11C or the injection amount as shown in FIG. 11D is controlled so that ignition and combustion can be performed in the vicinity of the spark gap at the optimum mixture degree. Also, when the microcomputer 25 determines that it is in the state shown in FIG. 11E, the same control is performed.

As described above, the present embodiment has the following features. (A) By controlling at least one of the ignition signal and the injection signal based on the observation result of the mixture formation degree, the observation result of the mixture formation degree can be reflected in the ignition signal and the injection signal. Therefore, the state of the spray injected into the cylinder in the direct cylinder injection can be reflected in the ignition signal and the injection signal to perform optimum ignition and optimum combustion. (Fifth Embodiment) Next, a fifth embodiment will be described.
The difference from the above embodiment will be mainly described.

FIG. 10 shows an in-cylinder observation device according to this embodiment. As shown in FIG. 10, a predetermined region of the combustion chamber is set as the image pickup region of the image pickup device 20, and image data of the combustion chamber by the image pickup device 20 after a certain period after fuel injection is fetched into the microcomputer 25. Then, the microcomputer 25 performs image processing to determine the behavior of the spray, and compares the result with the optimal spray behavior result which gives the optimum combustion that has been input in advance. Then, based on the comparison result, the microcomputer 25 controls at least one of the ignition signal and the injection signal in order to perform ignition and combustion at the optimum air-fuel mixture degree.

More specifically with reference to FIG. 6, in the state shown in FIG. 6B, the microcomputer 25 advances the ignition timing to ignite before the spray spreads, or delays the injection timing and delays the ignition timing. Prevent either spray from spreading. Further, in the case of the state shown in FIG. 6 (c), the ignition timing is delayed to spread the spray and then the ignition is performed.
Either one of delaying the injection timing and preventing the spray from coming off the cavity 7 is performed.

It should be noted that "after a predetermined period after fuel injection, which is the timing of observation," means, for example, 1/1200 rpm.
At the time of 2 loads, it is 1.3 msec after fuel injection. As described above, the present embodiment has the following features. (A) It is possible to easily observe the behavior of fuel spray from the image data obtained by the image pickup device 20 after a predetermined period after fuel injection. (B) By controlling at least one of the ignition signal and the injection signal based on the observation result of the behavior of the fuel spray, the observation result of the behavior of the fuel spray can be reflected in the ignition signal and the injection signal. It becomes possible to perform ignition and optimum combustion.

In addition to what has been described so far, the following may be carried out. Instead of guiding the light of the separate light source 23 through the optical fiber 21 to cause it to emit light, the light emitting section may itself emit light. That is, the light source itself may be incorporated in the spark plug, the cylinder head of the engine, or the like.

In addition, the image capturing by the in-cylinder observation device is
It may be continuous or at any time in each cycle, and may be limited to the starting time and the transient time. Further, in addition to the direct cylinder injection type engine, the engine may be implemented to inject fuel into the intake pipe. In this case, the ignition signal or the injection signal so that the degree of mixture formation near the spark gap of the spark plug is judged from the state of the mixture drawn into the cylinder of the internal combustion engine and ignition and combustion can be performed at the optimum mixture degree. At least one of the above may be controlled.

In the above description, as an observation item, the degree of mixture formation in the vicinity of the spark gap of the spark plug, the state of the mixture sucked into the cylinder, or the state of the spray injected into the cylinder. However, as another observation item, the combustion state immediately after ignition may be observed.

The light emission timing (light emission timing) of the strobe light may be set not by the microcomputer 25 but by a delay from this signal, for example, using a pulse signal issued every 720 ° CA as a reference signal.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an engine in which an in-cylinder observation device for an internal combustion engine according to a first embodiment is incorporated.

FIG. 2 is a partial sectional view of a spark plug.

FIG. 3 is a perspective view of an in-cylinder observation device.

FIG. 4 is a view showing an in-cylinder observation device.

FIG. 5 is a perspective view of an in-cylinder observation device for an internal combustion engine.

FIG. 6 is an explanatory view showing a sprayed state.

FIG. 7 is a perspective view of an in-cylinder observation device for an internal combustion engine according to a second embodiment.

FIG. 8 is a perspective view of an in-cylinder observation device for an internal combustion engine according to a third embodiment.

FIG. 9 is a diagram showing an in-cylinder observation device for an internal combustion engine according to a fourth embodiment.

FIG. 10 is a view showing an in-cylinder observation device for an internal combustion engine according to a fifth embodiment.

FIG. 11 is a diagram for explaining control in the fourth embodiment.

[Explanation of symbols]

1 ... Engine, 4 ... Cylinder, 15 ... Spark plug, 19
… Visualization window, 20… Image sensor, 21… Optical fiber, 2
5 ... Microcomputer.

Front Page Continuation (72) Inventor Kimitaka Saito 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute (72) Inventor Tokio Obama 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Car Parts Co., Ltd. Research Institute (72) Inventor Tatsuo Kobayashi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) Reference JP-A-7-288871 (JP, A) JP-A-7-43254 (JP, A) ) JP-A-2-176542 (JP, A) JP-A 61-218736 (JP, A) JP-A 61-217726 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 15/00

Claims (7)

(57) [Claims] 1. A visualization window arranged to face a cylinder of an internal combustion engine, a light emitting section for supplying light for imaging in the cylinder, and a visualization window arranged at a position facing the cylinder and passing through the visualization window. An imaging device for imaging the inside of a cylinder, and the visualization window between the cylinder and the imaging device.
An in-cylinder observation device for an internal combustion engine, characterized in that only an intervening device is used. 2. The in-cylinder observation apparatus for an internal combustion engine according to claim 1, wherein the degree of mixture formation near the spark gap of the spark plug is observed from image data obtained by the image pickup device immediately before ignition. . 3. The in-cylinder observation apparatus for an internal combustion engine according to claim 1, wherein the behavior of the fuel spray is observed from image data obtained by the image pickup device after a predetermined period has elapsed after fuel injection. 4. The in-cylinder observation apparatus for an internal combustion engine according to claim 2, wherein at least one of ignition timing and injection timing is controlled based on an observation result of the degree of mixture formation. . 5. The in-cylinder observation apparatus for an internal combustion engine according to claim 3, wherein at least one of ignition timing and injection timing is controlled based on an observation result of the behavior of the fuel spray. . 6. The visualization window, the light emitting unit, and the image sensor,
The in-cylinder observation device for an internal combustion engine according to claim 1, wherein the in-cylinder observation device is incorporated in an ignition plug. 7. The in-cylinder observation device for an internal combustion engine according to claim 1, wherein the visualization window has a recess on the cylinder side.