JPS6233080Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an engine combustion state observation device that optically observes the combustion state in an engine combustion chamber.

Conventionally, as disclosed in Japanese Patent Application Laid-open No. 51-37304, a quartz glass window is provided as a light detection window on the wall surface of the combustion chamber of the engine, and the quartz glass window is used as a combustion state observation device for such an engine. The window is connected to a phototransistor as a light-receiving element via a translucent fiber, and visible light and/or infrared rays generated within the combustion chamber are transmitted through the translucent fiber through the quartz glass window and guided to the phototransistor. It is known that the combustion state of the engine, such as misfire in the combustion chamber and combustion timing, can be observed by performing photoelectric conversion using a phototransistor and electrically detecting it.

However, with the above-mentioned conventional type, there is a problem in that the quartz glass window cracks and breaks due to thermal shock due to rapid temperature fluctuations in the gas in the combustion chamber that occur between the intake and combustion strokes and shock due to combustion pressure. Ta.

Further, since the end face of the conventional detection window is directly exposed to the combustion gas, deposits such as carbon adhere to the end face of the detection window when used for a long time, making observation impossible.

The present invention has been made in view of these points, and includes forming a detection window by encasing a translucent fiber with metal, and setting the detection window at a position where the sealing member of the piston comes into sliding contact. This not only improves the thermal shock resistance of the detection window, but also improves its heat resistance and impact resistance, making it possible to use it for long periods of time and under high load conditions, as well as preventing deposits from adhering to the detection window. The purpose is to enable effective detection over a long period of time.

In order to achieve this object, the configuration of the present invention is an engine combustion state observation device that optically observes the combustion state in the combustion chamber, and the detection window for detecting the combustion state in the combustion chamber is made of a light-transmitting fiber. By attaching the detection window to the wall of the combustion chamber so that the sealing member attached to the piston slides into contact with the end face of the translucent fiber, the thermal stress on the detection window is reduced by thermal expansion. A bundle of light-transmitting fibers with a low ratio is used for dispersion and relaxation, and a metal member surrounding the light-transmitting fibers is used to firmly fix the fibers to the combustion chamber wall, and a sealing member of the piston is used to remove deposits attached to the end surface of the detection window. It was designed to be scraped off.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 to 3 show a first embodiment of the present invention, in which 1 is a cylinder block in which a cylinder 2 is formed, 3 is a cylinder disposed on the cylinder block 1 via a gasket 4. head,
Reference numeral 5 denotes a piston fitted within the cylinder 2, and a combustion chamber 6 is formed by the cylinder 2, the piston 5, and the lower wall surface of the cylinder head 3.
Further, reference numeral 7 denotes a piston ring as a sealing member mounted on the outer peripheral surface of the piston 5, and the piston ring 7 slides on the wall surface of the cylinder 2 to seal the combustion chamber 6 against gas.

The cylinder 2 wall of the combustion chamber 6 has a through hole 8 that penetrates from the outer wall of the cylinder block 1 to the cylinder 2.
A detection window 9 made of translucent FRM is fitted and fixed by brazing from the opening of the through hole 8 on the cylinder 2 side to the center part, and the end surface 9a of the detection window 9 on the cylinder side is connected to the cylinder 2 wall surface. It is formed so that it is flush with the wall surface of the cylinder 2 during the honing process.

The detection window 9 is made of transparent fibers 10, 10, which are arranged parallel to the center line of the through hole 8 and made of a plurality of bundled glass fibers, SiO ₂ fibers, alumina fibers, etc., as shown in detail in FIG. …
The transparent fibers 10, 10, .
Aluminum, copper, formed into shapes corresponding to
The transparent fiber 10 is made of a metal member 11 made of nickel, zinc, magnesium, an alloy, etc., and the visible light and/or infrared rays received at the cylinder wall side end of the translucent fiber 10 are transmitted to the other end to cause combustion in the combustion chamber 6. The device is configured to optically detect the condition. Note that the translucent fiber 10 is connected to the metal member 11.
Methods for casting include molten metal impregnation method and molten metal forging method.

Further, the detection window 9 is located on the wall surface of the combustion chamber 6 (the wall surface of the cylinder 2) within the range where the piston rings 7, 7 that slide with the reciprocating motion of the piston 5 are in sliding contact with the cylinder side end surface of the translucent fiber 10. is set to be located.

Furthermore, in the through hole 8, a phototransistor 12 as a light receiving element is disposed on the other end surface 9b of the detection window 9, with its light receiving surface 12a facing each other, and a holder 13 holding the phototransistor 12 is transparent. It is fixed by screwing into the hole 8. Further, a signal transmission cord 14 for taking out the output voltage from the phototransistor 12 passes through the holder 13 and is led out to the outside of the cylinder block 1. still,
Reference numeral 15 denotes an oil ring as a sealing member attached to the piston 5.

Next, to explain the operation of the above embodiment,
The visible light and/or infrared rays generated in the combustion chamber 6 pass through the light-transmitting fiber 10 of the detection window 9 and reach the other end surface of the light-transmitting fiber 10, and then reach the light-receiving surface 12a of the phototransistor 12. The light is received, converted into voltage by the phototransistor 12, and transmitted as an electrical signal to the signal transmission code 14.
It is taken out from the cylinder block 1.
As a result, engine combustion conditions such as misfire in the combustion chamber 6 and combustion timing can be detected and observed outside the engine without affecting combustion.

Here, since the detection window 9 is composed of a plurality of light-transmitting fibers 10, 10... and a metal member 11, the usable temperature is as high as 400 to 1500 degrees Celsius due to their excellent heat resistance, so it is about 250 degrees Celsius. It can be used with sufficient thermal resistance even if it is installed on the cylinder 2 wall where the temperature rises, and it also has good thermal conductivity, so the cylinder side end surface 9a does not become a heat point and can be used for a long time. It is possible to observe the combustion state even under high load conditions.

In addition, the light-transmitting fibers 10, 10... constituting the detection window 9 have a low coefficient of thermal expansion, and since a plurality of fibers 10, 10... with a small cross-sectional area are bundled and cast around the metal member 11, Due to the sudden temperature fluctuation of the gas in the combustion chamber 6 that occurs between the intake and combustion strokes, the thermal stress can be diffused and relaxed due to the small amount of expansion and contraction, thereby preventing damage to the detection window 9. Its thermal shock resistance can be improved.

In addition, the transparent fiber 10 has a metal member 11
The metal member 1 is cast and held by
Since it is firmly fixed to the through hole 8 through the through hole 8 by brazing, it will not be damaged even if it receives the combustion pressure of the gas in the combustion chamber 6, and the impact resistance can be improved. The gas inside chamber 6 is passed through the hole 8
It is possible to improve the sealing performance without causing gas leakage. In this case, as the metal member 11 constituting the detection window 9, various metals can be used as described above, so if the same material as the cylinder head 3 is used, the brazing strength can be further increased and the durability can be increased. Impact resistance and sealing properties can be further improved.

Furthermore, the light-transmitting fiber 1 in the detection window 9
Since the cylinder side end face of No. 0 is in sliding contact with the piston rings 7, 7, even if deposits such as carbon are attached to the cylinder side end face, they are immediately scraped off by the piston rings 7, 7. Therefore, it is possible to maintain good optical sensitivity over a long period of time and effectively observe the combustion state.
In this case, since the cylinder side end surface 9a of the detection window 9 is formed flush with the wall surface of the cylinder 2, no ring wear occurs on the piston rings 7, 7.

FIG. 4 shows a second embodiment of the present invention, in which instead of forming the detection window 9 from the cylinder side opening of the through hole 8 to the central part in the first embodiment, the detection window 9 is formed over the entire length of the through hole 8'. 9', and a phototransistor 12' held by a holder 13' is disposed in contact with the other end surface 9'b of the detection window 9'. This makes surface machining easier. The rest of the configuration is the same as that of the first embodiment, and the same parts are given the same reference numerals and the explanation thereof will be omitted.

Furthermore, FIG. 5 shows a third embodiment of the present invention,
In the first embodiment, instead of directly brazing and fixing the detection window 9 to the through hole 8, the holder 13''
is extended to the cylinder side opening of the through hole 8, and the detection window 9'' is fixed in the holder 13'' with brazing, and the holder 13'' is screwed and fixed into the through hole 8'' via the sealing material 16. By doing so, the detection window 9'' can be placed in the holder 1.
The detection window 9'', together with the holder 13'', can be attached to and detached from the engine to improve the installation and maintenance of the observation device.

In the above embodiments, the present invention was applied to a reciprocating engine, but the present invention can also be applied to a rotary piston engine, in which case a detection window is provided in the rotor housing or side housing. It is sufficient to provide an apex seal or a side seal as a sealing member mounted on the rotary piston in sliding contact with the end surface of the detection window.

As explained above, according to the present invention, the detection window for observing the combustion state in the combustion chamber is constructed of a metal member in which a plurality of light-transmitting fibers are bundled and buried,
By attaching the detection window to the wall of the combustion chamber so that the sealing member attached to the piston slides into contact with the end face of the translucent fiber, the detection window has improved thermal shock resistance, as well as improved impact resistance and heat resistance. This enables long-term use and high-load use, and also prevents deposits from adhering to the cylinder side end face of the detection window, making it possible to effectively observe the combustion state over a long period of time. It is possible to provide a combustion state observation device that can perform

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a general schematic diagram of the first embodiment, FIG. 2 is a diagram showing the main parts of the first embodiment, and FIG. 3 is a perspective view of the detection window. Fourth
The figure is a diagram equivalent to FIG. 2 showing the second embodiment, and FIG. 5 is a diagram equivalent to FIG. 2 showing the third embodiment. 5... Piston, 6... Combustion chamber, 7... Piston ring, 9, 9', 9''... Detection window, 10... Translucent fiber, 11... Metal member.

Claims (1)

[Scope of utility model registration request] A combustion state observation device for an engine that optically observes the combustion state in a combustion chamber, wherein a detection window for detecting the combustion state in the combustion chamber is composed of a metal member in which a plurality of transparent fibers are bundled and buried, 1. A combustion state observation device for an engine, characterized in that the detection window is attached to a wall surface of a combustion chamber so that a sealing member attached to a piston is in sliding contact with an end surface of a translucent fiber.