JPH10115210A - Mist detecting device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive mist-detecting device, which has a long life span with stability and is easy for mist measuring and maintenance, by attaching the device directly on a mist exhaust pipe, through a conventional mist detecting device for an engine is so structurally complicated that it is expensive and difficult to handle or maintain. SOLUTION: A photoemission main body 10 providing a photoemission body module 16 with an emitter and a lens detachably is attached on one sensor mounting hole 8a in a pipe joint section 2 providing the penetration mounting holes 8 crossing a mist channel 7 penetrating around the center of a plate. An photoreception main body 11 providing a photoreception body module 34 detachably with a photoreception body and a lens is attached on the other sensor mounting hole 8b. An air outlet 20 formed at the top of a light path 22 of the photoemission main body 10 and the photoreception main body 11, and an air inlet 21 supplying a clean air, are provided. The photoemission body module 16 and the photoreception body module 34 are electrically connected to a mist densitometer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine mist detecting device for detecting the concentration of oil mist and blow-by gas (hereinafter collectively referred to as mist) discharged from a crankcase of an engine.

[0002]

2. Description of the Related Art In an engine such as a diesel engine, lubricating oil is supplied to sliding surfaces (a bearing portion of a connecting rod, a main bearing supporting a crankshaft, a sliding surface between a piston and a cylinder, etc.) in a crank chamber. However, there is heat generation on the sliding surface and splashing of the lubricating oil by the rotating body, and the combustion gas in the combustion chamber blows through the gap between the piston and the cylinder and mixes into mist in the crank chamber.

Since the pressure in the crank chamber is higher than the atmospheric thickness due to the mist phenomenon, a mist exhaust pipe communicating from the crank chamber of the engine to the outside is prevented in order to prevent the mist accompanying the internal pressure from being filled. Provided to escape to the atmosphere. Even when the engine is operating normally, there are low-concentration mist and blow-by gas from the combustion chamber in the crankcase, which are released to the atmosphere through the mist exhaust pipe and liquefied by natural cooling. , Some are collected.

When the sliding surface resistance of the engine increases for some reason or when the lubricating oil deteriorates or the supply amount becomes insufficient, heat generation increases due to an increase in sliding friction, and the mist concentration is lower than that in a normal state. Significantly increasing phenomena occur. or,
When the combustion pressure increases due to the difference in the ignition timing, the mist concentration due to the blow-by gas increases. In any case, the state of the engine can be grasped by constantly monitoring the mist concentration generated in the crankcase and comparing the mist concentration with the normal mist concentration, thereby preventing a serious accident from occurring. .

[0005] The structure of the crankcase of the engine can be roughly classified into a structure in which a partition is provided for each cylinder and separation, and a structure in which a plurality of cylinders are grouped together without providing a partition in the crankcase. 2. Description of the Related Art A conventional mist detection device has a configuration in which, for an engine in which a crankcase is separated by a partition wall, mist concentration can be detected in each of the separated sections (Japanese Utility Model Publication No. 56-46014). , Real Kimiaki 6
0-6590).

[0006]

In the mist detection device described in the above publication, in order to detect the mist concentration in each section of the crankcase of the engine, the same number of sections as the number of sections are newly added between each section and the detection device. It is necessary to provide a communication pipe, and inside the storage case of the detection device, a rotary valve for switching a port of the communication pipe connected to each section, a detection pipe provided with a projector and a light receiver at both ends, a rotary valve and a detection pipe are provided. The introduction hose to be connected, the blower for sucking the mist of each section, the measuring device and auxiliary equipment for detecting the motor and pump, and the parts are packed in a complicated manner, so the structure is complicated and handling and maintenance are complicated. Was difficult.

Further, since mist penetrates into auxiliary devices and components for introducing mist such as a rotary valve and a blower motor into detection, the durability of these devices and components is reduced, and early maintenance and inspection are required. There was a problem. Although it is multifunctional in terms of software, this function also includes a correction function on the electronic circuit to compensate for the insufficiency of the basic function of preventing mist from adhering to the lens surface. The price of the detection device was increasing.

[0008] Therefore, the conventional apparatus is not suitable for a user who wants an mist detecting apparatus which is low in cost because the crank chamber is not partitioned by a partition wall and has only a single function, and which does not require much running cost. Was. An object of the present invention is to provide an inexpensive mist detection device which can be used stably for a long period of time, can easily measure and maintain mist, and is inexpensive.

[0009]

In order to achieve the above object, an engine mist detecting device according to the present invention is provided with a mist flow path penetrating substantially parallel upper and lower surfaces, and intersects with the mist flow path. A light emitting module having a light emitting body and a lens is detachably attached to a rear end of one of the sensor mounting holes of a pipe connector which is sandwiched in the middle of an engine mist exhaust pipe. An optical path is formed between the air outlet holes at the tip from the light emitting module, and a light emitting body provided with an air inlet for supplying air pressure in the middle of the optical path, with the tip attached to the mist flow path, On the other side of the sensor mounting hole, a photoreceptor module having a photoreceptor and a lens is detachably attached to a rear end portion, and is concentric with the optical path of the luminous body between the photoreceptor module and an air blowing hole at the tip. Shape the light path Then, a photoreceptor body provided with an air inlet for supplying air pressure in the middle of the optical path is attached with the tip directed toward the mist flow path, and the luminous body and the photoreceptor are connected to a mist concentration measuring instrument via electric wires. Connected.

In the optical path of the light emitting module and the light receiving module, small diameter holes can be provided in front of the light emitting module and the light receiving module, respectively.
Further, an optical path shielding mechanism that opens and closes the optical path by an external operation can be provided in front of the light emitting module and the light receiving module in the optical path of the light emitting module and the light receiving module. It is preferable that the light emitting body and the light receiving body are formed to have the same size and shape, and the light emitting module and the light receiving module are formed to have the same size and shape.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a mist detecting device A without a mist concentration measuring device, and FIG.
FIG. 3 is a front view showing the overall configuration of the mist detection device A. As shown in FIG. 3, the mist exhaust pipe of the engine E includes a mist exhaust pipe 1a, a mist exhaust pipe 1b having a flexible structure, and a pipe connector 2 of the mist detection device A.
And a mist exhaust pipe 1c connected through the mist exhaust pipe 1c. The mist exhaust pipe 1b has a flexible structure in order to suppress vibration to the upper pipe and facilitate alignment.

The mist detecting device A includes a mist exhaust pipe 1b,
1c, a mist concentration measuring instrument 5 having a control unit 37 connected to the sensor unit 3 via an electric wire 4, a sensor unit 3 attached to the tube connector 2, and a mist It is constituted by an air line 6 connected from the pneumatic source 24 provided in the concentration measuring device 5 to the sensor section 3. As shown in FIG. 1, the pipe connector 2 has substantially parallel upper and lower surfaces serving as a sealing and mounting seat surface, and a mist flow path 7 penetrates substantially the center of a rectangular contour, and crosses the mist flow path 7. In addition, sensor mounting holes 8 penetrating through both end surfaces are provided, and bolt insertion holes 9 are provided at four locations outside the mist flow path 7.

The sensor mounting hole 8 is divided into a sensor mounting hole 8a on the left side of the mist flow path 7 and a sensor mounting hole 8b on the right side in FIG. The sensor section 3 detects the mist concentration flowing in the mist flow path of the pipe connector 2 by optical means, and emits light by fixing a flange provided on the luminous body 10 to the left sensor mounting hole 8a with a bolt. The light receiving portion 3b includes a portion 3a and a flange provided on the photoreceptor main body 11 fixed to the right sensor mounting hole 8b with a bolt. Concentric sensor mounting hole 8
An O-ring 12 that seals a gap between the light-emitting body 10 and the light-receiving body 11 is provided at a position 8a and 8b at a position crossing the outer surface of the pipe connector 2 (see FIG. 1).

The light-emitting body 10 has a structure in which a male screw 13 is provided on the outer peripheral surface of the rear end opposite to the front end 10a to be inserted into the left sensor mounting hole 8a, and a bottomed fitting hole 14 is provided on the rear end. Is formed. A head 16a of a light emitting module 16 having a lens and a light emitting (LED) element 15 is inserted into the fitting hole 14 with the bottom, and the mounting angle is fixed by a rotation preventing pin 17 (FIG. 1). reference). Therefore, even if the light emitting module 16 is attached or detached, the light emitting module 1
The positional deviation and the angular deviation of the optical axis 6 are prevented.

In order to minimize the output error due to the temperature characteristics of the light emitting (LED) element 15, the temperature sensor 18 is embedded in the light emitting module 16 in contact with the bottom surface of the light emitting (LED) element 15, The output fluctuation due to the temperature characteristics of the LED element itself is corrected by an electronic circuit based on the signal of the temperature sensor 18 (see FIG. 2). A cap nut 19 is screwed into the male screw 13 of the light emitting body 10, and a hole is provided at the center of the cap nut 19 to avoid interference with the light emitting module 16.

An O-ring 38 is inserted between the end face of the light emitting module 16 and the bottom surface of the fitting hole 14 having a bottom, and when the cap nut 19 is tightened, a gap between the light emitting module 16 and the light emitting body 10 is formed. Is sealed. The cap nut 19 fixes the luminous body module 16 to the luminous body 10, and the luminous body module 16 can be easily attached and detached by a simple operation of attaching and removing the cap nut 19.

Light emitted from the luminous element 15 passes through an optical path 22 passing through the axis of the luminous body 10 and irradiates the mist channel 7 from an air outlet 20 opening at the tip. The shape of the distal end portion 20a of the air blowing hole 20 is formed in a tapered shape whose diameter increases toward the distal end, thereby preventing liquefied mist from accumulating.

The hole shape of the air outlet hole 20 is an important factor together with the air flow rate in preventing mist intrusion. According to the results of an actual machine test, the inner diameter is 3 to 5 mm and the length is 8
A range of １５15 mm is considered appropriate. Although the shape of the air outlet hole 20 is illustrated as a parallel hole (see FIG. 1), it may be a streamline whose diameter decreases toward the tip. Light-emitting body 10
An air inlet 21 communicating with the air outlet 20 is provided from the lower surface of the mist concentration meter 5, and an air pump 24 connected to an air filter 23 provided inside the mist concentration measuring instrument 5 is connected to the air pipe 6.
Clean air is supplied to the air inlet 21 via the air inlet (see FIG. 2).

If the flow rate of the clean air is insufficient, the removal of the mist is insufficient, and if the flow rate is too high, the mist concentration in the mist flow path 7 is reduced, and the accurate concentration cannot be detected. Control of the flow rate is important.
In order to control the air flow rate as accurately as possible, a flow control valve 25 is provided at a position close to the air inlet 21 (FIG. 2, FIG.
(See FIG. 4).

The reason why the flow control valve 25 is provided near the air inlet 21 is that the pressure of clean air is
Immediately before, the pressure in the mist flow path 7 can be maintained at a much higher pressure, so that when the pressure P ₂ in the mist flow path 7 increases, the pressure in the optical path 22 is instantaneously increased, and This is for pushing out the mist M that is going to enter 20.

The clean air supplied to the air inlet 21 is supplied to the luminous element module 16 by mist entering the optical path 22.
In order to prevent the mist from adhering to the lens surface, a flow of air blown out from the air blowout hole 20 to the mist flow path is created. In the optical path 22 between the inlet 21 and the light emitting module 16, the diameter of the air
A small diameter portion 26 reduced by 2 mm is formed. Even if the mist is prevented from adhering to the luminous body module 16 as described above, the mist may adhere to the lens surface for any reason during continuous use of the mist detection device A for a long time. obtain.

The treatment in such a case may be as simple as wiping off the lens surface with a cotton swab dipped in a solution having a degreasing effect. The phenomenon that mist attaches even at the moment of desorption of the light occurs.
An optical path shielding mechanism 27 that opens and closes the optical path 22 is provided at a position close to. In this embodiment, the light path shielding mechanism 27 is provided in the small diameter portion 26.

FIG. 5 shows an embodiment of the light path shielding mechanism 27, in which a screw hole 29 penetrating downward is provided on the bottom surface of a hole 28 with a bottom opening on the lower surface of the small diameter portion 26, and the luminous body 1 is provided.
A cylindrical valve element 31 is placed over and fixed to the tip of a bolt 30 screwed into the screw hole 29 from below the screw hole 29. Hole 28 with bottom
An annular groove 32 is provided at a position where the bottom surface and the inner surface cross each other, and an O-ring 33 is inserted into the annular groove 32. With the optical path shielding mechanism 27 configured as described above, the valve element 31 can open and close the small diameter portion 26 by rotating the bolt 30 from the outside.

The photoreceptor main body 11 is formed in the same shape and the same size as the luminous body 10, and is completely the same as the luminous body 10 except that a photoreceptor module 34 is mounted in place of the luminous body module 16. The photoreceptor module 34
It has the same shape as the light emitting module 16 and is the same as the light emitting module 16 except that a light receiving element with a lens is provided instead of the light emitting element with a lens. Therefore, the processing of the light emitting body 10 and the light receiving body 11 and the processing of the light emitting module 16 and the light receiving module 34 are facilitated, and the same cap nut 19 and light path shielding mechanism 27 are attached, so that the assembling work is also facilitated. Therefore, there is an advantage that the entire manufacturing cost of the sensor unit 3 is reduced.

Next, the operation of the mist detecting device for an engine configured as described above will be described with reference to the drawings.
The pipe connector 2 to which the sensor unit 3 (the light emitting unit 3a and the light receiving unit 3b) is attached is inserted between the mist exhaust pipes 1c and 1b, and the bolt insertion holes of the flanges of the mist exhaust pipes 1c and 1b are connected to the pipe connector. 2 and the bolt insertion hole 9
5 and tighten the nut 36 to the bolt 35 (FIG. 3).
reference).

With the simple operation as described above, the pipe connection 2
Closely adheres to the flanges of the mist exhaust pipes 1c and 1b, and the inner surfaces of the mist exhaust pipes 1c and 1b and the mist flow path 7 of the pipe connection portion 2.
Almost match. The sensor unit 3 and the mist concentration measuring device 5 are connected by the electric wire 4 and the air line 6, and clean air is supplied to the air inlet 21 from the air pump 24 of the mist concentration measuring device 5 via the air line 6. .

The pressure in the crank chamber of the engine E is several mmAq higher than the atmospheric pressure, and the air containing mist in the crank chamber is sent to the mist passage 7 through the mist exhaust pipes 1a and 1b without using a pump. The clean air supplied to the air inlet 21 is sent from the air outlet 20 to the mist channel 7, and the mist M flowing through the mist channel 7 enters the optical path 22 and emits the light emitting module 16 and the light receiving module 34. (See FIGS. 2 and 4).

The luminous flux emitted from the light emitting element 15 of the light emitting module 16 is absorbed and scattered by the mist M in the mist channel 7, and the luminous intensity according to the mist concentration is received by the light receiving element of the light receiving module 34. Then, the magnitude of the luminous intensity is converted into an electric signal and sent to the control unit 37 of the mist concentration measuring instrument 5.

As a specific method for preventing mist adhesion, when the pressure in the optical path 22 is P ₁ and the pressure in the mist channel 7 is P ₂ , the differential pressure ΔP = P ₁ −P ₂ The pressure P ₂ in the mist flow path 7 periodically fluctuates within a range of ± several tens of mmAq. Therefore, in order to always keep the pressure difference ΔP positive, the pressure P ₁ in the optical path 22 must be maintained. Is set to be equal to or more than the maximum value of the pressure P ₂ in the mist flow path 7. In this state, when the pressure P ₂ in the mist channel 7 changes to the maximum negative pressure, the differential pressure ΔP shows the maximum value, and is approximately 2 · P
₂ or above.

Since the maximum value of the pressure P ₂ in the mist channel 7 in the actual machine investigation is 17 mmAq or more, when the maximum differential pressure is 34 mmAq and the wind speed at the time of blowing out from the air outlet 20 is 20 m / s or more, Since the maximum value of the wind speed in the mist flow path 7 in the state is 0.8 m / s, the mist M to be used for detection is dispelled, resulting in a problem that the sensitivity is considerably reduced.

In order to produce the maximum differential pressure ΔP,
Although it is necessary to flow a large amount of air or to make the air blowout hole 20 small, a small air pump 2 is required to flow a large amount of air.
No. 4 cannot cope with this, and if the air outlet 20 is made smaller, there is an adverse effect due to the smaller light flux. After all, since there is practically no practical way to always keep the differential pressure ΔP positive, in the present invention, when the pressure P ₂ in the mist flow path 7 increases, the mist M enters the air outlet 20 to some extent. The mist M is prevented from reaching the lenses of the light emitting module 16 and the light receiving module 34 in consideration of the possibility.

As a specific method, first, the air inlet 21 close to the light emitting module 16 and the light receiving module 34 is used.
, The pressure P _{0, which} is much higher than the pressure P ₂ in the mist flow path 7, is maintained until immediately before the light-emitting module 16 and the light-receiving module 34. Second, the provision of the small diameter portion 26 increases the flow resistance of the mist M toward the light emitting module 16 and the light receiving module 34.

In consideration of the above, an appropriate flow rate range where the air flow rate is excessively large and the sensitivity is not impaired, and the mist M is not excessively small and does not enter the light-emitting module 16 and the light-receiving module 34. As a result of a test on an actual machine, it was found that the discharge rate from the air pump 24 in the mist detection device A is preferably in the range of 2.5 to 5 L / min.

In order to remove the mist M adhered to the surface of the lens of the light emitting module 16 or the light receiving module 34 during the measurement of the mist concentration, the bolt 30 of the light path shielding mechanism 27 is operated to operate the light path by the valve 31. After closing the small-diameter portion 26 of the lens 22, the light-emitting module 16 or the light-receiving module 34 is removed, and the mist M adhered to the surface of the lens is removed.
Is easily wiped off with a cotton swab soaked in a solution (alcohol or the like) having a degreasing effect, and the light emitting module 16 or the light receiving module 34 returned to the initial state by the wiping is attached to the original state, and then the light path shielding mechanism 27 Can be opened.

While the small-diameter portion 26 of the optical path 22 is closed by the valve element 31, the mist M does not adhere to the light-emitting module 16 or the light-receiving module 34 during attachment or detachment. There is no leakage.

[0036]

Since the present invention is configured as described above, it has the following effects. (1) The mist detection device for an engine of the present invention has a simple structure, the luminous body and the photoreceptor main body are formed in the same shape and the same size, and the same parts are attached except for the luminous body module and the photoreceptor module. Since the light-emitting module and the light-receiving module have the same shape, it is easy to manufacture the sensor part of the engine mist detection device, and the manufacturing cost is reduced. (2) The conventional engine mist detection device is installed at a position separated from the mist exhaust pipe of the engine, connects the mist exhaust pipe and the mist detection device with a bypass line, and forces the mist through the bypass circuit. However, the mist detection device for an engine of the present invention is directly attached to the mist exhaust pipe of the engine, thereby eliminating the need for a bypass pipe or a suction facility and simplifying the configuration of the entire mist detection device. As a result, there are advantages such that the manufacturing cost is reduced and the maintenance is facilitated.

(3) The mist detection device for an engine of the present invention is convenient to use because it can be attached by a simple method of inserting a pipe connector with a sensor into the mist exhaust pipe and tightening with bolts. (4) The mist detection device for an engine of the present invention can make it difficult for mist to enter by providing a small diameter portion in the optical path, and by wiping the lenses of the light emitting module and the light receiving module by providing the optical path shielding mechanism. Can be easier.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mist detection device A excluding a measuring instrument.

FIG. 2 is an explanatory diagram of an operation of the mist detection device A.

FIG. 3 is a front view of a mist detection device A attached to a mist exhaust pipe of the engine.

FIG. 4 is a schematic diagram illustrating the flow of air.

FIG. 5 is a vertical sectional view of an optical path shielding mechanism.

[Explanation of symbols]

 A Mist for engine M Mist 1a, 1b, 1c Mist exhaust pipe 2 Pipe fitting 3 Sensor part 3a Light emitting part 3b Light receiving part 4 Electric wire 5 Mist concentration measuring instrument 7 Mist flow path 8a, 8b Sensor mounting hole 10 Light emitting body main body 11 Light receiving Body 16 Light emitting module 20 Air outlet 21 Air inlet 22 Optical path 24 Air pump 25 Flow control valve 26 Small diameter section 27 Optical path shielding mechanism 34 Light receiving module

Claims (4)

[Claims] A mist flow passage penetrating substantially parallel upper and lower surfaces, a sensor mounting hole intersecting the mist flow passage, and a sensor mounting hole provided through the mist flow passage. At one side of the sensor mounting hole, a light emitting module having a light emitting body and a lens is detachably attached to a rear end portion, and an optical path is formed between the light emitting module and an air blowing hole at a front end. A light-emitting body provided with an air inlet for supplying air pressure to the mist flow path is mounted with the front end facing the mist flow path, and a light-receiving body module having a light-receiving body and a lens on the other side of the sensor mounting hole at the rear end. A light receiving device which is detachably mounted on the light receiving module, forms an optical path concentric with the optical path of the light emitting body between the light emitting module and the air blowing hole at the tip, and has an air introduction port for supplying air pressure in the optical path. Body body, tip above It mounted toward the strike channel, the luminous body and engine mist detecting apparatus characterized by the photoreceptor through an electric wire connected to the mist concentration measuring instrument. 2. The engine mist detection device according to claim 1, wherein small-diameter holes are respectively provided in front of the light-emitting module and the light-receiving module in the light paths of the light-emitting module and the light-receiving module. apparatus. 3. The light path of the light emitting module and the light receiving module is provided with an optical path blocking mechanism for opening and closing the light path by an external operation in front of the light emitting module and the light receiving module. The mist detection device for an engine according to claim 1 or 2, wherein 4. The light-emitting body and the light-receiving body are formed to have the same size and shape, and the light-emitting module and the light-receiving body module are formed to have the same size and shape. 3. The mist detection device for an engine according to 3.