JPH0310336Y2 - - Google Patents

Description

[Detailed explanation of the invention] <Industrial field of application> The invention uses mist gas introduced from the crank chamber of a diesel engine through an introduction pipe installed at the upper end.
This invention relates to an oil droplet separator for a diesel engine that separates and collects oil droplets through a passage inside a cylindrical body, and discharges gas from which the oil droplets have been removed from an exhaust pipe provided at the lower end.

<Prior Art> Conventionally, as an oil droplet separator for this type of diesel engine, one shown in FIG. 3, for example, is known. This oil droplet separator is provided with an introduction pipe 12 at the center of the upper end of a cylindrical body 11 whose both ends are sealed, or an introduction pipe 13 at the upper side surface, and an exhaust pipe 14 which projects into the cylinder at the center of the lower end of the cylindrical body 11. , a bottomed cylinder 15 is provided inside the cylinder to cover the upper end of the exhaust pipe to form a passage, and an oil drain pipe 16 is attached to the lower end of the cylinder. The mist gas containing lubricating oil droplets and leaked combustion gas discharged from the crank chamber of the diesel engine flows from the introduction pipe 12 or 13 to the inner periphery of the cylindrical body 11 as shown by arrows A or A'. The oil droplets in the mist gas descend between the outer periphery of the bottom cylinder 15, then change direction at the bottom of the cylinder as shown by arrow B, and ascend between the inner periphery of the bottomed cylinder 15 and the outer periphery of the exhaust pipe 14. The mist gas is deposited here due to its own inertial force, and due to the weight difference between the mist gas and the gas due to the drop in flow velocity, it settles to the bottom of the cylinder, is separated and collected, and the gas from which oil droplets are removed is At the upper end of the exhaust pipe 14, the direction is changed as shown by arrow C, and the gas flows down inside the exhaust pipe 14 and is discharged to the outside.

<Problems to be Solved by the Invention> However, in the conventional oil droplet separator described above, the introduction pipe 12 or 13 is arranged axially at the center of the upper end of the cylindrical body 11 or at the upper side of the cylindrical body 11 with the axis of the cylindrical body. Because they are installed in orthogonal directions, the flow of mist gas inside the cylinder becomes a substantially axial flow, and the amount of oil droplets collected by contact with the passage wall is small.In other words, the oil droplet separation efficiency is low. There is a drawback.

Therefore, the purpose of this invention is to be able to create an optimal mist gas flow to increase the amount of collected oil by devising the size, shape, and installation position of the mist gas introduction pipe, and to improve the oil droplet separation efficiency significantly more than before. An object of the present invention is to provide an oil droplet separator for a diesel engine that can be improved.

<Means for Solving the Problems> In order to achieve the above object, the oil droplet separator for a diesel engine of the present invention includes a cylindrical body whose both ends are sealed with an upper cover and a lower cover, and the inside of this cylindrical body and the inside of the diesel engine. A mist gas is connected to the upper outer periphery of the cylindrical body, communicates with the crank chamber, and is attached to the upper outer periphery of the cylindrical body so that the central axis is substantially parallel to the tangent to the outer periphery of the cylindrical body in the cross section of the cylindrical body, and is eccentric from the center of the cylindrical body. an inlet pipe, an exhaust pipe whose end protrudes into the cylindrical body and is attached to the lower cover of the cylindrical body, and a pipe which is arranged inside the cylindrical body so as to cover the end of the exhaust pipe from above to form a mist gas passage. The inner diameter of the introduction pipe is the inner radius of the cylinder body.
The size is 0.2 times or more and 0.8 times or less, and the tip of the introduction tube protruding into the cylindrical body is formed to be inclined so as to protrude toward the center of the cylindrical body.

<Function> The mist gas in the crank chamber of a diesel engine is
It is ejected from the tip of the introduction tube in the tangential direction of the upper inner circumference of the cylinder, descends on the outside of the bottomed cylinder while rotating along the inner circumference of the cylinder, and when it collides with the lower cover of the cylinder, turns upward and the above-mentioned It ascends while turning between the inner circumference of the bottomed cylinder and the outer circumference of the exhaust pipe. Due to this swirling flow, oil droplets such as lubricating oil in the mist gas come into contact with the inner circumferential surface of the cylinder, the outer circumferential surface and inner circumferential surface of the bottomed cylinder, and the outer circumferential surface of the exhaust pipe over a wide area. Due to its own inertial force, it adheres to each of the above surfaces and is separated and collected, and as the flow rate of the swirling flow decreases due to flow path resistance, it settles on the bottom cover of the cylinder due to the weight difference with the gas and is separated. , collected. Finally, the gas from which the oil droplets have been removed collides with the bottom of the upper end of the bottomed cylinder, turns downward, descends within the exhaust pipe attached to the bottom cover of the cylinder, and is discharged to the outside. Further, oil droplets accumulated on the lower lid of the cylindrical body flow out from the oil drain hole.

<Example> Hereinafter, the present invention will be explained in detail with reference to the illustrated example.

Figures 1a, b, and c are a plan view, a vertical sectional view, and a front view, respectively, of an oil droplet separator for a diesel engine;
4 is a cylindrical body whose both ends are covered with an upper cover 2 and a lower cover 3, and 4 is a cylinder whose central axis 4a is parallel to the tangent line 1a to the outer circumference of the cylindrical body in the cross section of the cylindrical body 1, and eccentric from the central axis 1b of the cylindrical body. 5 is a mist gas introduction pipe attached to the upper outer periphery of the cylindrical body 1, 5 is an exhaust pipe attached to the lower lid 3 with the end 5a protruding above the central axis 1b inside the cylindrical body 1, and 6 is an exhaust pipe attached to the lower cover 3. A bottomed cylinder 8 is fixed to four ribs 7 provided on the outer periphery of the end 5a of the exhaust pipe 5, and covers the end 5a from above to form a mist gas passage. It is a hole.

The upper lid 2 has a large diameter circular hole 2a for inspection in the center and four bolt holes 2b on the periphery.
A lid (not shown) that seals the area is fixed with bolts. The introduction tube 4 has an inner diameter d that is 0.2 times or more and 0.8 times or less the inner radius R of the cylindrical body 1, and its outermost edge 4b and innermost edge 4c are parallel to the tangent 1a of the cylindrical body, respectively. It is eccentric so that it is located between the center axis 1b and a straight line passing through the central axis 1b. In addition, an introduction pipe 4 protruding into the cylindrical body 1
The tip 4d of the introduction tube 4 is obliquely cut at an angle of θ° (0°≦θ≦45°, see Fig. 1a) so as to protrude toward the center of the cylinder, while the rear end of the introduction tube 4 is Flange 4
It is communicated with the crank chamber of the diesel engine through a conduit (not shown) connected to e. The dimensions and shape of the introduction pipe 4 that maximize the oil droplet separation efficiency are such that its outermost edge 4b coincides with the tangent line 1a, d=0.5R,
It is clear from the test results described below that this is the case when θ=30°.

The oil droplet separator for a diesel engine with the above configuration is
It works like this:

Mist gas containing lubricating oil droplets and leaked combustion gas in the crank chamber of a diesel engine is removed from the inlet pipe 4.
is ejected from the tip 4d in the tangential direction of the upper inner circumference of the cylinder 1 as shown by arrow A, and turns along the inner circumference of the cylinder to form a so-called swirl flow, with the upper end being blocked by the bottom plate 6a. It descends as shown by arrow B on the outside of the cylinder 6, turns upward when it collides with the lower cover 3 of the cylinder, and rises as shown by arrow C while turning between the inner periphery of the bottomed cylinder 6 and the outer periphery of the exhaust pipe 5. Oil droplets in the mist gas are distributed on the inner circumferential surface 1c of the cylinder, the outer circumferential surface 6b and inner circumferential surface 6c of the bottomed cylinder, and the outer circumferential surface 5b of the exhaust pipe.
It comes in contact with the gas over a wide area, and is separated and collected by adhering to each surface due to its own inertia, and as the velocity of the swirling flow decreases due to flow path resistance, the difference in weight between the gas and the cylinder It settles on the lower lid 3 inside the body 1 and is separated and collected. Finally, the gas from which the oil droplets have been removed collides with the back surface of the bottom plate 6a of the bottomed cylinder 6, turns downward, descends inside the exhaust pipe 5 as shown by arrow D, and is discharged to the outside. Further, oil droplets that have been separated and collected and accumulated on the lower lid 3 inside the cylindrical body 1 flow down from the oil drain hole 8 to an external oil pan (not shown).

In the above embodiment, the introduction pipe 4 is attached so that its outermost line 4b substantially coincides with the tangent line 1a of the cylindrical body,
Since the tip 4d is obliquely cut at an appropriate angle so as to protrude toward the center of the cylinder, the mist gas released from the introduction pipe 4 can smoothly and quickly swirl along the circumferential surface 1c of the cylinder. Oil droplet separation efficiency can be further improved.

FIG. 2 is a graph showing the test results of tests conducted to determine the dimensions and shape of the introduction tube that maximized the oil droplet separation efficiency for the above embodiments. In the same figure, the vertical axis shows the number of residual oil droplets in the exhaust gas, with the maximum efficiency being 1, and the horizontal axis in Fig. 2a shows the ratio of the inner diameter d of the inlet pipe to the radius R of the cylinder body, and the horizontal axis in Fig. The horizontal axis indicates the cutting angle θ at the tip of the introduction tube. Second
As is clear from FIG.
It can be seen that in the range of ≦0.8, the effect is remarkable as it decreases to 70-50% of the conventional value, and d/R=0.5 is the optimum value. Furthermore, from FIG. 2b, it can be seen that the oil droplet separation efficiency is maximum when θ=30°.

In the embodiment shown in FIG. 1, the bottom of the cylinder with a bottom is a flat bottom plate 6a, but it may be a conical bottom with an upwardly protruding center.

<Effects of the invention> As is clear from the above explanation, the oil droplet separator for a diesel engine of the present invention has a mist gas introduction pipe arranged around the upper outer periphery of the cylindrical body, which is substantially parallel to the tangent to the cross section of the outer periphery. A bottomed cylinder is provided at the end of the exhaust pipe which is attached eccentrically from the center of the cylinder and attached to the lower cover of the cylinder and which projects into the cylinder, so as to cover it from above and form a mist gas passage. Since the inner radius and tip of the inlet pipe are formed with appropriate dimensions and shapes, the flow of mist gas becomes a so-called swirl flow that ascends and descends toward the exhaust pipe while swirling along the above-mentioned passage, creating a wide spread on the passage wall surface. Because of the contact over the area,
Oil droplets in mist gas can be separated and collected by the inertial force of the swirl with much higher efficiency than with conventional axial flow type oil droplet separators.

[Brief explanation of the drawing]

Figures 1a, b, and c show a plan view, longitudinal sectional view, and front view, respectively, of an embodiment of the oil droplet separation device for a diesel engine according to the present invention, and Figure 2 shows an oil droplet separation efficiency test according to the above embodiment. Figures 3a and 3b showing the results are a plan view and a vertical sectional view, respectively, of a conventional oil droplet separation device. 1...Cylindrical body, 2...Upper lid, 3...Lower cover, 4...
...Introduction pipe, 5...Exhaust pipe, 6...Bottomed cylinder, 7...
...Rib, 8...Oil drain hole.

Claims (1)

[Scope of utility model registration request] A cylindrical body whose both ends are sealed with an upper cover and a lower cover, the inside of this cylindrical body communicates with the crank chamber of a diesel engine, and the central axis is substantially parallel to the tangent to the outer circumference of the cylindrical body in the cross section of the cylindrical body. a mist gas introduction pipe attached to the upper outer periphery of the cylindrical body so as to be eccentric from the center of the cylindrical body; an exhaust pipe whose end protrudes into the cylindrical body and is attached to the lower cover of the cylindrical body; A bottomed cylinder is provided in the cylindrical body so as to cover the end of the pipe from above to form a mist gas passage, and an oil drain hole is provided in the lower cover of the cylinder, and the inner diameter of the introduction pipe is is 0.2 times or more and 0.8 times or less the inner radius of the cylindrical body, and the tip of the introduction tube protruding into the cylindrical body is formed to be inclined so as to protrude toward the center of the cylindrical body. Diesel engine oil droplet separator.