JPH0949414A - Oil return device for internal combustion engine - Google Patents

Abstract

(57) Abstract: An oil return device for an internal combustion engine having improved gas-liquid separation efficiency is provided. An oil return passage (5) for returning oil (3) staying in a cylinder head cover (2) to an oil pan (4) is provided,
An oil outlet passage 5 ₀ of the oil return passage, toward the oil strainer 6, and then arranged close to the oil strainer 6, excised passage wall at a position more distant the oil passage 5 upper from the oil strainer 6 Then, the lower passage wall was opened so as to approach the oil strainer 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil return device for an internal combustion engine, and more particularly to a device for effectively returning oil retained in a cylinder head of an internal combustion engine to an oil pan.

[0002]

2. Description of the Related Art Lubricating oil for an internal combustion engine draws oil accumulated in an oil pan from an oil strainer by an oil pump, lubricates and cools each part of a cylinder head and a cylinder body, and then descends an oil passage.
It is known to return to an oil pan.

Since the oil pump is driven by the crankshaft, the oil flow rate increases as the engine rotation speed increases, whereas the oil returning to the oil pan depends on gravity and returns in proportion to the increase in oil supply. It is difficult to obtain the flow rate, and it accumulates in each part of the engine, and the amount of oil in the oil pan decreases. Therefore, air is sucked from the suction port of the oil pump, which causes a hunting phenomenon.

Further, when the engine speed increases and the amount of oil retained in the cylinder head increases, the amount of oil sucked from the valve stem and stem seal increases, which causes an increase in the amount of HC in the exhaust gas. In addition, a PCV (positive
Crankcase ventilation) The amount of gas increases,
The descending oil flow becomes poor. Therefore, the crankcase internal pressure rises, and the amount of return oil to the oil pan further decreases.

[0005]

As means for solving the above-mentioned problem that the oil recirculation amount decreases as the engine speed increases, for example, in Japanese Unexamined Patent Publication No. 4-241713, an oil inlet is opened in the cylinder head. An oil return pipe that opens near the oil strainer, which is the suction port of the oil pump, is attached to the outside of the engine, and the suction force of the oil pump is used to positively retain the oil retained in the cylinder head in the oil pan. A refluxing device is disclosed.

If the oil pump positively sucks the oil, bubbles in the oil staying in the cylinder head may flow into the oil pump. Therefore, in the above publication, a housing is attached to the oil outlet, a hole for discharging bubbles is formed in the housing, a baffle plate is hung on the oil strainer side, and oil is sucked from the lower side of the baffle plate. Disclosed is a gas-liquid separator in which a fixed orifice for adjusting the amount of oil outflow on the strainer side is provided near the outlet of the reflux pipe.

However, the above device has a problem that the number of parts is large and the manufacturing cost is increased. Further, since this device positively sucks the oil in the cylinder head cover, when the engine speed decreases and the amount of oil in the cylinder head cover decreases, air is also sucked in together with the engine. There is a problem that poor lubrication occurs.

The present invention has been made in view of the above problems, and moreover, when the oil that positively stays in the cylinder head is returned to the oil pan by the oil pump, the structure is simple and the number of parts is small. Moreover, it is a first problem to be solved to provide an oil return device for an internal combustion engine with improved gas-liquid separation efficiency. Further, according to the present invention, when the oil staying positively in the cylinder head is returned to the oil pan by the oil pump, when the engine speed is slow and the amount of oil staying in the cylinder head is reduced, the oil pump sucks air. A second problem to be solved is to provide an oil return device for an internal combustion engine that does not cause the above-mentioned problems.

[0009]

An oil return device for an internal combustion engine according to the present invention for solving the first problem is provided with an oil return passage for returning oil retained in a cylinder head cover to an oil pan. The oil outlet side of the return passage is arranged toward the oil strainer, the upper passage wall upstream from the passage end is cut off, and the upper layer oil containing air bubbles is released into the oil pan at a position away from the oil strainer, The lower layer oil is formed so as to be sucked by an oil strainer.

The means for cutting off the upper passage wall on the upstream side is not particularly limited, and for example, the oil return passage may be cut obliquely from the upper side to the lower side toward the oil strainer, and the passage end portion may be cut off. The opening may be opened and the upper side may be cut off in a slit shape, or the upper side may be cut off stepwise toward the oil strainer. The oil return passage can be formed outside or inside the engine body. When it is installed externally, it can be assembled using pipes, hoses, etc., and its installation position should be installed on the intake manifold side where the ambient temperature is low, on the front or rear side of the engine, so that it is not affected by hot air. Preferably.

If a barrier that allows the oil flowing under the return passage to pass therethrough and blocks the oil flowing over the upper portion is provided in the opening cut out by inclining the oil return passage, the efficiency of removing bubbles from the return oil can be further enhanced. You can The barrier may be formed of a plate or the like. The second
The oil return device for an internal combustion engine of the present invention for achieving the above-mentioned problem is equipped with a float-type on-off valve at the oil inlet of the oil return passage, and when the oil level drops and the float drops, the valve is throttled. It was done.

The float type on-off valve may be of a conventionally used type. The oil return device is an OHC (overhead camshaft), O
It can be installed in all internal combustion engines equipped with an HV (overhead valve) and the like, as well as in horizontally opposed type, V type, vertical type, etc.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. The oil return device of the first embodiment shown in FIG. 1 is connected to an oil return passage 5 for returning the oil 3 retained in the cylinder head cover 2 of the internal combustion engine 1 to an oil pan 4 and an oil pump (not shown). It consists of a strainer 6. The oil return passage 5 is arranged on the intake manifold (not shown) side of the engine body, the oil inlet 7 is opened to the oil staying in the cylinder head cover 2, and the oil outlet 8 is the oil suction port 9 of the oil strainer 6. They are placed close to each other.

[0014] Oil outlet passage 5 _0, as shown in FIG. 1, through the side wall of the oil pan 4, arranged horizontally,
Air bubbles were made to collect easily on the upper layer side inside the passage. The oil outlet 8, excised tip of the oil outlet passage 5 ₀ diagonally upper open at farther from the oil strainer 6, the lower side is allowed to open so as to leave a passage wall to near the oil strainer 6 . The reference numeral 10 shown in FIG. 1 indicates that the suction force of the oil strainer 6 is greater than that of the oil return passage 5.
It is a baffle for turning to the side.

When the oil outlet 8 is formed in this manner, the upper side of the oil return passage 5 in which a large amount of air bubbles are mixed is opened relatively far from the oil strainer 6 into the oil pan 4, and the oil containing air bubbles flows upward. Therefore, it is possible to prevent the oil strainer 6 from being sucked.
In addition, the oil that does not mix bubbles flowing under the passage is
Guided by the passage wall to near the oil strainer 6,
The suction action of the oil strainer 6 can be applied to the oil return passage 5. Therefore, as the engine rotation speed increases, the force for sucking the oil in the oil return passage 5 toward the oil pan 4 increases, so that more oil 3 in the cylinder head cover 2 can be returned to the oil pan 4 side. .

2 and 3 show an application example of Embodiment 1, in which a barrier plate 11 is attached to the oil outlet 8. In this application, the oil stream containing bubbles dammed the barrier plate 11, to be sucked into the oil strainer 6 reliably prevented, oil flow bubbles through the lower layer of the oil outlet passage 5 ₀ is not mixed ( Only the arrow) is made to flow out to the oil strainer 6 side. The barrier plate
It is also possible to arrange it so as to be inclined so that the oil containing air bubbles rides on it.

The oil return passage 5 of the second embodiment shown in FIG.
Is bored in the cylinder head 12 and the cylinder body 13, and an oil outlet side passage ₅₀ is attached to the lower opening thereof.
The tip side thereof was bent in the horizontal direction and arranged so as to approach the oil strainer 6, and the oil outlet side passage ₅₀ was obliquely cut off and the oil outlet 8 was opened as in the first embodiment.
Reference numeral 14 shown in FIG. 4 is a passage for performing oil recirculation and PCV of blow-by gas.

By the way, when the internal combustion engine 1 shown in FIG. 4 is inclined to the right in the figure and the engine speed increases, oil flows to the passage 14 side, and oil is not sufficiently recirculated. Therefore, as shown in FIG. 5, the passage 14 ₀ is attached to the lower opening of the passage 14 and the oil outlet side passage 5 ₀ is attached.
The oil recirculation can be smoothly performed by merging with the oil.

By forming the oil return passages 5 and 14 on both sides of the internal combustion engine 1 as described above, the amount of oil descending in the other oil / PCV passages is reduced and the PCV at high engine speed is reduced. It can be done smoothly. As described above, the oil return passages 5 can be plural in number, and the connecting method for joining them is not limited to the Y or T type shown in the drawing, and any connecting method can be adopted.

The oil return device of the third embodiment shown in FIG.
Since the float type on-off valve 15 is attached to the oil inlet side and the other parts are formed in the same manner as in the first embodiment, the same members as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Float type on-off valve 15 is a valve body consisting of a float 16 and a needle.
17 and a return spring 18, and when the amount of oil 3 retained is small (A in the figure), the float 16 is lowered and the valve body 17
Is pressed against the valve seat 19 by the return spring 18 to close the valve. Therefore, even if the suction force of the oil strainer 6 (FIG. 1) acts, the amount of oil flowing into the oil return passage 5 becomes zero, and air suction does not occur.

When the amount of oil 3 retained increases, the float 16
Rises (B) and overcomes the elastic force of the return spring 18, and the lever 21 integrated with the float support arm 20 moves to the valve rod 22.
The valve element 17 is opened by pulling, and the accumulated oil 3 flows into the oil return passage 5. Reference numeral 24 shown in D and E of FIG. 6 is a through hole for passing the valve rod 22, and 25 is a lever 21.
Is a large-diameter portion that engages with the valve rod 22.

The return spring 18 and the bracket
26 (supporting the valve rod 22 and the float 16) is fixed to the casing 27, as can be seen by contrasting the views of FIGS. The bracket 26 is C in FIG.
Casing 27 with two arms 26 _{0 as} shown in cross section at
The oil is freely stuck in and out of the end of the casing 27. Incidentally, the arms 26 ₀ has been mounted toward the lateral direction in FIG. As shown in C~E 6, if necessary, be mounted longitudinally Other toward any direction Tekiru.

The oil return device of the fourth embodiment shown in FIG.
The configuration is similar to that of the third embodiment except that the lever 21 is curved as shown in the figure. 7A shows a state where the oil (not shown) staying in the cylinder head cover 2 is reduced and the float 16 is lowered. B of FIG. 7 shows a state in which the oil is increased and the float 16 is lifted up (the same applies to the following figures). That is, when the amount of oil increases and the float 16 rises, the lever 21 rotates and the tip end side engages with the large diameter portion 25. In this case, if the lever 21 is curved as shown in the figure, the stroke amount of the valve body 17 can be increased even when the lever 21 is rotated by the same angle as the lever 21 of the third embodiment.

In the oil return device of the fifth embodiment shown in FIG. 8A, the oil inlet 7 is formed by a plurality of through holes opened in the body of the casing 27, and the valve body 17 is a piston valve and a valve seat.
The same structure as in Example 3 was adopted except that 19 was used as the inner surface of the casing 27. The oil return device of the sixth embodiment shown in FIG. 9 has the same configuration as that of the fifth embodiment except that the oil inlet 7 is opened in a slit shape below the body of the casing 27. In the oil return device of the fifth embodiment, oil with less bubbles is added to the oil pan 4.
(Fig. 1). Example 7 shown in FIG.
The oil return device is outside where the valve face 17 ₀ and the valve seat 19 and conical formed in the same manner as in Example 6. This is also Example 6
Similarly to the above, oil with few bubbles can be returned to the oil pan 4.

The oil return device of the eighth embodiment shown in FIG.
The valve body 17 was formed in a plate shape, the valve rod 22 was pivotally supported by the valve body 17, and the float support arm 20 was directly pivotally supported by the casing 27, except that the float type on-off valve of each of the above-described embodiments was formed. The oil return device of the ninth embodiment shown in FIG. 12 is the same as that of the eighth embodiment except that the valve element 17 is a butterfly valve, the return spring 18 is a spiral spring, and the float 16 is a sphere. Thus, the shape of each member of the float on-off valve can be arbitrarily selected and implemented.

[0026]

As described above, the oil return device for an internal combustion engine of the present invention can exert the following effects. Oil that stays in the cylinder head is positively sucked by the oil return passage that opens near the oil strainer that sucks the oil in the oil pan, and is allowed to fall into the oil pan. The oil return device according to claim 1, which is opened away from the oil strainer, has a simple structure and can reliably circulate the oil with a small amount of air bubbles to each part of the engine, and further, reduce the number of parts. Because you can
Manufacturing and maintenance costs can be reduced.

Further, an oil return passage for returning the oil staying in the cylinder head to the oil pan is opened in the oil in the oil pan, and a float type on-off valve is attached to the oil inlet to reduce the amount of oil staying in the cylinder head cover. The oil return device according to claim 2, wherein the valve is closed in this case, sucks air when the oil retained in the cylinder head cover is positively returned through the oil return passage by the suction force of the oil strainer. Can be prevented.

As described above, it is possible to reliably prevent air from being mixed into the oil, and prevent problems such as hunting, oil film breakage, and seizure. Therefore, it becomes possible to operate with a smaller amount of oil put in the oil pan, and high economic effects and reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of an oil return device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a main part of an oil return device for an internal combustion engine according to an application example of the first embodiment shown in FIG.

3 is a sectional view taken along the line III-III of FIG.

FIG. 4 is a schematic explanatory diagram of an oil return device for an internal combustion engine according to a second embodiment of the present invention.

5 is an explanatory view of a main part of an application example of the oil return device shown in FIG.

FIG. 6 is an oil return device for an internal combustion engine according to a third embodiment of the present invention, in which A is a vertical cross-sectional view of a portion where a float type on-off valve in a closed state is attached, and B is a float rising and a valve opening. 7 is a vertical cross-sectional view showing a state, C is a cross-sectional view taken along the line CC of FIG. 6A, D is a view taken along the line D-D of FIG. 6A, and E is a line E of FIG. It is a sectional view taken along the line E.

FIG. 7 is a cross-sectional view of an essential part of an oil return device for an internal combustion engine according to a fourth embodiment of the present invention, where A is a vertical cross-sectional view of a float type on-off valve using a needle valve, and B is a vertical cross-section showing the valve open state. The surface.

FIG. 8 is a cross-sectional view of an essential part of an oil return device for an internal combustion engine according to a fifth embodiment of the present invention, in which A is a vertical cross-sectional view of a float type on-off valve using a piston valve, and B is a vertical cross-section showing the valve open state. The surface.

FIG. 9 is a cross-sectional view of an essential part of an oil return device for an internal combustion engine according to a sixth embodiment of the present invention, where A is a vertical cross-sectional view of a float type on-off valve using a piston valve, and B is a vertical cross-section showing the valve open state. The surface.

FIG. 10 is a cross-sectional view of an essential part of an oil return device for an internal combustion engine according to a seventh embodiment of the present invention, where A is a vertical cross-sectional view of a float type on-off valve having a tapered valve surface, and B is its open state. FIG.

FIG. 11 is a sectional view of an essential part of an oil return device for an internal combustion engine according to an eighth embodiment of the present invention, where A is a vertical sectional view of a float type on-off valve having a plate-like on-off valve and B is its open state. FIG.

FIG. 12 is a cross-sectional view of an essential part of an oil return device for an internal combustion engine according to a ninth embodiment of the present invention, A is a vertical cross-sectional view of a float type on-off valve having a butterfly valve, and B is its open state. It is a vertical section.

[Explanation of symbols]

1 Internal Combustion Engine 2 Cylinder Head Cover 3 Oil 4 Oil Pan 5 Oil Return Passage 5 ₀ Oil Outlet Passage 6 Oil Strainer 7 Oil Inlet 8 Oil Outlet 9 Oil Suction Inlet Float Open / Close Valve 15 17 Valve Body Return Spring 18 19 Valve Seat Casing 27

Claims (3)

[Claims] 1. An oil return passage for returning oil accumulated in a cylinder head cover to an oil pan is provided, and an oil outlet side of the oil return passage is arranged toward an oil strainer, and an upper passage wall upstream of a passage end portion. The oil return passage of the internal combustion engine formed by removing the upper layer oil containing air bubbles into the oil pan at a position away from the oil strainer, and sucking the lower layer oil by the oil strainer. 2. The oil outlet side of the oil return passage,
The oil return passage of the internal combustion engine according to claim 1, which is obliquely cut from the upper side to the lower side toward the oil strainer. 3. An oil return passage for an internal combustion engine according to claim 2, wherein a float-type on-off valve is attached to the oil inlet of the oil return passage so that the valve is throttled when the oil level is lowered and the float is lowered.