JPS58113521A - Oil returning device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the returning of oil at high speed rotary operation, by utilizing pulsating pressure generated in a crank chamber to circulate air and forcibly returning oil through this circulative air flow to the crank chamber and onto a partitioning plate. CONSTITUTION:A partitioning plate 20 is provided between a crank chamber 3 and oil pan 7 in a crank case 1 to separate both the chamber and the oil pan, then the case 1 can be closed by the plate 20 to apply back pressure of a piston 6 fully to said chamber 3. In consequence, vertically reciprocating motion of the piston 6 causes pressure in the chamber 3 to largely change resulting in the remarkable generation of positive and negative pulsating pressure. Accordingly, at operation, a check valve 22 is opened by positive pressure of pulsating air in the chamber 3 to discharge air to a rocker chamber 13 via a passage 27 simultaneously a check valve 30 in a side of the plate 20 is also opened to discharge the air to the oil pan 7. Reversely at negative pulsating pressure, another check valve 24 is opened to suck air from the chamber 13 and forcibly return a large amount of oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to returning oil supplied to a valve mechanism in an internal combustion engine to the crank chamber side, and preventing oil from collecting on a partition plate separating the crank chamber and the oil pan from the oil pan. This relates to an oil return device that forcibly returns oil to the side.

Generally, in an internal combustion engine, in order to return the oil that has slipped through the valve mechanism, the rocker chamber containing the valve mechanism and the crank chamber are communicated through an oil return passage, and the oil is returned by falling under its own weight in this oil return passage. It has become.

In addition, especially for high-speed machines, a partition plate is used to partition the darkness between the crank chamber and the oil pan to prevent the oil in the oil pan from splashing up and creating resistance to the rotation of the crankshaft. There is. In this case, all of the oil that slips through the above-mentioned spacing mechanism, crankshaft journal, etc. and returns to the crank chamber will accumulate on the bulkhead plate, so the oil on this bulkhead plate will be drained through the opening. As in the case of the oil return passage described above, the oil falls through the hole provided under its own weight and returns to the oil pan side.

By the way, the pressure in the crank chamber fluctuates between positive and negative due to piston back pressure accompanying the reciprocating movement of the piston, creating so-called pulsating pressure. Especially in the case of high speed rotation, this pulsating pressure has a very short cycle and the above-mentioned oil It may also act on the return passage and the holes in the partition plate to bring them into the ms state. When the engine rotates at such high speeds, the oil pump for lubrication is also driven at high speed, and a large amount of oil is supplied to each part of the engine. Therefore, it is necessary to increase the amount of oil returned, but as mentioned above, if the oil return is impaired, Inevitably, excessive oil will frequently flow into the locker room and bulkhead panels, causing problems such as oil spray.

The present invention was developed in view of the above circumstances, and utilizes the pulsating pressure caused by pressure fluctuations in the piston back pressure generated in the crank chamber to reduce the gap between the crank chamber and the rocker chamber, and between the crank chamber and the fIIm! Air is circulated between the oil pans through the plates, and this circulating airflow forces the oil in the locker room to return to the crank chamber, and the oil on the bulkhead plate of the crank chamber to return to the oil pan. It is an object of the present invention to provide an oil return device for an internal combustion engine that allows oil to return satisfactorily especially during high speed rotation.

In addition, as a prior art regarding the point that the crank chamber is partitioned by partition plates in the present invention, for example, Japanese Patent Publication No. 48-3
There is Japanese Patent No. 4005, which uses pulsating pressure in a closed crank chamber to perform a pumping action for supplying secondary air. In addition, as a prior art related to flowing air in one direction through the crank chamber using pulsating pressure in the crank chamber, for example, there is Japanese Patent Publication No. 46-23977, which circulates air in a completely closed system. In addition, it is used to ventilate the crank chamber and discharge blow-by gas, and neither of these are related to the oil return that is the object of the present invention.5 Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. Explain in detail. First, the present invention can be applied not only to single-cylinder internal combustion engines but also to multi-cylinder internal combustion engines as long as pressure fluctuations can be caused in the crank chamber by piston back pressure. That is, in a multi-cylinder internal combustion engine in which pistons move back and forth simultaneously, such as in a four-cycle two-cylinder engine, a common crank chamber can be used as is.

Therefore, regardless of whether the engine in Figure 1 is single-cylinder or multi-cylinder,
It is possible to cause pressure fluctuations in the crank chamber, and reference numeral 1 is a crankcase, and 2 is a cylinder. A crankshaft 4 is rotatably provided in a crank chamber 3 below the cylinder 2 of the crankcase 1, and the crankshaft 4 is connected to a piston 6 inserted into the cylinder 2 via a connecting rod 5. At the bottom of the oil pan 7
is installed and lubricating oil is collected there.

A cylinder head 8 is mounted on the upper part of the cylinder, and a combustion chamber 9 and intake and exhaust bows communicating therewith are)-10, 11.
is formed in the locker chamber 13 inside the rocker cover 12 which is attached to the cylinder head 8.
．． Valve mechanism 16 for intake and exhaust valves 14 and 15 that open and close 11
is the provision. The intake port 10 is further connected to the intake pipe 1.
7 to a carburetor 19 equipped with an air cleaner 18.

Further, a partition plate 20 is provided between the crank chamber 3 and the oil pan 1 in the crankcase 1 to separate the two. A portion is curved downward to prevent this from happening, and at the same time forms a recess 21 for an oil reservoir. In this way, the opening at the bottom of the crankcase 1 is closed by the partition plate 20, thereby forming a relatively narrow crank chamber 3 that is sealed to an extent that allows rotation of the crankshaft 4. All the piston back pressure when the piston 6 reciprocates up and down during engine operation acts on the crank chamber 3. That is, the pressure in the crank chamber 3 fluctuates greatly due to the negative pressure when the piston 6 moves to the top dead center and the positive pressure when the piston 6 moves to the bottom dead center.
This causes significant pulsating pressure.

In such a configuration, to first explain the forced return of oil to the locker chamber 13 after lubricating the valve mechanism 16, a check valve 22 is provided on the crankcase 1 side that opens with positive pressure of the pulsating pressure of the crank chamber 3. An outlet 23 and an inlet 25 equipped with a check valve 24 that opens under the negative pressure of the pulsating pressure are provided. Further, there is an inlet 26 at a location on the rocker cover 12 side where there is no fear of oil inflow, and this inlet 26 and the above-mentioned outlet 23 communicate with each other through an air exhaust passage 27. There is an outlet 28 at the bottom where oil is collected on the side, and this outlet 28 communicates with the above-mentioned inlet 25 through a suction passage 29 which also serves as an oil return. In this way, a closed system air circulation path is constructed between the crank chamber 3 and the locker chamber 13 by the outgoing path on the exhaust passage 27 side and the incoming path on the suction passage 29 side.

Next, to explain the forced return of the oil accumulated in the recess 21 of the partition plate 20, a hole 31 equipped with a check valve 30 that opens in response to the positive pulsating pressure of the crank chamber 3 is bored at the bottom of the recess 21. . In addition, a hole 33 equipped with a check valve 32 that opens with the negative pressure of the pulsating pressure in the crank chamber 3 is bored in another part of the partition plate 20. Also, an air circulation path of a closed system is constituted by an outgoing path on the hole 31 side and a return path on the hole 33 side.

Since the present invention is configured in this way, the check valve 22 is opened by the positive pulsating pressure in the crank chamber 3 during engine operation, and a part of the air in the crank chamber 3 is discharged through the exhaust passage 21 to the locker chamber 13. At this time, the check valve 30 on the partition wall plate 20 side is also opened and the oil is discharged into the oil pan 1. Next, the other check valve 24 is opened by the negative pressure of the pulsating pressure, and the locker room 1 is opened.
3 through the suction passage 29, and at this time, the other check valve 32 on the partition wall plate 20 side is also opened and air is sucked in from the oil pan 7. In this way, the crank chamber 3, the rocker chamber 13, and Air circulates between the oil pans 7 at the same time. Here, the outlet 2 on the locker room 13 side
8 is provided at the bottom where the oil is stored, so the oil in the locker chamber 13 is sucked together with the air by the air flow during the above-mentioned suction action, and is forcibly returned to the crank chamber 3.

In addition, the oil that has been forcibly returned to the crank chamber 3 from the locker chamber 13 in this way, and the oil that has been in contact with the sliding parts of the crankshaft 4, piston 6, and cylinder 2 in the crank chamber 3, is deposited on the partition plate 20. It falls and accumulates in the recess 21, but there is an air flow in the hole 31 at the bottom of the recess 21 due to the evacuation action during positive pulsating pressure in the crank chamber 3. Therefore, along with the air, the oil accumulated in the recess 21 is also discharged by this air flow and is forcibly returned to the oil pan 7.
And it accumulates there. The oil accumulated in the oil pan 1 is held stationary because the pulsating pressure of the crank chamber 3 does not act on it and air simply flows in one direction within the oil pan 7.

In this way, in synchronization with the positive and negative pulsating pressures of the crank chamber 3, the oil in the locker chamber 13 is forced back when the pressure is negative, and then the oil in the recess 21 of the partition plate 20 is forced back alternately when the pressure is positive. It is done repeatedly.

The forced return action of the oil along with the cycle of the pulsating pressure in the crank chamber 3 changes in accordance with the engine speed, which is equivalent to the pressure action of the oil pump. A large amount of oil is also forced back.

Next, referring to FIG. 2, to explain the case of a multi-cylinder engine other than a single cylinder or a 4-cycle two-cylinder engine, the inside of the crankcase 1 is partitioned by a partition wall 34, and the common oil pan 7 is partitioned and separated by a fill plate 20. By doing so, three completely independent crank chambers 3a, 3b, and 3c of, for example, three cylinders are formed for each cylinder, and pulsating pressure is generated in each crank chamber. And, in the darkness between each crank chamber 3a, 3b, 3c and the locker chamber 13, check valves 22a, 22b for each crank chamber are installed.
, 22c, and a check valve 24a.
, 24b, 24c are in communication. Also, between each crank chamber 3a, 3b, 3c and the oil pan 7, there is a check valve 30a for each crank chamber.
, 30b, and 30c, and the suction passage 36, which has check valves 32a, 32b, and 32c, communicate with each other to form an air circulation path.

Thus, in this embodiment, each crank chamber 3a, 3b.

Since the positive pressure of the pulsating pressure of 3C constantly acts on the locker chamber 13, it can become pressurized, so that the oil is forced back even more effectively when the pulsating pressure becomes a negative pressure. Similarly, each crank chamber 3a.

The positive pressure of the pulsating pressures 3b and 3c continuously acts on the oil pan 7 side and can put it in a pressurized state, so that the oil level in the oil pan 7 can be stabilized.

As is clear from the above description, according to the present invention, in the structure in which the crank chamber 3 and the oil pan 7 are partitioned by the partition plate 20, the oil accumulated in the partition plate 20 and the locker chamber 13 is removed from the crank chamber 3. Since the oil is forcibly returned by the circulating air flow using pulsating pressure, the return of the oil is very good and there are no problems during high speed rotation. In addition, since the negative and positive pressures of the pulsating pressure are used to return the oil to the locker chamber 13 and the partition wall plate 20 in alternating cycles, the forced return of each type of oil is reliably carried out, and the pulsating pressure There is no waste in using.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the device according to the present invention;
Figure μ is a schematic diagram showing another embodiment. 3, 3a, 3b, 3c...crank chamber, 7...
-Oil pan, 13...Locker room, 20-...Partition plate, 22.22a, 22b. 22c, 24.24a, 24b, 24cm
...Check valve, 27...Discharge passage, 29...Suction passage, 30.30a, 30b, 30c, 3
2゜32a, 32b, 32cm...Check valve, 3
1.33-...hole, 34-1 wall, 35...discharge passage,
36 river intake passage. Patent Applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Nobu Kobashi Jodo Patent Attorney Susumu Murai Figure 1 Figure 2

Claims (2)

[Claims] (1) The pulsating pressure of the crank chamber is generated between the crank chamber and the rocker chamber, which generate pulsating pressure due to pressure fluctuations due to piston back pressure, and between the oil pans, which are partitioned from the crank chamber by a partition plate. A circulation system path is configured to circulate air, and the airflow of the circulation system path forcibly returns oil accumulated in the locker chamber to the crank chamber and oil accumulated on the partition plate to the oil pan. An oil return device for an internal combustion engine, characterized in that it is configured as follows. (2) A plurality of independent crank chambers for each cylinder to generate pulsating pressure due to pressure fluctuations due to piston back pressure;
A circulation system that is separated from the oil pan by a partition plate, and circulates air between each crank chamber and the locker room, and between each crank chamber and the oil pan using the pulsating pressure of each crank chamber. are constructed separately, and the air flow in the circulation system is used to force the oil in the locker chamber into each crank chamber, and the oil on the bulkhead plate in each crank chamber into the oil pan. An oil return device for an internal combustion engine, characterized in that it is configured to return oil.