JP2004143952A - Multicylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the whole internal combustion engine; and to realize high performance by storing oil in an oil pan having a simple structure by sucking out the oil by a single scavenging pump by gathering the oil in a small space in a multicylinder internal combustion engine for lubricating by sending the recovered oil again to respective parts in the internal combustion engine by an oil pump by recovering the oil after lubricating by lubricating the inside of the internal combustion engine by the oil. <P>SOLUTION: A partition wall is arranged in a lower part of a crankcase of the internal combustion engine, and the oil gathered in a lower part of the partition wall is sucked out by the scavenging pump, and is recovered to the oil pan arranged under the partition wall, and the recovered oil is supplied to the respective parts of the internal combustion engine by a feed pump. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-cylinder internal combustion engine.
[0002]
[Prior art]
Conventionally, a dry sump lubrication method has been used in order to avoid output loss and oil temperature rise due to a collision between a crankshaft balance weight and a transmission gear and oil in a wet sump lubrication method. In the dry sump lubrication system, the oil pan at the lower part of the internal combustion engine is abolished, a separate oil tank is provided, and oil is sucked from the crank chamber by a scavenging pump without holding the oil in the crank chamber, and is sent to the oil tank. The oil is sucked up from the oil tank by a feed pump and fed to an oil supply point in the internal combustion engine.
[0003]
In order to reduce pumping loss caused by the vertical movement of the piston in the intake and exhaust strokes, a large-capacity pump is used as the scavenging pump, and the air in the crank chamber is strongly discharged to depressurize the crank chamber. Has been done.
[0004]
In the conventional multi-cylinder internal combustion engine, in order to achieve the above-mentioned object, a plurality of scavenging chambers communicating with each of the mutually partitioned crank chambers are provided, and oil is supplied by a plurality of scavenging pumps directly connected to the respective scavenging chambers. Is sucked, sent to one oil tank, and then pressure-fed to each part by a feed pump (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Utility Model Application No. 1-141992 (Japanese Utility Model Application Laid-Open No. 3-82814) microfilm (page 5, page 9, FIG. 1, FIG. 2).
[0006]
[Problem to be solved]
Conventionally, a plurality of scavenging chambers each communicating with each crank chamber are provided, and oil is suctioned by a plurality of scavenging pumps directly connected to each scavenging chamber. Furthermore, the oil pan was abolished and an independent oil tank was provided at a position away from the crankcase. This structure requires a space for a scavenging chamber for collecting oil and an oil tank for storing oil, and the installation of multiple scavenging pumps makes the entire internal combustion engine larger and more complex. Therefore, there is a problem that the internal combustion engine must be downsized and simplified.
[0007]
The present invention collects oil in a small space, allows the oil to be sucked out with only one scavenging pump, stores the oil in an oil pan having a simple structure, and makes the entire internal combustion engine smaller and simpler. , And high performance.
[0008]
Means and effects for solving the problem
The present invention has solved the above-mentioned problem, and the invention according to claim 1 lubricates the inside of an internal combustion engine with oil, collects the lubricated oil, and recycles the collected oil with an oil pump. In a multi-cylinder internal combustion engine that feeds and lubricates various parts in the engine, a partition is provided at a lower part of a crankcase of the internal combustion engine, oil in the partition is sucked out by a scavenging pump, and an oil pan is provided below the partition. The oil collected and supplied to the oil pan is supplied to each part of the internal combustion engine by a feed pump.
[0009]
As described above, in the present invention, a partition is provided between the lower portion of the crankcase and the oil pan to close the lower surface of the crankcase. Oil flowing down from the plurality of crank chambers collects at the lower part of the partition wall. It is not necessary to provide a scavenging chamber in each crank chamber as in the related art. Further, in the present invention, since an oil pan is used without providing an independent oil tank, a large space is not required for collective storage of oil. Since the oil collects in the lower part of the partition wall, it becomes possible to suck out the oil with only one scavenging pump. By combining the above effects, it is possible to provide a high-performance multi-cylinder internal combustion engine having a simple structure and a small size.
[0010]
According to a second aspect of the present invention, there is provided a multi-cylinder internal combustion engine which lubricates the inside of an internal combustion engine with oil, collects the lubricated oil, and sends the collected oil again to each part in the internal combustion engine by an oil pump to lubricate. A scavenging pump for forming a closed crank chamber by providing a partition at a lower portion of a crankcase of the internal combustion engine, and depressurizing the inside of the closed crank chamber; and a closed crank chamber for collecting oil discharged from the scavenging pump. And an oil pan provided below the oil pan, and the oil collected in the oil pan is supplied to each part of the internal combustion engine by a feed pump.
[0011]
Thus, the present invention provides a closed crank chamber by forming a closed crank chamber by providing a partition at the lower portion of the crank case, depressurizing the inside of the closed crank chamber by a scavenging pump, and collecting discharged oil. Since the oil pan is provided below the pump, the pumping loss generated in the intake and exhaust strokes can be reduced with a simple structure.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a cross-sectional view of a four-cylinder internal combustion engine according to an embodiment of the present invention, showing a crankcase and a portion connected to a lower portion thereof. The crankcase includes an upper crankcase 1 and a lower crankcase 2, and the upper crankcase 1 is integrally formed with four cylinders C1, C2, C3, and C4. A crankshaft 4 is rotatably supported by a bearing 3 between the upper crankcase 1 and the lower crankcase 2. A piston 5 is slidably fitted to each of the cylinders C1 to C4, and each of the pistons 5 is connected to a portion of the crankshaft 4 corresponding to each of the cylinders C1 to C4 via a connecting rod 6. The crank chambers K1 to K4 corresponding to the cylinders C1 to C4 are separated from each other by partition walls. In particular, the crankcases K1, K2, K3 are separated from the crankcase K4 and the transmission by a side wall 8 extending all around. The lower portions of the crank chambers K1 to K4 are open.
[0013]
An oil pan 7 is attached to a lower portion of the lower crankcase 2. A bottom partition 9 is provided below the crank chambers K1, K2, K3 of the lower crankcase 2. This is provided above the oil pan 7. The crank chambers K1, K2, and K3 communicate with each other in the bottom wall 9, but are sealed from the outside by the side walls 8 and the bottom wall 9. In the following description, the entirety of the crank chambers K1, K2, and K3 is referred to as a "closed crank chamber." A lower oil inflow portion 10 is formed in a part of the bottom wall 9 so that oil can easily flow in. Oil that has fallen after lubricating the bearing portion 3 and the piston 5 of the crankshaft 4 in the closed crank chamber is collected by the bottom wall 9 and flows into the oil inflow portion 10. An oil suction pipe 11 connected to a scavenging pump described later is connected to the oil inflow section 10. FIG. 4 is a plan view and a sectional view of the bottom wall 9.
[0014]
FIG. 2 is a cross-sectional view showing a part such as a pump connected to the oil suction pipe 11 of the four-cylinder internal combustion engine. FIG. 3 is a longitudinal sectional view of a portion below a lower crankcase of the four-cylinder internal combustion engine. In the figure, a scavenging pump 12 and a feed pump 13 are provided adjacently above an oil pan 7. These are rotationally driven by a common rotating shaft 14.
[0015]
The oil suction pipe 11 is connected to a suction port of the scavenging pump 12, and a discharge pipe 15 is connected to a discharge port of the scavenging pump 12. The scavenging pump 12 is a large-capacity pump and sucks out oil with almost no oil kept in the closed crankcase. In addition, air is sucked out, and the pressure in the closed crank chamber is reduced. The discharge pipe 15 of the scavenging pump 12 is directed upward, and part of the discharged oil is injected as an oil jet to gears and sliding parts of the transmission, and then falls into the oil pan 7. The remaining oil falls directly into the oil pan 7.
[0016]
The suction port of the feed pump 13 is used to suck up the oil discharged from the scavenging pump 12 and dropped and stored in the oil pan 7, and the oil dropped directly from the crank chamber K4 to the oil pan 7 and stored. Are connected. A supply pipe 17 is connected to a discharge port of the feed pump 13 so as to send oil to an oil filter 18. The oil purified by the oil filter 18 is sent to the bearing of the crankshaft 4, the piston 5, and the like. The supply pipe 17 is provided with a relief valve 19. The small arrow drawn in FIG. 2 indicates the flow of the oil.
[0017]
The configuration of the four-cylinder internal combustion engine of the present embodiment is as described above. The scavenging pump 12 is a large-capacity pump that sucks almost no oil into the closed crank chamber, and further sucks air in the closed crank chamber to reduce the pressure. Since the oil does not stay in the closed crank chamber, the crank web or the connecting rod does not collide with the oil or the oil mist when the crankshaft 4 rotates, so that a decrease in the output and an increase in the oil temperature can be avoided. Further, the pumping loss generated in the intake and exhaust strokes is reduced by the pressure reduction in the closed crank chamber, so that the output of the internal combustion engine is improved.
[0018]
In the present embodiment, a bottom wall 9 that covers the lower surface of the closed crank chamber is provided between the lower portion of the closed crank chamber and the oil pan 7. Oil flowing down from the plurality of crank chambers in the closed crank chamber collects in the lower portion of the bottom wall 9, that is, in one oil inflow portion 10. Since it is not necessary to provide a scavenging chamber in each crank chamber and a scavenging pump in each scavenging chamber as in the related art, space can be saved. Also, since an independent oil tank for storing oil is not provided and an oil pan having a simple structure is used, the size is reduced. Since the oil collects at one location in the lower portion of the bottom partition wall, even a single scavenging pump can suck out the oil, and the configuration of the device is simplified.
[0019]
This makes it possible to lubricate both the advantages of a dry sump system (reducing power loss and oil temperature rise) and the advantages of a wet sump system (simplified structure), resulting in a simple and compact high-performance multi-cylinder internal combustion engine. Can be provided.
[0020]
The above embodiment has shown an example in which the crank chambers K1 to K3 are hermetically closed due to the arrangement of the primary drive gear between the crank chambers K3 and K4 among all four cylinders. However, in general, by applying the present invention by sealing the crankcases corresponding to all the cylinders of the multi-cylinder internal combustion engine or the crankcases corresponding to some of the cylinders, the pumping in the sealed crankcase is performed. Loss and oil temperature rise can be reduced, and the space required for scavenging for a closed crankcase can be saved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a four-cylinder internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a part such as a pump of the four-cylinder internal combustion engine.
FIG. 3 is a longitudinal sectional view of a main part of the four-cylinder internal combustion engine.
FIG. 4 is a plan view and a sectional view of a bottom partition wall of the four-cylinder internal combustion engine.
[Explanation of symbols]
C1, C2, C3, C4 ... cylinder, K1, K2, K3, K4 ... crank chamber, 1 ... upper crankcase, 2 ... lower crankcase, 3 ... bearing part, 4 ... crankshaft, 5 ... piston, 6 ... connecting rod , 7 ... oil pan, 8 ... side wall, 9 ... bottom wall, 10 ... oil inlet, 11 ... oil suction pipe, 12 ... scavenging pump, 13 ... feed pump, 14 ... rotary shaft, 15 ... discharge pipe, 16 ... suction pipe, 17 ... supply pipe, 18 ... oil filter, 19 ... relief valve.

Claims (2)

In a multi-cylinder internal combustion engine that lubricates the interior of the internal combustion engine with oil, collects the lubricated oil, and sends the collected oil again to various parts in the internal combustion engine with an oil pump,
A partition is provided at a lower portion of a crankcase of the internal combustion engine, oil in the partition is sucked out by a scavenging pump, collected in an oil pan provided below the partition, and the oil collected in the oil pan is fed to a feed pump. The multi-cylinder internal combustion engine is supplied to each part of the internal combustion engine by the internal combustion engine. In a multi-cylinder internal combustion engine that lubricates the interior of the internal combustion engine with oil, collects the lubricated oil, and sends the collected oil again to various parts in the internal combustion engine with an oil pump,
A partition is provided at the lower part of the crankcase of the internal combustion engine to form a closed crank chamber, a scavenging pump for decompressing the inside of the closed crank chamber, and a closed crank chamber for collecting oil discharged from the scavenging pump. A multi-cylinder internal combustion engine, comprising: an oil pan provided below; and oil supplied to the oil pan is supplied to each part of the internal combustion engine by a feed pump.

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