JPH04246216A - Lubricating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To miniaturize a dry sump type lubricating device similarly to a wet sump type, and make processing of blow-by gas in an oil tank portion. CONSTITUTION:An oil tank portion 10 is formed at the underside of an oil pan 4, with its capacity set at relatively small level. In a pump storing portion 8 which is provided by recessing the bottom of the oil pan 4, a pump unit 12 in which a scavenging pump, a pressure pump and an air-liquid separator are integrated with each other is stored. In a partition 11 for covering the upper side of the oil tank portion 10, an overflow hole 36 for connecting it to the inside of a crankcase 2 is opened.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a lubricating system for an internal combustion engine, and particularly to an improvement of a dry sump type lubricating system in which lubricating oil that has fallen onto the bottom of an oil pan is transferred to the outside of the crankcase and stored therein. .

0002

[Prior Art] Lubricating systems for internal combustion engines using forced lubrication systems include two types: a wet sump type lubricating system that constantly stores excess lubricating oil in an oil pan on the bottom of the crankcase; It is broadly classified into a dry sump type lubricating system in which excess lubricating oil is transferred to an oil tank using a scavenge pump and stored in the external oil tank. The latter dry sump type lubricating device is known to have the advantage of suppressing a reduction in output due to collision of a rotating body such as a crankshaft with a lubricating oil surface and suppressing scattering of oil mist due to scraping up of lubricating oil.

[0003] In this dry sump type lubricating device, a separate oil tank is generally arranged at a position remote from the engine body, and the lubricating oil is transferred from the oil pan through an oil pipe.

[0004] Also, in Japanese Utility Model Application Publication No. 1-179109,
The deep bottom of the oil pan is partitioned to form an oil tank.
A dry sump type lubricating device has also been proposed in which lubricating oil is transferred from the shallow bottom of the oil pan using a scavenge pump.

[0005]

[Problems to be Solved by the Invention] However, in a typical dry sump type lubricating system that has a separate oil tank located away from the engine body, there are problems with the mounting position of the oil tank, mounting space, and piping layout. Due to these limitations, it is difficult to widely apply it to general automobile internal combustion engines.

In the latter configuration, although the oil tank is formed integrally with the oil pan, the oil tank is completely separate and independent from the inside of the crankcase. Once blow-by gas enters, it becomes difficult to dispose of it. In other words, blow-by gas is sent to various parts of the engine together with lubricating oil, causing poor lubrication. Further, when lubricating oil is sent back in excess of the capacity of the oil tank, the excess lubricating oil cannot be disposed of. In other words, it is necessary to set the volume of the oil tank sufficiently large so that there is always room inside the oil tank. The problem is that it becomes extremely large.

[0007]

[Means for Solving the Problems] A lubricating device for an internal combustion engine according to the present invention includes an oil pan attached to cover the lower surface of a crankcase of an engine, and a partition wall formed on the lower surface of the oil pan. an oil tank section separated from the crankcase by a scavenge pump that transfers lubricating oil from the oil pan to the oil tank section through an oil strainer placed on the bottom of the oil pan;
The oil tank is configured to include a pressure pump that supplies lubricating oil from the oil tank to each part of the engine, and an overflow hole formed in a partition wall on the upper surface of the oil tank.

[0008]

[Operation] In the above structure, the lubricating oil that has flowed down to the bottom of the oil pan is immediately transferred to the oil tank section by the scavenge pump and stored there. From here, it is sent to each part of the engine by a pressure pump. Here, the blow-by gas that has entered the oil tank is
It returns into the crankcase through the overflow hole and is treated by a suitable blow-by gas treatment mechanism.

Furthermore, if an excessive amount of lubricating oil is transferred into the oil tank in a low-speed range where the amount of lubricating oil supplied is small, it naturally overflows from the overflow hole on the top surface and returns onto the oil pan.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 are cross-sectional views showing the main parts of an internal combustion engine equipped with a lubricating device according to the present invention. A case housing 3 is attached, and a relatively shallow oil pan 4 is attached so as to cover the lower opening of the crankcase housing 3. The oil pan 4 defines a crankcase 2 that accommodates rotating bodies such as a crankshaft 5 and a balancer shaft 6. Incidentally, the crankshaft 5 rotates in the direction shown by the arrow in FIG.

FIG. 3 is a plan view showing the oil pan 4. As shown in FIG. This oil pan 4 is cast, for example, from an aluminum alloy or the like, and has a flange portion 7 formed around its periphery, and a flange portion 7 on one side of the end rearward of the engine.
The pump accommodating portion 8 is recessed in a substantially rectangular shape. The bottom surface of the other portions except for the pump accommodating portion 8 is formed substantially flat. In addition, an oil tank lower 9 having a cup shape is provided on the lower surface of the oil pan 4 in line with the pump housing portion 8.
is attached, which allows oil tank part 1
0 is defined (see FIG. 1). That is, the oil tank section 10 has a part of the oil pan 4 attached to the partition wall 1 on the upper surface side.
It is separated from the crankcase 2 in the form of 1. As shown in FIG. 1, the bottom of the pump accommodating portion 8 and the bottom of the oil tank lower 9 are at approximately the same height to avoid unnecessary unevenness. Further, the volume of the oil tank section 10 is set smaller than the amount of lubricating oil for the entire engine. Specifically, based on the high-speed range where the amount of oil supplied to each part of the engine is large, the volume is the minimum volume obtained by subtracting the amount of oil accumulated in each part from the total amount of lubricating oil, and we are trying to make it smaller. There is.

As will be described later, the pump housing section 8 houses a pump unit 12 which is formed by integrating a scavenge pump 13, a pressure pump 14, and a centrifugal gas-liquid separator 15.

4 to 6 show this pump unit 12, and the pump housing 16 is composed of a pump block 17, a rear end plate 18, a front end plate 19, and a separator cover 20, as shown in FIG. At the center is a drive shaft 2 that simultaneously drives the three components.
1 is arranged. The drive shaft 21 has an end 21a protruding from the pump housing 16 toward the rear end of the engine.
It is driven by the crankshaft 5 as described later. Furthermore, the scavenge pump 13, the pressure pump 14, and the gas-liquid separator 15 are arranged in series, with the scavenge pump 13 in the center being sandwiched between the pressure pump 14 at the rear end of the engine and the gas-liquid separator at the front end of the engine. 15 are arranged respectively.

Oil tank section 10 from the bottom of oil pan 4
As shown in FIG. 5, the scavenge pump 13 that transfers the lubricating oil to the first scavenge pump 13A is composed of an external gear pump. and the second scavenge pump 13B are substantially configured. The end of a suction pipe 25 arranged along the side of the oil pan 4 is connected to the suction port 24 of the first scavenge pump 13A, as shown in FIG. The suction pipe 25 is provided with oil strainers 26 and 27 that open toward the bottom surface of the oil pan 4 at two locations, one at the tip and one at the middle. Further, the suction port 28 of the second scavenge pump 13B is connected to an oil strainer 29 formed integrally with the pump housing 16, which is bent downward and opens toward the bottom surface of the pump accommodating portion 8. In other words, the scavenge pump 13 absorbs the lubricating oil that has flowed down to the bottom of the oil pan 4 and the pump accommodating portion 8.
It is designed to simultaneously suck up both lubricating oil that has flowed into the bottom. Note that wind pressure acts on the bottom surface of the oil pan 4 in the direction shown by arrow C in FIG. 3 as the crankshaft 5 rotates, and a suction pipe 25 is disposed on the side downstream of this wind pressure. 6, the pressure pump 14 supplies lubricating oil to various parts of the engine from the oil tank part 10, which has oil strainers 26 and 27 that are open to the sides and receive the lubricating oil pushed by wind pressure.
As shown in FIG. 2, the pump is constructed of an external gear pump having a driving gear 30 and a driven gear 31. The suction port 32 of this pressure pump 14 has an oil tank section 10.
The end of a suction pipe 33 that communicates with is connected (see FIG. 3). Also, the discharge port 34 of the pressure pump 14
As shown in FIG. 1, the lubricating oil is opened in the side wall of the pump accommodating portion 8, and supplies lubricating oil to each part of the engine through a supply pipe 35 serving as an external piping.

The suction pipe 33 is connected to the oil tank section 1.
The oil tank portion 10 is passed through the overflow hole 36 opened in the bottom surface of the oil pan 4 that covers the top surface of the oil tank 4, that is, the partition wall 11.
The tip thereof reaches the bottom of the oil tank section 10. Here, the overflow hole 36 opens sufficiently larger than the outer diameter of the suction pipe 33, and has a gap through which lubricating oil can flow.

The gas-liquid separator 15 separates air mixed in the lubricating oil sucked up by the scavenge pump 13, and as shown in FIG. Inlet section 38 and oil outlet section 3
It is located between 9 and 9. The oil inlet portion 38 communicates with a discharge port (not shown) of the scavenge pump 13 through a passage (not shown) in the pump housing 16 . Further, the oil outlet portion 39 communicating with the outer peripheral portion of the rotor 37 communicates with a discharge port 40 of the gas-liquid separator 15, and a discharge pipe 41 is connected to the discharge port 40 as shown in FIG. . An air exhaust hole 42 is formed in the boss portion 37a of the rotor 37 in the radial direction, and the air exhaust hole 42 communicates with the outside of the pump housing 16. That is, due to the centrifugal separation effect accompanying the rotation of the rotor 37, only the lubricating oil that does not contain air is collected toward the outer circumferential side and is sent out to the oil outlet portion 39. Air is collected at the center and discharged to the outside through the air discharge hole 42 and the communication hole 46 at the center of the shaft.

The discharge pipe 41, like the suction pipe 33, enters the oil tank section 10 through an overflow hole 43 opened in the partition wall 11 on the upper surface of the oil tank section 10. Further, the overflow hole 43 is arranged in the discharge pipe 4 such that there is a sufficient gap between the overflow hole 43 and the discharge pipe 41.
The opening is formed to be larger than one outer diameter.

Here, the total opening area of the gap between the overflow holes 36 and 43, which serve as a substantial overflow passage, is set approximately equal to the passage cross-sectional area of the discharge pipe 41, which serves as a lubricating oil inflow passage. ing. For example, the cross-sectional area of the flow path of the discharge pipe 41 is set to about 4 cm 2 , and the total opening area of the gap portion is set to about 5 cm 2 . In other words, the size of the overflow holes 36 and 43 is determined by the size of the oil tank portion 10.
This is the minimum necessary to prevent wind pressure from reaching the area. Further, as shown in the figure, each overflow hole 36, 43 opens toward the center of the oil tank portion 10 at a certain distance from the side wall to prevent lubricating oil from flowing out when the vehicle turns or when the oil level swings. .

As shown in FIG. 1, a chain sprocket 44 is attached to the end 21a of the drive shaft 21 of the pump unit 12, and is linked to the balancer shaft 6 via a chain 45. The balancer shaft 6 is connected to a reversing gear 47 disposed at the front end of the engine.
48 and the crankshaft 5 via a chain 49. As a result, the pump unit 12
is driven in the direction shown by the arrow in FIG.

Therefore, in the above configuration, as the crankshaft 5 rotates, the scavenge pump 13, pressure pump 14, and gas-liquid separator 15 operate together. The lubricating oil that has flowed down from various parts of the engine onto the bottom of the oil pan 4 is immediately sucked up by the scavenge pump 13 through three oil strainers 26, 27, and 29, and transferred to the oil tank section 10 via the gas-liquid separator 15. Ru. Note that since air and blow-by gas are separated in the gas-liquid separator 15, the oil tank section 1
There are very few air bubbles contained in the lubricating oil transferred to zero.

Furthermore, the lubricating oil in the oil tank section 10 is sucked up by the pressure pump 14 and sent to each section of the engine via the supply pipe 35.

Therefore, there is usually almost no lubricating oil on the oil pan 4, and collision between the crankshaft 5 and the oil surface and the phenomenon of the lubricating oil being scraped up are avoided. It also provides a stable supply of lubricating oil even when turning. Incidentally, since the overall discharge capacity of the scavenge pump 13 is approximately twice that of the pressure pump 14, the lubricating oil can be transferred reliably.

On the other hand, the upper space of the oil tank section 10 is
Since it is constantly in communication with the crankcase 2 side through the overflow holes 36 and 43 on the top surface, even if blow-by gas is mixed with the lubricating oil and sent, it will naturally flow to the crankcase 2 side through the overflow holes 36 and 43. It is discharged and is not sent to other parts of the engine. Note that the blow-by gas in the crankcase 2 is treated by a known blow-by gas treatment device.

Furthermore, in a low speed range of the engine, the amount of oil accumulated in each part of the engine decreases, so that the oil tank section 10 is filled with lubricating oil. In this case, the oil tank section 10
The lubricating oil that has been transferred in excess will overflow onto the oil pan 4 through the overflow holes 36 and 43. Therefore, problems such as an increase in the pressure inside the oil tank section 10 will not occur. In this state, some lubricating oil will accumulate on the oil pan 4, but in a low speed range, there will be no collision with the oil surface. etc. are not a particular problem and there is no problem. Moreover, as shown in FIG. 3, the oil strainer 27
Since it is located on the downstream side of the flow caused by the wind pressure of the overflow holes 36 and 43, for example, lubricating oil that temporarily overflows from the overflow holes 36 and 43 is immediately sucked back through the oil strainer 27. , the amount of lubricating oil flowing onto the oil pan 4 can be kept as low as possible.

[0026]

[Effects of the Invention] As is clear from the above explanation, according to the lubricating device for an internal combustion engine according to the present invention, since the oil tank portion is formed substantially integrally with the oil pan,
As with the wet sump type lubrication device, it can be constructed in a small size and does not require complicated external piping. In particular, by providing an overflow hole in the partition wall that partitions the top surface of the oil tank, excess lubricating oil will naturally return to the oil pan, allowing the volume of the oil tank to be minimized. . In addition, blow-by gas mixed in the oil tank can be discharged to the crankcase side and disposed of.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of an internal combustion engine equipped with a lubricating device according to the present invention.

FIG. 2 is a vertical cross-sectional view.

FIG. 3 is a plan view showing the oil pan of this embodiment.

FIG. 4 is a sectional view showing the pump unit of this embodiment.

FIG. 5 is a sectional view taken along line A-A in FIG. 4.

FIG. 6 is a sectional view taken along line BB in FIG. 4;

[Explanation of symbols]

2...Crank case 4...Oil pan 8...Pump housing section 10...Oil tank part 12...Pump unit 13...Scavenge pump 14...Pressure pump 15... Gas-liquid separator 36...Overflow hole 43...Overflow hole

Claims (1)

[Claims] Claim 1: An oil pan attached to cover the bottom surface of a crankcase of an engine, an oil tank portion formed on the bottom side of the oil pan and whose top surface is partitioned from the crankcase by a partition wall, and a bottom surface of the oil pan. a scavenge pump that transfers lubricating oil from the oil pan to the oil tank through an oil strainer installed in the oil tank, a pressure pump that feeds lubricating oil from the oil tank to each part of the engine, and a partition wall on the top surface of the oil tank. A lubricating device for an internal combustion engine, comprising: an overflow hole having an opening formed therein;