JPH0115850Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blow-by gas reduction device for a V-type engine in which cylinders are arranged in a V-shape.

[Prior Art] In an engine, blow-by gas leaking from the combustion chamber into the crank chamber is usually oil-removed at the upper part of the head cover, and then returned to the intake system and combusted again in the combustion chamber. When blow-by gas treatment is performed above the head cover, a passage is required for the recovered oil and the oil used to lubricate the equipment above the head to quickly return to the oil pan. In the case of a V-type engine, the oil return passages must be located along the outer surfaces of the left and right banks in order to receive the flowing oil because the cylinders are inclined to the left and right. It won't happen. This oil return passage usually also serves as a blow-by gas passage, with blow-by gas rising from the crank chamber to the head cover interior space, and oil flowing down from the head cover interior space into the crank chamber.

In such a blow-by gas return device, when the oil level in the oil pan is uneven, such as when the vehicle turns or when going up or down a slope, the lower end of the oil return passage becomes below the oil level. The oil return passage may become blocked. For this reason,
A pressure difference is created between the head cover interior space and the crank chamber, which not only worsens oil return but also poses a risk of oil being discharged from the blow-by gas passage into the intake system.

Furthermore, during high-speed operation, the oil surface becomes uneven due to wind pressure caused by the rotation of the balance weight of the crankshaft, and the same problem as described above occurs on the uneven head side.

Further, a similar problem occurs even when a blow-by gas outlet is provided on the side surface of the block.

In order to solve the above-mentioned problems, the present applicant proposed that the blow-by gas passage 1' be located above the crankcase and between the left and right banks 2' and 3' in a V-type engine, as shown in FIG. By arranging the blow-by gas in this position, even if the oil level in the oil pan is uneven, the blow-by gas passage will not be blocked by the oil level, and the oil will not be discharged. A passage structure was proposed (Utility Application No. 146675 (1982)
No. 55714)).

With this kind of blow-by gas passage structure, the blow-by gas passage is not on the side of the crankcase, so even if the oil in the oil pan becomes uneven when the vehicle turns, climbs or descends a slope, etc., the blow-by gas passage will not be filled with oil. There is no possibility of oil discharge due to the pressure difference that would occur if the blow-by gas passage were blocked.

[Problems to be solved by the invention] However, while there are the above advantages, in a blowby gas reduction device in which the blowby gas passage is provided in the middle between the left and right banks, the PCV chamber connected to the blowby gas passage is located in the crankcase. Because the engine is close to the engine, splashes from the rotation of the crankshaft can easily enter the PCV chamber, and the blow-by gas blowing up from the crankcase collides with the oil trying to return to the crankcase, resulting in poor oil return. . Therefore, in a structure in which gas is directly vented from the PCV chamber between the left and right banks, there remains a risk that oil will blow out or be returned to the intake system, leading to an increase in oil consumption.

In addition, the installation of catalysts is now becoming commonplace in response to exhaust gas regulations, but it is said that the main cause of catalyst deterioration is phosphorus poisoning contained in engine oil. Therefore, reducing oil consumption has become an extremely important issue in engine design.

In order to solve the above-mentioned problems, this invention further improves the blow-by gas return device for a V-type engine, which has a blow-by gas extraction passage between the left and right banks, and suppresses oil blow-out during engine operation. , and by reducing oil in blow-by gas, the purpose is to reduce oil consumption of the engine and suppress oil deterioration of the catalyst.

[Means for Solving the Problems] In order to achieve this object, the blow-by gas reduction device of the present invention consists of the following. That is,
A blow-by gas extraction passage with one end opening into the crank chamber is formed in the middle part between the left and right banks of the V-type engine and directly above the oil pan, and the other end of the extraction passage is formed only by a blow-by gas passage passing inside the cam housing. is connected to the intake system, and a first oil separator chamber and a first oil separator chamber are provided on the blow-by gas passage.
A blow-by gas reduction device for a V-type engine, characterized in that a second oil separator chamber is provided in the cam housing of the left and right banks on the downstream side of the oil separator chamber.

[Function] In the blowby gas reduction device for the V-type engine configured as described above, the blowby gas discharged into the crankcase is sent to the middle part between the left and right banks along with the oil that is blown away by the rotation of the crankshaft. It is extracted from the crank chamber through the provided extraction passage. Therefore, even if the oil in the oil pan becomes uneven, the blow-by gas passage will not be blocked. The blow-by gas that has passed through the extraction passage enters the first oil separator chamber, where the first oil drain is performed. However, this may be insufficient, and the blow-by gas containing oil is guided to the second oil separator chamber, where a second oil cut is performed.
As a result, when the blowby gas is guided to the blowby gas suction port of the intake system, the blowby gas is in a sufficiently oil-free state. Therefore, when using the blowby gas reduction device for a V-type engine of the present invention, the two-stage oil cutting means substantially completely drains the blowby gas, and the blowby gas when returned to the intake system. Since the amount of oil inside is reduced, engine oil consumption is small and catalyst oil deterioration is also suppressed.

[Embodiments] Hereinafter, preferred embodiments of the blow-by gas reduction device for a V-type engine according to the present invention will be described with reference to the drawings.

2 and 3 show a V-type engine equipped with the blow-by gas reduction device of the present invention. In the figure, numeral 1 denotes a crankcase which has a crank chamber 2 inside. Cylinder blocks 3 and 4 stand diagonally upward in a V-shape on the left and right sides of the crankcase 1. Pistons (not shown) are slidably provided in cylinder bores in the cylinder blocks 3, 4, and each is connected to a crankshaft 8 via a connecting rod (not shown).
Cylinder heads 5, 6 are mounted above the cylinder blocks 3, 4, and cam housings 9, 10 containing cams are mounted thereon. Oil return passage 1 is located along the outer surface of cylinder blocks 3 and 4.
1 and 12 are provided, and a cam housing 9,
The oil from the inner space of the engine 10 is returned to the crank chamber 2. The lower side of the crankcase 1 is covered with an oil pan 13, and oil 14 is stored in the oil pan 13. Of these, the left and right cylinder blocks 3, 4, cylinder heads 5, 6, and cam housings 9, 10 are connected to the left and right banks 1, respectively.
5 and 16.

Above the crankcase 1 and on the left and right banks 1
A blow-by gas extraction passage 17 is provided at a position 7 between the oil pans 5 and 16 and directly above the oil pan 13, and its lower end opens into the crank chamber 2.
The extraction passage 17 may be constructed by forming a groove opening downward on the lower surface of the cylinder head, covering this groove with a plate, and forming holes as the blow-by gas extraction passage 17 in the plate. A first oil separator chamber 18 is connected to the upper part of the blow-by gas extraction passage 17.
An oil separator 19 is provided inside to separate oil from blow-by gas. The downstream side of the oil separator 19 of the first oil separator chamber 18 is connected to second oil separator chambers 20 and 21 provided in the cam housings 9 and 10 via blow-by gas passages 22 and 23. The blow-by gas passages 22 and 23 are formed inside the left and right banks 15 and 16 of the V-type engine. However, the blow-by gas passages 22 and 23 are not opened to the oil reservoir portion of the bottom surface of the inner space of the cam housings 9 and 10, and are separated from the oil reservoir portion by a wall that blocks oil inflow. Therefore, the blow-by gas passages 22 and 23 are not also used as oil return passages. Second oil separator chamber 20, 21
are separated from the space inside the cam housings 9, 10 by oil separators 24, 25, and are provided above the oil reservoirs inside the cam housings 9, 10. 26 and 27 indicate camshafts. The downstream outlets 28 and 29 of the second oil separator chambers 20 and 21 are connected to a blow-by gas inlet of an intake system (not shown). Note that the outlets 28 and 29 may be open to the atmosphere.

Note that the upper end of the extraction passage 17 is connected to the blow-by gas passages 22, 2 through the inside of the cam housings 9, 10.
3, and is not connected to the intake system by any passage that does not pass through the cam housing.

Next, the operation of the above device will be explained. First, blow-by gas and return oil flow through separate passages. That is, the blow-by gas flows from the crank chamber 2 to the first oil separator chamber 18 through the blow-by gas extraction passage 17, where the oil is drained for the first time by the oil separator 19, and from there, the blow-by gas flows through the second oil separator chamber 18. The oil flows into chambers 20 and 21, where oil separators 24 and 25 perform a second oil cut. In this way, the oil is drained twice, so the second oil separator chamber 2
0 and 21, the blow-by gas, which had a large amount of oil splashed by the crankshaft 18 before entering the extraction passage 17, is completely drained of oil. The blow-by gas leaving the second oil separator chambers 20, 21 is returned to the intake system through the blow-by gas outlets 28, 29 or is discharged to the atmosphere.

The oil in the cam housings 9, 10 flows to the oil pan 13 through oil return passages 11, 12. Therefore, the flow of oil and the flow of blow-by gas do not interfere with each other.

In this state, if the oil is biased due to centrifugal force when the vehicle turns, climbs or descends a slope, or due to the tilt of the vehicle,
Or, if the oil is biased by the rotation of the balance weight 10 at high speed and the oil level is tilted beyond the position indicated by the two-dot chain line A in FIG. 1, the oil return passages 11 and 12 in FIG. Although either one is blocked, the blow-by gas extraction passage 17 is not blocked even in such a case. Therefore, the flow of blow-by gas is stable. in this case,
The removal of blow-by gas can be facilitated by the rotational wind pressure of the crankshaft. Furthermore, even if one of the oil return passages 11 and 12 is blocked, the space inside the cam housings 9 and 10 and the crank chamber 2 are connected to the blow-by gas extraction passage 17, the first oil separator chamber 18, and the blow-by gas passages 22 and 23. Since they are in communication through the blow-by gas outlets 28 and 29, and the generation of pressure differences is suppressed, a phenomenon in which oil is discharged from the blow-by gas outlets 28 and 29 due to a difference in gas pressure due to blockage cannot occur.

When looking at the above passage structure from a space design perspective, since the first oil separator chamber 18 is provided between the left and right banks 15 and 16, the left and right banks 15 and 16 of the V-type engine, which used to be an empty space,
16 is effectively used, and the engine does not become larger. Furthermore, the second oil separator chambers 20 and 21 are small in size because their capacities are small due to the presence of the first oil separator chamber 18, and they are housed in empty spaces within the cam housings 9 and 10. This also prevents the engine from becoming larger. On the other hand, in the conventional structure in which a large oil separator chamber that required a large capacity was provided inside the head cover, the size of the engine increased due to securing the volume of the oil separator chamber. Utilization of the empty space between them makes it possible to reduce the size of the engine by downsizing the second oil separator chambers 20, 21.

[Effects of the Invention] As is clear from the above explanation, the following effects can be obtained by using the blow-by gas reduction device for a V-type engine of the present invention.

First, the oil separator chambers 18, 20, and 21 are provided in two stages to drain the blow-by gas, so even if oil enters from the blow-by gas extraction passage 17, the oil is completely drained and the oil is drained completely. Consumption can be reduced and catalyst oil deterioration can be prevented.

In addition, since the blow-by gas extraction passage 17 is provided in the middle between the left and right banks 15 and 16,
There is no fear that the blow-by gas extraction passage 17 will be clogged due to fluctuations in the oil level in the oil pan, and the problem of increased oil consumption is eliminated. Further, the removal of blow-by gas can be facilitated by the rotational wind pressure of the crankshaft.

Furthermore, since the space inside the cam housings 9, 10 and the crank chamber 2 are communicated with each other through a dedicated passage for blow-by gas, even if the oil return passages 11, 12 are blocked by oil, the oil cannot be returned to the oil pan 13. No deterioration occurs.

In addition, a blow-by gas passage structure is provided between the left and right banks 15 and 16 in what used to be an empty space, so space can be used effectively, and a second oil separator chamber is provided in the cam housing. Since the engine is equipped with a small engine, its volume can be kept small, and the overall size of the engine can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a V-type engine equipped with a blow-by gas reducing device that has already been proposed, and FIG. 2 is a partial cross-sectional view of a V-type engine equipped with a blow-by gas reducing device according to an embodiment of the present invention. Figure 3 is the second
FIG. 2 is a plan view of the V-type engine shown in FIG. 1...Crank case, 2...Crank chamber,
3, 4... Cylinder block, 5, 6... Cylinder head, 7... Intermediate position between left and right banks, 8...
Crankshaft, 9, 10...cam housing, 11, 12...oil return passage, 13...oil pan, 14...oil, 15, 16...left and right banks, 17...blow-by gas extraction passage,
18... First oil separator chamber, 19... Oil separator, 20, 21... Second oil separator chamber, 22, 23... Blow-by gas passage, 24, 25... Oil separator, 26, 2
7...Camshaft, 28, 29...Exit.

Claims (1)

[Scope of utility model registration request] An oil return passage is formed along the outer surface of the left and right banks of the V-type engine, and a blow-by gas extraction passage whose one end opens into the crank chamber is formed at an intermediate portion between the left and right banks and directly above the oil pan; The other ends of the extraction passage are connected to the intake system only by blow-by gas passages extending along the inner surfaces of the left and right banks, and on the blow-by gas passage,
A blow-by V-type engine characterized in that a first oil separator chamber and a second oil separator chamber are located downstream of the first oil separator chamber in cam housings of left and right banks. Gas reduction device.