JP3052483B2 - Blow-by gas processing device for V-type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas processing device configured to return blow-by gas in a crankcase of an internal combustion engine to an engine intake system, and more particularly to an improvement in an oil separator of a blow-by gas processing device in a V-type internal combustion engine. About.

[0002]

2. Description of the Related Art A blow-by gas processing apparatus in which fresh air is introduced into a crankcase of an internal combustion engine and blow-by gas extruded by the fresh air is returned to an engine intake system and burned has been widely used. However, in this type of device, an oil separator is required at the outlet of the blow-by gas from the crankcase in order to prevent the lubricating oil from being taken out together with the blow-by gas from inside the crankcase.

[0003] This oil separator generally has a relatively simple structure in which a baffle plate is provided in the oil separator chamber to form a curved flow path. However, in many cases, the oil separator is provided on the side of the crankcase. Is arranged, and the blow-by gas passing therethrough is taken out by an external pipe.

Japanese Utility Model Laid-Open Publication No. Sho 60-147708 discloses a V-type internal combustion engine in which an oil separator chamber is formed at a position between V banks of a cylinder block and communicates with a lower crankcase through a communication hole. Is disclosed.

[0005]

However, in the above-mentioned conventional configuration, the oil separator is located relatively below the engine and is close to the oil surface in the oil pan and the crankshaft. As a result, the lubricating oil scattered tends to enter the oil separator chamber, and the lubricating oil accumulates inside the oil separator. In particular, in the configuration disclosed in Japanese Utility Model Laid-Open No. 60-147708, since the lower communication hole is opened directly toward the crankshaft, oil droplets scattered from the crankshaft to the outer peripheral side due to centrifugal force are generated in the oil separator chamber. It is easy to jump into and accumulate.

[0006]

According to the present invention, fresh air is introduced into a crankcase of a V-type internal combustion engine, and blow-by gas is guided from the crankcase to an engine intake system through a chain chamber at a front end of the engine. In the blow-by gas processing apparatus for a V-type internal combustion engine, an oil separator chamber is formed above the chain chamber and at a position between the cam sprockets of the left and right banks, and an oil separator is formed so as to cover an inlet at a lower part of the oil separator chamber. The engine mount boss is located below the chamber.

[0007]

In an internal combustion engine in which the valve mechanism is driven by a timing chain, the chain chamber at the front end of the engine makes the inside of the cylinder head and the crankcase largely communicate with each other. It becomes a flow path. In the above configuration, the oil separator chamber is formed using the space between the cam sprockets in the upper part of the chain chamber, and blow-by gas is taken out to the outside through the oil separator chamber.

Since the oil separator chamber is located above the chain chamber and the lower part is covered with the engine mount boss, the oil separator chamber is urged by the lubricating oil or centrifugal force that is lifted with the rotation of the crankshaft. The scattered oil mist does not easily flow into the oil separator chamber.

[0009]

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

FIG. 3 is an exploded perspective view of a V-type six-cylinder internal combustion engine provided with a blow-by gas processing apparatus according to the present invention. As shown in FIG. The head 2 is fixed, and a chain case rear 3 formed in a plate shape by, for example, aluminum die casting is attached so as to cover the front surfaces of the cylinder block 1 and the cylinder head 2. A cover-like chain case front 4 is further attached to the front of the chain case rear 3, so that a chain chamber 5 is formed between them. FIG. 1 shows such a V-type internal combustion engine with the chain case front 4 removed, that is, the chain chamber 5.
2 shows an internal configuration. The upper part of the chain room 5
As shown in FIG. 1, it is covered by the front end of the cylinder head cover 6.

This V-type internal combustion engine has a DOHC type valve operating mechanism. As shown in FIG. 1, a crank sprocket 9 is provided on a crankshaft 8 below a cylinder block 1, and intake air in left and right banks is provided. One timing chain 12 is wound around the first cam sprocket 11 provided on the side camshaft 10 and the crank sprocket 9 so as to form a substantially triangular shape. The first cam sprocket 11 is provided on the intake side camshaft 10.
A second cam sprocket 13 having a small diameter is provided so as to overlap the cam sprocket 15 of the exhaust side camshaft 14.
A sub-timing chain 16 is wound around each of the second cam sprockets 13 adjacent thereto. In other words, the intake camshafts 10 in the left and right banks are driven by the crankshaft 8 rotating in the direction of arrow A in FIG. 1, and the exhaust-side camshafts 14 are interlocked therewith via the sub-timing chain 16.

A lower end is rotatably supported between the first cam sprocket 11 on the left side of the timing chain 12 and the crank sprocket 9 on the loose side of the timing chain 12, and a hydraulic chain tensioner 17 is provided on the upper end. A provided chain guide 18 is provided, and thereby an appropriate tension is applied to the timing chain 12. A chain guide 19 is attached between the pair of left and right first cam sprockets 11, and slightly presses the timing chain 12 inward.

On the other hand, a water pump 21 is disposed between the first cam sprocket 11 and the crank sprocket 9 on the right side of the drawing, which is the tension side of the timing chain 12, and a water pump attached to a drive shaft 22 thereof. The sprocket 23 meshes with the back side, that is, the outer peripheral side of the timing chain 12. The water pump sprocket 23 is located substantially in the middle between the first cam sprocket 11 and the crank sprocket 9 and the timing chain 12
Into the inner peripheral side. Chain guides 24 and 25 are provided above and below the water pump sprocket 23, respectively.

As shown in FIG. 3, the water pump 21 mainly includes a pump housing 28 attached to the opening 26 of the chain case rear 3 with bolts, and an impeller 29 fixed to the tip of the drive shaft 22. The impeller 29 is located in a pump chamber 30 recessed in the front of the cylinder block 1. In addition, this water pump 21
An opening 31 serving as a working hole is provided in the chain case front 4 corresponding to the mounting position of the above, and this is closed by a cover 32.

Further, a central portion of the front surface of the cylinder block 1,
Specifically, an engine mount boss portion 33 including three columnar bosses 33a is provided on the inner peripheral side of the timing chain 12 and near the center of gravity of the engine. The above-mentioned three bosses 33a are arranged two symmetrically upward,
And one that is arranged below, the upper two,
Chain case rear 3 and chain case front 4
Are exposed on the outer surface of the chain case front 4 through substantially triangular openings 34 and 35 provided in the front side. The lower one is also exposed to the outer surface of the chain case front 4 through cylindrical openings 36 and 37 provided in the chain case rear 3 and the chain case front 4. Here, around the above-mentioned substantially triangular openings 34 and 35, wall portions 34 protruding inside the chain chamber 5 so as to face each other.
a and 35a are provided, and their ends abut against each other, and are sealed using, for example, a liquid gasket. Also around the lower openings 36 and 37, the chain case rear 3 and the chain case front 4
Are sealed using, for example, a liquid gasket. And, in the engine mount boss part 33,
As shown in FIG. 3, an engine mount bracket 38 having three legs 38a corresponding to each boss 33a is fixed by bolts (not shown). still,
In FIG. 3, reference numeral 39 denotes engine mount brackets provided on the left and right sides of the rear end of the cylinder block 1, respectively.

On the other hand, an upper part of the chain chamber 5 comprising the chain case rear 3 and the chain case front 4, specifically, between the first cam sprockets 11 of the left and right banks,
An oil separator chamber 41 is formed. The oil separator chamber 41 is defined by the tips of walls 42 and 43 integrally formed on the chain case rear 3 and the chain case front 4 being in close contact with each other, as shown in FIG. The upper edge is located along the lower edge of the chain guide 19, the left and right edges are arc-shaped along the peripheral edge of the first cam sprocket 11, and the inlet 44 is open at the lower part. A flow path bent upward from the inlet 44 is formed in the oil separator chamber 41, and a blow-by gas outlet 45 is provided on the chain case rear 3 side so as to communicate with the upper part of the flow path. An opening is formed. This blow-by gas outlet 45 penetrates the back surface, that is, the cylinder block 1 side, and as shown in FIG.
Are connected to a blow-by gas hose 46 disposed between the V banks.

Here, as shown in FIG. 1, the separator chamber 41 is located above the engine mount boss 33 and the walls 34a, 35a around the openings 34, 35.
Thus, a layout in which the lower part of the lower entrance 44 is covered is provided.

FIG. 2 is an explanatory view showing the overall gas flow in the blow-by gas processing apparatus of the V-type internal combustion engine. Fresh air indicated by a white arrow passes through a fresh air introduction hose 45 to one bank. From the rear end of the cylinder head cover 6 into the fresh air passage 46 in the cover 6. Part of the fresh air is introduced into a fresh air passage 48 in the cylinder head cover 6 of the other bank via a connecting hose 47 between the banks. Then, the fresh air is introduced into the cylinder head 2 from the fresh air inlets 49, 50, 51 of the fresh air passages 46, 48,
The inside of the cylinder head 2 is scavenged, and is guided into a crankcase defined by the oil pan 52 and the cylinder block 1 through an oil return passage (not shown). Some fresh air flows into the crankcase through the chain chamber 5 at the front end of the engine. On the other hand, blow-by gas indicated by a black arrow is pushed out of the crankcase with the inflow of fresh air, rises in the chain chamber 5, and flows into the oil separator chamber 41. Then, after the lubricating oil component is separated and removed here, the lubricating oil component is guided to the blow-by gas passage 53 in the cylinder head cover 6 through the blow-by gas hose 46, and is further not shown through a blow-by gas hose 55 further provided with a flow control valve 54. Inhaled by the intake collector. Some blow-by gas flows into the blow-by gas passage 53 from the upper part of the chain chamber 5. The blow-by gas passage 53 functions as an oil separator for the blow-by gas.

In the configuration of the above embodiment, the oil separator chamber 41 is located at the uppermost part of the chain chamber 5, and the lower part of the inlet 44 is defined by walls 34a and 35a around the engine mount boss 33. Because it is covered, the crankshaft 8 and crank sprocket 9
As a result, lubricating oil droplets that are lifted upward and scatter in the chain chamber 5 are less likely to enter the oil separator chamber 41, and a high lubricating oil separation performance can be obtained. In particular,
A large amount of lubricating oil accumulates in the oil separator chamber 41 because the oil droplets blown upward by the centrifugal force from the crank sprocket 9 collide with the walls 34a and 35a and do not go directly to the vicinity of the oil separator chamber 41. There is no such thing as. Further, since the oil separator chamber 41 is located on the inner periphery of the timing chain 12, oil droplets attached to the timing chain 12 and blown toward the outer periphery do not jump into the oil separator chamber 41.

In the above embodiment, since the oil separator chamber 41 is formed by the chain case rear 3 and the chain case front 4, there is no need to use any separate member, the number of parts is reduced, and a pair of The oil separator chamber 41 is provided by effectively using a wasteful space between the one cam sprockets 11, which is advantageous in reducing the size of the entire engine.

[0021]

As is apparent from the above description, according to the blow-by gas processing apparatus for a V-type internal combustion engine according to the present invention, the lubricating oil droplets scattered in the chain chamber due to the rotation of the crankshaft and the crank sprocket are reduced to oil. This makes it difficult for the lubricant to enter the separator chamber, improves the oil separation performance for blow-by gas, and suppresses the removal of lubricating oil to the intake system.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration inside a chain chamber of a V-type internal combustion engine provided with a blow-by gas processing device according to the present invention.

FIG. 2 is an explanatory diagram showing a gas flow in the blow-by gas processing device of the internal combustion engine.

FIG. 3 is an exploded perspective view of the internal combustion engine.

[Explanation of symbols]

 5: Chain chamber 11: First cam sprocket 33: Engine mount boss 41: Oil separator chamber

Continuation of the front page (56) References JP-A 52-151245 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01M 13/04

Claims (1)

(57) [Claims] 1. A blow-by of a V-type internal combustion engine configured to introduce fresh air into a crankcase of the V-type internal combustion engine and to guide blow-by gas from the crankcase to an engine intake system through a chain chamber at a front end of the engine. In the gas processing apparatus, an oil separator chamber is formed above the chain chamber and at a position between the cam sprockets in the left and right banks, and an engine mount boss portion is provided below the oil separator chamber so as to cover an inlet at a lower part of the oil separator chamber. A blow-by gas processing apparatus for a V-type internal combustion engine, wherein: