JP2000248919A - Blow-by gas circulating device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the blow-by gas passage by connecting a discharge port opened to the side surface of an engine body for taking out blow-by gas from a crank chamber to a connection port to an oil separator arranged in the upper part of the engine body through a piping extending along the side surface of the engine body. SOLUTION: Blow-by gas which leaked to a crank chamber through the cylinder sliding clearance of a piston is extracted through an opening on the lower surface of a discharge port having a cover mounted thereon and introduced into an oil separator provided within a cylinder head 3 and connected to an intake system through a piping 16. The piping is formed of a metal pipe extended substantially horizontally, further bent at a right angle, and extended vertically in the area nipped between an exhaust pipe and a cylinder block, and a rubber hose 16a is interposed therein in the vicinity of the connection port 15 of the oil separator. According to this structure, since the piping 16 receives the heat of the exhaust pipe, the oil in the blow-by gas passing in the inner part thereof is reduced in viscosity and separated from the gas while it is passed through the piping 16.

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 circulation device for an internal combustion engine.

[0002]

2. Description of the Related Art As a blow-by gas circulating apparatus for an internal combustion engine, one disclosed in Japanese Patent Application Laid-Open No. Hei 5-44423 has a structure in which a blow-by passage is formed inside a cylinder block and a cylinder head. However, if the flow path for the blow-by gas is provided inside the cylinder block in this way, the path becomes more complicated, and the cylinder block and the like become thicker, so that their size and weight cannot be avoided.

[0003] Further, in Japanese Unexamined Patent Application Publication No. 8-86221, a blow-by gas control valve is provided on an upper surface of a rocker cover containing an oil separator so as to reduce an oil component which is recirculated into intake air together with blow-by gas. It is configured to be arranged directly. However, in a diesel engine in which a common rail and a high-pressure fuel pipe are arranged on the upper surface of the rocker cover, there is a problem that the blow-by control valve easily interferes with these and maintenance becomes difficult.

An object of the present invention is to solve such a problem, and aims at simplifying a blow-by path, reducing the size and weight of an engine body, and facilitating maintenance of a control valve.

[0005]

According to a first aspect of the present invention, there is provided a blow-by gas circulating apparatus for an internal combustion engine that recirculates blow-by gas to an intake system. And a connection port to an oil separator disposed on the upper portion of the engine body and communicating with the intake system, is connected by a pipe extending substantially along the side surface of the engine body.

According to a second aspect, in the first aspect, the pipe extends substantially horizontally along a side surface of the cylinder block between the cylinder block and the exhaust pipe, bends at some point, and extends substantially vertically upward. And is connected to the cylinder head side.

In a third aspect based on the first or second aspect, the pipe is formed of a metal pipe, and a flexible hose is interposed in the middle of the pipe.

According to a fourth aspect of the present invention, in the first to third aspects, a cylindrical fixed seat for extracting blow-by gas that has passed through the oil separator projects from an upper portion of the engine body. Install the control valve,
The blow-by control valve and the intake system were connected by a hose.

In a fifth aspect based on the fourth aspect, the fixed seat is integrally protruded from a head cover that covers an upper surface of the engine body, and is located below a blow-by control valve attached to the fixed seat. Then, a common rail for storing high-pressure fuel is attached to the head cover in the longitudinal direction of the head cover, and a high-pressure fuel pipe for distributing high-pressure fuel from the common rail to the fuel injection valves is disposed in a direction substantially orthogonal to the common rail.

In a sixth aspect based on the fifth aspect, the blow-by control valve attached to the fixed seat is supported on the head cover by a bracket and a stay.

[0011]

According to the first aspect of the present invention, the flow path for guiding blow-by gas from the crank chamber of the engine body to the oil separator on the upper part of the engine body is constituted by a pipe arranged most of the way outside the engine body. Therefore, the structure of the flow path of the blow-by gas is simplified as compared with the case where the flow path is formed inside the engine body, the manufacture thereof is facilitated, and there is no need to secure the flow path inside the engine body.
Reduced waste of the engine main body can be reduced in size and weight.

According to the second aspect of the present invention, the piping can be arranged even if the space between the exhaust pipe and the cylinder block is a small space.
In addition, the pipe that receives moderate heat extends almost horizontally and then rises vertically.During this time, the oil in the blow-by gas adheres to the inner wall surface, and is easily liquefied and dropped along the wall surface. Is promoted.

According to the third aspect of the present invention, the degree of freedom in connecting the pipes is increased by the hose interposed in the middle of the pipes, and the assembly and productivity are improved.

In the fourth invention, the blow-by gas taken out of the engine crankcase passes through the pipe, passes through the oil separator at the upper part of the engine body, and passes through the blow-by control valve disposed at the highest position above the oil separator. By returning to the intake system, the oil contained in the blow-by gas can be sufficiently removed before reaching the blow-by control valve, stabilizing the control performance of the blow-by control valve, and reducing the flow of oil components into the intake air. Can be.

Further, since the blow-by control valve having a relatively large occupied area is mounted on the upper part of the cylindrical fixed seat protruding from the upper part of the engine body, interference with other parts arranged above the engine body is avoided. Thus, the space below or around the valve can be effectively used for other parts.

In the fifth invention, the blow-by control valve is mounted on the fixed seat and is located above the common rail, so that mutual interference is prevented, and the assembly and disassembly of the blow-by control valve is performed on the common rail and the high-pressure fuel pipe. It can be performed without moving, which is advantageous in terms of maintenance.

According to the sixth aspect, the blow-by control valve can be firmly fixed, vibration resistance is improved, and control stability and durability are improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3, reference numeral 1 denotes an engine main body, and the engine main body 1 is roughly composed of a cylinder block 2 and a cylinder head 3.

As shown in FIG. 3, a plurality of cylinders 21 are formed in a cylinder block 2 in parallel, and a piston 22 is housed in each cylinder 21 so as to be freely slidable. Each piston 22 is connected to a crankshaft 24 extending in the cylinder row direction in a crank chamber 26 via a connecting rod 23, and the reciprocating motion of the piston 22 causes the crankshaft 2 to move.
4 rotates, and this rotational force is taken out as an engine output.

The cylinder head 3 is provided with intake and exhaust valves 31 and fuel injection valves 32 for each cylinder. Fresh air is introduced into the combustion chamber 25 during the intake stroke, and fuel is injected near the compression top dead center. The combustion gas is exhausted in the exhaust stroke. A camshaft 34 for driving the intake and exhaust valves 31 is arranged in the cylinder head 3.

Reference numeral 35 denotes an intake pipe, 36 denotes an exhaust pipe, and the exhaust pipe 3
6 is provided with a turbocharger 37 for supercharging the intake air. Further, a part of the exhaust gas is recirculated into the intake air via the exhaust gas recirculation passage 38.

An oil pan 25 is mounted on the lower surface of the cylinder block 2, and the crank chamber 26 is defined between them.

In order to discharge the blow-by gas leaked into the crank chamber 26 from the gap between the piston 22 and the cylinder, the inside of the cylinder block 2 is located above the oil level and on the front side with respect to the rotation direction of the crank shaft 24 ( The blow-by discharge port 11 is located at the position where the oil is hit). A cover 11 a is attached to the outlet 11 at an opening facing the crank chamber 26 of the cylinder block 2, and blow-by gas flows into the internal passage 12 from an opening 11 b on the lower surface thereof.

In the middle of the internal passage 12, an oil separation net 13 is provided.
Is interposed to separate oil. The internal passage 12 is connected to an outlet 14 opened on the side surface of the cylinder block 2, and connects the outlet 14 and a connection port 15 provided on the same side surface of the cylinder head 3 via a pipe 16.

As shown in FIGS. 1 and 4, the pipe 16 is disposed inside the exhaust pipe 36 along the side of the cylinder block on which the exhaust pipe 36 is disposed. It is formed of a metal pipe that bends at a substantially right angle to a vertical portion.
A flexible rubber hose 16a is interposed in the middle of
This increases the degree of freedom in positioning the pipe 16 with respect to the outlet 14 and the connection port 15 and facilitates connection.

As shown in FIG. 6, the cylinder head 3
An oil separator 40 formed as a space meandering in the longitudinal direction is provided inside the cylinder head at an upper portion of the camshaft 34, and an upper opening surface of the oil separator 40 is formed by a head cover 39. Covered. In the oil separator 40, a meandering space is formed by a plurality of partition walls 40a arranged alternately from both sides of the cylinder head. The connection port 15 communicates with the most end of the oil separator 40, and blow-by gas is supplied into the oil separator from here. Introduce.

A fixed seat 42 for taking out blow-by gas is provided integrally with the head cover 39 at a position distant from the connection port 15 on the opposite side. The fixing seat 42 is formed in a substantially conical cylindrical shape, and projects substantially perpendicularly to the head cover 39. A blow-by control valve 43, which will be described later, is attached to the tip of the fixed seat 42, thereby adjusting the amount of blow-by gas recirculated to the intake system.

As can be seen from FIG. 5, the cylinder head 3
A common rail 50 is disposed above the head cover 39 in parallel with the longitudinal direction of the cylinder head 3 and is fastened together with the head cover 39 to the cylinder head 3 by a plurality of bolts. High-pressure fuel is fed into the common rail 50 from a fuel pump 55, and the stored fuel is supplied to the fuel injection valve 32 of each cylinder via each high-pressure fuel pipe 53. in this case,
Each high-pressure fuel pipe 53 is disposed substantially orthogonal to the longitudinal direction of the common rail 50, and is connected to the fuel injection valve 32 of each cylinder through a shortest distance.

The blow-by control valve 43 attached to the fixed seat 42 is located above the common rail 50 and each high-pressure fuel pipe 53, and
The blow-by control valve 43 is disassembled and removed from above as necessary, without moving the high-pressure fuel pipe 53 or the like during maintenance, for example, by bolting to the bracket 52a and the stay 52b attached to the bracket 9. It is possible to assemble.

A hose 54 is connected to the blow-by control valve 43.
The hose 54 is connected to the intake pipe 35 so that blow-by gas is recirculated during intake.

Reference numeral 56 denotes a filler cap, which is disposed in front of the cylinder head and can be opened and closed without interfering with other parts.

The configuration is as described above. Next, the operation will be described.

The blow-by gas that has leaked into the crank chamber 26 from the cylinder sliding gap of the piston 22 flows out of the discharge port 11, but the balance weight of the crankshaft 24 hits the oil surface in the blow-by gas. Contains a lot of mist.

A cover 11a is attached to the discharge port 11, and blow-by gas is taken out only from the opening 11b on the lower surface, so that the amount of mixed oil mist is reduced. Mist is separated.

The blow-by gas passes through the pipe 16 and rises toward the cylinder head.
In the region between the cylinder block 2 and the cylinder block 2, it extends substantially in the horizontal direction, further bends at a right angle, and extends in the vertical direction.

The pipe 16 receives heat from the exhaust pipe 36, and the heat reduces the viscosity of the oil in the blow-by gas passing through the inside of the pipe 16. The oil is separated from the gas while passing through the pipe 16, and is particularly substantially horizontal. It liquefies by hitting the upper inner wall surface at the part and falls.

The speed of the blow-by gas flowing from the end into the oil separator 40 on the cylinder head side from the pipe 16 is reduced, and the oil is further separated while passing through the meandering flow path. It reaches a blow-by control valve 43 provided above a certain fixed seat 42.

The blow-by control valve 43 is located at the highest position, and the oil mist in the blow-by gas is sufficiently removed on the way.
3 is less likely to be soiled by the adhesion of oil, and stable controllability is maintained.

The opening degree of the blow-by control valve 43 is controlled in accordance with the operation state, and the blow-by gas from which oil has been separated is recirculated to the intake pipe 35. At the same time, it is sucked into the engine again and burned.

As described above, the flow path of the blow-by gas is not formed inside the engine main body, but is formed mostly outside by the pipe 16, so that the flow path configuration is simplified as compared with the case where the flow path is formed inside the engine. As a result, the productivity is good, and the wall thickness for forming the flow path can be reduced as compared with the case where the flow path is formed inside the cylinder block 2 and the cylinder head 3, which leads to a reduction in size and weight.

The pipe 16 is provided with a rubber hose 1
Because of the interposition of 6a, even if there is some error in the shape of the pipe 16 in connecting the outlet 14 and the connection port 15, this can be absorbed, and the degree of freedom in assembling is high.

The blow-by control valve 43 has a relatively large projected area on the plane, and therefore occupies a large portion of the space above the cylinder head 3. The blow-by control valve 43 has a cylindrical fixed seat 42 projecting from the head cover 39. Since it is mounted on the upper portion, the space between the blow-by control valve 43 and the upper surface of the head cover can be effectively used. Therefore, even if the common rail 50 and the high-pressure fuel pipe 52 are arranged in this space, the space does not interfere with the blow-by control valve 43. Blow-by control valve 43 which is relatively frequently maintained
Can be disassembled and assembled without moving the common rail 50 or the high-pressure fuel pipe 53.

The blow-by control valve 43 is mounted at a high position on the fixed seat 42. The fixed seat 42 is formed integrally with the head cover 39, has high rigidity, and the blow-by control valve 43 has the bracket 52a and the stay 5
2b, the mounting strength is high, vibration resistance,
The durability is improved.

The high pressure fuel pipe 53 connected to the fuel injection valve 32 is shortened because the common rail 50 is disposed above and in parallel with the cylinder head 3 and connected to the high pressure fuel pipe 53 substantially orthogonally. The space occupied above the cylinder head can be reduced, and the components can be arranged in a narrow space without interfering with each other.

It is apparent that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is an engine side view showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view partially cut away.

FIG. 4 is a partial side view showing a part of a blow-by pipe.

FIG. 5 is a perspective view of an upper portion of a cylinder head.

FIG. 6 is an exploded perspective view of a part of an upper portion of a cylinder head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder block 3 Cylinder head 11 Discharge port 15 Connection port 16 Pipe 16a Rubber hose 26 Crank chamber 35 Intake pipe 36 Exhaust pipe 39 Head cover 40 Oil separator 42 Fixed seat 43 Blow-by control valve 50 Common rail 52a Bracket 52b Stay 53 High-pressure fuel pipe 54 hose

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yasuyuki Iwade 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term in Nissan Motor Co., Ltd. (reference) 3G015 AA05 AA07 BD04 BD05 BD10 BD24 BE00 BE05 BF10 CA04 CA06 DA11 EA04 EA25

Claims (6)

[Claims] 1. A blow-by gas circulating apparatus for an internal combustion engine that recirculates blow-by gas to an intake system. A blow-by gas circulation device for an internal combustion engine, wherein a connection port to an oil separator communicated with the oil separator is connected by a pipe extending substantially along a side surface of the engine body. 2. The pipe extends between the cylinder block and the exhaust pipe substantially horizontally along the side surface of the cylinder block, bends at some point, extends substantially vertically upward, and connects to the cylinder head side. The blow-by gas circulation device for an internal combustion engine according to claim 1. 3. The pipe according to claim 1, wherein the pipe is formed of a metal pipe, and a flexible hose is interposed in the pipe.
4. A blow-by gas circulation device for an internal combustion engine according to claim 1. 4. A cylindrical fixed seat for taking out blow-by gas passing through the oil separator protrudes from an upper portion of the engine body, and a blow-by control valve is attached to the fixed seat. The blow-by gas circulation device for an internal combustion engine according to claim 1, wherein the blow-by gas circulation device is connected by: 5. A common rail for projecting the fixed seat integrally with a head cover covering an upper surface of the engine body, and being located below a blow-by control valve attached to the fixed seat, for storing high-pressure fuel in the head cover. 5. A blow-by gas circulation device for an internal combustion engine according to claim 4, wherein the high-pressure fuel pipe is mounted in a longitudinal direction of the head cover, and a high-pressure fuel pipe for distributing high-pressure fuel from the common rail to the fuel injection valve is disposed in a direction substantially orthogonal to the common rail. 6. The blow-by gas circulation device for an internal combustion engine according to claim 5, wherein the blow-by control valve attached to the fixed seat is supported on a head cover by a bracket and a stay.