JPH0610645A - Blow-by gas reflux device for internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate outside piping and suck blow-by gas excluding oil component in a cylinder in a blow-by gas reflux device for internal combustion engine which sucks blow-by gas in a cylinder head by intake air negative pressure for re-combustion. CONSTITUTION:By blocking the inside of a rocker cover 4 with partition walls 6-8, a rocker chamber 10 for storing a valve system, an expansion chamber 13 for separating oil component from blow-by gas by pressure reduction, and an air intake chamber 12 for sucking blow-by gas after oil separation in an air intake port 11 are formed, adjoining to each other. A cylinder head 2 and a cylinder block 1 are made to communicate with the expansion chamber 13 and a crankcase 3 to form a passage 5. Moreover, the cylinder head 2 is made to communicate with the air intake port 11 and the air intake chamber 12 to form a communicating part (opening), and a partition wall 7 between the expansion chamber and air intake chamber 12 is made to communicate with the expansion chamber 13 and the air intake chamber 12 to form an orifice 14.

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 recirculation system for an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine, part of exhaust gas generated in a combustion chamber passes between a piston ring and a cylinder and fills a crankcase. This exhaust gas is generally called blow-by gas, but if it is left as it is while the crank case is filled with blow-by gas, the crankcase pressure will continue to rise and eventually cause problems such as oil leaks. Some sort of action is required because it will be reached. As the most primitive method, there is a method of releasing blow-by gas into the atmosphere as it is, but the blow-by gas probably contains an oil component, which is not an environmentally preferable method. For this reason,
The present applicants communicate the inside of the cylinder head cover (rocker cover) with the downstream side of the intake pipe by an external pipe, and suck the blow-by gas in the crankcase into the cylinder by the suction negative pressure of the intake air and re-burn it. I am considering what I did.

As a related technique, an attempt has been made to establish communication between the inside of the cylinder head cover, the downstream of the intake port, and a small hole (Japanese Utility Model Publication No. 53-145007).

[0004]

However, even the device studied has the following problems.

External piping connecting the intake port and the crankcase is required.

The blow-by gas contains a large amount of oil diffused by parts such as a valve system, and if the blow-by gas is sucked into the cylinder as it is, the oil consumption will increase. There is a risk that an oil hammer may occur and a serious accident may occur.

The object of the present invention is to reduce the intake negative pressure
In a blow-by gas recirculation device for an internal combustion engine in which blow-by gas is sucked into the cylinder and re-combusted, the blow-by gas after removing the external pipe and separating the oil component is sucked into the cylinder.

[0008]

A first aspect of the present invention is to provide a rocker chamber for partitioning the inside of a rocker cover with a partition to store a valve mechanism therein, and an expansion chamber for separating an oil component from blow-by gas by decompression. And an intake chamber for sucking the blow-by gas after oil separation into the intake port are formed adjacent to each other, and a passage is formed by connecting the expansion chamber and the crankcase to the cylinder head and the cylinder block, A communication portion is formed by connecting the intake port and the intake chamber to the cylinder head, and an orifice is provided in the partition wall of the expansion chamber and the intake chamber so that the expansion chamber and the intake chamber communicate with each other. .

In a second aspect of the invention, a rocker chamber for partitioning the inside of the rocker cover with a partition to store the valve operating mechanism therein, an expansion chamber for separating the oil component from the blow-by gas by depressurization, and an oil separation chamber after the oil separation. An intake chamber for sucking blow-by gas into the intake port is formed adjacent to each other, a passage is formed in the cylinder head and the cylinder block by communicating the expansion chamber with the crankcase, and the intake port is formed in the cylinder head. And an intake chamber are communicated with each other to form a communication portion, and an orifice is provided in the partition wall of the expansion chamber and the intake chamber to communicate the expansion chamber and the intake chamber with each other.
The rocker cover is provided with vent holes for the expansion chamber and the intake chamber before and after the partition wall as a center, and a diaphragm is attached to the outer peripheral surface of the rocker cover so as to isolate the vent hole from the outside, When the expansion chamber pressure is below a predetermined value, this diaphragm isolates the vents from each other.
The elastic means is attached to allow the ventilation ports to communicate with each other when the predetermined value is exceeded.

[0010]

When the internal pressure in the crankcase rises, blow-by gas is taken into the expansion chamber from the passage. This blow-by gas undergoes expansion and decompression due to the sufficient volume of the expansion chamber, and the mist-like oil component contained in the blow-by gas is separated and liquefied (condensed) and accumulated in the expansion chamber,
The blow-by gas after the oil content is removed enters the intake chamber through the orifice. Therefore, the liquid oil accumulated in the expansion chamber returns to the crankcase through the passage, and the blow-by gas that has entered the intake chamber is in the cylinder due to the suction negative pressure of the intake port that acts on the intake chamber via the communicating portion. Enters and is reburned here.

In the second aspect of the invention, when the crankcase internal pressure is below a predetermined value, the orifice functions in the same manner as in the first aspect of the invention, however, when the crankcase internal pressure exceeds the predetermined value, the diaphragm moves into the expansion chamber and the intake chamber. Connect the communication ports of. Therefore, even in the case where the crankcase internal pressure rises abnormally beyond the capacity of the orifice, it is possible to prevent the crankcase internal pressure from abnormally rising.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a longitudinal sectional view of an internal combustion engine, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is B of FIG.
A cross section taken along line -B is shown in FIG. 4, and a cross section taken along line CC of FIG. 2 is shown.

When the blow-by gas is taken into the rocker cover from the inside of the crankcase through the cylinder block and the cylinder head, it is necessary to provide an intake port near a part that is constantly moving, such as a valve train part. The mechanism for separation will be unnecessarily complicated.

Therefore, in this embodiment, as shown in FIG. 1, the cylinder block 1 and the cylinder head 2 are
In addition, a blow-by gas intake passage 5 is provided at a side portion (referred to as a side in the column direction of the cylinder) away from moving parts such as valve train parts so as to communicate the inside of the crankcase 3 and the inside of the rocker cover 4. ing.

As shown in FIG. 2, the rocker cover 4 seated on the cylinder head 2 is mounted on the cylinder head 2 by means of first, second, and third partition walls 6, 7, and 8 to operate a valve valve such as a rocker arm 9. A rocker chamber 10 for storing the mechanism, an intake chamber 12 for sucking the blow-by gas after oil removal into an intake port 11 in the cylinder head 2, and a blow-by gas from the intake passage 5 are taken in and expanded ( It is separated into three chambers, an expansion chamber 13 for decompressing and liquefying (condensing) the oil component of blow-by gas for separation. The volume of the expansion chamber 13 is set to a volume that can sufficiently separate the oil component from the blow-by gas, and the blow-by gas intake passage 5 is formed in communication with the expansion chamber 13. And the expansion chamber 13 and the intake chamber 12
The second partition wall (common partition wall) 7 that isolates the intake chamber 12 is provided with an orifice 14 that connects the expansion chamber 13 and the intake chamber 12, and the cylinder head 2 is a portion that forms the floor of the intake chamber 12. Is provided with an opening (communication portion) 15 that allows the intake port 11 and the inside of the intake chamber 12 to communicate with each other.

The operation of this embodiment will be described below.

As shown in FIG. 1, part of the exhaust gas generated by combustion is generated by the piston ring 16 and the cylinder 17.
The internal pressure in the crankcase 3 rises due to the entry into the crankcase 3 through a slight gap between the two. As shown in FIG. 2, blow-by gas is taken into the expansion chamber 13 from the intake passage 5. The gas taken into the expansion chamber 13 is expanded and depressurized due to its sufficient volume. For this reason, the mist-like oil component contained in the blow-by gas is liquefied (condensed) and accumulated in the expansion chamber 13, and the blow-by gas after the oil component is removed is the orifice 1
Enter the intake chamber 12 through 4. The liquid oil accumulated in the expansion chamber 13 returns to the crankcase 3 through the intake passage 5, and the blow-by gas that has entered the intake chamber 12 is
Due to the suction negative pressure of the suction port acting in the suction chamber 12 through the opening 15, the suction pressure is sucked into the cylinder 17 and re-combusted therein.

In this embodiment, the orifice 14
The diameter of is set by test or analysis so that the optimum crankcase internal pressure is obtained.

(Embodiment 2) With the construction as in Embodiment 1, the oil content is separated from the blow-by gas to prevent abnormal oil consumption of the internal combustion engine while preventing oil hammer, which is the original purpose. The problem of oil leakage of the crankcase 3 can be solved.

However, even if the internal pressure of the crankcase can be adjusted by the orifice 14, since the diameter of the orifice 14 is not variable but fixed, the exhaust amount of blow-by gas due to deterioration of the engine over time. Is increased, or the suction negative pressure is increased due to clogging of the air cleaner element, or the required allowable crankcase internal pressure range is narrow, the crankcase 3 pressure must be adjusted. It can be difficult.

This embodiment solves this kind of problem without changing the basic structure of the first embodiment. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 5 shows a cross section of the rocker hippo 4 at the same location as in FIG.

The rocker cover 4 is provided with vent holes 18 and 19 of the expansion chamber 13 and the intake chamber 12 at the front and rear positions around the second partition 7, and the vent holes 18 and 19 are provided on the outer surface of the rocker cover 4. A diaphragm 20 is attached so as to isolate 19 from the outside. The diaphragm 20 has a peripheral edge portion 21 formed by a flange 23 of a cup-shaped container 22 having a diameter dimension capable of isolating the vent holes 18 and 19 of the expansion chamber 13 and the intake chamber 12 from the outside.
It is integrally and airtightly attached to the rocker cover 4. Then, in the container 20, at all times, that is, at a pressure lower than the crankcase internal pressure determined by the diameter of the orifice 14, the ventilation port 18 of the expansion chamber 13 and the intake port 19 of the intake chamber 12 are closed to cut off communication between the two. Every (Fig. 6),
When the pressure is exceeded, both vent holes 18 and 19 of the expansion chamber 13 and the intake chamber 12 are opened to communicate with each other, and the expansion chamber 1
A repulsion means (return spring) 24 for allowing the 3 and the intake chamber 12 to communicate with each other as a result is housed.

Therefore, the discharge amount of blow-by gas abnormally increases due to the deterioration of the internal combustion engine, or the air cleaner element (not shown) is clogged.
In a case where the suction negative pressure is increased, or in a case where the required crankcase internal pressure has a narrow allowable range, it is possible to prevent an abnormal increase in the crankcase internal pressure and solve the problem of oil leakage of the crankcase 3. Yes (Figure 7).

In order to communicate or isolate the vent holes 18 and 19, it is of course possible to use a diaphragm valve in which the diaphragm 20, the container 22 and the elastic means 24 are integrated.

[0027]

As is clear from the above description, the present invention exhibits the following excellent effects.

(1) Abnormal consumption of oil can be reduced, oil hammer can be prevented, and oil leakage of the crankcase can be prevented.

(2) The external piping required for the blow-by gas intake recirculation can be eliminated.

(3) The internal pressure of the crankcase can be normally maintained by the diaphragm and the elastic means, and the oil leakage of the crankcase can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a vertical cross section of an internal combustion engine according to the present invention.

FIG. 2 is a view showing a cross section taken along line AA of FIG.

FIG. 3 is a view showing a cross section taken along line BB of FIG.

FIG. 4 is a view showing a cross-sectional view taken along the line CC of FIG.

FIG. 5 is a diagram showing a detailed cross section of a main part of another embodiment.

FIG. 6 is a diagram showing a detailed cross section of a main part of the embodiment of FIG.

FIG. 7 is a diagram showing a detailed cross section of a main part of FIG.

[Explanation of symbols]

 1 Cylinder Block 2 Cylinder Head 3 Crank Case 4 Rocker Cover 5 Passage (Intake Passage) 6,7,8 Partition 10 Rocker Chamber 11 Intake Port 12 Intake Chamber 13 Expansion Chamber 14 Orifice 18, 19 Vent 20 20 Diaphragm 24 Ejection Means

Claims (2)

[Claims] 1. A rocker chamber for partitioning the inside of a rocker cover with a partition to store a valve mechanism therein, an expansion chamber for separating oil from blow-by gas by decompression, and intake of blow-by gas after oil separation. An intake chamber for intake to the port is formed adjacent to each other, and the cylinder head and the cylinder block communicate with the expansion chamber and the crankcase to form a passage, and the cylinder head has the intake port and the intake chamber. A blow-by gas recirculation apparatus for an internal combustion engine, characterized in that a communicating portion is formed by communicating with each other, and an orifice is provided in a partition wall between the expansion chamber and the intake chamber so that the expansion chamber and the intake chamber communicate with each other. 2. A rocker chamber for partitioning the inside of the rocker cover with a partition to store the valve operating mechanism therein, an expansion chamber for separating the oil component from the blow-by gas by depressurization, and an intake of the blow-by gas after the oil separation. An intake chamber for intake to the port is formed adjacent to each other, and the cylinder head and the cylinder block communicate with the expansion chamber and the crankcase to form a passage, and the cylinder head has the intake port and the intake chamber. To form a communication portion, and an orifice is provided in a partition wall between the expansion chamber and the intake chamber so that the expansion chamber and the intake chamber communicate with each other, and the rocker cover is expanded forward and backward around the partition wall. A ventilation hole is provided for the air chamber and the intake chamber, and a diaphragm is attached to the outer peripheral surface of the rocker cover so as to isolate the ventilation hole from the outside. A blow-by for an internal combustion engine, characterized in that an elastic means for isolating the vent holes from each other when the expansion chamber pressure is equal to or lower than a predetermined value, and allowing the communication between the vent holes when the pressure exceeds the predetermined value is attached to the ear flap. Gas recirculation device.