JP4442813B2 - Oil separation device for blow-by gas in internal combustion engines - Google Patents

Description

  The present invention relates to an apparatus for separating oil contained in a blow-by gas when the blow-by gas in the crankcase of the internal combustion engine is guided to a blow-by gas processing unit such as an intake system.

Conventionally, this type of oil separation device is provided with a gas-liquid separation chamber on the side surface of a cylinder block, for example, as described in Patent Document 1, and blow-by gas in a crankcase is placed in the gas-liquid separation chamber. The oil is introduced into the lower part through an introduction passage, and then discharged from a discharge port in the upper part to a blow-by gas processing unit such as an intake system, whereby oil in the blow-by gas is separated.
Japanese Utility Model Publication No. 61-88017

  By the way, this conventional oil separation device introduces blow-by gas in the crankcase into the lower part of the gas-liquid separation chamber through an introduction passage, but the oil separated from the blow-by gas in the gas-liquid separation chamber is Since it flows down into the crankcase through the introduction passage, the blow-by gas flowing into the gas-liquid separation chamber and the oil flowing down from the gas-liquid separation chamber face each other in the introduction passage.

  If it does so, there exists a possibility that the oil once isolate | separated from blow-by gas may flow into a gas-liquid separation chamber again with a blow-by gas in the said introduction channel, and there existed a problem that the separation rate of oil fell only by this accompanying amount.

  The present invention pays attention to the fact that the pressure in the crankcase in the internal combustion engine has a pulsation in which the pressure becomes higher or lower due to the reciprocating motion of the piston. That is, the present invention provides an oil separation device that eliminates a decrease in oil separation rate.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A gas-liquid separation chamber is provided on the side of the cylinder block in the internal combustion engine, and a blow-by gas introduction passage from the inside of the crankcase at the bottom of the cylinder block is opened at the bottom of the gas-liquid separation chamber. In the oil separator comprising a blow-by gas outlet at the top,
While the opening to the crankcase in the blow-by gas introduction passage is located in a portion of the crankcase far from the cylinder bore, the communication passage from the crankcase is opened at the bottom of the gas-liquid separation chamber , The opening into the crankcase in the communication path is located in a vent hole formed in a bulk portion between the cylinder bores in the crankcase . "
It is characterized by that.

Further, claim 2 of the present invention provides
“In the first aspect of the present invention, the opening to the gas-liquid separation chamber in the communication passage is located at a lower position than the opening to the gas-liquid separation chamber in the blow-by gas introduction passage.”
It is characterized by that.

In the crankcase, pulsation (the pressure in the crankcase increases or decreases) is caused by the reciprocating motion of the piston. The difference in pressure change due to pulsation is larger in the crankcase near the cylinder bore , i.e., in the crankcase, the portion in the vent hole formed in the bulk portion between the cylinder bores is farther from the cylinder bore. In some places, the internal pressure does not change much.

According to the configuration of claim 1, the opening into the crankcase in the blow-by gas introduction passage is located in a portion of the crankcase that is far from the cylinder bore, and at the bottom of the gas-liquid separation chamber from the inside of the crankcase. Since the opening to the crankcase in the communication path is located in a vent hole formed in a bulk portion between the cylinder bores in the crankcase, the cylinder bore When the inner piston moves downward , the pressure in the vent hole in the bulk portion located between the cylinder bores is significantly increased, so both the blow-by gas introduction passage and the communication passage enter the gas-liquid separation chamber. Blow-by gas flows in.

On the other hand, when the piston moves up , the pressure in the vent hole in the bulk portion is greatly reduced, so that the separated oil that has accumulated in the bottom of the gas-liquid separation chamber passes through the communication passage to the crank. It is discharged as if it is sucked into the case. Also, some of the blow-by gas you flowing into the gas-liquid separating chamber through said blow-by gas introducing passage, it means that the flow towards the communication passage, the flow of the blow-by gas, the gas-liquid separation chamber The oil accumulated at the bottom of the cylinder is forcibly pushed out from the communication path into the crankcase.
By the way, the oil in the crankcase is agitated by the rotation of the crankshaft and splashes along the rotation direction, while the vent hole in the bulk portion is in the thickness direction of the bulk portion, that is, in the rotation direction of the crankshaft. By penetrating in the direction crossing the oil, there is almost no possibility that oil that scatters in the rotation direction of the crankshaft enters the inside of the vent hole. Since the communication passage extending from the separation chamber into the crankcase is opened, it is possible to reliably prevent oil from entering the communication passage from the crankcase side.

  Therefore, the separated oil collected at the bottom of the gas-liquid separation chamber can be efficiently discharged into the crankcase using the pulsation caused by the reciprocating motion of the piston. Thereby, there is an effect that oil take-out is reduced and oil consumption can be reduced.

  According to the configuration of the second aspect, since the opening to the gas-liquid separation chamber in the communication passage is located at a lower position than the opening to the gas-liquid separation chamber in the blow-by gas introduction passage, the gas-liquid Oil accumulated in the separation chamber does not flow down to the blow-by gas introduction passage.

  Therefore, the oil once separated from the blow-by gas in the gas-liquid separation chamber can be reliably prevented from being accompanied by the blow-by gas in the blow-by gas introduction passage and flowing again into the gas-liquid separation chamber. It has the effect of contributing to the improvement of the oil separation rate.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings (FIGS. 1 and 2). FIG. 1 is a longitudinal front view of an internal combustion engine to which the present invention is applied, and FIG. 2 is an enlarged vertical side view taken along the line II-II of FIG.

  As shown in FIG. 1, in a multi-cylinder internal combustion engine 1 having a plurality of cylinders arranged in a row, an oil pan 4 for storing lubricating oil is mounted on the lower surface of a crankcase 3 below the cylinder block 2. ing.

  A gas-liquid separation chamber 6 for separating oil contained in blow-by gas leaking into the crankcase 3 is formed on the side surface of the cylinder bore 5 in the cylinder block 2. In the upper part of the gas-liquid separation chamber 6, there is provided a discharge port 7 for discharging the blow-by gas in the gas-liquid separation chamber 6 to a blow-by gas processing section (not shown) such as an intake system.

  A blow-by gas introduction passage 8 extending in the longitudinal direction (reciprocating direction of the piston) is formed on the side surface of the crankcase 3. One end (upper end) of the blow-by gas introduction passage 8 opens toward the inside of the gas-liquid separation chamber 6. The other end (lower end) of the blow-by gas introduction passage 8 opens toward the inside of the oil pan 4 at a position far from (distant from) the cylinder bore 5 in the crankcase 3.

  In this embodiment, the bottom portion of the gas-liquid separation chamber 6 is formed in a stepped shape in which a portion overlapping a bulk portion 11 described later in a side sectional view protrudes one step downward (see FIG. 2). An opening 9 at one end of the blow-by gas introduction passage is located in the upper bottom portion 6 a of the upper layer side of the bottom portion of the gas-liquid separation chamber 6. One end opening 16 of a communication path 15 to be described later is formed in the lower bottom 6b of the lower layer side. Therefore, the opening 16 of the communication passage 15 in the lower bottom portion 6b is located at a position lower than the opening 9 of the blow-by gas introduction passage 8 in the upper bottom portion 6a by the height dimension HT.

In the crankcase 3, a cut wall-shaped bulk portion 11 including a bearing portion 12 that rotatably supports the crankshaft 10 is provided integrally with the crankcase 3 at a portion between the cylinder bores 5. It is .

  The air permeability between the crank chambers 13 defined by the bulk portion 11 is improved at a location close to the cylinder bore 5 in each bulk portion 11, in other words, at a location above the bearing portion 12 through which the crankshaft 10 passes. A vent hole 14 is formed in the plate thickness direction (the direction in which the crankshaft 10 extends).

  A communication passage 15 for allowing the gas-liquid separation chamber 6 and the vent hole 14 to communicate with each other is formed through the bulk portion 11 at a location overlapping the gas-liquid separation chamber 6 in a side sectional view. The opening 16 at one end of the communication path 15 is located in the lower bottom 6 b of the gas-liquid separation chamber 6. The opening 17 at the other end of the communication path 15 is located on the inner diameter side of the vent hole 14. In this embodiment, the communication path 15 is inclined obliquely downward from the opening 16 at one end on the gas-liquid separation chamber 6 side toward the opening 17 at the other end on the vent hole 14 side (see FIG. 1).

  In the above configuration, pulsation (the pressure in the crankcase 3 increases or decreases) is generated in the crankcase 3 due to the reciprocating motion of the piston. The difference in pressure change due to pulsation is larger in the crankcase 3 at a location near the cylinder bore 5 and does not change much at a location far from the cylinder bore 5.

Accordingly, when the piston in the cylinder bore 5 moves downward, the pressure in the crankcase 3 close to the cylinder bore 5 , that is, the pressure in the vent hole 14 of the bulk portion 11 is significantly increased. From both the blow-by gas introduction passage 8 facing the oil pan 4 located at the center and the communication passage 15 facing the vent hole 14 located above the bearing portion 12 in the bulk portion 11, it enters the gas-liquid separation chamber 6. A flow of blow-by gas flowing in is formed.

  In the gas-liquid separation chamber 6, oil is separated from the blow-by gas, and the separated oil is stored in a lower bottom portion 6 b that protrudes one step down from the bottom portion of the gas-liquid separation chamber 6.

On the other hand, when the piston rises, the pressure in the crankcase 3 near the cylinder bore 5 , that is, the pressure in the vent hole 14 of the bulk portion 11 is greatly reduced, so the lower bottom portion 6b of the gas-liquid separation chamber 6 is reduced. The oil accumulated in is sucked and discharged into the crankcase 3 through the communication passage 15. Further, a part of the blow-by gas flowing in from the blow-by gas introduction passage 8 flows toward the communication passage 15, so that the flow of the blow-by gas causes the oil accumulated in the lower bottom portion 6 b to flow from the communication passage 15 to the crankcase 3. It acts to forcibly push in.

  Accordingly, since the separated oil accumulated in the lower bottom portion 6b of the gas-liquid separation chamber 6 can be efficiently and reliably discharged into the crankcase 3 using the pulsation caused by the reciprocating motion of the piston, the amount of oil taken out is reduced. Consumption can be saved.

  In particular, in this embodiment, the opening 16 at one end of the communication passage 15 in the lower bottom portion 6b of the gas-liquid separation chamber 6 is only the height dimension HT than the opening 9 at one end of the blow-by gas introduction passage 8 in the upper bottom portion 6a. Since it is located at a low location, the oil accumulated in the gas-liquid separation chamber 6 does not flow down into the blow-by gas introduction passage 8. Therefore, the oil once separated from the blow-by gas can be reliably avoided from flowing again into the gas-liquid separation chamber 6 along with the blow-by gas in the blow-by gas introduction passage 8, thereby improving the oil separation rate from the blow-by gas. It contributes.

In addition to this, in this embodiment, the vent hole 14 formed at a location close to the cylinder bore 5 in the bulk portion 11 penetrates in the plate thickness direction, that is, the direction intersecting the rotation direction of the crankshaft 10 . As a result , the oil that is stirred by the rotation of the crankshaft 10 and scatters in the crankshaft rotation direction in the crank chamber 13 hardly enters the vent hole 14. Since the opening 17 at the other end of the communication passage 15 is opened on the inner diameter side of the vent hole 14, it is possible to reliably avoid oil from entering the communication passage 15 from the crankcase 3 side. .

The present invention can be embodied in various forms other than the illustrated embodiment. For example, the blow-by gas introduction passage and the communication passage can be formed in a tapered shape or the inner diameter of each passage or opening can be freely set according to the amount of blow-by gas or oil flowing in and out, the flow direction, and the like. . In the oil separator according to the present invention, it is sufficient that there is at least one combination of the blow-by gas introduction passage and the communication passage. Furthermore, the opening to the gas-liquid separation chamber in the communication passage and the opening to the gas-liquid separation chamber in the blow-by gas introduction passage are not limited to the bottom surface of the gas-liquid separation chamber, but include the lower peripheral wall portion in the vicinity of the bottom surface, etc. It is sufficient if it is formed on the bottom. Note that the opening 9 of the blow-by gas introduction passage 8 and the opening 16 of the communication passage 15 incline the entire internal combustion engine in FIG. 1 with the axis of the cylinder in either the right direction or the left direction. Even in this case, the opening 16 of the communication passage 15 is always located at a position lower than the opening 9 of the blow-by gas introduction passage 8.

1 is a longitudinal front view of an internal combustion engine to which the present invention is applied. FIG. 2 is a longitudinal side view taken along II-II in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-cylinder internal combustion engine 2 Cylinder block 3 Crankcase 4 Oil pan 5 Cylinder bore 6 Gas-liquid separation chamber 6a Upper bottom part 6b Lower bottom part 8 Blow-by gas introduction passage 9 Opening part by the side of gas-liquid separation chamber in blow-by gas introduction passage 11 Bulk part 14 Ventilation hole 15 Communication path 16 Opening part on the gas-liquid separation chamber side in the communication path 17

Claims (2)

A gas-liquid separation chamber is provided on the side surface of the cylinder block in the internal combustion engine, and a blow-by gas introduction passage from the inside of the crankcase at the bottom of the cylinder block is opened at the bottom of the gas-liquid separation chamber, while the upper portion of the gas-liquid separation chamber In the oil separator comprising a blow-by gas discharge port,
While the opening to the crankcase in the blow-by gas introduction passage is located in a portion of the crankcase far from the cylinder bore, the communication passage from the crankcase is opened at the bottom of the gas-liquid separation chamber , The blow-by gas oil in the internal combustion engine is characterized in that an opening into the crankcase in the communication path is located in a vent hole formed in a bulk portion between the cylinder bores in the crankcase. Separation device.   2. The internal combustion engine according to claim 1, wherein an opening portion of the communication passage into the gas-liquid separation chamber is positioned lower than an opening portion of the blow-by gas introduction passage into the gas-liquid separation chamber. Blowby gas oil separator.

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