JP2006009647A - Oil separating device for blow-by gas in internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a lowering of an oil separation rate caused by facing of blow-by gas flowing into a gas-liquid separating chamber 6, and oil flowing down from the gas-liquid separating chamber 6, in a blow-by gas lead-in passage 8, focusing on and utilizing the presence of pulsation of pressure becoming high or low with the reciprocating motion of a piston, in pressure in a crankcase. <P>SOLUTION: The gas-liquid separating chamber 6 is provided at the side face of a cylinder block 2. The blow-by gas lead-in passage 8 extending from the inside of the crankcase 3 is opened to the bottom part of the gas-liquid separating chamber 6. The upper part of the gas-liquid separating chamber 6 is provided with a blow-by gas exhaust port 7. An opening into the crankcase 3 in the blow-by gas lead-in passage 8 is located at a part far from a cylinder bore 5 in the crankcase 3, while a communicating passage 15 extending to a part close to the cylinder bore 5 in the crankcase 3 is opened to the bottom part of the gas-liquid separating chamber 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 oil separation rate fell only by this entrained part.

  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,
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, while the bottom of the gas-liquid separation chamber is connected to a portion of the crankcase that is close to the cylinder bore. Open the communication path. "
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 greater in the crankcase at locations close to the cylinder bore, and the internal pressure does not change much at locations far from the cylinder bore.

  According to the configuration of the first aspect, the opening into the crankcase in the blow-by gas introduction passage is located in the portion far from the cylinder bore in the crankcase, while the bottom of the gas-liquid separation chamber is in the crankcase. Since the communication passage to the portion close to the cylinder bore is opened, when the piston in the cylinder bore moves downward, the pressure near the cylinder bore is greatly increased, so the blow-by gas introduction passage and the communication passage The blow-by gas flows into the gas-liquid separation chamber from both.

  On the other hand, when the piston moves up, the pressure near the cylinder bore is greatly reduced, so that the separated oil that has accumulated at the bottom of the gas-liquid separation chamber passes through the communication path into the crankcase. Is sucked out. Further, part of the blow-by gas flowing in from the blow-by gas introduction passage flows toward the communication passage, and therefore the flow of the blow-by gas causes the oil accumulated in the bottom portion to flow into the crankcase from the communication passage. It will be forced to push out.

  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 plurality of partition wall-shaped bulk portions 11 that rotatably support the crankshaft 10 are provided corresponding to the respective cylinders. In this embodiment, the bulk portion 11 is provided integrally with the crankcase 3.

  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.

  Therefore, when the piston in the cylinder bore 5 moves downward, the pressure in the crankcase 3 close to the cylinder bore 5 is greatly increased, so that the blow-by gas introduction facing the oil pan 4 located below the crankcase 3 is introduced. A flow of blow-by gas flowing into the gas-liquid separation chamber 6 is formed from both the passage 8 and the communication passage 15 facing the vent hole 14 located above the bearing portion 12 in the bulk portion 11. .

  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 moves up, the pressure near the cylinder bore 5 in the crankcase 3 is greatly reduced, so that the oil accumulated in the lower bottom 6b of the gas-liquid separation chamber 6 passes through the communication passage 15. And sucked and discharged into the crankcase 3. 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.

  Further, 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 with the rotation direction of the crankshaft 10. There is almost no possibility that the oil stirred in the rotation direction of the shaft 10 and scattered in the crank chamber 13 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.

1 is a longitudinal front view of an internal combustion engine to which the present invention is applied. FIG. 2 is an enlarged vertical side view taken along the line 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 Opening part on the ventilation hole side in the communication path

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,
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, while the bottom of the gas-liquid separation chamber is connected to a portion of the crankcase that is close to the cylinder bore. An oil separator for blow-by gas in an internal combustion engine, wherein the communication passage is opened.   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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