JP2016098674A - Oil separator for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator for an internal combustion engine capable of: preventing oil mist, which flows from a vapor-liquid separation chamber to a valve chamber, from flowing back to the vapor-liquid separation chamber; and easily discharging the oil mist out of the vapor-liquid separation chamber.SOLUTION: An oil separator 41 comprises: a gas introduction hole 43A to introduce blow-by gas from a valve chamber 13; a vapor-liquid separation chamber 44 which has a bottom wall 43 extended in a shaft line direction of an exhaust camshaft 8 and separates oil mist from the blow-by gas introduced through the gas introduction hole 43A; a gas lead-out hole 43B which leads the blow-by gas with the oil mist separated therefrom in the vapor-liquid separation chamber 44 to an intake pipe 34; and an oil dripping hole 52C which is formed on the bottom wall 43 of the vapor-liquid separation chamber 44 at a position close to the gas lead-out hole 43B and discharges the oil mist separated from the blow-by gas into the valve chamber 13. A peripheral wall 53 which encloses the oil dripping hole 52C is installed on the bottom wall 43 of the vapor-liquid separation chamber 44 at a side of the valve chamber 13. An inner diameter of the peripheral wall 53 is larger than the inner diameter of the oil dripping hole 52C.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an oil separator for an internal combustion engine, and more particularly to an oil separator for an internal combustion engine that separates oil mist from blow-by gas.

  In an internal combustion engine mounted on a vehicle such as an automobile, blow-by gas including unburned gas and exhaust gas leaks into a crankcase from a combustion chamber through a gap between a cylinder and a piston. For this reason, an oil separator for ventilating the inside of the crankcase is provided in order to prevent air pollution and engine oil deterioration.

  As this type of conventional oil separator, a cylinder head cover of an internal combustion engine having a valve operating chamber in which a camshaft is accommodated is provided adjacent to the valve operating chamber (see, for example, Patent Document 1). ).

  This oil separator has a gas introduction hole that introduces blow-by gas from the valve operating chamber by negative suction pressure, and a bottom wall that extends in the axial direction of the camshaft, and separates oil mist from the blow-by gas introduced from the gas introduction hole The gas mist separation chamber, the gas derivation hole for leading the blow-by gas from which the oil mist has been separated from the gas-liquid separation chamber to the intake pipe, and the oil mist separated from the blow-by gas formed in the bottom wall of the gas-liquid separation chamber And an oil pit for discharging the valve to the valve train chamber.

JP2012-219665A

  In such an oil separator of a conventional internal combustion engine, an oil pit for discharging oil mist separated from blow-by gas to the valve operating chamber is formed in the bottom wall of the gas-liquid separation chamber. Is in a negative pressure state because it communicates with the gas outlet hole communicating with the intake pipe.

  The valve chamber is larger in volume than the gas-liquid separation chamber and communicates with the gas-liquid separation chamber via the gas introduction hole, so that the gas-liquid separation chamber is larger than the negative pressure acting on the valve chamber. The negative pressure acting on the gas is large, and the pressure difference between the valve chamber and the gas-liquid separation chamber is large.

  As a result, oil mist flowing from the oil pit into the valve operating chamber after being separated from the blow-by gas in the gas-liquid separation chamber may flow backward to the gas-liquid separation chamber. In particular, when the oil pit is provided in the vicinity of the gas outlet hole, the oil flowing into the valve chamber from the oil pit is greatly affected by the negative suction pressure acting on the gas-liquid separation chamber. Mist tends to flow back into the gas-liquid separation chamber, and oil mist may not be easily discharged from the gas-liquid separation chamber.

  The present invention has been made paying attention to the above-described problems, and can prevent the oil mist flowing from the gas-liquid separation chamber to the valve operating chamber from flowing back to the gas-liquid separation chamber. It is an object of the present invention to provide an oil separator for an internal combustion engine that can easily discharge oil mist.

  The present invention is provided in a cylinder head cover of an internal combustion engine having a valve operating chamber in which a camshaft is accommodated, adjacent to the valve operating chamber, and after separating oil mist contained in the blowby gas, the blowby gas is supplied to the intake pipe. An oil separator to be led out, having a gas introduction hole for introducing blow-by gas from the valve operating chamber and a bottom wall extending in the axial direction of the camshaft, and separating oil mist from the blow-by gas introduced from the gas introduction hole A gas-liquid separation chamber, a gas lead-out hole through which the blow-by gas from which the oil mist has been separated in the gas-liquid separation chamber is led out from the gas-liquid separation chamber to the intake pipe, and the gas-liquid separation chamber so as to be positioned in the vicinity of the gas lead-out hole An oil separator having an oil mist discharge hole that is formed on the bottom wall of the engine and discharges oil mist separated from blow-by gas to the valve operating chamber. On the side, a peripheral wall surrounding the oil mist discharge hole provided the inner diameter of the peripheral wall, and a made larger than the inner diameter of the oil mist discharge hole.

According to the present invention, the peripheral wall surrounding the oil mist discharge hole is provided on the valve chamber side of the bottom wall of the gas-liquid separation chamber, and the inner diameter of the peripheral wall is formed larger than the inner diameter of the oil mist discharge hole.
Thereby, a space surrounded by the inner peripheral surface of the peripheral wall can be provided between the gas-liquid separation chamber and the valve operating chamber, and the pressure difference between the gas-liquid separation chamber and the valve operating chamber can be reduced by this space. . For this reason, the oil mist flowing from the gas-liquid separation chamber to the valve operating chamber can be prevented from flowing back to the gas-liquid separation chamber, and the oil mist can be easily discharged from the gas-liquid separation chamber.

FIG. 1 is a view showing an embodiment of an oil separator of an internal combustion engine according to the present invention, and is an external view of the engine. FIG. 2 is a diagram showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a schematic configuration diagram of the engine showing the flow of blow-by gas and fresh air during low-load operation of the engine. FIG. 3 is a view showing an embodiment of an oil separator for an internal combustion engine according to the present invention, and is a longitudinal sectional view of a cylinder head. FIG. 4 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a perspective sectional view of the cylinder head cut in the vicinity of the oil mist guide plate. FIG. 5 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a bottom view of the cylinder head cover as viewed from the cam chamber side. FIG. 6 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a cross-sectional view taken along the line VI-VI in FIG. FIG. 7 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a cross-sectional view taken along the line VII-VII in FIG. FIG. 8 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a bottom view of the main part of the cylinder head cover. FIG. 9 is a view showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a perspective sectional view of the cylinder head cut in the vicinity of the oil mist guide plate. FIG. 10 is a diagram showing an embodiment of the oil separator of the internal combustion engine of the present invention, and is a schematic configuration diagram of the engine showing the flow of blow-by gas and fresh air during high-load operation of the engine.

Hereinafter, an embodiment of an oil separator of an internal combustion engine according to the present invention will be described with reference to the drawings.
FIGS. 1-10 is a figure which shows the oil separator of the internal combustion engine of one Embodiment which concerns on this invention.
First, the configuration will be described. 1 to 10, the left and right front-rear direction represents the left and right front-rear direction of the vehicle 21 as viewed from the driver's seat.

  In FIG. 1, an engine 1 as an internal combustion engine is mounted on a vehicle 21. 1 and 2, the engine 1 includes a cylinder block 2, a cylinder head 3 provided on the upper part of the cylinder block 2, a cylinder head cover 4 provided on the upper part of the cylinder head 3, and a lower part of the cylinder block 2. And an oil pan 5 provided.

  In FIG. 2, the cylinder block 2 accommodates a piston 28 accommodated in a cylinder 27 so as to be movable up and down, a crankshaft 6 for converting the vertical motion of the piston 28 into a rotational motion, and the like. Is integrally provided with a crankcase 2A that rotatably supports the crankshaft 6. A crank chamber 24 is formed between the crankcase 2 </ b> A and the oil pan 5.

  2, 3, and 4, the cylinder head 3 extends along the arrangement direction of the cylinders 27, and is arranged in parallel with the intake camshaft 7 having the intake cam 7 a (see FIG. 6) and the intake camshaft 7. The exhaust camshaft 8 is provided with an exhaust cam 8 a (see FIG. 6) that extends along the arrangement direction of the cylinders 27 and is provided in front of the intake camshaft 7 in the front-rear direction of the vehicle 21.

  Here, the intake camshaft 7 and the exhaust camshaft 8 of the present embodiment constitute the camshaft of the present invention. As shown in FIG. 2, when the engine 1 is mounted on the vehicle 21, the axis of the cylinder 27 is inclined forward of the vehicle 21 with respect to the vertical axis, and the intake camshaft 7 and the exhaust camshaft 8 are It extends in the width direction.

  In the engine 1 of the present embodiment, a space between the cylinder head 3 and the cylinder head cover 4 in which the intake camshaft 7 and the exhaust camshaft 8 are housed constitutes a valve operating chamber 13.

  In FIG. 2, an intake port 29 and an exhaust port 30 are formed in the cylinder head 3, and the intake port 29 and the exhaust port 30 are driven by an intake valve 31 and an exhaust valve 31 driven in accordance with the rotation of the intake cam 7a and the exhaust cam 8a. The exhaust valve 32 is opened and closed.

  When the intake port 29 and the exhaust port 30 are opened and closed, the combustion chamber 14 formed in the upper part of the cylinder 27 and the intake port 29 and the exhaust port 30 are communicated and blocked. An intake manifold 33 is attached to the cylinder head 3, and an air cleaner 35 is connected to the intake manifold 33 via an intake pipe 34.

  The air cleaner 35 purifies the intake air Ai taken from the outside. The intake air Ai purified by the air cleaner 35 is sucked into the intake manifold 33 from the intake pipe 34, and each intake port 29 from the intake manifold 33. Are distributed to each cylinder 27 through the intake.

The intake pipe 34 is provided with a throttle valve 34 </ b> A, and this throttle valve 34 </ b> A adjusts the amount of air taken into the cylinder 27.
An oil separator 41 is provided in the cylinder head cover 4, and the oil separator 41 is provided adjacent to the valve operating chamber 13 above the exhaust camshaft 8 installed in the valve operating chamber 13. 3 and 4, the oil separator 41 protrudes upward from the cylinder head cover 4 and extends in the axial direction of the exhaust camshaft 8. The oil separator 41 is provided below the housing 42 and extends in the axial direction of the exhaust camshaft 8. And a bottom wall 43.

  In FIG. 3, the bottom wall 43 is inclined in the front-rear direction with respect to the vertical axis. As shown in FIGS. 1 and 2, the engine 1 of the present embodiment is mounted on the vehicle 21, but the axis of the cylinder 27 is inclined forward of the vehicle 21 with respect to the vertical axis. 1, the bottom wall 43 is inclined in the front-rear direction with respect to the vertical axis.

  A space surrounded by the housing 42 and the bottom wall 43 constitutes a gas-liquid separation chamber 44, and the bottom wall 43 partitions the gas-liquid separation chamber 44 and the valve operating chamber 13. A gas introduction hole 43A is formed on the right side in the vehicle width direction of the bottom wall 43, and the gas-liquid separation chamber 44 communicates with the valve train chamber 13 through the gas introduction hole 43A (see FIG. 5). . Thereby, blow-by gas is introduced into the gas-liquid separation chamber 44 from the valve operating chamber 13 through the gas introduction hole 43A.

  In FIG. 7, a plurality of collision walls 45 are provided inside the gas-liquid separation chamber 44. The collision walls 45 are provided alternately in the front-rear direction of the vehicle 21 along the axial direction of the exhaust camshaft 8, and blow-by gas introduced into the gas-liquid separation chamber 44 collides with the collision wall 45 to blow-by. Oil mist is separated from the gas.

  A gas outlet hole 43B is formed at the left end of the housing 42 in the vehicle width direction, and the gas outlet hole 43B communicates with a breather passage (not shown) inside the breather pipe 46 that extends outward from the left end of the housing 42 in the vehicle width direction. doing.

  The breather pipe 46 communicates with the intake manifold 33 via a gas outlet pipe 47, and blow-by gas that has flowed into the gas-liquid separation chamber 44 is sucked from the gas outlet pipe 47 through the intake manifold 33 due to the negative suction pressure of the engine 1. It is sucked into the tube 34.

  The blow-by gas sucked into the intake manifold 33 is introduced into the combustion chamber 14 of the engine 1 and combusted in the combustion chamber 14 together with the air-fuel mixture.

  A PCV valve 48 is provided between the gas-liquid separation chamber 44 and the gas outlet pipe 47, and the PCV valve 48 adjusts the flow rate of blow-by gas flowing from the gas-liquid separation chamber 44 to the gas outlet pipe 47.

  The intake pipe 34 upstream of the cylinder head cover 4 and the throttle valve 34A is connected by a fresh air introduction pipe 49. The fresh air introduction pipe 49 moves a part of the intake air Ai, that is, the fresh air An. It introduces into the valve chamber 13.

  A fresh air introduction passage 50 is formed in the cylinder block 2 and the cylinder head 3, and the fresh air introduction passage 50 communicates the valve operating chamber 13 and the crank chamber 24. The fresh air An introduced into the valve operating chamber 13 from the fresh air introducing pipe 49 by the suction negative pressure is introduced into the valve operating chamber 13 from the crank chamber 24 through the communication passage 51 that connects the crankcase 2A and the valve operating chamber 13. The

  The fresh air An introduced into the valve operating chamber 13 is drawn into the gas-liquid separation chamber 44 through the gas introduction hole 43A, and then introduced into the cylinder 27 from the gas outlet pipe 47 through the intake manifold 33. Thereby, the inside of the engine 1 including the valve operating chamber 13 and the crank chamber 24 is ventilated by the fresh air An.

5 to 7, oil drop holes 52 </ b> A to 52 </ b> C are formed in the bottom wall 43 of the gas-liquid separation chamber 44, and the oil drop holes 52 </ b> A to 52 </ b> C communicate the gas-liquid separation chamber 44 and the valve operating chamber 13. ing. The oil drop holes 52A to 52C are located below the bottom wall 43 in the inclination direction (the oil drop holes 52C are shown in FIGS. 3 and 4).
As a result, the oil mist separated from the blow-by gas in the gas-liquid separation chamber 44 is collected along the bottom wall 43 in the inclined direction, and then discharged to the valve train chamber 13 through the oil drop holes 52A to 52C. Here, the oil drop hole 52C of the present embodiment constitutes an oil mist discharge hole of the present invention.

  The oil drop hole 52C provided at the left end in the vehicle width direction is located in the vicinity of the gas outlet hole 43B (see FIGS. 5 and 7). Note that the vicinity of the gas outlet hole 43B indicates that the gas outlet hole 43B is positioned more in the axial direction (vehicle width direction) of the crankshaft 6 of the engine 1 than the center of the gas-liquid separation chamber 44 in the vehicle width direction.

  3, 5, and 6, a peripheral wall 53 is provided on the bottom wall 43 on the valve operating chamber 13 side, and the peripheral wall 53 surrounds the oil dropping hole 52 </ b> C. The inner diameter of the peripheral wall 53 is formed larger than the inner diameter of the oil drop hole 52 </ b> C, and the cylinder head cover 4 of the present embodiment has a volume inside the peripheral wall 53 with respect to the volume of the gas-liquid separation chamber 44 with the bottom wall 43 interposed therebetween. And the volume of the valve operating chamber 13 is larger than the volume of the gas-liquid separation chamber 44.

  The peripheral wall 53 extends downward from the bottom wall 43. 8 and 9, an oil mist guide plate 54 having a side surface continuous to the peripheral wall 53 and a top surface continuous to the bottom wall 43 is provided outside the peripheral wall 53 in the radial direction and below the bottom wall 43. The lower surface 54 a of the oil mist guide plate 54 is continuous with the lower surface 53 a of the peripheral wall 53.

  Here, the oil mist guide plate 54 of the present embodiment constitutes an oil mist guide part of the present invention. As described above, the oil separator 41 of the engine 1 of the present embodiment has the oil mist guide plate 54, and the oil mist guide plate 54 has the lower surface 54 a continuous with the lower surface 53 a of the peripheral wall 53, and the radial direction of the peripheral wall 53 It extends outward.

  As shown in phantom lines in FIG. 1, the lower surface 54 a of the oil mist guide plate 54 is inclined obliquely forward and downward from the peripheral wall 53 in the state where the engine 1 is mounted on the vehicle 21.

  In addition, in a state where the engine 1 is mounted on the vehicle 21, the lower surface 53a of the peripheral wall 53 is inclined with respect to the vertical axis, and the lower surface 53a of the peripheral wall 53 and the lower surface 54a of the oil mist guide plate 54 are on the vertical axis. In contrast, they are inclined on the same straight line.

  3, 4, and 9, a sensing rotor 55 is provided at the end of the exhaust camshaft 8. The sensing rotor 55 is detected by a rotation angle sensor (not shown), and the rotation angle sensor detects the rotation angle of the exhaust camshaft 8. The rotation angle sensor transmits rotation angle information to a control device (not shown), and the control device calculates the rotation speed of the exhaust camshaft 8 based on the rotation angle information.

  The oil mist guide plate 54 extends from the bottom wall 43 to a position that blocks the upper end of the sensing rotor 55, and the lower surface 54 a of the oil mist guide plate 54 extends toward the exhaust camshaft 8 through the upper end of the sensing rotor 55. ing.

  The oil mist guide plate 54 extends from the lower end of the bottom wall 43 toward the upper end in the inclined direction on the lower surface of the bottom wall 43, and has a larger surface area than the cross-sectional area of the exhaust camshaft 8.

Next, the operation will be described.
When blow-by gas containing unburned gas and exhaust gas leaks into the crank chamber 24 from the combustion chamber 14 through the gap between the cylinder 27 and the piston 28, NOx (nitrogen oxide) and moisture contained in the blow-by gas. Reacts to produce nitric acid, and the oil is agglomerated by the nitric acid to generate sludge.

  This sludge is a tar-like substance, and if the sludge is mixed into the oil that lubricates the engine 1, it will cause deterioration of the oil, malfunction of the hydraulic system, crankshaft 6, intake camshaft 7 and exhaust cam. Lubrication failure of the sliding member such as the shaft 8 is caused, the sliding resistance of the engine 1 is increased, and the fuel consumption of the engine 1 is deteriorated. Here, sliding means moving a moving member that performs a rotational motion or a linear motion while sliding on a support member that supports the moving member.

  In FIG. 2, when the engine 1 is operated at a low load, the throttle valve 34 </ b> A has a small opening, so the intake negative pressure of the engine 1 is large. The blow-by gas leaked into the crank chamber 24 during low-load operation of the engine 1 is introduced into the gas-liquid separation chamber 44 through the communication passage 51, the valve operating chamber 13, and the gas introduction hole 43A by suction negative pressure. Here, the flow of blow-by gas is indicated by an arrow B.

The blow-by gas B introduced into the gas-liquid separation chamber 44 flows toward the gas outlet hole 43B after oil mist is separated from the blow-by gas B while colliding with the collision wall 45. The blow-by gas flowing through the gas outlet hole 43B is guided from the breather pipe 46 to the gas outlet pipe 47 and then sucked from the gas outlet pipe 47 through the intake manifold 33 to the intake pipe 34. The blow-by gas sucked into the intake manifold 33 is introduced into the combustion chamber 14 of the engine 1 and combusted in the combustion chamber 14 together with the air-fuel mixture.
Further, when the engine 1 having a large suction negative pressure is operated at a low load, fresh air An is introduced into the valve train chamber 13 from the fresh air introduction pipe 49, and the crank chamber 24 is ventilated by the fresh air An.

  As shown in FIG. 10, when the engine 1 is operated at a high load, the opening of the throttle valve 34 </ b> A is large, so the intake negative pressure of the engine 1 is small, and a part of the blow-by gas in the crank chamber 24 is fresh air introduction passage 50. To the intake manifold 33 through the fresh air introduction pipe 49. Here, the flow of blow-by gas is indicated by an arrow B.

  The blow-by gas sucked into the intake manifold 33 through the fresh air introduction pipe 49 is introduced into the combustion chamber 14 of the engine 1 together with the blow-by gas sucked into the intake manifold 33 through the gas outlet pipe 47 from the breather pipe 46. At the same time, it is burned in the combustion chamber 14.

  On the other hand, the oil mist separated from the blow-by gas in the gas-liquid separation chamber 44 is collected along the bottom wall 43 in the inclined direction and then discharged to the valve train chamber 13 through the oil dropping holes 52A to 52C.

  Of the oil drop holes 52A to 52C, the oil drop hole 52C is closest to the breather pipe 46 and receives a suction negative pressure larger than that of the oil drop holes 52A and 52B. The valve operating chamber 13 has a larger volume than the gas-liquid separation chamber 44 and communicates with the gas-liquid separation chamber 44 through the gas introduction hole 43A. Thereby, the negative pressure acting on the gas-liquid separation chamber 44 is larger than the negative pressure acting on the valve-operating chamber 13, and the pressure difference between the valve-operating chamber 13 and the gas-liquid separation chamber 44 is large.

  For this reason, particularly when the engine 1 is in a low load operation, the oil mist separated from the blow-by gas in the gas-liquid separation chamber 44 may flow backward to the gas-liquid separation chamber 44 from the oil drop hole 52C.

  On the other hand, according to the oil separator 41 of the present embodiment, the peripheral wall 53 surrounding the oil dropping hole 52C is provided on the valve chamber 13 side of the bottom wall 43 of the gas-liquid separation chamber 44, and the inner diameter of the peripheral wall 53 is reduced to the oil level. It was formed larger than the inner diameter of the pit 52C.

  Thereby, a space surrounded by the inner peripheral surface of the peripheral wall 53 can be provided between the gas-liquid separation chamber 44 and the valve operating chamber 13, and the space between the gas-liquid separation chamber 44 and the valve operating chamber 13 can be provided by this space. The pressure difference can be reduced.

  For this reason, the oil mist flowing from the gas-liquid separation chamber 44 to the valve operating chamber 13 can be prevented from flowing back to the gas-liquid separation chamber 44, and the oil mist can be easily discharged from the gas-liquid separation chamber 44. Thereby, it can suppress that sludge mixes with engine oil, and can suppress that oil deteriorates. As a result, it is possible to prevent the malfunction of the hydraulic system and the lubrication failure of the sliding members such as the crankshaft 6, the intake camshaft 7 and the exhaust camshaft 8, and to increase the sliding resistance of the engine 1. This can prevent the fuel consumption of the engine 1 from deteriorating.

  In addition, although the surrounding wall 53 of this embodiment is formed in the cylindrical shape, the shape of the surrounding wall may be formed in a columnar shape, a conical shape, or a square shape. The peripheral wall may be formed in a shape such that the inner diameter increases stepwise from the bottom wall 43 downward.

  Here, even if the oil separator 41 is provided with the peripheral wall 53 for reducing the pressure difference between the gas-liquid separation chamber 44 and the valve operating chamber 13, the oil mist flowing out to the peripheral wall 53 is prevented from flowing into the gas-liquid separation chamber. There is a risk of being pulled by the suction negative pressure 44 and accumulating on the inner peripheral surface of the peripheral wall 53 over time.

  When the oil mist accumulated on the inner peripheral surface of the peripheral wall 53 closes the oil drop hole 52C, the pressure difference between the gas-liquid separation chamber 44 and the valve operating chamber 13 increases, and the oil mist accumulated on the inner peripheral surface of the peripheral wall 53 May flow back to the gas-liquid separation chamber 44 from the oil drop hole 52C.

  On the other hand, the oil separator 41 of the present embodiment has an oil mist guide plate 54, and the oil mist guide plate 54 has a lower surface 54 a that is continuous with the lower surface 53 a of the peripheral wall 53, and is outside the radial direction of the peripheral wall 53. It is formed to extend in the direction.

  Thereby, the oil mist adhering to the inner peripheral surface of the peripheral wall 53 can be guided to the oil mist guide plate 54 from the inner peripheral surface of the peripheral wall 53. For this reason, oil mist can be prevented from accumulating on the inner peripheral surface of the peripheral wall 53, and the oil mist can be prevented from flowing back from the inner peripheral surface of the peripheral wall 53 to the gas-liquid separation chamber 44.

  In particular, according to the oil separator 41 of the present embodiment, the lower surface 54 a of the oil mist guide plate 54 is inclined obliquely downward from the peripheral wall 53 when the engine 1 is mounted on the vehicle 21.

  Thus, after oil mist adhering to the inner peripheral surface of the peripheral wall 53 is guided from the inner peripheral surface of the peripheral wall 53 to the oil mist guide plate 54, the exhaust mist shaft 8 and the exhaust camshaft 8 are moved along the lower surface 54 a of the oil mist guide plate 54. They can be collected in front of the orthogonal gas-liquid separation chamber 44 and dropped downward by their own weight.

  In addition, according to the oil separator 41 of the present embodiment, the lower surface 53a of the peripheral wall 53 is inclined with respect to the vertical axis while the engine 1 is mounted on the vehicle 21, and the lower surface 53a of the peripheral wall 53 and The lower surface 54a of the oil mist guide plate 54 was inclined on the same straight line with respect to the vertical axis.

  As a result, after being guided from the inner peripheral surface of the peripheral wall 53 to the oil mist guide plate 54, the front of the gas-liquid separation chamber 44 orthogonal to the exhaust camshaft 8 along the lower surface 54 a of the oil mist guide plate 54 is more effective. It can be collected and dripped downward by its own weight.

  Further, according to the oil separator 41 of the present embodiment, the oil mist guide plate 54 extends from the bottom wall 43 to a position that blocks the upper end of the sensing rotor 55, and the lower surface 54 a of the oil mist guide plate 54 is connected to the sensing rotor 55. And extended to the exhaust camshaft 8.

  In addition to this, the oil mist guide plate 54 extends from the lower end of the bottom wall 43 toward the upper end in the inclined direction on the lower surface of the bottom wall 43 to have a surface area larger than the cross-sectional area of the exhaust camshaft 8.

  Accordingly, the oil mist discharged from the oil drop hole 52C to the valve operating chamber 13 and guided to the lower side in the inclination direction of the oil mist guide plate 54 through the lower surface 54a of the oil mist guide plate 54 is further distant from the oil drop hole 52C. You can keep away. For this reason, it is possible to more effectively prevent the oil mist from flowing backward from the valve operating chamber 13 to the gas-liquid separation chamber 44.

  According to the oil separator 41 of the present embodiment, the oil mist adhering to the inner peripheral surface of the peripheral wall 53 is discharged by the oil mist guide plate 54, but is not limited to this.

  For example, the oil mist guiding portion may include a member on a line having a lower surface continuous with the lower surface of the peripheral wall and extending outward in the radial direction of the peripheral wall. However, the oil mist guiding portion is not limited to a line member.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

  DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 4 ... Cylinder head cover, 7 ... Intake camshaft (camshaft), 8 ... Exhaust camshaft (camshaft), 13 ... Valve operating chamber, 21 ... Vehicle, 34 ... Intake pipe, 41 ... Oil separator, 43 ... bottom wall, 43A ... gas inlet hole, 43B ... gas outlet hole, 44 ... gas-liquid separation chamber, 52C ... oil drop hole (oil mist discharge hole), 53 ... peripheral wall, 53a ... lower surface, 54 ... oil mist Guide plate (oil mist guide), 54a ... bottom surface

Claims (5)

Oil provided in a cylinder head cover of an internal combustion engine having a valve operating chamber in which a camshaft is accommodated, adjacent to the valve operating chamber and separating the oil mist contained in the blowby gas and then leading the blowby gas to the intake pipe A separator,
A gas introduction hole for introducing blow-by gas from the valve operating chamber;
A gas-liquid separation chamber having a bottom wall extending in the axial direction of the camshaft and separating oil mist from blow-by gas introduced from the gas introduction hole;
A gas outlet hole through which the blow-by gas from which oil mist is separated in the gas-liquid separation chamber is led out from the gas-liquid separation chamber to the intake pipe;
An oil separator having an oil mist discharge hole formed on the bottom wall of the gas-liquid separation chamber so as to be positioned in the vicinity of the gas outlet hole and discharging oil mist separated from blow-by gas to the valve chamber In
An oil separator for an internal combustion engine, wherein a peripheral wall surrounding the oil mist discharge hole is provided on the valve wall side of the bottom wall, and an inner diameter of the peripheral wall is larger than an inner diameter of the oil mist discharge hole.   2. The oil mist guiding portion according to claim 1, wherein the oil mist guiding portion has a lower surface continuous with a lower surface of the peripheral wall and extends outward from the peripheral wall in a radial direction of the peripheral wall. Oil separator for internal combustion engines.   3. The oil separator for an internal combustion engine according to claim 2, wherein a lower surface of the oil mist guiding portion is inclined obliquely downward from the peripheral wall in a state where the internal combustion engine is mounted on a vehicle.   The oil separator for an internal combustion engine according to claim 2, wherein the lower surface of the peripheral wall is inclined with respect to a vertical axis in a state where the internal combustion engine is mounted on a vehicle.   The oil separator for an internal combustion engine according to any one of claims 2 to 4, wherein the lower surface of the peripheral wall and the lower surface of the oil mist guiding portion are inclined on the same straight line with respect to a vertical axis. .

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