JP2017115776A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of having oil easily discharged from a vacuum pump.SOLUTION: A vacuum pump 67 fitted to an engine 1 comprises: a pump case 72 having a pump chamber 72A formed inside; a vacuum pump drive shaft 68 accommodated in the pump chamber 72A; a vacuum pump bearing part 69 formed at the pump case 72 and bearing the vacuum pump drive shaft 68 rotatably; a rotary cylinder accommodated in the pump chamber 72A to rotate integrally with the vacuum pump drive shaft 68, and partitioning the pump chamber 72A into a plurality of working chambers 72b; and an oil feed path 70 formed at the pump case 72 and supplying oil to the vacuum pump bearing part 69. At a bottom part of the pump case 72, an oil discharge hole 72B is formed which communicates with the pump chamber 72 and discharges oil out of the pump chamber 72A to the outside.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an internal combustion engine provided with a vacuum pump.

  As an internal combustion engine mounted on a vehicle such as an automobile, one having a vacuum pump that generates negative pressure is known (see, for example, Patent Document 1).

JP-A-9-68101

  However, the internal combustion engine described in Patent Document 1 does not describe a configuration in which lubricating oil is supplied to a bearing portion that supports a drive shaft that drives a vacuum pump. As a result, it is impossible to know that oil mist is jetted from the vacuum pump together with the compressed air due to the oil mixed into the compressed air generated inside the vacuum pump. Therefore, it is impossible to know how to process air containing oil mist from the internal combustion engine described in Patent Document 1.

  An object of this invention is to provide the internal combustion engine which can discharge | emit oil easily from a vacuum pump.

  The present invention includes a cylinder head in which a cam shaft having a cam for driving a valve is accommodated, and a vacuum pump installed on a side wall of the cylinder head, the vacuum pump having a pump chamber formed therein. A pump case, a vacuum pump drive shaft housed in the pump chamber, a vacuum pump bearing portion formed in the pump case and rotatably supporting the vacuum pump drive shaft, and an integral rotation with the vacuum pump drive shaft An internal combustion engine including a rotating body that is housed in the pump chamber and partitions the pump chamber into a plurality of working chambers, and an oil supply passage that is formed in the pump case and supplies oil to the vacuum pump bearing portion. The pump case communicates with the pump chamber at the bottom of the pump case and discharges oil from the pump chamber to the outside. Le discharge portion is formed.

  According to the present invention, oil can be easily discharged from a vacuum pump.

FIG. 1 is a schematic configuration diagram of an internal combustion engine provided with a vacuum pump according to an embodiment of the present invention, and also shows a flow of blow-by gas. FIG. 2 is a right side view of the internal combustion engine according to the embodiment of the present invention. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a perspective view of the internal combustion engine with the cylinder head cover and the chain case removed in the internal combustion engine according to the embodiment of the present invention. FIG. 5 is a perspective view of the main part of the cylinder head with the cylinder head cover removed in the internal combustion engine according to the embodiment of the present invention. FIG. 6 is a cross-sectional view of the internal combustion engine taken along a plane passing through the fuel pump and the intake camshaft in the internal combustion engine according to the embodiment of the present invention. FIG. 7 is a perspective view of an oil separator showing a part of a cover member in cross section in an internal combustion engine according to an embodiment of the present invention. FIG. 8 is a diagram showing the flow of oil separated from blow-by gas and blow-by gas in the oil separation chamber in the internal combustion engine according to the embodiment of the present invention. FIG. 9 is a perspective view of the cover member of the internal combustion engine according to the embodiment of the present invention. FIG. 10 is a diagram showing the internal structure of the vacuum pump in a state where a part of the pump case mounted on the internal combustion engine according to the embodiment of the present invention is removed. FIG. 11 is a front view of the cylinder head with the cylinder head cover removed in the internal combustion engine according to the embodiment of the present invention.

Hereinafter, an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.
1 to 11 are views showing an internal combustion engine according to an embodiment of the present invention.
First, the configuration will be described. 1 to 8 and 11, the left and right and front and rear directions represent the left and right and front and rear directions of the vehicle as viewed from the driver's seat.

  1 to 3, an engine 1 as an internal combustion engine includes a cylinder block 2, a cylinder head 3 provided on the top of the cylinder block 2, a cylinder head cover 4 provided on the top of the cylinder head 3, and a cylinder block. 2 is provided with an oil pan 5 provided at a lower portion.

  In FIG. 1, the cylinder block 2 accommodates a piston 28 that is accommodated in a cylinder 27 so as to be movable up and down, a crankshaft 6 that converts 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, and the crankcase 2 </ b> A forms a skirt portion that extends in the longitudinal direction of the vehicle from the upper side to the lower side in the axial direction of the cylinder 27. Yes.

  The engine 1 according to the present embodiment is composed of a horizontal engine in which cylinders 27 are installed in series in the vehicle width direction. 1 and 5, the cylinder head 3 extends in the vehicle width direction, which is the arrangement direction of the cylinders 27, and is arranged in parallel with the intake camshaft 7 including the intake cam 7A and the intake camshaft 7. 27 and an exhaust camshaft 8 provided with an exhaust cam 8A.

  The intake cam shaft 7 and the exhaust cam shaft 8 of the present embodiment constitute a cam shaft of the present invention, and the intake cam 7A and the exhaust cam 8A constitute a cam of the present invention.

  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 cam shaft 7 and the exhaust cam shaft 8 are accommodated constitutes a cam chamber 13 (see FIG. 1). As shown in FIG. 5, the intake camshaft 7 and the exhaust camshaft 8 are rotatably supported by a lower cam housing 3 </ b> A and an upper cam housing 25 that serve as bearings installed on the upper part of the cylinder head 3.

  In FIG. 1, 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 that are driven as the intake cam 7 </ b> A and the exhaust cam 8 </ b> A rotate. The exhaust valve 32 is opened and closed. The intake valve 31 and the exhaust valve 32 of the present embodiment constitute a valve of the present invention.

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, and the intake air Ai purified by the air cleaner 35 is sucked into the intake manifold 33 from the intake pipe 34 and from the intake manifold 33 through the intake ports 29 to the cylinders. 27 is distributed and inhaled.
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.

  In FIG. 4, an intake cam sprocket 9 is provided at the end of the intake camshaft 7, and a timing chain 11 is wound around the intake cam sprocket 9. An exhaust cam sprocket 10 is provided at the end of the exhaust cam shaft 8, and a timing chain 11 is wound around the exhaust cam sprocket 10.

  A crank sprocket 12 is provided at the end of the crankshaft 6, and a timing chain 11 is wound around the crank sprocket 12. Thereby, the rotation of the crankshaft 6 is transmitted from the crank sprocket 12 to the intake cam sprocket 9 and the exhaust cam sprocket 10 via the timing chain 11, and the intake camshaft 7 and the exhaust camshaft 8 rotate.

  When the intake cam 7A and the exhaust cam 8A rotate, the intake valve 31 and the exhaust valve 32 open and close the intake port 29 and the exhaust port 30 (see FIG. 1), respectively, so that the combustion chamber 14 ( 1) and the intake port 29 and the exhaust port 30 are communicated and blocked. In this way, the intake chain 31 and the exhaust valve 32 are operated according to the rotation of the crankshaft 6 by the timing chain 11.

  2 and 3, a chain case 21 is provided at the ends of the cylinder block 2 and the cylinder head 3 (on the right side of the engine 1). The chain case 21 covers the timing chain 11 and forms a chain housing chamber 22 between the cylinder block 2 and the chain case 21 (see FIG. 3). The chain housing chamber 22 communicates with the crank chamber 24. ing.

  5 and 6, a fuel pump 61 and a fuel pump mounting bracket 62 are attached to the cylinder head 3. In FIG. 6, the fuel pump 61 is provided with a fuel supply pipe 63, and low pressure fuel is supplied to the fuel pump 61 from the fuel supply pipe 63.

  The intake camshaft 7 is provided with a pump drive cam 7B. The fuel pump 61 supplies the fuel pressurized in the pressurizing chamber 61B to the fuel injection valve (not shown) through the delivery pipe (not shown) from the fuel supply pipe 65 by the plunger 61A being moved up and down by the pump drive cam 7B. .

  The left end portion 7a of the intake cam 7A extends leftward from the left side wall portion 3B of the cylinder head 3, and the left end portion 7a of the intake cam shaft 7 is covered with a case member 66.

The case member 66 is fixed to the left side wall portion 3B, and a cooling water passage and a thermostat (not shown) are provided inside the case member 66, and the cooling water passage is formed inside the cylinder head 3 in the figure. The cooling water flowing through the water jacket is not discharged.
A vacuum pump 67 is attached to the fuel pump attachment bracket 62 and the left side wall 3 </ b> B via a case member 66. The left side wall 3B of the present embodiment constitutes the side wall of the cylinder head of the present invention.

  The vacuum pump 67 has a pump case 72, and a pump chamber 72 </ b> A is formed inside the pump case 72. A vacuum pump drive shaft 68 is accommodated in the pump chamber 72A.

  The vacuum pump drive shaft 68 is eccentrically disposed downward with respect to the central axis of the pump case 72, and the vacuum pump drive shaft 68 is connected to the left end portion 7 a of the intake cam shaft 7. As a result, the vacuum pump drive shaft 68 rotates integrally with the intake camshaft 7 by receiving the power of the intake camshaft 7.

  The vacuum pump 67 includes a vacuum pump bearing portion 69 that rotatably supports a vacuum pump drive shaft 68. The vacuum pump bearing portion 69 is constituted by a part of a pump case 72, and includes a pump chamber 72A and a cam chamber 13. And is divided.

  In FIG. 10, a rotary cylinder 71 is accommodated in the pump chamber 72 </ b> A, and the rotary cylinder 71 rotates integrally with the vacuum pump drive shaft 68. The rotary cylinder 71 partitions the pump chamber 72A into a plurality of working chambers 72a and 72b.

  The rotary cylinder 71 includes vanes 71A and 71B. The vanes 71A and 71B are pressed against the inner peripheral surface of the pump case 72 by a spring (not shown) so as to be movable in the radial direction of the pump case 72. .

  The pump case 72 includes a pipe 73, and the pipe 73 sucks outside air into the pump chamber 72A. An oil supply passage 70 is formed in the pump case 72, and the oil supply passage 70 supplies lubricating oil between the vacuum pump bearing portion 69 and the vacuum pump drive shaft 68. Thereby, the vacuum pump bearing portion 69 and the vacuum pump drive shaft 68 are lubricated by the oil.

  An oil discharge hole 72B is formed at the bottom of the pump case 72, and the oil discharge hole 72B is formed at the lowermost part of the pump case 72 in the vertical direction. The oil discharge hole 72B communicates with the pump chamber 72A and discharges oil from the pump chamber 72A to the outside. The rotating cylinder 71 of the present embodiment constitutes a rotating body of the present invention, and the oil discharge hole 72B constitutes an oil discharge portion of the present invention.

  In the vacuum pump 67 having such a configuration, the vanes 71A and 71B rotate while contacting the inner peripheral surface of the pump case 72 when the vacuum pump drive shaft 68 rotates counterclockwise in FIG. . As a result, the volume of the pump chamber 72A is enlarged or reduced by the vanes 71A and 71B. That is, the vanes 71A and 71B rotate while increasing or decreasing the volume of the working chamber 72a with respect to the pump chamber 72A.

  The vacuum pump 67 sucks air (negative pressure) from a brake booster (not shown) through the working chamber 72a whose volume is increased, and generates a negative pressure in the brake booster. Further, the air in the working chamber 72b whose volume is reduced is compressed and discharged from the oil discharge hole 72B.

  Further, the vacuum pump 67 is supplied with oil from the oil supply passage 70 to the vacuum pump bearing portion 69. As a result, the vacuum pump bearing portion 69 is lubricated by the oil, and the lubricated oil flows into the pump chamber 72A and accumulates at the bottom of the pump case 72. The oil collected at the bottom of the pump case 72 flows downward from the pump chamber 72A through the oil discharge hole 72B.

  3, 7, and 8, the oil separator 17 is formed on the side surface of the cylinder block 2, and the oil separator 17 includes the case portion 40 formed on the side surface of the cylinder block 2 and the side surface of the cylinder block 2. The three oil separation chambers 41 to 43 are formed by the cover member 51 (see FIG. 9) attached to.

  The oil separation chambers 41 to 43 include a plurality of partition walls 45 </ b> A and 45 </ b> B formed on the side surface of the cylinder block 2. The partition wall 45 </ b> A extends in the axial direction of the cylinder 27, and the partition wall 45 </ b> A partitions the case portion 40 into an oil separation chamber 41 and an oil separation chamber 42 in the axial direction of the crankshaft 6.

  The partition wall 45 </ b> B extends in the axial direction of the cylinder 27, and the partition wall 45 </ b> B partitions the case portion 40 into the oil separation chamber 42 and the oil separation chamber 43 in the axial direction of the crankshaft 6. The oil separation chamber 41 has a blow-by gas inlet 41 </ b> A formed therein, and the blow-by gas inlet 41 </ b> A communicates with the chain housing chamber 22 through a communication passage 23 formed in the cylinder block 2.

  Thereby, blow-by gas flowing from the cam chamber 13 to the chain housing chamber 22 and blow-by gas flowing from the crank chamber 24 to the chain housing chamber 22 flow into the oil separation chamber 41 from the communication path 23 through the blow-by gas inlet 41A.

  An oil drain hole 42 </ b> A is formed on the bottom surface of the oil separation chamber 42. An oil drain passage 20 is formed in the cylinder block 2, and the oil drain hole 42 </ b> A communicates with the oil pan 5 through the oil drain passage 20.

  In FIG. 9, the cover member 51 includes a flat plate portion 52 and partition walls 53 and 54 that protrude from the flat plate portion 52 toward the case portion 40. The cover member 51 is configured to close the case portion 40 (see FIG. 4), and the flat plate portion 52 is fixed to the side surface of the cylinder block 2 by a bolt (not shown).

  7 and 8, the partition wall 53 of the cover member 51 is abutted against the partition wall 45A of the case portion 40, and the oil separation chamber 41 is separated from the oil separation chamber 42 by the partition wall 53 and the partition wall 45A. It is done.

  The partition wall 54 of the cover member 51 is abutted against the partition wall 45B of the case portion 40, and the oil separation chamber 42 is partitioned from the oil separation chamber 43 by the partition wall 54 and the partition wall 45B.

  A pair of communication holes 53 a are formed in the partition wall 53, and the communication holes 53 a circulate blow-by gas flowing into the oil separation chamber 41 from the blow-by gas introduction port 41 </ b> A to the oil separation chamber 42.

  The cover member 51 has a collision wall 56, and the collision wall 56 protrudes from the flat plate portion 52 toward the case portion 40.

  7 and 8, the collision wall 56 is installed in the oil separation chamber 42 so as to face the communication hole 53a of the partition wall 53. The collision wall 56 flows into the oil separation chamber 42 through the communication hole 53a. The blow-by gas that collides.

  That is, the collision wall 56 is provided downstream of the partition wall 53 in the flow direction of blow-by gas. In addition, since one side surface of the collision wall 56 with respect to the direction orthogonal to the axial direction of the crankshaft 6 (the vehicle front-rear direction) is not abutted against the partition wall 45A, blow-by gas that has collided with the collision wall 56 The oil flows into the oil separation chamber 42 from the space between 45A and the collision wall 56.

  In the oil separator 17 of the present embodiment, the oil separation chamber 41 is provided on the chain housing chamber 22 side with respect to the oil separation chambers 42 and 43. The oil separation chamber 43 is provided adjacent to the oil separation chamber 42 on the side opposite to the oil separation chamber 41.

A communication hole 54 a is formed in the partition wall 54. The cover member 51 has a collision wall 57, and the collision wall 57 protrudes from the flat plate portion 52 toward the case portion 40.
The collision wall 57 is installed in the oil separation chamber 43 so as to face the communication hole 54a of the partition wall 54, and blow-by gas flowing into the oil separation chamber 43 through the communication hole 54a collides with the collision wall 57. That is, the collision wall 57 is provided downstream of the partition wall 54 in the flow direction of blow-by gas.

  Further, since one side surface of the collision wall 57 with respect to the direction orthogonal to the axial direction of the crankshaft 6 is not abutted against the partition wall 45B, the blow-by gas that collided with the collision wall 57 is separated from the partition wall 45B and the collision wall 57. Flows into the oil separation chamber 43 from the space between the two.

  The bottom surfaces of the oil separation chambers 41 and 42 are inclined downward from the right in the vehicle width direction toward the oil drain hole 42A of the oil separation chamber 42. Thereby, the oil that has flowed into the oil separation chamber 42 from the oil separation chamber 41 flows into the oil drain hole 42 </ b> A along the bottom surface of the oil separation chamber 42. The oil that has flowed into the oil drain hole 42 </ b> A is returned from the oil drain passage 20 to the oil pan 5 through the crank chamber 24.

7 to 9, a blow-by gas discharge port 52 a is formed in the flat plate portion 52 of the cover member 51, and the blow-by gas discharge port 52 a faces the oil separation chamber 43.
The oil drain passage 20 is formed between the partition walls 45A and 53 and the partition walls 45B and 54 on the bottom surface of the oil separation chamber 42 that constitutes a part of the blow-by gas passage.

  1 and 3, the vacuum pump 67 and the cover member 51 are connected by an oil discharge pipe 55. The oil discharge pipe 55 has a communication passage 55A that connects the oil discharge hole 72B and the oil separation chamber 41 of the oil separator 17, and extends downward from the oil discharge hole 72B toward the oil separator 17. The oil discharge pipe 55 may be made of a heat-resistant resin or metal, and the material is not particularly limited.

  In FIG. 9, an opening 52b is formed in the flat plate portion 52 of the cover member 51, and the end of the oil discharge pipe 55 faces the inside of the oil separation chamber 41 through the opening 52b. Thus, the oil supplied between the vacuum pump drive shaft 68 and the vacuum pump bearing portion 69 from the oil supply passage 70 flows into the oil discharge pipe 55 from the pump chamber 72A through the oil discharge hole 72B, and then the oil discharge pipe 55. Through the oil separation chamber 41. The oil discharge pipe 55 of the present embodiment constitutes an oil discharge passage portion of the present invention.

  In FIG. 1, the blow-by gas discharge port 52 a communicates with the intake manifold 33 through the blow-by gas discharge pipe 36. The blow-by gas that has flowed into the oil separation chamber 43 is introduced into the combustion chamber 14 of the engine 1 from the blow-by gas discharge pipe 36 through the intake manifold 33 by the suction negative pressure of the engine 1 after the oil is separated.

  A PCV (Positive Crankcase Ventilation) valve 37 is provided between the oil separation chamber 43 and the blow-by gas discharge pipe 36, and the PCV valve 37 controls the flow rate of blow-by gas flowing from the oil separation chamber 43 to the blow-by gas discharge pipe 36. adjust. Here, the PCV valve 37 of the present embodiment constitutes the on-off valve of the present invention.

  In FIG. 1, the intake pipe 34 upstream of the cylinder head cover 4 and the throttle valve 34A is connected by a fresh air introduction pipe 38. The fresh air introduction pipe 38 is a part of the intake air Ai, that is, Fresh air An is introduced into the cam chamber 13.

  A fresh air inflow passage 39 is formed in the cylinder block 2 and the cylinder head 3, and the fresh air inflow passage 39 communicates the cam chamber 13 and the crank chamber 24. Fresh air An introduced into the cam chamber 13 from the fresh air introduction pipe 38 by the suction negative pressure is introduced into the oil separation chamber 41 from the chain housing chamber 22 through the communication passage 23, and from the chain housing chamber 22 to the crank chamber 24, The oil is introduced into the oil separation chamber 41 through the communication passage 23.

The blow-by gas introduced into the oil separation chamber 41 is sucked into the oil separation chamber 43 through the oil separation chamber 42 and then introduced into the cylinder 27 from the blow-by gas discharge pipe 36 through the intake manifold 33. As a result, the interior of the engine 1 including the cam chamber 13, the chain housing chamber 22, and the crank chamber 24 is ventilated with fresh air An.
5 and 6, a sensing rotor 81 is provided at the left end 7 a of the intake camshaft 7 that extends to the outside from the left side wall 3 </ b> B of the cylinder head 3.

  In FIG. 11, the sensing rotor 81 is formed with a plurality of protrusions 81A having different lengths in the circumferential direction. A cam angle sensor 82 is provided at a position facing the sensing rotor 81, and the cam angle sensor 82 detects the rotation angle of the sensing rotor 81. The cam angle sensor 82 of the present embodiment constitutes a rotation angle detection unit of the present invention.

  The cam angle sensor 82 is attached to the case member 66. The cam angle sensor 82 includes a main body 82A having a signal extraction coupler, and a detection element (not shown) that protrudes from the main body 82A toward the sensing rotor 81 and faces the sensing rotor 81 radially outward of the sensing rotor 81. I have.

  In FIG. 5, the cam angle sensor 82 is installed above the end of the oil discharge pipe 55 connected to the vacuum pump 67. Therefore, the cam angle sensor 82 is installed above the oil discharge hole 72B.

Next, the operation will be described.
1 and FIG. 8 and the arrow B1 of FIG. 8 show the flow of blow-by gas, and the arrow O shows the flow of oil mist separated from blow-by gas.

  In the engine 1, oil is supplied from the oil supply passage 70 between the vacuum pump drive shaft 68 and the vacuum pump bearing portion 69, and the vacuum pump drive shaft 68 and the vacuum pump bearing portion 69 are lubricated by this oil. The lubricated oil flows into the pump chamber 72A and accumulates at the bottom of the pump case 72.

  On the other hand, the vacuum pump 67 draws air from the brake booster into the working chamber 72a by setting the working chamber 72a in a negative pressure state by the working chamber 72a whose volume is increased, while the air in the working chamber 72b whose volume is reduced. It compresses and discharges compressed air from oil discharge hole 72B.

  For this reason, the oil that has flowed into the pump chamber 72A is refined by high-speed compressed air, floats in the air, becomes oil mist, and air containing this oil mist may be injected from the oil discharge hole 72B.

  In the vacuum pump 67 of the present embodiment, an oil discharge hole 72B that communicates with the pump chamber 72A and discharges oil from the pump chamber 72A to the outside is formed at the bottom of the pump case 72. As a result, the oil flowing into the bottom of the pump case 72 is discharged from the oil discharge hole 72B before the oil level becomes higher at the bottom of the pump case 72.

  One end of an oil discharge pipe 55 is connected to the pump case 72 so as to communicate with the oil discharge hole 72B, and the other end of the oil discharge pipe 55 is connected to the cover member 51 so as to communicate with the oil separation chamber 41. The oil discharge pipe 55 extends downward from the oil discharge hole 72B toward the oil separator 17.

Accordingly, the oil discharged from the oil discharge hole 72B is discharged to the oil separation chamber 41 through the oil discharge pipe 55. The oil that has flowed into the oil separation chamber 41 flows from the bottom surface of the oil separation chamber 41 to the bottom surface of the oil separation chamber 42, passes through the bottom surface of the oil separation chamber 42, and is discharged into the oil drain hole 42 </ b> A.
The oil discharged to the oil drain hole 42A is returned to the oil pan 5 from the oil drain passage 20.

On the other hand, when the oil flowing into the pump chamber 72A becomes air containing oil mist by high pressure compressed air and is injected from the oil discharge hole 72B, the oil containing oil mist is separated from the oil through the oil discharge pipe 55. Flows into the chamber 41.
In addition to the oil mist discharged from the oil discharge hole 72B, blow-by gas flows into the oil separation chamber 41 through the following path.

  In the chain housing chamber 22, the timing chain 11 is lubricated by injecting oil from the oil jet 26 (see FIG. 4) provided in the cylinder block 2 to the timing chain 11.

  For this reason, if the chain storage chamber 22 is not sufficiently ventilated, NOx (nitrogen oxide) contained in the blow-by gas introduced into the chain storage chamber 22 reacts with moisture to generate nitric acid, and the oil The nitric acid agglomerates to generate sludge.

  This sludge is a tar-like substance, and when the sludge is mixed into the oil that lubricates the engine 1, it causes deterioration of the oil, malfunction of the hydraulic system, the crankshaft 6, the intake camshaft 7, and the 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.

  As shown in FIG. 3, in the engine 1 of the present embodiment, the cylinder block 2 has a communication passage 23 that connects the oil separation chamber 41 and the chain housing chamber 22, and the communication passage 23 is a blow-by gas inlet. It communicates with the oil separation chamber 41 through 41A.

  Thereby, blow-by gas can be flowed directly from the chain housing chamber 22 to the oil separation chamber 41. For this reason, the chain housing chamber 22 can be directly ventilated through the communication path 23, and sludge can be prevented from being generated in the chain housing chamber 22.

  Further, the cam chamber 13 and the chain housing chamber 22 communicate with each other, and the cam chamber 13 communicates with the communication path 23 through the chain housing chamber 22. Further, the crank chamber 24 and the chain housing chamber 22 communicate with each other, and the crank chamber 24 communicates with the communication passage 23 through the chain housing chamber 22. Thereby, the cam chamber 13 and the crank chamber 24 can be ventilated through the communication passage 23.

  The blowby gas B flowing from the chain housing chamber 22 toward the oil separation chamber 41 through the communication passage 23 flows into the oil separation chamber 41 from the blowby gas inlet 41A as shown in FIG.

  The blow-by gas B flows into the oil separation chamber 42 after the flow velocity is increased and the collision wall 56 is collided by the flow path being throttled through the communication hole 53a. By increasing the flow rate of the blow-by gas B, the aggregation of the oil mist O is promoted to separate the oil, and the separated oil mist O is discharged through the bottom surface of the oil separation chamber 42 into the oil drain hole 42A.

  The blow-by gas B that has flowed into the oil separation chamber 42 is throttled by the communication hole 54a of the partition wall 54, the flow velocity is increased, and then collides with the collision wall 57, so that the oil mist O that has not been completely separated from the blow-by gas B. Are separated. The oil mist O separated from the blow-by gas B passes through the bottom surface of the oil separation chamber 42 and is discharged to the oil drain hole 42A.

  The blow-by gas B from which the oil mist O has been separated in the oil separation chamber 42 flows into the oil separation chamber 43 from the space between the partition wall 45B and the collision wall 57, and then the suction negative pressure of the engine 1 causes the cover member 51 to The air is sucked into the combustion chamber 14 through the blow-by gas discharge port 52a through the blow-by gas discharge pipe 36, the intake manifold 33 and the intake pipe 34.

On the other hand, the oil mist O separated from the blow-by gas B passes through the bottom surface of the oil separation chamber 42 and is discharged to the oil drain hole 42A. The oil mist O discharged to the oil drain hole 42 </ b> A is returned to the oil pan 5 from the oil drain passage 20.
When air containing oil mist is injected from the oil discharge hole 72 </ b> B, the air containing oil mist is discharged to the oil separation chamber 41 through the oil discharge pipe 55.

  The air containing the oil mist flowing into the oil separation chamber 41 (indicated by the arrow B1 in FIG. 8) is separated from the air by separating the oil mist O from the air in the same manner as the flow of the blowby gas B flowing through the oil separator 17. The oil mist O is returned to the oil pan 5 through the oil drain passage 20 from the oil drain hole 42A.

  As described above, according to the engine 1 of the present embodiment, the bottom of the pump case 72 is formed with the oil discharge hole 72B that communicates with the pump chamber 72A and discharges the oil from the pump chamber 72A to the outside.

  As a result, the oil supplied between the vacuum pump drive shaft 68 and the vacuum pump bearing portion 69 and flowing into the pump chamber 72A can be quickly discharged from the pump chamber 72A before accumulating at the bottom of the pump case 72. .

  For this reason, oil can be reliably returned to the oil pan 5, and it can prevent that oil is consumed excessively. Further, it is possible to prevent the oil level from being excessively lowered in the oil pan 5, and for example, it is possible to prevent the oil strainer that sucks in oil from sucking air.

  Further, in the engine 1 of the present embodiment, the oil discharge hole 72B may be formed at the lowest position of the pump case 72 in the vertical direction. In this way, the oil can be quickly discharged from the pump chamber 72A before the oil accumulates at the bottom of the pump case 72. Thereby, the oil discharge performance can be improved more effectively.

  In the engine 1 of the present embodiment, an oil separator 17 that separates oil mist contained in blow-by gas is provided below the vacuum pump 67. Furthermore, an oil discharge pipe 55 that guides oil discharged from the oil discharge hole 72B to the oil separator 17 may be provided, and the oil discharge pipe 55 may extend downward from the oil discharge hole 72B toward the oil separator 17. .

  In this way, the oil discharged from the oil discharge hole 72B can be guided to the oil separator 17 by its own weight, and the oil can be discharged more effectively from the oil discharge hole 72B. In addition, the oil flowing through the oil discharge pipe 55 can be prevented from flowing back into the pump chamber 72A.

  Further, in the engine 1 of the present embodiment, a cam angle sensor 82 for detecting the rotation angle of the intake cam shaft 7 may be provided, and the cam angle sensor 82 may be installed above the oil discharge hole 72B.

  In this way, it is possible to prevent the cam angle sensor 82 from becoming an obstacle when the oil discharge pipe 55 is routed, and the workability of the operation of routing the oil discharge pipe 55 can be improved. Further, by providing the oil discharge pipe 55 below the cam angle sensor 82, a space for installing the oil discharge pipe 55 and a space for installing the cam angle sensor 82 can be secured around the engine 1 in advance.

  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), 3 ... Cylinder head, 3B ... Left side wall part (cylinder head side wall), 7 ... Intake cam shaft (cam shaft), 7A ... Intake cam ( Cam), 8 ... exhaust cam shaft (cam shaft), 8A ... exhaust cam, 17 ... oil separator, 67 ... vacuum pump, 68 ... vacuum pump drive shaft, 69 ... vacuum Pump bearing portion, 70 ... oil supply passage, 71 ... rotary cylinder (rotating body), 72A ... pump chamber, 72B ... oil discharge hole (oil discharge portion), 72a, 72b ... work chamber , 82 ... Cam angle sensor (rotation angle detector)

Claims (4)

A cylinder head in which a camshaft having a cam for driving a valve is accommodated, and a vacuum pump installed on a side wall of the cylinder head,
The vacuum pump includes a pump case having a pump chamber formed therein, a vacuum pump drive shaft housed in the pump chamber, and a vacuum pump formed in the pump case and rotatably supporting the vacuum pump drive shaft. A bearing part, a rotary body that is housed in the pump chamber so as to rotate integrally with the vacuum pump drive shaft, partitions the pump chamber into a plurality of working chambers, and is formed in the pump case, and an oil is supplied to the vacuum pump bearing part. An internal combustion engine having an oil supply passage for supplying
An internal combustion engine characterized in that an oil discharge portion is formed at the bottom portion of the pump case so as to communicate with the pump chamber and discharge oil from the pump chamber to the outside.   The internal combustion engine according to claim 1, wherein the oil discharge portion is formed at a lowermost position of the pump case in a vertical direction. An oil separator that separates oil mist contained in blow-by gas is provided below the vacuum pump,
An oil discharge passage portion is provided for guiding oil discharged from the oil discharge portion to the oil separator;
The internal combustion engine according to claim 1, wherein the oil discharge passage portion extends downward from the oil discharge portion toward the oil separator. The vacuum pump drive shaft is configured such that power is transmitted from the cam shaft,
The rotation angle detection part which detects the rotation angle of the said cam shaft is provided, The said cam angle sensor is installed above the said oil discharge part, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The internal combustion engine according to item.