JP2005155495A - Breather structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a breather structure of an internal combustion engine capable of sufficiently performing gas-liquid separation of blow-by gas without increasing the size of the entire internal combustion engine. <P>SOLUTION: In the breather structure of the internal combustion engine in which an accessory is mounted on a side wall of a cylinder block 3 via an accessory bracket 10, a first breather chamber 21 is formed of the side wall of the cylinder block 3 and the accessory bracket 10 therebetween, and a separate second breather chamber 60 is provided in a communicating manner on the downstream side of the first breather chamber 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a breather structure for an internal combustion engine.

  Some internal combustion engines are provided with a blow-by gas reduction device that reduces blow-by gas leaking into the crank chamber during the compression stroke to an intake system to prevent release to the atmosphere.

The blow-by gas reduction device is provided with a breather chamber for gas-liquid separation, and the oil in the blow-by gas is separated by gas-liquid separation, and the remaining blow-by gas containing the oil that cannot be separated is sent to the intake system for recombustion. It is intended to be used.

In an internal combustion engine in which an auxiliary machine is attached to the side wall of the cylinder block via an auxiliary machine bracket, the breather structure in which the breather chamber is formed between the side wall of the cylinder block and the auxiliary machine bracket is a prior example related to the same applicant. (See Patent Document 1).
JP 2001-73738 A

  In Patent Document 1, since the breather chamber is formed between the cylinder block side wall using the auxiliary machine bracket, space efficiency is improved using the space between the cylinder block and the auxiliary machine. Larger size can be avoided

  However, since the breather chamber is formed between the cylinder block and the auxiliary machine, it is difficult to expand the breather chamber without increasing the size of the entire engine to provide a large-capacity breather chamber. Insufficient gas-liquid separation is possible.

  If the gas-liquid separation is not sufficient, if the oil adheres to the intake pipe or reaches the combustion chamber and combusts, an emission problem will occur and the oil will decrease more quickly.

  The present invention has been made in view of such points, and the object of the present invention is to provide a breather structure for an internal combustion engine that can sufficiently perform gas-liquid separation of blow-by gas without increasing the size of the entire internal combustion engine. It is in.

  In order to achieve the above object, according to the present invention, in an internal combustion engine in which an accessory is attached to a side wall of a cylinder block via an accessory bracket, a first breather is provided between the side wall of the cylinder block and the accessory bracket. The internal combustion engine has a breather structure in which a chamber is formed and a separate second breather chamber is provided downstream from the first breather chamber.

  Since the second breather chamber is provided separately from the first breather chamber formed between the cylinder block side wall and the accessory bracket and communicates with each other, the entire internal combustion engine is not increased in size. The breather chamber can be substantially expanded to perform sufficient gas-liquid separation of blow-by gas.

  According to a second aspect of the present invention, in the breather structure of the internal combustion engine according to the first aspect, the second breather chamber is provided between the cylinder head cover and the intake manifold.

  The second breather chamber separates the blow-by gas after the gas-liquid separation in the first breather chamber, so a small one is sufficient. The small second breather chamber is connected to the cylinder head cover and the intake manifold. By disposing them, the dead space can be effectively used and the entire internal combustion engine can be made compact.

  According to a third aspect of the present invention, in the breather structure of the internal combustion engine according to the second aspect, the second breather chamber is inclined from the cylinder head cover to the intake manifold, and the second breather chamber is inclined. A breather return port to the intake passage is provided at an upper position of the first breather chamber, and a communication port communicating with the first breather chamber is provided at a lower position of the inclined second breather chamber.

  The oil accumulated after the gas-liquid separation of the blow-by gas in the second breather chamber can be smoothly returned to the first breather chamber via the breather communication passage from the communication port located below the inclined second breather chamber. In addition, it can be quickly returned to the cylinder side together with the oil after gas-liquid separation in the first breather chamber.

  In addition, since the breather return port to the intake passage is located above the inclined second breather chamber, the oil after gas-liquid separation in the second breather chamber is unlikely to flow into the intake system from the breather return port.

  According to a fourth aspect of the present invention, in the breather structure of the internal combustion engine according to the first aspect, a breather communication pipe that communicates the first breather chamber and the second breather chamber is provided along the cooling water pipe. It is characterized by that.

The breather communication pipe that communicates the first breather chamber and the second breather chamber is provided along the cooling water pipe, so that the breather communication pipe exposed to the outside can be heated by the cooling water pipe. It is possible to prevent water vapor from condensing.
If the condensed water is mixed with the oil, the deterioration of the oil is accelerated, and this can be prevented.

  According to a fifth aspect of the present invention, in the breather structure of the internal combustion engine according to the first aspect, a cooling water passage swells into the first breather chamber on at least one of a side wall of the cylinder block or the accessory bracket. A guide wall that is formed and that guides blow-by gas to flow around the cooling water passage is provided in the first breather chamber.

  The cooling water passage is formed so as to swell into the first breather chamber, and the guide wall for guiding the blow-by gas to flow around the cooling water passage is provided, so that the length of the breather passage is configured in a compact shape. Gas-liquid separation can be promoted, and condensation of water vapor can be further prevented by the breather passage being along the cooling water passage.

An embodiment according to the present invention will be described below with reference to FIGS.
The internal combustion engine 1 according to the present embodiment is a water-cooled four-stroke cycle in-line four-cylinder internal combustion engine as shown in FIGS. 1 to 4, and is mounted horizontally on a vehicle with the crankshaft 7 oriented in the left-right direction. Is done.

  A cylinder block 3, a cylinder head 4, and a cylinder head cover 5 are sequentially stacked on the crankcase 2 and fastened together, and an oil pan 6 is connected to the lower surface of the crankcase 2.

An intake manifold 8 is fixed to the front surface of the cylinder head 4.
The intake manifold 8 extends from a surge tank 16 that extends to the right side from a throttle body 15 that is located in front of the left side (right side in FIG. 1) of the body of the internal combustion engine 1. The upper ends of the intake pipes 17 are bent rearward and held together on the connection support base 18, and the connection support base 18 is joined to the front surface of the cylinder head 4.

A cover member 19 covers the upper side of the connection support base 18.
As shown in FIG. 4, the front surface of the cylinder head 4 is formed with a mating surface 4a to which the coupling support base 18 is joined, and the four mating surfaces 4a are provided with four intake port coupling ports 4b arranged at the left end. The cooling water connection port 4c is opened, and a horizontally elongated breather long groove 4d is formed on the left and right above the four intake port connection ports 4b.

  As shown in FIG. 5, the connection support base 18 has a mating surface 18a on the back surface thereof, and the four intake port connection ports 4b of the cylinder head 4 are connected to the cylinder head 4 and the cooling water connection. Four intake passages 18b and cooling water passages 18c corresponding to the openings 4c are formed, and breather communication grooves 18d corresponding to the breather long grooves 4d are formed so as to be cut out in the upper openings of the intake passages 18b. ing

  Further, a breather communication hole 18e is opened on the mating surface 18a at a position facing the breather long groove 4c of the cylinder head 4 at the upper center, and the breather communication hole 18e extends forward and bends upward and protrudes upward. To the connecting pipe 18f.

  The connection support base 18 includes a casing portion 18g that extends upward from the mating surface 18a with the four intake passages 18b and opens upward to form an EGR gas recirculation chamber 18h above the four intake passages 18b. The front surface of the casing portion 18g is formed as a mating surface 18i for attaching a connecting plate 17a that connects the downstream ends of the four intake pipes 17, and as shown in FIGS. 2 and 3, the mating surface 18i. The four intake passages 18b are arranged in parallel to communicate with the four intake pipes 17, respectively.

  The cooling water passage 18 c communicates with a connecting pipe 18 j that protrudes to the right of the connection support base 18.

A cover member 19 is covered so as to close the upper opening of the casing portion 18g of the connection support base 18, and an EGR gas recirculation chamber 18h is configured.
As shown in FIG. 6, the cover member 19 is formed with a cooling water passage 19a protruding upward in the horizontal direction in the upper part, and the cooling water passage 19a swells into the EGR gas recirculation chamber 18h. Is formed.
Connection pipes 19b and 19c are fitted into both ends of the cooling water passage 19a.

  FIG. 2 and FIG. 3 show a state in which the connection support base 18 with the cover member 19 covered and fixed with bolts is fixed with the alignment surface 18a facing the alignment surface 4a of the cylinder head 4 in the state shown in FIG. Show.

  Then, the four intake port connection ports 4b of the cylinder head 4 are connected to the four intake passages 18b of the connection support base 18, the cooling water connection port 4c is connected to the cooling water passage 18c, and the connection support base 18 is connected. A breather communication hole 18e communicating with the connecting pipe 18f protruding upward is communicated with the breather long groove 4d of the cylinder head 4, and the breather long groove 4d is connected to each intake passage 18b via the four breather communication grooves 18d of the connection support base 18. And a reduction path for blow-by gas to the intake system is formed.

  In the space on the right side of the connection support base 18 of the intake manifold 8, accessories such as a hydraulic pump 11, an AC generator 12, a compressor 13, and a water pump 14 are attached to the cylinder block 3 via the accessory bracket 10.

As shown in FIG. 4, before attaching the accessory bracket 10, a peripheral wall 21 that is framed in a generally rectangular shape that forms a half portion of the first breather chamber 20 is formed on the right side portion of the front side wall of the cylinder block 3. The inside is recessed to form the bottom wall 22.
The end face of the peripheral wall 21 forms a coplanar mating surface 21a, and bolt holes 21b are formed at the upper left and right corners.

  Further, a part of the right peripheral wall 21 is bent inward to form a cylindrical wall 23 that forms a cooling water passage at its end, and the discharge-side cooling water passage 24 in the cylindrical wall 23 is a side wall of the cylinder block 3. And a water jacket formed around the cylinder bore.

Referring to FIG. 4, a portion having a bottom wall 22 surrounded by a peripheral wall 21 and a cylindrical wall 23 (a portion hatched with a lattice hatch) is a first breather chamber 20.
In the first breather chamber 20, a guide wall 25 extends concentrically with the cylindrical wall 23 from the left side wall of the peripheral wall 21 obliquely downward to the right.

  This guide wall 25 forms a semicircular arc-shaped downstream breather passage 20b along the outer periphery of the cylindrical wall 23 in the first breather chamber 20, and an arcuate upstream breather passage 20a below the guide wall 25. The breather passages 20a and 20b are connected so as to go around the right end of the guide wall 25.

  A blow-by gas introduction port 26 is opened in the bottom wall 22 at the upper left end of the upstream breather passage 20a. The blow-by gas introduction port 26 is formed in the side wall of the cylinder block 3 and the side wall of the crankcase 2 in the vertical direction. It is a downstream end opening of a blow-by gas introduction passage communicating with the crankcase 2.

In addition, an oil recovery port 27 is opened in the bottom wall 22 at the lower right end of the upstream breather passage 20a inclined obliquely downward to the right. From the oil recovery port 27 to the right (left side in FIG. 4) The oil recovery passage that extends while expanding downward is in communication with a cam chain chamber covered with a chain case 28 on the right side (left side in the figure) of the internal combustion engine 1.
The cam chain chamber communicates with the lower oil pan 6.

  On the side wall of the cylinder block 3 below the first breather chamber 20 as described above, a pair of left and right mounting boss portions 29, 29 having bolt holes are formed protrudingly.

Auxiliary equipment brackets 10 that are vertically and vertically attached to the side walls of the cylinder block 3 are integrally integrated brackets that support the plurality of auxiliary equipments with a single bracket.
The accessory bracket 10 is shown in FIGS.

  The accessory bracket 10 is formed in a generally rectangular shape when viewed from the front (see FIG. 7), and has a bracket body 31 that is curved so that the center front surface is recessed backward (see FIGS. 9 and 10).

  The bracket body 31 is curved and has an AC generator 12 attached to the front surface, and a rear wall 35 and a cylindrical shape corresponding to the peripheral wall 21 and the cylindrical wall 23 forming the half portion of the first breather chamber 20 of the cylinder block 3 on the back surface. A wall 36 is formed so as to protrude, and end surfaces of both the walls become a mating surface 35a (see FIG. 8), and are connected to the peripheral wall 21 and the cylindrical wall 23 of the cylinder block 3 via the packing 38.

  A guide wall 37 is also formed on the accessory bracket 10 in correspondence with the guide wall 25 of the cylinder block 3, and the first breather chamber 20 with the lattice hatching in FIG. 8 serves as the upstream breather passage 20 a and the discharge side cooling water. It comprises a semicircular arc-shaped downstream breather passage 20b along the outer periphery of the cylindrical walls 23, 36 forming the passage 24.

  A gas outlet hole 39 is formed in the uppermost downstream end of the downstream breather passage 20b. The gas outlet hole 39 passes forward through the bracket body 31, and the gas outlet hole 39 is connected to the PCV valve 40. Is inserted (see FIGS. 2 and 15).

  Further, a suction side cooling water passage 41 having a circular hole penetrating the lower portion of the bracket body 31 in the horizontal direction is formed, and a discharge side cooling water passage 42 is formed above the right end surface opening above the suction side cooling water passage 41. The discharge side cooling water passage 24 communicates.

The suction-side cooling water passage 41 is a circular hole penetrating the left and right, but the discharge-side cooling water passage 42 has a right end surface opening that is formed large in the vertical direction and gradually reduces the cross-sectional area to the cylindrical wall 36 to reach the discharge wall. It communicates with the side cooling water passage 24.
The pump case 14 a of the water pump 14 is joined to the right mating surface of the bracket body 31 of the auxiliary machine bracket 10.

A support plate 32 having a triangular shape in a side view perpendicular to the left-right direction is formed on the upper portion of the bracket body 31 so that the hydraulic pump 11 is attached to the support plate 32.
The compressor 13 is attached to a pair of projecting portions 33 and 33 projecting slightly downward from the left and right of the lower portion of the bracket body 31.

  Mounting holes 35b are formed in the bracket body 31 at four locations on the top, bottom, left, and right of the peripheral wall 35 in the front-rear direction. As shown in FIG. 4, the front surface of the cylinder block 3 before the auxiliary bracket 10 is mounted. Stud bolts are screwed into the bolt holes of the upper left and right bolt holes 21b and the lower left and right mounting bosses so that the stud bolts pass through the mounting holes 35b of the auxiliary machine bracket 10 and the auxiliary machine. When the brackets 10 are overlapped, the peripheral walls 21 and 35 and the cylindrical walls 23 and 36 constituting the breather chamber 20 are brought together at the mating surface via the packing 38, and a nut is screwed and fixed to the exposed end of the stud bolt.

  The state in which the accessory bracket 10 is thus attached is the state shown in FIG. 2, the water pump 14 is attached to the right end surface of the accessory bracket 10, the hydraulic pump 11 is attached to the upper support plate 32, and the AC is attached to the front surface recessed in the middle. The state where the compressor 12 is attached to the generator 12 and the lower protrusions 33, 33 is the state shown in FIG.

  As shown in FIG. 1, a drive pulley 7a fitted to a crankshaft 7, an idler pulley 50, a driven pulley 11a of a hydraulic pump 11, a driven pulley 12a of an AC generator 12, a driven pulley 14b of a water pump 14, and a driven of a compressor 13 An endless belt 51 is stretched between the pulleys 13a so as to be driven all at once.

  The first breather chamber 20 formed by attaching the accessory bracket 10 to the side wall of the cylinder block 3 communicates with the inside of the crankcase 2 through a blow-by gas introduction passage 26 formed on the cylinder block 3 side. The blow-by gas leaking into the chamber is introduced into the first breather chamber 20 from the inside of the crankcase 2 through the blow-by gas introduction passage 26 together with the introduced fresh air (see FIG. 4).

The blow-by gas introduced into the first breather chamber 20 passes through the upstream breather passage 20a and the downstream breather passage 20b formed by the guide walls 25 and 37, and is separated into gas and liquid.
Since the flow path is elongated by the upstream breather passage 20a and the downstream breather passage 20b, gas-liquid separation is further promoted.

  The oil component that has been gas-liquid separated in the first breather chamber 20 in this manner flows out into the cam chain chamber through the oil recovery passage 27 opened at the lowest point of the first breather chamber 20 and is recovered in the oil pan 6. The

  On the other hand, the blow-by gas from which the oil component has been separated is discharged from the gas outlet hole 39 in the upper part of the breather chamber 20 through the PCV valve 40, and is guided to the second breather chamber 60 described later.

  The cooling water passage formed in the accessory bracket 10 is connected to the cooling water circulation passage of the thermostat 43 at the left side opening of the suction side cooling water passage 41 and is sucked into the water pump 14 from the right end opening of the suction side cooling water passage 41. The cooling water thus discharged is discharged to the right end opening of the discharge-side cooling water passage 42 and is led to the water jacket of the cylinder block 3 through the discharge-side cooling water passage 42 and the discharge-side cooling water passage 24.

  A thermostat 43 connected to the left-side opening of the suction-side cooling water passage 41 of the accessory bracket 10 is provided with a connecting pipe 44 to which a return path from a radiator (not shown) is connected as shown in FIG. A heater pipe 45 piped from a heater core (not shown) is connected.

  A connecting pipe 19c fitted from the right side (left side in FIG. 3) into the cooling water hose 49 connected to the connecting pipe 45a projecting in the middle of the heater pipe 45 and the cooling water passage 19a formed in the cover member 19. A connecting pipe 48 connects the cooling water hose 47 connected to the.

  The cooling water hose 46 connected to the connecting pipe 19b fitted from the left side into the cooling water passage 19a is connected to the cooling pipe 18c of the cooling water flowing out from the cylinder head 4 on the base end side of the connecting pipe 18j of the connection support base 18. It is connected to the.

  The connecting pipe 18j of the support base 18 is connected to an upstream tank of a radiator (not shown) by a radiator hose, and a radiator hose extending from the downstream tank of the radiator is connected to the thermostat 43 to the connecting pipe 44. .

  Therefore, the cooling water cooled by recirculating the radiator flows into the thermostat 43, and the heated cooling water flowing out from the heater core or the main body of the internal combustion engine 1 through the heater pipe 45 is supplied with the cooling water hose 46 and the cooling water passage. 19a, the cooling water hose 47, the connecting pipe 48, and the cooling water hose 49 flow in, and one of them is introduced into the suction side cooling water passage 41 of the accessory bracket 10 by switching the valve of the thermostat 43.

  Here, during the warming-up immediately after the internal combustion engine 1 is started, the cooling water heated by the internal combustion engine 1 by the thermostat 43 opening the heater pipe 45 side directly enters the intake-side cooling water passage 41 adjacent to the breather chamber 20. The cooling water sent and discharged from the water pump 14 flows directly through the discharge-side cooling water passages 42 and 24 adjacent to the breather chamber 20, so that the breather chamber 20 can be efficiently warmed up in the first breather chamber 20. Water vapor condensation can be prevented.

  By preventing the condensation of water vapor in the first breather chamber 20, it is possible to prevent water from being mixed with the oil that has been separated into the gas and liquid and recovered, and the deterioration of the oil can be avoided as much as possible.

  The suction-side cooling water passage 41 and the discharge-side cooling water passages 42, 24 are both formed to bulge into the first breather chamber 20, and the downstream breather passage 20 b of the first breather chamber 20 is connected to the discharge-side cooling water passage 24. Since it is formed along the periphery, the heating effect is great and the first breather chamber 20 can be efficiently and quickly heated.

  During normal running, cooling water cooled by the radiator is introduced into the suction-side cooling water passage 41 and the discharge-side cooling water passages 42, 24, and the first breather chamber 20 is cooled to cool the first breather chamber. The gas-liquid separation of the blow-by gas in 20 can be promoted.

  Further, the cooling water flowing out from the main body of the internal combustion engine 1 partially flows through the cooling water passage 19a of the cover member 19, whereby the EGR gas recirculated from the exhaust system in the EGR gas recirculation chamber 18h where the cooling water passage 19a swells. The temperature of EGR gas is lowered while being heated by itself.

In this breather structure, a second breather chamber 60 is provided further downstream of the first breather chamber 20 constituted by the accessory bracket 10.
The second breather chamber 60 is configured in a breather case 61 disposed between the cylinder head 4 and the intake manifold 8.

  As shown in FIGS. 11 to 13, the breather case 61 is composed of a lower case 62 and an upper cover 63 of a rectangular housing, and a second breather chamber 60 is formed inside by combining them.

The bottom case 62 swells downward from the rectangular frame 62a of the lower case 62, and the bottom wall 62b is stretched with the front side inclined low, and the right side from the right side (left side in FIG. 12) of the rectangular frame 62a having the lowest bottom wall 62b. A connecting pipe 65 is formed to protrude.
Locking rods 66, 66 having a pair of tips projecting downward from the left and right protrusions 62c, 62c of the front side of the rectangular frame 62a are formed to project.

On the other hand, the upper cover 63 bulges upward from the rectangular frame 63a facing the rectangular frame 62a of the lower case 62, and the upper wall 63b is stretched with the front side inclined at a high level, and the upper wall 63b is lower than the rectangular frame 63a. A connecting pipe 67 is formed protruding from the left side to the left.
A locking rod 68 whose tip bulges rearward from the left side of the rear side of the rectangular frame 63a is formed to project.

A breather case 61 is formed in which the lower case 62 and the upper cover 63 are joined together by the rectangular frames 62a and 63a and vibration welded to form the second breather chamber 60 therein.
The breather case 61 is attached between the cylinder head cover 5 and the intake manifold 8 via brackets 70 and 71.

  Referring to FIG. 14, bracket 70 is a strip-shaped plate piece with one end bent. The long piece end is screwed to cylinder head cover 5 with bolt 75, and the short piece facing forward has a circular hole. Then, a locking rod 68 protruding rearward of the breather case 61 through the rubber elastic member 76 is penetrated and supported in the same circular hole.

On the other hand, the bracket 71 is a U-shaped plate member, both end pieces are bent in a crank shape, each end has a circular hole, and the connecting portion connecting the both end pieces is a bolt 77. Screwed onto the cover member 19 of the intake manifold 8.
A pair of locking rods 66 protruding downward from the front side of the breather case 61 through the rubber elastic member 78 are supported by passing through the circular holes of the left and right end pieces extending forward.

  In this manner, the breather case 61 is attached to the dead space between the cylinder head cover 5 and the intake manifold 8 with the front inclined downward as shown in FIG. The upper surface of the breather case 61 is smoothly along a flat inclined surface that reaches the upper surface of the engine, so that the entire internal combustion engine 1 is compactly gathered.

  Since the breather case 61 is supported via the brackets 70 and 71 and the rubber elastic members 76 and 78, the vibration of the internal combustion engine 1 is absorbed and is not directly transmitted to the breather case 61.

The breather case 61 is inclined forward and downward, the connection pipe 65 of the lower case 62 is at the lowermost position of the second breather chamber 60, and the connection pipe 67 of the upper cover 63 is at the uppermost position.
The connecting pipe 81 connects the breather hose 82 connected to the connecting pipe 65 located at the lowest position and the breather hose 80 connected to the PCV valve 40 projecting from the auxiliary equipment bracket 10. The breather hoses 80 and 82 and the connecting pipe 81 communicate with the first breather chamber 20 formed inside and the second breather chamber 60 in the breather case 61.

  The connecting pipe 81 is disposed in parallel with the connecting pipe 48 that is a flow path of the cooling water flowing from the inside of the cover member 19. Therefore, the blow-by gas in the communication path is warmed when warming up, and the connecting pipe 48 is heated. It is possible to prevent water vapor from condensing inside.

  Note that the cooling water connecting pipe 48 and the blow-by gas connecting pipe 81 may be held by a common stay, so that the connecting pipes 81 and 48 can be easily positioned, and the both are aligned. Can be easily done.

Further, one end of a breather hose 85 is connected to the connecting pipe 67 at the uppermost position of the second breather chamber 60 (see FIG. 3), and the other end is connected to a connecting pipe 18f protruding above the connection support base 18. Connected.
As described above, the connecting pipe 18f communicates with the four intake passages 18b.

  Accordingly, the blow-by gas is firstly gas-liquid separated in the first breather chamber 20, and further, the blow-by gas that is insufficiently separated reaches the second breather chamber 60 and is gas-liquid separated, so that sufficient gas-liquid separation can be performed. .

  Since the second breather chamber 60 is for separating the blow-by gas after the gas-liquid separation in the first breather chamber 20, a small breather case 61 is sufficient, and the small breather case 61 is used for the cylinder head cover 5 and the intake manifold. By arranging between the two, the dead space can be effectively used and the whole internal combustion engine can be made compact.

Oil accumulated after the gas-liquid separation of blow-by gas in the second breather chamber 60 is passed through the first breather through the breather hoses 80 and 82 and the coupling tube 81 from the connecting pipe 65 located below the inclined second breather chamber 60. It can be returned smoothly to the chamber 20, and can be quickly returned to the cylinder side together with the oil after gas-liquid separation in the first breather chamber 20.

  Further, since there is a connection pipe 67 as a breather return port to the intake passage at the uppermost position of the inclined second breather chamber 60, oil after gas-liquid separation in the second breather chamber 60 is taken from the connection pipe 67 to the intake system. Difficult to flow into.

  The blow-by gas separated from the gas and liquid in the second breather chamber 60 is reduced from the connection pipe 67 through the breather communication hole 18e of the connection support base 18 of the intake manifold 8 to the four intake passages 18b as described above.

1 is an overall perspective view of an internal combustion engine according to an embodiment of the present invention. It is the perspective view in which a part of the internal combustion engine was omitted. It is the perspective view seen from the same another angle. FIG. 2 is a front view of the internal combustion engine with the auxiliary machine bracket removed. It is a reverse view of a connection support base. It is the front view made into the partial cross section of the cover member. It is a front view of an auxiliary machine bracket. FIG. It is the same right view. It is the left side view. It is a side view of a breather case. It is the same top view. It is sectional drawing cut | disconnected along the XIII-XIII line | wire in FIG. It is explanatory drawing for demonstrating the attachment structure of a breather case. It is a side view in the state where the breather case was attached.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank case, 3 ... Cylinder block, 4 ... Cylinder head, 5 ... Cylinder head cover, 6 ... Oil pan, 7 ... Crankshaft, 8 ... Intake manifold, 9 ... Pipe length switching control valve,
10 ... Auxiliary bracket, 11 ... Hydraulic pump, 12 ... AC generator, 13 ... Compressor, 14 ... Water pump, 15 ... Throttle body, 16 ... Surge tank, 17 ... Intake pipe, 18 ... Connection support base, 19 ... Cover Element,
20 ... 1st breather chamber, 21 ... Perimeter wall, 22 ... Bottom wall, 23 ... Cylindrical wall, 24 ... Discharge-side cooling water passage, 25 ... Guide wall, 26 ... Blow-by gas introduction passage, 27 ... Oil recovery passage, 28 ... Chain Cover, 29 ... Mounting boss,
31 ... Bracket body, 32 ... Upper support plate, 33 ... Projection, 35 ... Circumferential wall, 36 ... Cylindrical wall, 37 ... Guide wall, 38 ... Packing, 39 ... Gas outlet hole, 40 ... PCV valve, 41 ... Cooling on suction side Water passage, 42 ... Discharge-side cooling water passage, 43 ... Thermostat, 44 ... Connection pipe, 45 ... Heater pipe, 46, 47 ... Cooling water hose, 48 ... Connection pipe, 49 ... Cooling water hose,
50 ... idler pulley, 51 ... endless belt,
60 ... 2nd breather chamber, 61 ... Breather case, 62 ... Lower case, 63 ... Upper cover, 65 ... Connection pipe, 66 ... Locking bar, 67 ... Connection pipe, 68 ... Locking bar,
70, 71 ... Bracket, 75 ... Bolt, 76 ... Rubber elastic body, 77 ... Bolt, 78 ... Rubber elastic body,
80 ... Breather hose, 81 ... Connecting pipe, 82 ... Breather hose, 85 ... Breather hose.

Claims (5)

In an internal combustion engine in which an auxiliary machine is attached to the side wall of the cylinder block via an auxiliary machine bracket,
A first breather chamber is formed between the cylinder block side wall and the accessory bracket,
A breather structure for an internal combustion engine, wherein a separate second breather chamber is provided downstream from the first breather chamber.   2. The breather structure for an internal combustion engine according to claim 1, wherein the second breather chamber is provided between the cylinder head cover and the intake manifold. The second breather chamber is provided inclined from the cylinder head cover to the intake manifold,
A breather return port to the intake passage is provided above the inclined second breather chamber,
3. The breather structure for an internal combustion engine according to claim 2, wherein a communication port communicating with the first breather chamber is provided at a position below the inclined second breather chamber.   2. A breather structure for an internal combustion engine according to claim 1, wherein a breather communication pipe that communicates the first breather chamber and the second breather chamber is provided along the cooling water pipe. A cooling water passage is formed in at least one of the side wall of the cylinder block or the auxiliary equipment bracket so as to bulge into the first breather chamber,
2. The breather structure for an internal combustion engine according to claim 1, wherein a guide wall for guiding blow-by gas to flow around the cooling water passage is provided in the first breather chamber.

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