JP5881354B2 - Internal combustion engine structure - Google Patents

Description

  The present invention relates to a structure of an internal combustion engine, and more particularly to a structure of an internal combustion engine characterized by a blow-by gas passage when a blow-by gas passage from a crank chamber to a cylinder head is provided at an end of the cylinder head.

  In an internal combustion engine of a type in which a piston is moved up and down in a cylinder to burn fuel, unburned gas that escapes from the combustion chamber through the gap between the cylinder and the piston is generated. This is called blow-by gas, and contains components such as hydrocarbons. If released as it is, it will lead to environmental pollution. Further, if blowby gas is stored in the crank chamber, it becomes a movement resistance of the piston, leading to output loss. Therefore, blow-by gas is again returned to the intake side and recombusted.

  The blow-by gas leaking into the crank chamber passes through the environment in which the balance weight and the like are scooping up the oil in the oil pan, and therefore contains not only unburned gas but also mist of engine oil. As a result, the engine oil mixed in the blow-by gas is recombusted. This promotes the consumption of engine oil, which is not preferable.

  In view of this, a device called oil dropping is known in which engine oil is removed in a blow-by gas passage that moves blow-by gas from the crank chamber to the cylinder head.

  Patent Document 1 discloses a configuration in which a crank chamber of a first cylinder and a second cylinder and a third cylinder and a fourth cylinder communicate with each other through a space in a balancer case in a four-cylinder engine. In this way, the pistons with different phases are communicated with each other, thereby reducing the movement resistance of the pistons due to the blow-by gas in the crank chamber. Further, the blow-by gas is temporarily stored in the space in the balancer case, so that the blow-by gas is calmed down and the oil is separated.

  Patent Document 2 discloses the structure of a blow-by gas passage in a V-type engine. In Patent Document 2, a blow-by gas chamber parallel to the crankshaft is provided. A recess is formed in one end wall of the cylinder head, and a blow-by gas passage is formed between the end plate and the end wall when the end plate covers the end wall.

  Blow-by gas enters the blow-by gas chamber from the other end of the cylinder head from the crank chamber, drops oil while passing through the blow-by gas chamber, and is formed between one end wall and the end plate. In addition, a configuration is disclosed in which it passes through the blow-by gas passage to the cylinder head side.

JP 61-104149 A JP 2000-220433 A

  The blow-by gas passage disclosed in Patent Document 1 passes through the blow-by gas passage that passes once in the direction parallel to the crankshaft when the blow-by gas is transferred from the crank chamber to the cylinder head. Although this has the advantage that oil can be dropped, the structure becomes complicated and the problem that it is difficult to miniaturize the engine arises.

  Further, in the blow-by gas passage disclosed in Patent Document 2, the blow-by gas passage provided between one end wall and the end plate has a large blow-by gas chamber, although it is configured compactly. There arises a problem that it is difficult to downsize the engine.

  If a passage with the crank chamber is provided immediately below the blow-by gas passage formed by the end wall of the cylinder block and the end plate disclosed in Patent Document 2, it is preferable for the engine to be downsized. However, since the blow-by gas that has passed through the environment in which the balance weight or the like is scratching the oil in the oil pan passes as it is, the problem that the consumption of engine oil is promoted is not solved.

  In particular, considering the case of a two-cylinder engine, a large rotating gear may be attached to the crankshaft in order to rotate a balance shaft having a large rotational moment. In such a case, there is a problem that the lubricant in the portion supporting the balance shaft is also mixed into the shaft case and mixed into the blow-by gas.

  The present invention has been conceived in view of the above-described problems, and is a blow-by gas passage in which engine oil consumption is unlikely to occur even in a blow-by gas passage provided with a large rotating gear attached to a crankshaft. An internal combustion engine having a structure is provided.

Specifically, the structure of the internal combustion engine of the present invention is:
A crankshaft that pivotally supports a rotating body having irregularities;
A cylinder block having a concave shape on an end wall for positioning the rotating body outside and supporting the crankshaft;
An oil pan that is positioned on the inner side and is connected to a position under which the rotating body scoops up oil below the cylinder block;
An oil retainer connected to the upper side of the oil pan and covering the cylinder block end wall;
A structure of an internal combustion engine provided with a blow-by gas passage that communicates a crank chamber constituted by the cylinder block and the oil pan and a cylinder head connected to the upper side of the cylinder block;
The blow-by gas passage is
Adjacent to the concave shape,
Using at least one rib shape of a rib shape protruding outward from the cylinder block end wall or a rib shape provided on the inner surface of the oil retainer,
Formed between the cylinder block end wall and the inner surface of the oil retainer ;
The oil pan is formed with a shielding wall provided toward the crank chamber from a position corresponding to the rib shape formed in the cylinder block .

  Since the present invention forms a closed blow-by gas passage between the end wall of the cylinder block and the oil retainer, the blow-by gas is hardly affected by the oil splashed by the rotary gear even if it is adjacent to the rotary gear. , Oil consumption can be reduced.

  Further, since no special parts are provided for forming the blow-by gas passage, a low-cost structure can be achieved.

  Further, by providing a through hole in the cylinder block following the blow-by gas passage according to the present invention, an opening can be provided on the inner upper surface of the cylinder block even if the blow-by gas passage is formed in the end wall of the cylinder block. it can. Moreover, since this opening can be formed by one casting, it is easy to form a cylinder block.

1 is an assembled perspective view of an internal combustion engine according to the present invention. It is a figure which shows a part of FIG. It is a perspective view just before attaching an oil retainer. It is a figure which shows the AA cross section of FIG.

  The structure of the internal combustion engine of the present invention will be described below with reference to the drawings. The following description exemplifies an embodiment of the present invention, and changes within the scope of the present invention are included in the technical scope of the present invention without departing from the spirit of the present invention. Needless to say.

  FIG. 1 is an assembled perspective view showing a part of the structure of the internal combustion engine of the present invention. The internal combustion engine 1 of the present invention is a two-cylinder engine. In the figure, a cylinder block 10, an oil pan 12, and an oil retainer 14 are shown. Also shown are a rotary gear 16 attached to the crankshaft and a drive gear 18 attached to the balance shaft. Note that FIG. 2 shows only the cylinder block 10 of FIG.

  The ends of the balance shaft and the crankshaft protrude from the end wall 20 at one end of the cylinder block 10. In FIG. 1, each protrusion hole 21 and the bearing part 22 (it demonstrates also in FIG. 2) were shown. Since the piston movement of the two-cylinder engine is in phase, the vibration is large and a balance shaft is provided in parallel with the crankshaft. A drive gear 18 is attached to the end of the balance shaft.

  A rotation gear 16 fitted to the drive gear 18 of the balance shaft is attached to the crankshaft. The rotating gear 16 may be referred to as a rotating body having irregularities. An oil pan 12 is connected below the cylinder block 10. The crank chamber 24 is an internal space surrounded by the cylinder block 10 and the oil pan 12. Note that the cylinder head is not shown.

  Referring to FIG. 2, the end wall 20 of the cylinder block 10 is provided with a concave shape 26 for supporting the crankshaft. A bearing member 27 is disposed below the concave shape 26, and the crankshaft is pivotally supported by the concave shape 26 of the end wall 20 and the bearing member 27. This portion is called a bearing portion 22. Both the drive gear 18 and the rotation gear 16 are disposed outside the end wall 20. Here, the outside means the outside with respect to the crank chamber 24.

  A rib shape 30 protruding outward from the end wall 20 is formed at a position adjacent to the crankshaft of the end wall 20 (that is, a position adjacent to the concave shape 26). The rib shape 30 extends from the lower end 10 u of the cylinder block 10 to the upper portion of the end wall 20 through the vicinity of the rotary gear 16 attached to the crankshaft. The rib shape 30 is provided adjacent to the flange 20 f for joining the oil retainer 14 (see FIG. 1) to the end wall 20. Accordingly, a passage 31 is formed by the inner vertical wall 20fa of the flange 20f and the rib shape 30.

  Since the upper end 30t of the rib shape 30 is also integrated with the flange 20f of the end wall 20 of the cylinder block 10, this passage 31 has a groove shape in which the lower end 10u of the cylinder block 10 is opened. Hereinafter, the passage 31 is also referred to as a groove shape 31.

  On the other hand, on the upper surface 10t of the cylinder block 10, an opening 11a of a hole 11 serving as a blow-by gas passage is provided together with the cylinder upper end 9. This hole 11 is a hole 11 formed by casting when the cylinder head 10 is manufactured. The bottom 11b of the hole 11 is formed to a position that substantially coincides with the upper end 31t of the groove shape 31 formed in the end wall 20 in the horizontal direction. Here, the horizontal direction means a direction parallel to the crankshaft.

  After the cylinder block 10 is cast, the groove shape 31 and the bottom 11b of the hole 11 are communicated with each other by performing post-processing from the upper end 31t of the groove shape 31 formed on the end wall 20 with a drill or the like. That is, the groove shape 31 formed using the rib shape 30 communicates with the hole 11 formed in advance.

  Referring again to FIG. 1, the oil pan 12 is a container-shaped member attached below the cylinder block 10. On the end wall 20 side of the oil pan 12 (referred to as an oil pan side wall 12s), a concave shape 12a is formed that constitutes a window exposing the crankshaft. In the structure of the internal combustion engine 1 according to the present invention, the oil pan 12 is similarly formed with a shielding wall 12 w from the position corresponding to the rib shape 30 formed in the cylinder block 10 toward the inside of the crank chamber 24. The shielding wall 12w is arranged to secure a passage for blow-by gas and prevent the blow-by gas passing therethrough from being mixed with engine oil mist scraped up by a weight balancer (not shown) or the rotating gear 16. The

  An oil retainer 14 is attached to the end wall 20 of the cylinder block 10 so that the lubricating oil does not scatter from the driving gear 18 that rotates the balance shaft and the rotating gear 16 connected to the crankshaft. A rib shape 40 is also formed on the inner side of the oil retainer 14 at a position corresponding to the rib shape 30 formed on the cylinder block 10.

  FIG. 3 shows a state in which the balance shaft drive gear 18 and the crankshaft rotation gear 16 are attached to the end wall 20 of the cylinder block 10 and mounted on the oil pan 12. The drive gear 18 and the rotation gear 16 are housed on the crank chamber 24 side from the side wall 12s of the oil pan 12. The oil retainer 14 is formed with a recessed shape 14 a that is responsive to the recessed shape 12 a formed on the side wall 12 s of the oil pan 12. A part of the rotary gear 16 is exposed by the recessed shape 12a on the oil pan 12 side and the recessed shape 14a on the oil retainer 14 side. An oil seal (not shown) is disposed between the rotary gear 16 and the oil retainer 14 to prevent oil leakage.

  When the cylinder block 10 and the oil pan 12 are connected, the shielding wall 12w of the oil pan 12 and the rib shape 30 of the end wall 20 are abutted at each other's joint surface. Here, an outlet 32 for blow-by gas that leads from the crank chamber 24 to the end wall 20 side of the cylinder block 10 is formed. Further, the rib shape 40 provided on the inner side of the oil retainer 14 is flush with the rib shape 30 on the end wall 20 side of the cylinder block 10 in the upper surface. Here, the upper surfaces of the rib shape 30 and the rib shape 40 are denoted by reference numerals 30h and 40h, respectively (see FIG. 4).

  When viewed from the end wall 20 side of the cylinder block 10, the groove shape 31 opened to the outside is covered. As a result, the outlet 32 from the crank chamber 24 passes through the passage formed by the groove shape 31, enters the hole 11 formed by casting, and communicates with the opening 11 a of the upper surface 10 t of the cylinder block 10. The communication path 50 (see FIG. 4) is completed.

  The blow-by gas communication passage 50 is a closed communication passage through which the splash of lubricating oil in the oil pan 12 that is swung up by the weight balancer attached to the rotary gear 16 or the crankshaft does not enter. Despite being formed adjacent to the part, it does not promote oil consumption.

  In particular, when the rotation direction of the crankshaft is configured to be counterclockwise when viewed from the mounting side of the rotation gear 16 (the arrow direction indicated by the rotation gear 16 in FIG. 3), the oil is directed toward the blow-by gas communication path 50. Due to the configuration of scooping up, the closed communication path as described above is effective in that it does not promote oil consumption.

  Moreover, since it can form in the vicinity of a drive part, an engine itself can be reduced in size. Moreover, since it is not formed only by the straight part as a channel | path, it also has an oil dropping effect. In FIG. 3, the arrow indicates that the blow-by gas passes from the crank chamber 24 through the outlet 32, passes through the hole 11 from the groove shape 31, and exits from the opening 11 a.

  FIG. 4 is a cross-sectional view taken along the line AA in FIG. Here, AA sectional drawing is a section in the state where oil retainer 14 was installed. 4A, the upper side is the cylinder block 10 side, and the lower side is the oil retainer 14 side.

  A rib shape 30 is formed on the end wall 20 of the cylinder block 10. A rib shape 40 is also formed on the oil retainer 14 side at a position corresponding to the rib shape 30. When the oil retainer 14 and the end wall 20 of the cylinder block 10 are joined, the rib-shaped upper surfaces (30h, 40h) abut each other, and the blow-by gas communication path 50 is formed between the inner vertical wall 20fa of the flange 20f. It is formed.

  As described above, the present invention is characterized in that the blow-by gas communication passage 50 is formed between the oil retainer 14 and the end wall 20 where the driving portion of the cylinder block 10 is disposed, and FIG. Such a configuration can also be taken.

  FIG. 4B shows a case where the rib shape 40 is extended from the oil retainer 14 side to the crank chamber 24 side. That is, the rib shape 30 may not be provided on the end wall 20 side of the cylinder block 10. 4C shows the case where the rib shape 30 is extended from the cylinder block 10 side. That is, in order to form the blow-by gas communication passage 50, a rib shape formed from at least one of the end wall 20 side and the oil retainer 14 side of the cylinder block 10 can be used.

  The structure of the internal combustion engine of the present invention can be suitably used for a two-cylinder engine, and can also be used for an engine having two or more cylinders.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 9 Cylinder upper end 10 Cylinder block 10u (Cylinder block) lower end 10t (Cylinder block) upper surface 11 (Cylinder block upper surface) hole 11a (Hole) opening 11b (Hole) bottom 12 Oil pan 12a (Oil Dent shape 12s oil pan side wall 12w shielding wall 14 oil retainer 14a dent shape (oil retainer) 16 rotation gear 18 drive gear 20 end wall 20f flange flange 20fa (end wall flange) inner vertical Wall 21 Projection hole 22 Bearing portion 24 Crank chamber 26 Concave shape 27 Bearing member 30 (End wall) rib shape 30h (End wall rib shape) upper surface 30t (End wall) rib shape upper end 31 Passage (groove shape)
31t (top of groove shape) 32 outlet (for blow-by gas) 40 rib shape (for oil retainer) 40h upper surface (for rib shape of oil retainer) 50 Blow-by gas communication path

Claims (1)

A crankshaft that pivotally supports a rotating body having irregularities;
A cylinder block having a concave shape on an end wall for positioning the rotating body outside and supporting the crankshaft;
An oil pan that is positioned on the inner side and is connected to a position under which the rotating body scoops up oil below the cylinder block;
An oil retainer connected to the upper side of the oil pan and covering the cylinder block end wall;
A structure of an internal combustion engine provided with a blow-by gas passage that communicates a crank chamber constituted by the cylinder block and the oil pan and a cylinder head connected to the upper side of the cylinder block;
The blow-by gas passage is
Adjacent to the concave shape,
Using at least one rib shape of a rib shape protruding outward from the cylinder block end wall or a rib shape provided on the inner surface of the oil retainer,
Formed between the cylinder block end wall and the inner surface of the oil retainer ;
A structure of an internal combustion engine, wherein a shielding wall provided toward the inside of the crank chamber from a position corresponding to the rib shape formed on the cylinder block is formed on the oil pan .