JP2005155477A - Head cover for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head cover for an internal combustion engine having a breather passage not susceptible to entering splashed oil drops therein and for quickly draining the oil drops therefrom. <P>SOLUTION: In the internal combustion engine 1 mounting a cylinder thereon so that a cylinder axis is tilted, the head cover 5 is constituted by defining a breather passage 16 extending along a camshaft 7 with a baffle plate 15. In the head cover 5 structure, a plurality of lateral holes (semi-circular parts 22) are formed in a lower side of the inclination of the baffle plate and along the camshaft so that the lateral holes are opened to a face in parallel with the camshaft. The lateral hole formed on inlet (a blowby gas flow-in port 19) side of the breather passage is opened to a direction opposite to a rotation direction of the camshaft, and the lateral hole formed on an outlet (a joint 18) side of the breather passage is opened to a direction along the rotation direction of the camshaft. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a head cover for an internal combustion engine, and more particularly to a head cover configured to form a part of a blow-by gas reduction device.

  In a four-cycle internal combustion engine, in order to reduce pressure pulsation in the crankcase due to the reciprocating motion of the piston and to prevent deterioration of the lubricating oil, the crankcase and the head cover are communicated with each other, and a new one is provided in the head cover. I try to introduce my mind. In such a so-called PCV system, since the blow-by gas is finally circulated to the combustion chamber, it is necessary to remove the lubricating oil mixed in the blow-by gas.

Conventionally, for such gas-liquid separation, a structure in which a breather passage is defined in a head cover by partitioning with a baffle plate is known (see, for example, Patent Document 1).
JP-A-10-212925

  The gas-liquid separation system described above is designed so that the oil droplets blown off by the rotation of the camshaft are less likely to enter, and the oil droplets that have become larger from the mist are not mixed again into the blow-by gas. It is desirable to configure so that oil droplets are discharged quickly.

  The present invention has been devised to satisfy such a demand, and the main object of the present invention is to provide a breather passage configured such that scattered oil droplets are less likely to enter and are quickly discharged. It is providing the head cover of the internal combustion engine provided with.

  In order to achieve such an object, in claim 1 of the present invention, a breather passage (16) extending along a cam shaft (7) in an internal combustion engine (1) mounted with an inclined cylinder shaft. ) Is defined by a baffle plate (15), and a lateral hole (semicircular portion 22) that opens in a plane parallel to the cam shaft is formed along the cam shaft on the inclined lower side of the baffle plate. A plurality of horizontal holes arranged on the breather passage inlet (blow-by gas inlet 19) side are opened in a direction facing the rotational direction of the camshaft, and arranged on the breather passage outlet (joint 18) side. The lateral hole is opened in a direction along the rotation direction of the cam shaft.

  In particular, in addition to the above-described configuration, the lateral hole is formed to protrude from the baffle plate by press molding, and the second hole (rectangular portion 21) that opens in the vertical direction is formed continuously with the lateral hole. The second hole is disposed on the inclined lower side with respect to the lateral hole (Claim 2), and the second hole on the outlet side is disposed on the inclined upper side with respect to the lateral hole (Claim 3). Or better.

  According to such a configuration of the first aspect of the present invention, the direction of the lateral hole disposed on the inlet side of the breather passage and the direction of the lateral hole disposed on the outlet side are mutually set with respect to the rotation direction of the cam shaft. Since they are different, the inlet side can promote the inflow of blow-by gas, and the outlet side can promote the discharge of the separated oil droplets while suppressing the entry of the blow-by gas. According to the second aspect of the present invention, since the second hole that opens in the longitudinal direction continuously to the lateral hole on the inlet side is disposed on the inclined lower side, the oil droplets accumulated in the lower portion of the breather passage are discharged. And the formation of the lateral holes is easy. Furthermore, according to the configuration of the third aspect, since the second hole that opens in the vertical direction continuously to the lateral hole on the outlet side is disposed on the inclined upper side, the oil droplet can be discharged while suppressing the intrusion of the oil droplet. It can be facilitated and the formation of the lateral holes is easy. Therefore, it is possible to achieve a great effect in achieving a high level of compatibility between the function of suppressing the intrusion of lubricating oil scattered by the rotation of the camshaft and the function of discharging large-sized lubricating oil.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an elevational view of an in-line four-cylinder internal combustion engine to which the present invention is applied, as viewed from the flywheel side. The internal combustion engine 1 is mounted on a vehicle body with the cylinder row directed in the vehicle width direction and the cylinder shaft tilted somewhat rearward, and an intake manifold 3 is coupled to the front surface of the cylinder head 2. An exhaust manifold 4 is coupled to the rear surface of the two. A head cover 5 that covers the valve operating mechanism is coupled to the upper surface of the cylinder head 2.

  In the head cover 5, as shown in FIG. 2, two cam shafts 7 (only the exhaust side is shown) are supported in parallel by vertically divided cam shaft holders 6a and 6b. The internal combustion engine 1 is an in-cylinder injection engine that directly injects fuel into the combustion chamber, and the upper surface of the upper camshaft holder 6a is exposed from the opening 8 at the center of the head cover 5 as a fixed portion of the fuel injection valve. However, since this is irrelevant to the essence of the present invention, the description thereof is omitted.

  As shown in FIG. 3, the head cover 5 is formed with an annular bulging portion 9 for defining a cavity surrounding the opening 8 through which the fixed portion of the fuel injection valve is exposed. The head cover 5 abuts the seal member 11 mounted on the circumferential groove 10 formed on the lower end edge of the outer peripheral wall against the upper surface of the cylinder head 2 and the circumferential groove formed on the lower end edge of the inner peripheral wall. 12 is brought into contact with the upper surface of the upper camshaft holder 6a, and in this state, the boss portions 14 formed at the four corners of the outer peripheral wall are bolted, for example, so that the inside is sealed. It is coupled to the cylinder head 2 in a state.

  On the inner side of one side (exhaust side) of the annular bulging portion 9, the surface facing the camshaft 7 (for exhaust valve driving) is closed with a baffle plate 15 (see FIG. 4), thereby along the camshaft 7. An extended breather passage 16 is defined. Inside the breather passage 16, three baffle plates 17a, 17b and 17c having a rib shape are formed. At one end (flywheel side) in the cylinder row direction, a joint 18 is connected to connect a hose that guides the blow-by gas from which the lubricating oil is separated to the intake passage (see FIG. 5).

  The baffle plate 15 is L-shaped, and a blow-by gas inlet 19 is formed at the end of the portion along the axis of the camshaft 7 on the side opposite to the flywheel by pressing the end edge downward by press molding. ing. Further, a total of three oil drain holes 20a, 20b, 20c, one near the inlet 19 and two near the joint 18, that is, two on the outlet side, on the side that is inclined downward when fixed inside the head cover 5. Is formed. These oil drain holes 20a, 20b, and 20c are, as shown in FIG. 6, a rectangular portion (second hole) 21 vertically penetrated by shear punching and non-shear punching on one side of the rectangular portion 21. A semicircular portion (lateral hole) 22 that is formed by pushing down downward is formed in a continuous manner. The relationship between the rectangular portion 21 and the semicircular portion 22 in the three oil drain holes 20a, 20b, and 20c is that the rectangular portion 21 is inclined downward with respect to the semicircular portion 22 in one 20a located on the inlet 19 side. As for two 20b * 20c located in an outflow port side, the rectangular part 21 is located in the inclination upper side with respect to the semicircular part 22.

  On the other hand, the baffle plate 17a located on the inlet 19 side of the blow-by gas is inclined from the protruding end of the protruding portion 23 protruding inward from the outer wall surface of the breather passage 16 so that its tip approaches the outer wall surface. It is extended. Similarly, the baffle plates 17b and 17c located on the joint 18 side extend in opposite directions from the projecting ends of the projecting portions 24 projecting inwardly from the outer wall surface of the breather passage 16. These baffle plates 17b and 17c are also inclined so that their tips approach the outer wall surface. The oil drain holes 20a, 20b, and 20c are formed so as to be located on the base side of the baffle plates 17a, 17b, and 17c.

  The blow-by gas filled in the head cover 5 flows into the breather passage 16 from the inlet 19 that opens to the intake manifold side. Here, since the opening area of the inflow port 19 is sufficiently large, the intake gas amount becomes sufficiently large, and oil droplets having a large inertial mass are difficult to flow in. In the breather passage 16, the section where the baffle plates 17 a, 17 b, and 17 c are provided is narrowed by the projecting portions 23 and 24, so that the blow-by gas flowing through the breather passage 16 is repeatedly compressed and expanded. The mist is condensed by the density difference generated at that time, and oil separation is promoted.

  The separated oil component temporarily accumulates on the upper surface of the baffle plate 15, flows on the inclined surface of the baffle plate 15, and is discharged from the rectangular portions 21 of the oil drain holes 20 a, 20 b, and 20 c. Further, the oil drain holes 20a, 20b, and 20c are opened to the side that passes from the end edges of the corresponding baffle plates 17a, 17b, and 17c, that is, in a bag-like position. Here, in the portions of the protrusions 23 and 24, the passage pressure is reduced because the cross section of the passage is narrowed. The baffle plates 17a, 17b, and 17c are provided so as not to be affected by the negative pressure. Since the oil drain holes 20a, 20b, and 20c are opened on the side farther from the edges of the baffle plates 17a, 17b, and 17c, the oil droplets are easily collected and the discharge is promoted. Further, the joint 18 which is the outlet of the blow-by gas is opened at the uppermost position of the breather passage 16 and the inner end of the joint 18 enters the breather passage 16, so that a gas with a small specific gravity is easily released. In addition, the outflow of oil droplets adhering to the wall surface of the breather passage 16 is prevented by the outer peripheral surface of the entry portion of the joint 18.

  Incidentally, the rotation direction of the cam shaft 7 is the counterclockwise direction in FIG. Therefore, the oil droplets blown off with the rotation of the camshaft 7 are easy to enter from the semicircular portion 22 on the side close to the inflow port 19 facing the rotation direction of the camshaft 7 and vice versa. On the side close to the joint 18 that opens in the direction along the rotation direction, the oil droplets scattered with the rotation of the cam shaft 7 are difficult to enter, and the lubricating oil separated from the blow-by gas flows out. Is not inhibited.

  As described above, the oil drain holes 20a disposed on the inlet 19 side of the breather passage 16 and the oil drain holes 20b and 20c disposed on the outlet (joint 18) side are directed in opposite directions. Thus, the inflow of blow-by gas is not hindered on the inlet side, and the lubricant oil in droplets can be discharged, and the outlet side is separated from the lubricant while suppressing the intrusion of the lubricating oil scattered by the rotation of the camshaft 7. Oil discharge can be promoted.

It is the elevation view seen from the flywheel side of the in-line 4 cylinder internal combustion engine to which the present invention was applied. FIG. 4 is a partial cross-sectional view taken along line II-II in FIG. 3. It is a bottom view of the cylinder head by this invention. It is a bottom view of a baffle plate. It is a fragmentary sectional view which follows the VV line in FIG. It is the perspective view which looked at the oil drain hole from the lower part.

Explanation of symbols

1 Internal combustion engine 5 Head cover 7 Cam shaft 15 Baffle plate 16 Breather passage 18 Joint (exit)
19 Blow-by gas inlet (inlet)
20a to 20c Oil drain hole 21 Rectangular portion (second hole)
22 Semicircular part (horizontal hole)

Claims (3)

A head cover in which a breather passage extending along a cam shaft in an internal combustion engine mounted with an inclined cylinder shaft is defined by a baffle plate,
A plurality of lateral holes are provided along the cam shaft on the inclined lower side of the baffle plate.
Opening the lateral hole arranged on the inlet side of the breather passage in a direction facing the rotational direction of the camshaft;
A head cover for an internal combustion engine, wherein the lateral hole disposed on the outlet side of the breather passage is opened in a direction along a rotation direction of the cam shaft.   The lateral hole is formed so as to protrude from the baffle plate by press molding, and a second hole that opens vertically is provided continuously with the lateral hole, and the second hole on the inlet side is provided. The head cover for an internal combustion engine according to claim 1, wherein the head cover is disposed on an inclined lower side than the lateral hole.   The lateral hole is formed so as to protrude from the baffle plate by press molding, and a second hole that opens vertically is provided continuously with the lateral hole, and the second hole on the outlet side is provided. The head cover for an internal combustion engine according to claim 1, wherein the head cover is disposed on an inclined upper side with respect to the lateral hole.

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