JP2009013941A - Engine breather equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent oil from entering a breather chamber from a blowby gas inlet while preventing freezing of a blowby gas inside the breather chamber.
Since a predetermined gap α is formed between the outer surface of a breather chamber 26 disposed inside the head cover 13 and the inner surface of the head cover 13, the gap α is insulated from the space even when the outside air temperature decreases. It is possible to prevent the blow-by gas from freezing. In addition, since the blow-by gas inlet 30 formed on the wall surface of the breather chamber 26 is opened at a position facing the inner surface of the head cover 13, the blow-by gas inlet 30 is opened as compared with the case where the blow-by gas inlet 30 is opened on the lower surface of the breather chamber 26. Not only can the degree of freedom of the position 30 be increased, but the oil separation effect can be exerted by the gap α between the breather chamber 26 and the head cover 13 to prevent the oil from entering the breather chamber 26.
[Selection] Figure 5

Description

  The present invention is an engine breather device in which a breather chamber is disposed inside a head cover coupled to a cylinder head of an engine, and oil contained in blow-by gas flowing back to an intake system via the breather chamber is separated. The invention relates to a structure in which a predetermined gap is formed between the outer surface of the breather chamber and the inner surface of the head cover.

  When the engine blow-by gas is returned to the engine intake system via the breather chamber provided in the head cover, the oil contained in the blow-by gas is separated in the breather chamber to prevent oil from entering the intake system. is doing.

When the outside air temperature is lowered, the engine head cover is cooled, so that the blow-by gas in the breather chamber disposed therein may freeze and the blow-by gas passage may be blocked. Therefore, it is known from Patent Document 1 below that a gap functioning as a heat insulating space is formed between the head cover and the breather chamber (oil separator) to prevent the blow-by gas from freezing at low temperatures.
Japanese Utility Model Publication No. 6-25623

  However, since the blow-by gas inlet of the breather chamber is formed in the lower surface of the breather chamber in the above-mentioned conventional one, oil generated by the camshaft rotating inside the cylinder head and the centrifugal force generated by turning the vehicle There is a problem that the biased oil easily enters the breather chamber from the blow-by gas inlet.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to reliably prevent oil from entering from the blow-by gas inlet into the breather chamber while preventing the blow-by gas from freezing inside the breather chamber. And

  To achieve the above object, according to the first aspect of the present invention, a breather chamber is disposed inside a head cover coupled to a cylinder head of an engine, and the air is returned to the intake system via the breather chamber. An engine breather device for separating oil contained in blowby gas, wherein a predetermined gap is formed between an outer surface of the breather chamber and an inner surface of a head cover, and is formed on a wall surface of the breather chamber. A breather device for an engine is proposed in which the blow-by gas inlet is opened at a position facing the inner surface of the head cover.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, a recess in which a combustion chamber insertion member is disposed is formed on the upper wall of the head cover, and the breather chamber avoids the recess. A breather device for an engine is proposed in which the blow-by gas inlet is opened at a position facing the inner surface of the recess.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the cam is disposed around the camshaft disposed below the breather chamber and closest to the blow-by gas inlet. A first region on the side where the tip of the cam passes upward from below by a plane parallel to the cylinder axis including the shaft axis, and a second region on the side where the tip of the cam passes downward from above The engine breather device is proposed in which the blow-by gas inlet opens into the second region.

  According to the invention described in claim 4, in addition to the structure of any one of claims 1 to 3, the inner surface of the head cover and the breather are provided at a position where the blow-by gas inlet is formed. The engine breather apparatus according to any one of claims 1 to 3, wherein a minimum distance from an outer surface of the chamber is set to be smaller than a vertical length of the blow-by gas inlet. Proposed.

  According to the invention described in claim 5, in addition to the configuration of any one of claims 1 to 4, the breather chamber communicates with the blow-by gas outlet passage, and the opening area of the blow-by gas inlet A breather device for an engine is proposed in which the blower gas outlet passage is formed larger than the minimum passage cross-sectional area.

  The exhaust camshaft 23 of the embodiment corresponds to the camshaft of the present invention, the exhaust cam 25 of the embodiment corresponds to the cam of the present invention, and the injector 29 of the embodiment is a member inserted into the combustion chamber of the present invention. The blowby gas outlet 31 and the joint 13c of the embodiment correspond to the blowby gas outlet passage of the present invention.

  According to the configuration of the first aspect, the predetermined gap is formed between the outer surface of the breather chamber disposed inside the head cover and the inner surface of the head cover. It is possible to prevent the blow-by gas from freezing. In addition, since the blow-by gas inlet formed on the wall surface of the breather chamber is opened at a position facing the inner surface of the head cover, the degree of freedom in the position of the blow-by gas inlet compared to the case where the blow-by gas inlet is opened at the lower surface of the breather chamber. In addition, the gap between the breather chamber and the head cover can exhibit an oil separation effect and prevent the oil from entering the breather chamber.

  According to the second aspect of the present invention, the breather chamber is disposed at a position avoiding the recess formed in the upper wall of the head cover, and the blow-by gas inlet is opened at a position facing the inner surface of the recess. The shape can be complicated and the oil separation effect can be enhanced.

  According to the third aspect of the present invention, the first region which is disposed below the breather chamber and is on the side where the tip of the cam passes from below to above around the camshaft closest to the blow-by gas inlet, When the tip is divided into the second region that passes from the upper side to the lower side, the blow-by gas inlet is opened to the second region, so that the cam shaft rotates and the blow-by gas blows away from the side that repels oil. A gas inlet will be arranged and the amount of oil entering the breather chamber can be minimized.

  According to the fourth aspect of the present invention, at the position where the blow-by gas inlet is formed, the minimum distance between the inner surface of the head cover and the outer surface of the breather chamber is set smaller than the vertical length of the blow-by gas inlet. In addition, the flow of the blow-by gas can be narrowed before the blow-by gas inlet, and the oil separation effect can be exhibited.

  According to the fifth aspect of the present invention, since the opening area of the blow-by gas inlet of the breather chamber is larger than the minimum passage cross-sectional area of the blow-by gas outlet passage, the flow velocity of the blow-by gas flowing into the blow-by gas inlet is reduced, Oil along with the gas can be made difficult to enter the breather chamber.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 8 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of a head portion of an in-line four-cylinder engine (cross-sectional view taken along line 1-1 in FIG. 2), and FIG. 3 is a sectional view taken along line 3-3 in FIG. 1, FIG. 4 is an exploded perspective view of the head cover, breather chamber main body and cover plate, FIG. 5 is a sectional view taken along line 5-5 in FIG. 5 is a sectional view taken along line 6-6 in FIG. 5, FIG. 7 is a sectional view taken along line 7-7 in FIG. 3, and FIG. 8 is a sectional view taken along line 8-8 in FIG.

  As shown in FIG. 1, a cylinder head 12 is coupled to the upper end of the cylinder block 11 of the cylinder fuel injection engine, and a head cover 13 is coupled to the upper end of the cylinder head 12. In this specification, the vertical direction is defined with the cylinder block 11 side as the lower side and the head cover 13 side as the upper side.

  The cylinder head 12 is formed with a combustion chamber 14, an intake port 15 and an exhaust port 16 connected to the combustion chamber 14. The intake port 15 is opened and closed by an intake valve 17, and the exhaust port 16 is exhausted. The valve 18 opens and closes. A camshaft holder 19 and a cap 20 are overlapped on the upper surface of the cylinder head 12 and fastened with a plurality of bolts 21... And an intake camshaft 22 rotatably supported between the camshaft holder 19 and the cap 20 and An intake cam 24 and an exhaust cam 25 are provided on the exhaust cam shaft 23, respectively. A breather chamber 26 is disposed between the upper surface of the cap 20 and the lower surface of the head cover 13. The breather chamber 26 is made of synthetic resin, and is configured by joining an upper breather chamber main body 27 and a lower cover plate 28.

  Next, the structure of the breather chamber 26 will be described with reference to FIGS.

  As shown in FIGS. 2 to 5, the head cover 13 whose bottom surface is released is formed with a recess 13 a whose center is recessed toward the cylinder head 12 along the crankshaft axis L <b> 1 (see FIGS. 2 and 3). In this case, four injectors 29 (see FIGS. 1 and 2) are arranged. The breather chamber 26 is generally U-shaped as a whole, and has a blow-by gas inlet 30 formed at one end thereof and a blow-by gas outlet 31 formed at the other end. Inside the head cover 13, an annular space is formed between the outer peripheral wall and the recess 13a, and the U-shaped breather chamber 26 is disposed in the space.

  As clearly shown in FIG. 4, the breather chamber main body 27 is a trough-like member having an open bottom surface, and the open portion is closed by a flat cover plate 28. That is, a joining surface 28a (a portion shaded in light color) formed on the outer periphery of the cover plate 28 is joined to the joining flange 27a formed along the outer periphery of the breather chamber body 27 by vibration welding. Accordingly, the breather chamber 26 is formed in a tube shape. A plurality (15 in the embodiment) of the joining flanges 28b... (Shaded portions in dark color) are projected on the outside of the joining joint 28a of the cover plate 28, and these joining flanges 28b. Are joined to the joining surface 13b (see FIG. 5) on the inner surface of the head cover 13 by vibration welding. The joint surface 13b of the head cover is also shaded in FIG.

  With the breather chamber 26 fixed in the interior of the head cover 13 in this way, a gap α (FIGS. 1 and 5) that forms a heat insulation space between the outer surface of the breather chamber main body 27 and the inner surface of the head cover 13. To FIG. 7).

  As is clear from FIG. 4, the blow-by gas inlet 30 formed on one end side of the breather chamber main body 27 opens sideways. The blow-by gas outlet 31 formed on the other end side of the breather chamber main body 27 opens upward, and an annular joining flange 27b is formed around the outlet. An oil drop hole 28c is formed in the middle portion of the cover plate 28, and a pair of first and second baffle plates 28d and 28e are provided between the oil drop hole 28c and the blow-by gas inlet 30. Two pairs are provided.

  As apparent from FIGS. 3, 7, and 8, the first hanging wall 27 c and the second hanging wall 27 d are suspended from the upper wall of the breather chamber body 27, and the first hanging wall 27 c is divided into three. A plurality of ribs 27e are formed on the surface of the second hanging wall 27d on the first hanging wall 27c side so as to extend in the vertical direction. The first baffle plate 28d, the first drooping wall 27c, the second baffle plate 28e, and the second drooping wall 27d are alternately arranged, thereby forming the labyrinth 32 that suppresses the flow of blow-by gas. Two sets of the labyrinth 32 having the above configuration are arranged in series.

  As is apparent from FIGS. 3 to 5, the blow-by gas inlet 30 of the breather chamber 26 opens sideways so as to face the inner surface of the recess 13 a of the head cover 13. An exhaust camshaft 23 on the side closer to the blowby gas inlet 30 of the breather chamber 26 is located, and the exhaust camshaft 23 rotates clockwise in FIG. With reference to a plane P extending in the direction of the cylinder axis L3 through the axis L2 of the exhaust camshaft 23, in the first region R1 on the left side, the exhaust cam 25 rotates from bottom to top, and the second In the region R2, the exhaust cam 25 rotates from top to bottom. The blow-by gas inlet 30 of the breather chamber 26 opens in a direction away from the plane P in the second region R2.

  As apparent from FIGS. 3, 5 and 6, the joining flange 27 b surrounding the blow-by gas outlet 31 of the breather chamber body 27 is joined to the lower surface of the upper wall of the head cover 13 by vibration welding. A joint 13c is integrally formed with the breather chamber main body 27 in the vicinity of the blow-by gas outlet 31, and the joint 13c is connected to an engine intake system via a breather hose (not shown).

  The opening area of the blowby gas inlet 30 is set larger than the blowby gas outlet passage, that is, the minimum passage crossing area of the blowby gas outlet 31 and the joint 13c. This is because the flow rate of the fluid is the product of the channel cross-sectional area and the flow velocity, so that the flow velocity can be reduced as the flow channel cross-sectional area is increased. Therefore, by ensuring a large opening area of the blow-by gas inlet 30, it is possible to reduce the flow rate of the blow-by gas at that portion and effectively prevent the oil from entering the breather chamber 26 together with the blow-by gas.

  As is apparent from FIG. 1, the oil dropping hole 28 c formed in the cover plate 28 of the breather chamber 26 is formed in the oil return passage 20 a formed in the cap 20, the oil return passage 19 a formed in the camshaft holder 19, and the cylinder head 12. The oil pan (not shown) communicates with the oil return passage 12 a formed and the oil return passage 11 a formed in the cylinder block 11. As described above, the oil return passages 19a and 20a from the breather chamber 26 are formed by using the camshaft holder 19 and the cap 20, so that they are formed outside the camshaft holder 19 and the cap 20. The width of the head cover 13 can be reduced.

  As apparent from FIG. 5, the minimum distance X between the inner surface of the recess 13 a of the head cover 13 and the outer surface of the breather chamber 26 at the position where the blow-by gas inlet 30 is formed is the vertical length of the blow-by gas inlet 30. It is set smaller than Y.

  As shown in FIGS. 2, 3 and 5, the head cover 13 provided with the breather chamber 26 having the above structure is fixed to the upper surface of the cylinder head 12 with a plurality of bolts 33, and The recess 13a is fixed to the upper surface of the cylinder head 12 with a plurality of bolts 34.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  The breather chamber 26 to which blow-by gas is supplied has a gap α that functions as a heat insulation space between the head cover 13 and the blow-by gas in the breather chamber 26 is prevented from freezing when the outside air temperature decreases. In addition, it is possible to avoid blocking the blow-by gas passage.

  The blow-by gas in the head cover 13 flows into the breather chamber 26 from a blow-by gas inlet 30 provided at one end of the breather chamber 26 formed in a substantially U shape. Does not open downward, but opens sideways so as to face the inner surface of the side wall of the recess 13a of the head cover 13, so that even if the blowby gas inlet 30 is formed large to reduce the flow rate of blowby gas, It is possible to effectively suppress the oil repelled by the valve mechanism disposed below the breather chamber 26 from entering the breather chamber 26 from the blow-by gas inlet 30. In addition, the degree of freedom in layout of the blowby gas inlet 30 can be increased as compared with the case where the blowby gas inlet 30 is opened downward.

  In particular, in FIG. 5, the blow-by gas inlet 30 is disposed in the second region R <b> 2 where the exhaust cam 25 provided on the exhaust cam shaft 23 moves from top to bottom, i.e., the region where oil does not splash up toward the breather chamber 26. As a result, it is possible to more reliably prevent oil from entering the breather chamber 26.

  Further, in the vicinity of the blow-by gas inlet 30, the minimum distance X between the inner surface of the recess 13 a of the head cover 13 and the outer surface of the breather chamber 26 is set to be smaller than the vertical length Y of the blow-by gas inlet 30. This makes it difficult for oil to enter between the inner surface of the recess 13 a of the head cover 13 and the outer surface of the breather chamber 26, thereby preventing the oil from entering the breather chamber 26.

  The blow-by gas that has flowed into the breather chamber 26 from the blow-by gas inlet 30 still contains a small amount of oil. However, while the blow-by gas flows through the breather chamber 26, two labyrinths 32, 32 ( By passing through FIGS. 3, 7, and 8), the oil is reliably separated from the blow-by gas. The oil separated from the blow-by gas flows along the bottom wall of the breather chamber 26 and returns to the oil pan from the oil dropping hole 28c (see FIGS. 1 and 3) through the oil return passages 20a, 19a, 12a, and 11a. It is.

  The blow-by gas from which the oil has been separated in this way further flows inside the breather chamber 26 toward the blow-by gas outlet 31, while the oil that could not be separated by the two labyrinths 32, 32 is further separated. The At this time, since the shape of the breather chamber 26 is formed in a U shape so as to surround the concave portion 13a formed in the central portion of the head cover 13, the shape of the breather chamber 26 can be complicated to promote oil separation. it can. The blow-by gas from which the oil has been finally separated returns to the engine intake system from the blow-by gas outlet 31 through the joint 13c and a breather hose (not shown).

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although an in-cylinder fuel injection engine is exemplified in the embodiment, the present invention can be applied to both a gasoline engine and a diesel engine, and can also be applied to a port injection type gasoline engine. In this case, instead of the injectors 29..., A spark plug serves as a combustion chamber insertion member.

  In the embodiment, the blow-by gas inlet 30 of the breather chamber 26 is opened sideways toward the inner surface of the recess 13 a of the head cover 13, but the blow-by gas inlet 30 is turned sideways toward the inner surface of the outer peripheral wall of the head cover 13. Even if it opens to the inner surface of the ceiling wall of the head cover 13, it is possible to effectively prevent oil from entering the breather chamber 26 through the blow-by gas inlet 30. .

Sectional view of engine head (cross-sectional view taken along line 1-1 in FIG. 2) 2 direction view of FIG. 3-3 line view of FIG. Exploded perspective view of head cover, breather chamber body and cover plate Sectional view along line 5-5 in FIG. 6-6 sectional view of FIG. Sectional view along line 7-7 in FIG. Sectional view taken along line 8-8 in FIG.

Explanation of symbols

12 Cylinder head 13 Head cover 13a Recess 13c Joint (blow-by gas outlet passage)
23 Exhaust camshaft (camshaft)
25 Exhaust cam (cam)
26 Breather chamber 29 Injector (combustion chamber insertion member)
30 Blow-by gas inlet 31 Blow-by gas outlet (Blow-by gas outlet passage)
L2 Camshaft axis L3 Cylinder axis P The plane R1 including the camshaft axis and parallel to the cylinder axis R1 First region R2 Second region X Minimum distance Y between the inner surface of the head cover and the outer surface of the breather chamber Y Blow-by gas Inlet vertical length α Clearance

Claims (5)

A breather chamber (26) is arranged inside a head cover (13) coupled to the cylinder head (12) of the engine, and oil contained in blow-by gas returning to the intake system is separated via the breather chamber (26). A breather device for an engine, wherein a predetermined gap (α) is formed between the outer surface of the breather chamber (26) and the inner surface of the head cover (13).
A breather device for an engine, wherein a blow-by gas inlet (30) formed in a wall surface of the breather chamber (26) opens at a position facing the inner surface of the head cover (13).   A recess (13a) in which a combustion chamber insertion member (29) is disposed is formed on the upper wall of the head cover (13), the breather chamber (26) is disposed at a position avoiding the recess (13a), and the blow-by The breather device for an engine according to claim 1, characterized in that the gas inlet (30) opens at a position facing the inner surface of the recess (13a).   A cylinder axis (L3) including the axis (L2) of the camshaft (23) around the camshaft (23) disposed below the breather chamber (26) and closest to the blow-by gas inlet (30). A first region (R1) on the side where the tip of the cam (25) passes from below to above due to a plane (P) parallel to the top, and a side where the tip of the cam (25) passes from above to below 3. The engine breather according to claim 1, wherein the blow-by gas inlet (30) opens into the second region (R 2) when divided into the second region (R 2). apparatus.   At the position where the blow-by gas inlet (30) is formed, the minimum distance (X) between the inner surface of the head cover (13) and the outer surface of the breather chamber (26) is above and below the blow-by gas inlet (30). The engine breather device according to any one of claims 1 to 3, wherein the engine breather device is set to be smaller than a directional length (Y).   The breather chamber (26) communicates with the blow-by gas outlet passage (31, 13c), and the opening area of the blow-by gas inlet (30) is larger than the minimum passage cross-sectional area of the blow-by gas outlet passage (31, 13c). The engine breather device according to claim 1, wherein the breather device is formed.

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