JPH0240861B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a cylinder head cover structure in an engine in which blow-by gas is taken out to the outside via a rocker chamber covered with a cylinder head cover.

(Prior Art) Conventionally, in this type of engine, in order to separate and recover oil mist contained in blow-by gas, oil is installed in the cylinder head cover as disclosed in, for example, Japanese Utility Model Application Publication No. 56-149013. A separator is provided. Generally, an oil separator is equipped with a maze of partition walls inside and at the inlet, and while the blow-by gas bypasses the partition walls, oil mist collides with and adheres to the partition walls and the inner wall of the separator. Efforts are being made to separate and recover the waste.

(Problems to be Solved by the Invention) By the way, in order to more reliably separate the blow-by gas and oil mist as described above and to reduce oil consumption, it is better to improve the ability of the oil separator. However, as mentioned above, in a device that separates oil mist by partitioning the inside of the separator into a labyrinth with partition walls, in order to obtain sufficient oil separation performance, the size of the internal space of the separator must be made considerably large. This tends to cause new problems, such as an increase in weight and manufacturing costs, and less flexibility in designing the layout. Due to these circumstances, conventional oil separators have been set to be somewhat smaller in terms of capacity and structure, and a certain increase in oil consumption has been unavoidable.

The present invention has a simple structure that utilizes an existing structure and has an oil separation function that separates oil mist using the entire cylinder head cover, thereby separating oil without causing a significant increase in weight or manufacturing cost. The aim is to improve performance and reduce oil consumption.

(Means for Solving the Problems) In the present invention, a blowby gas passage for introducing blowby gas into the cylinder head cover is provided on one side in the longitudinal direction of the engine, and an outlet for leading out the blowby gas is provided on the other side, and at least An oil separation function is added to the rocker chamber, which serves as a passage for blow-by gas between them, in addition to the conventional oil separator, so that oil mist can be separated using the entire cylinder head cover.

Specifically, on one side of the cylinder head cover in the longitudinal direction of the engine, one end of the blowby gas passage that recirculates the blowby gas in the crankcase into the cylinder head cover communicates with the rocker chamber partitioned by the cylinder head cover. A fresh air inlet is open and allows outside air to be introduced into the cylinder head cover. On the other side of the cylinder head cover in the longitudinal direction of the engine, there is an oil separator for separating oil mist contained in the blow-by gas introduced into the rocker chamber, and an oil separator for guiding the blow-by gas after passing through the oil separator to the outside. An outlet is provided. At least between the opening of the blow-by gas passage and the outlet on the inner surface of the cylinder head cover, a rib member extends in a direction substantially perpendicular to the direction in which the cylinders are arranged. The rib member is disposed in the rocker chamber at a position shifted from the valve mechanism disposed in the cylinder head in the cylinder arrangement direction, and the outline of the rib member and the outline of the valve mechanism are disposed in such a manner that It is assumed that at least a portion of the cylinders overlaps when viewed from the cylinder arrangement direction.

(Function) Accordingly, in the present invention, the valve operating mechanism and the rib member partition the rocker chamber in a state in which they protrude in opposite directions at positions shifted in the cylinder arrangement direction. Therefore, the blow-by gas introduced into the cylinder head cover from one side in the longitudinal direction of the engine is mixed with fresh air (outside air) taken in from the fresh air inlet, and then the blow-by gas is passed through the valve mechanism and rib member in the opposite direction. It detours in the opposite direction, meandering up and down toward the outlet provided on the other side in the longitudinal direction of the engine, and repeatedly collides with the outer surface of the components of the valve mechanism or the inner wall of the cylinder head cover as it moves. become. During this transition process, the oil mist liberated in the blowby gas due to the mixing of the blowby gas and fresh air may collide and adhere to the structures inside the rock car chamber when the blowby gas collides, or the oil mist that is liberated in the blowby gas due to the mixing of the blowby gas and fresh air may collide and adhere to the structures in the rock car chamber, or when the blowby gas detours, there is a difference in mass. By separating from the gas flow and attaching to the structure due to the inertial force of
It will be separated from the blow-by gas. Furthermore, oil mist remaining in the blow-by gas is separated by an oil separator provided on the other longitudinal side of the engine.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 2, a cylinder head 1 and a cylinder head cover 2 covering the upper surface of the cylinder head 1 define a rocker chamber 4 in which a valve mechanism 3 is housed. The valve mechanism 3 includes a camshaft 5 disposed at the inner bottom of the rocker chamber 4 and extending in the longitudinal direction of the engine;
It consists of a rocker shaft 6 extending in the longitudinal direction of the engine disposed above and to the left and right of the camshaft 5, a rocker arm 7 supported by the rocker shaft 6, and the like, and opens and closes an intake valve 8 and an exhaust valve 9. The camshaft 5 is rotationally driven synchronously by a crank (not shown) via a timing gear 10 fixed to one longitudinal end (front end) of the engine and a chain 11 wound around the gear 10.

The blow-by gas leaking from the combustion chamber into the crank chamber is pushed out from the crank chamber by the downward movement of the piston, and is formed in a chain case 12 that covers the outer surface of the chain 11 provided on one side in the longitudinal direction of the engine. It ascends the blow-by gas passage 22 and reaches the rocker chamber 4. In order to separate and recover the oil mist contained in the blow-by gas, the inside of the rocker chamber 4 is connected to the valve mechanism 3 disposed in the cylinder head 1 and the inner surface of the cylinder head cover 2, as shown in FIG. Rib member 13 provided
It is divided into a plurality of parts along the cylinder arrangement direction. The rib member 13 is provided to protrude downward toward the space between adjacent valve mechanisms 3, and extends from one side edge of the opening side of the cylinder head cover 2 toward the other in a state perpendicular to the cylinder arrangement direction. ing. In other words, it protrudes downward so as to cross orthogonally cross the flow of blow-by gas moving in the rocker chamber 4 along the axial direction of the camshaft 5. As shown in FIG. 2, the rib member 13 is made larger at the left and right corners of the inner surface of the cylinder head cover 2 so that the outline of the rib member 13 and the outline of the rocker arm 7 overlap vertically when viewed from the cylinder arrangement. It is overhanging.

Further, in order to collect a small amount of oil mist remaining in the blow-by gas, an oil separator 15 is provided near the other end (rear end) of the cylinder head cover 2 in the longitudinal direction of the engine (the side farthest from the chain case 2). . As shown in FIG. 3, the oil separator 15 includes a convex partition wall 15a that opens downward and a cover 16 that closes the opening edge of the partition wall 15a.
The interior is divided into three front and rear chambers by a partition wall 15b perpendicular to the cylinder arrangement direction, and each chamber is divided into a plurality of chambers by a partition wall 15c extending inward of the cylinder arrangement. Blow-by gas is supplied through gas inlets 1 opened on one side of the chamber at both front and rear ends.
7 into the oil separator 15, flows into the central chamber in a U-turn shape, and is taken out to the outside through an outlet 18 provided in this chamber. A pipe 19 communicating with the intake passage is connected to the outlet 18 .

Further, as shown in FIG. 3, on the inner surface of one end (front end) in the engine longitudinal direction of the cylinder head cover 2,
A breather chamber 20 for taking in fresh air is divided, and this breather chamber 20 opens in its side wall and communicates with outside air through a fresh air introduction port 21.
Fresh air (outside air) is taken in and mixed with the blow-by gas that has flowed into one side in the longitudinal direction of the engine, making it easier to liberate oil mist contained in the blow-by gas.

Therefore, in the above embodiment, the blow-by gas introduced into one side of the engine longitudinal direction of the Rocker chamber 4 is first mixed with fresh air (outside air) taken in from the fresh air inlet 21, and oil is mixed in the blow-by gas. The mist becomes free. This blow-by gas moves within the rocker chamber 4 from the chain case 12 side on one side in the longitudinal direction of the engine toward the oil separator 15 side on the other side in the engine longitudinal direction. At this time, since the rocker chamber 4 is divided into a plurality of front and rear sections inwardly of the cylinder arrangement by the valve train mechanism 3 and the rib member 13, the blow-by gas alternately passes through the valve train mechanism 3 and the rib member 13 in opposite directions. While detouring, it meandered up and down and moved to Rotsuker Arm 7.
It repeatedly collides with the cylinder head cover 2 and the rib member 13. Due to this collision between the structures in the rocker chamber 4 and the blow-by gas, the oil mist contained in the blow-by gas adheres to the structures and is separated from the blow-by gas. Also,
When the blow-by gas bypasses the rib member 13 and the like, only the oil mist moves straight due to the inertia force applied to the blow-by gas flow, separates from the blow-by gas, and adheres to nearby structures. thus,
Most of the oil mist contained in the blow-by gas is separated before it flows into the oil separator 15. Therefore, the oil separator 15
In this case, it is sufficient to separate only a small amount of oil mist remaining, and the oil separation ability may be small. The oil mist separated in the rocker chamber 4 accumulates on the inner bottom of the rocker chamber 4, and then flows down to the crank chamber and is collected for reuse.

In the above embodiments, a so-called SOHC type valve mechanism has been described, but this is not necessarily necessary, and the present invention can also be applied to a DOHC type or OHV type. Further, the rib members 13 do not need to be orthogonal to the inward direction of the cylinder arrangement, and the point is that the rib members 13 may be formed as a series in a direction that obstructs the flow of blow-by gas while crossing it, that is, in a direction that is substantially perpendicular to the flow. .

Furthermore, in the above embodiment, the outline of the rib member 13 and the outline of the valve mechanism 3 are set to overlap only partially, but in some cases, the outline may be set so that most of the outlines overlap. It's okay.

(Effects of the Invention) As described above, according to the present invention, when the blow-by gas introduced from one longitudinal side of the engine and in which oil mist is liberated passes through the rocker chamber toward the other longitudinal side of the engine, the valve train The oil is forcibly detoured in the opposite direction by the and rib members, and moves in a meandering manner up and down, so that oil separation can be performed directly and effectively within the rocker chamber.
Further, the oil mist remaining in the blow-by gas is separated and extracted by the oil separator provided on the other side in the longitudinal direction of the engine, thereby making it possible to significantly reduce oil consumption.

Therefore, we made use of the entire cylinder head cover including the rocker chamber, which has a sufficiently large internal space, and also used the existing valve mechanism to effectively separate the oil, which is more effective than the conventional oil separation method. This makes it possible to reliably separate oil without increasing engine weight or significantly increasing manufacturing costs.Furthermore, it is possible to reduce the oil separation capacity of the oil separator installed in the cylinder head cover, making it possible to reduce the oil separation capacity during design. This is advantageous in that there are fewer restrictions on the layout of the oil separator.

[Brief explanation of drawings]

1 to 3 show embodiments of the present invention,
FIG. 1 is a longitudinal sectional side view schematically showing the internal structure of the rocker chamber, FIG. 2 is a sectional view taken along line A--A in FIG. 1, and FIG. 3 is a bottom view of the cylinder head cover. 2... Cylinder head cover, 3... Valve mechanism, 4... Rocker chamber, 13... Rib member, 15
...Oil separator, 17...Outlet port, 21...
...Fresh air introduction port, 22...Blow-by gas passage.

Claims (1)

[Scope of Claims] 1. On one side of the cylinder head cover in the longitudinal direction of the engine, one end of a blowby gas passage for circulating blowby gas in the crankcase into the cylinder head cover communicates with a rocker chamber partitioned by the cylinder head cover. A fresh air introduction port is provided on the other side of the cylinder head cover in the longitudinal direction of the engine to introduce outside air into the cylinder head cover. an oil separator for separating oil mist contained in the cylinder head; and an outlet for guiding the blow-by gas to the outside after passing through the oil separator; A rib member extending in a direction substantially orthogonal to the cylinder arrangement direction is protruded between the cylinder head and the cylinder head, and the rib member is connected to a valve mechanism disposed at the cylinder head in the rocker chamber. is arranged at a position shifted in the cylinder arrangement direction, and
A cylinder head cover structure for an engine, characterized in that an outline of a rib member and an outline of a valve mechanism at least partially overlap when viewed from the cylinder arrangement direction.