JPH077528Y2 - Cam cover device for V-type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement in a cam cover device having an improved function of separating oil mist in blow-by gas in a V-type internal combustion engine.

(Prior Art) In order to smoothly recirculate blow-by gas of an internal combustion engine to an intake system downstream of an intake throttle valve, a cam cover accommodating a cam mechanism of a cylinder head has a blow-by gas for introducing fresh air to be replaced with the blow-by gas. One end of the pipe is connected.
The other end of the blow-by pipe is an intake duct (upstream of the intake throttle valve)
The new air is introduced into the cam cover during normal operation, but the pressure relationship is reversed when the engine output is high, as the amount of blowby gas generated increases and the pressure in the intake passage that recirculates the blowby gas increases. Then, a part of the blow-by gas may flow back to the blow-by pipe. The blow-by gas that flows backward contains a lot of oil mist in which the lubricating oil sucked from the oil pan is fed to each part of the engine through the oil pump, and then part of the lubricating oil is atomized. In order to prevent the oil mist from being taken out, the following oil separating mechanism is normally provided inside the cam cover and is located at the connecting portion of the blow-by pipe. 10 and 11 show a conventional example of an oil separation mechanism in a V-type internal combustion engine (for example, Japanese Examined Patent Publication 63).
-14182).

To briefly explain this, first, in FIG. 10, a plurality of cylinders (for example, three cylinders or four cylinders) are arranged in each of the left and right banks 1a and 1b configured in a V shape, and a common crankshaft 2 ( Output shaft) piston 3 of each cylinder
Are connected.

Cam covers 7 are attached to the upper portions of the cylinder heads 5a and 5b of the banks 1a and 1b, respectively, for accommodating the valve operating cam mechanism 6 therein.

The intake manifolds 8a and 8b provided corresponding to the banks 1a and 1b for introducing intake air into each cylinder are collector parts.
9a and 9b are disposed above the cylinder heads 5a and 5b, and branch portions 10a and 10b branched from the collector portions 9a and 9b in correspondence with the number of cylinders are provided to the banks 1b and 1a facing each other. Connected to ports 12b and 12a.

In other words, inside both banks 1a and 1b, the intake port of each cylinder
12a and 12b are arranged so that they face each other, and the exhaust manifold
13a and 13b are connected to the outside of the banks 1a and 1b, so that the intake manifolds 8a and 8b extend to the opposite side so as to cross each other.

Next, as shown in FIG. 11, a partition wall 15 is provided inside the cam cover 7 in parallel with the top surface of the cam cover 7 in order to separate the oil mist in the blow-by gas. With baffle plate 16 on the inside
The oil separation passages 18 are defined by arranging 17 alternately.

A blow-by pipe 20 is connected to a connection port 19 of the oil separation passage 18, and this blow-by pipe 20 is communicated with an intake duct (not shown), whereby fresh air is introduced into the cam cover 7 from the intake duct, and a control valve (not shown) is provided. It is replaced with the blow-by gas that is returned to the downstream side of the intake throttle valve via. One end of the oil separation passage 18 opens inside the cam cover 7 and introduces fresh air from the internal space of the cam cover 7 into a crank chamber 22 defined by an oil pan 21 below the cylinder block via a passage (not shown).

The blow-by gas blown into the crank chamber 22 from the sliding gap of the piston 3 is returned to the intake passage downstream of the intake throttle valve via a control valve from a passage (not shown), and is introduced from the blow-by pipe 20. The generated fresh air is introduced into the crank chamber 22 from the internal space of the cam cover 7 and is quickly replaced with blow-by gas, and the blow-by gas is returned to the downstream side of the intake throttle valve.

A large amount of blow-by gas is generated when the engine is heavily loaded,
Moreover, during operation in which the pressure downstream of the intake throttle valve increases, the pressure relationship reverses and the control valve closes.
A part of the blow-by gas flows backward from the cam cover 7 through the oil separation passage 18 to the blow-by pipe 20, and flows into the intake duct upstream of the throttle valve.

At this time, in order to prevent the oil mist contained in the blow-by gas from flowing into the intake duct, the oil separation passage 18
Baffle plates 16 and 17 are alternately arranged on the base plate, and blow-by gas is made to collide with these and the effective passage length is lengthened to separate and remove the oil mist in the blow-by gas.

(Problems to be solved by the invention) By the way, in such a conventional device, as the effective length of the oil separation passage 18 is increased, the oil separation effect is enhanced. The size must be increased, which not only makes the cam cover 7 larger, but also increases the engine height, which increases the overall height of the engine room of the vehicle, which increases the aerodynamic characteristics of the vehicle and the degree of freedom in design. Will be lost.

The present invention aims to solve such a problem.

(Means for Solving the Problems) Therefore, in the present invention, the collector portion of the intake manifold is
It is arranged above the cylinder head of each bank formed into a mold, and the branch part branched from the collector part is connected to each cylinder of the opposing bank, while part of the top surface of the cam cover attached to the cylinder head is An oil separating passage for blow-by gas is defined above the inside of the cam cover through a partition wall between the branch portions, and a baffle plate is provided in the oil separating passage at the protruding portion.

(Operation) As described above, the protrusion is formed on the top surface of the cam cover located between the branch portions of the intake manifold, and the baffle plate is arranged inside this to form the oil separation passage. Without doing so, the effective length of the oil separation passage can be sufficiently expanded, and the separation function of the oil mist in the blow-by gas can be enhanced. As a result, the position of the intake manifold arranged above the cam cover can be lowered, and the overall height of the engine can be lowered.

Further, since the protrusion formed on the cam cover enhances the rigidity and strength of the cam cover structure, vibration of the cam cover can be suppressed and radiation noise can be reduced.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a V6 internal combustion engine. As shown in FIG. 1, the collector portions 9a and 9b of the intake manifolds 8a and 8b are parallel to the banks 1a and 1b. Branches 10a and 10b extending in the direction and connected to the cylinders of the banks 1b and 1a facing each other branch at right angles from the collectors 9a and 9b.

A cam cover 7 is attached to the upper part of the cylinder heads 5a, 5b to house the valve operating cam mechanism 6. In this embodiment, the valve operating cam mechanism 6 operates in the intake valve system and the exhaust valve system. Since the cam covers 7 are independently formed, two cam covers 7 are formed in each of the banks 1a and 1b correspondingly.

3 and 4 show cam covers 7a and 7b of the intake valve system, and FIGS. 5 and 6 show cam covers 7c and 7d of the exhaust valve system.

Since the valve operating cam mechanisms of the intake valve system are arranged inside the respective banks 1a and 1b, the intake valve system cam covers 7a and
7b is also located inside, and therefore exhaust valve system cam covers 7c and 7d are arranged outside each bank 1a and 1b.

Branch portions 10a and 10b of the intake manifolds 8a and 8b
And the opposite banks 1b so that they cross each other.
It is connected to the intake port of 1a, but for this,
The branch portions 10a and 10b extending from above the cylinder heads 5a and 5b toward the opposed intake ports pass through positions close to the upper surfaces of the inner cam covers 7a and 7b.

On the other hand, on the cam covers 7a and 7b, as shown in FIG.
The blow-by pipes 20a and 20b branched from the intake duct 30 are connected to each other in order to introduce fresh air that replaces the blow-by gas. The blow-by gas is circulated through the blow-by pipes 31a and 31b and the control valves 32a and 32b to the collector portions 9a and 9b downstream of the intake throttle valve, but the blow-by gas is taken out by the blow-by pipe 31a. It is performed only from one cam cover 7c, and the blow-by pipe 31b is branched in the middle.

As shown in FIG. 3 and FIG. 4, the cam covers 7a and 7b of the intake valve system are located between the branches 10a and 10b, and a protrusion 34 is formed on the top surface thereof. The protruding portion 34 is inserted between the branch portions 10a (10b) (7th
See FIG. 8).

In this embodiment, since each branch portion 10a and 10b is divided into three cylinders, the number of protrusions 34 sandwiched between them is two.
The cam covers 7a and 7b are formed individually.
These protrusions 34 arranged orthogonally to the longitudinal direction of the cam cover 7 increase the rigidity strength of the cam covers 7a and 7b as a structure.

A partition wall 35 is formed above the insides of the cam covers 7a and 7b substantially parallel to the top surface thereof, and the partition wall 35 and the cam cover
An oil separation passage 37 for separating oil mist from the blow-by gas is formed between the ceiling wall 36 of 7a, 7b. The oil separation passage 37 has one end opened to the valve operating chamber 38 inside the cam covers 7a and 7b, and the blow-by pipe 20a (20b) is connected to the closed other end. A partition wall 39 is provided so as to project downward from the ceiling wall 36 in the vicinity of the open end of the oil separation passage 37. Further oil separation passage 37
A baffle plate 40, which extends upward from the partition wall 35 toward the protrusion 34, is provided inside the protrusion 34, and a plurality of small partitions are provided between the ceiling wall 36 and between the protrusions 34. The wall 41 is lowered, and a baffle plate 42 is provided so as to project from the partition wall 35 corresponding to these partition walls 41.

In this way, inside the oil separation passage 37, the baffle plate 40 and the partition wall 41 arranged corresponding to the protrusions 34 bend the passage of the blow-by gas to increase the effective passage length, and By changing the flow direction of the blow-by gas, the separating action of oil mist contained in the blow-by gas is enhanced.

The partition wall 35 at the bottom of the oil separation passage 37 is formed with alternating stepped portions 44 corresponding to the protruding portions 34, and drain pipes 45 are attached to the lower portions of these to move the separated oil. It is designed to be returned to the valve chamber 38.

The cam cover 7b in FIG. 4 is provided with an engine oil supply port 46, and all necessary engine oil is supplied from this supply port 46.

5 and 6 show cam covers 7c and 7d of the exhaust valve system. As shown in FIG. 5, in one cam cover 7c to which the blow-by pipe 31a is connected in order to recirculate the blow-by gas to the intake system, as with the oil separation passage 37,
The oil separation passage 48 is provided above the inside of the cam cover 7c, and by the partition wall 50, the baffle plate 51, the partition wall 52, etc.
The flow of blow-by gas is bent to separate the oil mist. 53 is a drain pipe.

However, since the cam cover 7d of FIG. 6 has no connection of the blow-by pipe, no oil separation passage is formed.

In FIG. 2, reference numeral 60 denotes an ignition coil that supplies a high voltage ignition current to the spark plug 61. The ignition coil 60 is provided for each cylinder, and is attached to the side surface of the branch portion 10a to ensure its cooling performance.

It is configured as described above, and the operation will be described below.

Figure 9 shows the flow of blow-by gas.
The blow-by gas blown into the cylinder head side is introduced into the inside of the cam cover 7c on the cylinder head side, while fresh air from the intake duct 30 flows from the blow-by pipes 20a and 20b into the cam cover 7c.
It flows into the insides of a and 7b and is introduced into the crank chamber 22 to replace the blow-by gas.

Blow-by gas is blow-by pipe 31 from cam cover 7c
It is recirculated to the intake collectors 9a and 9b according to the openings of the control valves 32a and 32b through a and 31b.

During normal partial load, the blow-by gas is thus recirculated into the intake air, and at the same time fresh air is taken into the crank chamber 22.

Note that FIG. 7 shows the flow of fresh air in the oil separation passage 37 of the cam cover 7a at the time of partial load.

Further, as shown in FIG. 5, the cam cover 7c is provided with the oil separation passage 48, so that the amount of oil taken out from the blow-by pipe 31a to the intake system can be reduced.

On the other hand, when the amount of blow-by gas generated at the time of high speed and high load increases and the generated pressure in the intake passage (suction negative pressure) also rises, the control valves 31a, 31b that respond to these differential pressures For closing, part of the blow-by gas flows backward from the cam covers 7a, 7b to the intake duct 30 upstream of the throttle valve via the blow-by pipes 20a, 20b.

Fig. 8 shows the oil separation passage when the blow-by gas flows backward.
At 37, the oil mist in the blow-by gas is separated.The oil mist is gradually separated and removed as the blow-by gas flows through the bent oil separation passage 37 while repeatedly colliding with the baffle plate 40 and the like. The separated oil is returned to the valve operating chamber 38 from the drain pipe 45 provided in the partition wall 35 on the bottom surface.

By the way, since the oil separation passage 37 is provided with the baffle plate 40 so as to bite into the protrusion 34, and the effective length of the passage is greatly extended by this, the separation function of the oil mist is remarkably enhanced. Since the 34 is fitted between the branch portions 10a and 10b, the cam covers 7a and 7b do not interfere with the intake manifolds 8a and 8b. In other words, this does not impair the oil separation function and the intake manifold 8a. It means that the mounting position of 8b can be lowered.

By the way, the plurality of protrusions 34 formed orthogonally to the longitudinal direction of the cam covers 7a and 7b serve to enhance the rigidity of the cam covers 7a and 7b as a structural body, and to prevent vibration from the internal valve operating cam mechanism 6. When received, it is possible to reduce the noise emitted from the cover surface.

Although this embodiment shows an example in which the present invention is applied to a V-type 6-cylinder internal combustion engine, it goes without saying that the present invention can be applied to other than this, and in that case, it is sandwiched between branch parts. The number of protrusions also correspondingly increases or decreases.

As described above, according to the present invention, the protrusion is formed on the top surface of the cam cover located between the branch portions of the intake manifold, and the baffle plate is arranged inside the protrusion to form the oil separation passage. Since it is formed, the effective length of the oil separation passage can be sufficiently expanded without interfering with the intake manifold, and the effect of separating oil mist in blow-by gas can be enhanced. Further, this makes it possible to lower the mounting position of the intake manifold and lower the overall height of the engine, and in the case of a bonnet type vehicle, the aerodynamic characteristics can be improved by the low bonnet and the degree of freedom in design can be improved.

Further, since the protrusion formed on the cam cover enhances the rigidity and strength of the structure of the cam cover, there is an effect that vibration of the cam cover is suppressed and radiated noise is reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is its A-
A sectional view taken along the line A, FIGS. 3 to 6 are sectional views of the cam cover, FIGS. 7 and 8 are operation explanatory views of blow-by gas flowing inside the cam cover, and FIG. 9 is an overall blow-by gas. FIG. 10 is a cross-sectional view showing the flow of FIG. 1, FIG. 10 is a cross-sectional view of a conventional example, and FIG. 1a, 1b …… Bank, 5a, 5b …… Cylinder head, 7a, 7b…
… Cam cover, 8a, 8b …… Intake manifold, 9a, 9b ……
Collector part, 10a, 10b …… Branch part, 34 …… Projection part, 3
5 ... Partition, 37 ... Oil separation passage, 40 ... Baffle plate.

Claims (1)

[Scope of utility model registration request] 1. A collector portion of an intake manifold, which is arranged above a cylinder head of each V-shaped bank, and a branch portion branched from the collector portion is connected to each cylinder of an opposing bank. A part of the top surface of the cam cover attached to the cylinder head is projected between the branch parts to define an oil separation passage of blow-by gas above the inside of the cam cover through a partition wall, and this oil separation passage is A cam cover device for a V-type internal combustion engine, wherein a baffle plate is provided at the protruding portion.