JP2000352362A - 4-cycle multi-cylinder engine - Google Patents

Abstract

(57) [Summary] [Object] To provide a four-cycle multi-cylinder engine capable of securing a sufficient ventilation volume in a cylinder head cover without providing a separate ventilation case. The intake air that has passed through an air cleaner is supplied from a surge tank 16 to each cylinder via an intake manifold 19, and blow-by gas is supplied to a cylinder head cover 15.
In the four-cycle multi-cylinder engine 1 that is introduced into the surge tank 16 through the inside, the cylinder head cover 15 and the surge tank 16 are integrated. According to the present invention, since the cylinder head cover 15 and the surge tank 16 are integrated, no gap is formed between them, and a sufficient ventilation volume can be secured in the cylinder head cover 15. No translation case is required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a four-cycle multi-cylinder engine.

[0002]

2. Description of the Related Art For example, in a four-cycle multi-cylinder engine used as an automobile engine, intake air passing through an air cleaner is supplied from a surge tank to each cylinder via an intake manifold, and blow-by gas is supplied through a cylinder head cover. It adopts a method of introducing it into the tank.

[0003]

Incidentally, in the conventional four-cycle multi-cylinder engine, the cylinder head cover and the surge tank are composed of different parts, and a gap is required between the two. The ventilation volume was limited, and a separate ventilation case had to be provided in some cases.

Accordingly, it is an object of the present invention to provide a four-cycle multi-cylinder engine capable of securing a sufficient ventilation volume in a cylinder head cover without providing a separate ventilation case. is there.

[0005] The flow rate of blow-by gas leaking into the crankcase from between the piston and the cylinder wall is controlled by a PCV valve (Positive Crankcase Ventilation Valve). The PCV valve and the surge tank are connected by a hose. Was. For this reason, parts such as hoses and hose clips are required, and a space for the hose is required, which increases the number of parts and reduces the appearance of the engine. The problem of freezing occurred, and I was struggling with the measures.

Accordingly, it is an object of the present invention to provide a four-cycle multi-cylinder engine capable of reducing the number of parts, improving the appearance, and eliminating the freezing problem.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, intake air passing through an air cleaner is supplied from a surge tank to each cylinder via an intake manifold, and blow-by gas is supplied to a cylinder head cover. In the four-cycle multi-cylinder engine that is introduced into the surge tank through the above, the cylinder head cover and the surge tank are integrated.

According to a second aspect of the present invention, in the first aspect of the invention, an engine is mounted on the cylinder head cover.
A DOHC engine having two cam chambers, wherein blow-by gas is taken out from one cam chamber and introduced into the surge tank, and the cam chamber on the blow-by gas take-out side and the surge tank are integrated. .

According to a third aspect of the present invention, in the first or second aspect, a PCV valve is incorporated in the integrated cylinder head cover and surge tank.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a PCV distribution chamber is defined in the integrated cylinder head cover and the surge tank, and the PCV valve faces the PCV distribution chamber. In addition, a surge tank communication hole is formed for each cylinder.

A fifth aspect of the present invention is characterized in that, in the fourth aspect of the invention, the surge tank communication hole is increased as the distance from the PCV valve increases.

Therefore, according to the first or second aspect of the present invention, since the cylinder head cover and the surge tank are integrated, no gap is formed between them and a sufficient ventilation volume is secured in the cylinder head cover. This eliminates the need for a separate ventilation case.

According to the third aspect of the present invention, since the PCV valve is incorporated in the integrated cylinder head cover and surge tank, there is no need to connect the PCV valve and the surge tank with a hose as in the prior art. It is possible to reduce the number of parts, improve the appearance of the engine, eliminate the problem of freezing in the hose, etc.

According to the fourth aspect of the present invention, a PCV distribution chamber is defined in the integrated cylinder head cover and the surge tank, and a PCV valve faces the PCV distribution chamber, and a surge tank for each cylinder is provided. Since the communication holes are formed, the blow-by gas is substantially equally distributed by the surge tank communication holes and supplied to the respective cylinders, so that there is no imbalance in the output between the cylinders.

According to the fifth aspect of the present invention, since the surge tank communication hole is made larger as being farther from the PCV valve, blow-by gas is more evenly distributed to each cylinder by the surge tank communication hole.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a partially broken sectional view of a four-cycle engine according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

A four-cycle multi-cylinder engine (hereinafter simply referred to as an engine) 1 according to the present embodiment is a four-cycle
In the cylinder engine, as shown in FIG. 1, an intake passage 3 and an exhaust passage 4 are formed in a cylinder head 2 for each cylinder, and an intake passage 3 and an exhaust passage 4 are formed in a combustion chamber S.
The intake port 3a and the exhaust port 4a which are opened at the appropriate timing are respectively opened and closed by the intake valve 5 and the exhaust valve 6 at appropriate timing to perform required gas exchange.

That is, the intake valve 5 and the exhaust valve 6
Are the valve guides 7, 8 press-fitted into the cylinder head 2.
Slidably inserted and held by
It is urged to the closing side by the valve springs 9 and 10,
The intake cam 13a and the exhaust cam 14a are in contact with each other via the valve lifters 11 and 12, respectively.

The intake cam 13a and the exhaust cam 14a are integrally formed on the intake cam shaft 13 and the exhaust cam shaft 14, respectively, and these are DOHC (Double Overhead Camshaft).
ft) type valve train. When the intake camshaft 13 and the exhaust camshaft 14 are driven to rotate, the intake valve 5 and the exhaust valve 6 are opened and closed at appropriate timings as described above.

Further, as shown in FIG.
A cylinder head cover 15 is attached to an upper part of the cylinder head, and a cylinder block (not shown) is attached to a lower part of the cylinder head 2. Four cylinder heads are arranged on the cylinder block in a direction perpendicular to the plane of FIG. A piston (not shown) is slidably fitted to each of the cylinders. still,
An ignition plug (not shown) is screwed into the center of each cylinder of the cylinder head 2, and an injector (not shown) for injecting fuel into each intake passage 3 is attached to the intake side.

The cylinder head cover 15
, An intake side cam chamber S1 and an exhaust side cam chamber S2 are formed, respectively, and a surge tank 16 is integrally formed above a portion of the cylinder head 2 which constitutes the intake side cam chamber S1. An air cleaner (not shown) is connected to the center of one end wall of the surge tank 16 in the width direction via a throttle body 17.
At the other end wall, four intake manifolds 19 penetrate, and one end of each intake manifold 19 having a bell mouth shape facing the surge tank 16 is suitable for the length direction of the surge tank 16 as shown in FIG. Open in parallel with an interval,
The other end is connected to each intake passage 3 formed in the cylinder head 2. The throttle body 17
Is provided with a throttle valve 20.

The PCV distribution chamber S3 defined by the plate 21 is formed in the intake cam chamber S1 in the cylinder head cover 15, and the plate 21 has a PCV valve 22 opening to the PCV distribution chamber S3. Is attached. Here, when the openings of the intake manifold 19 corresponding to the first to fourth cylinders to the surge tank 16 are denoted by reference numerals # 1 to # 4 as shown in FIG.
The CV valve 22 has openings # of the intake manifolds 19 of the first cylinder and the second cylinder in the length direction of the surge tank 16.
It is arranged at a position between # 1 and # 2.

As shown in FIG. 2, the upper wall (bottom wall of the surge tank 16) 15a of the cylinder head cover 15, which divides the surge tank 16 and the PCV distribution chamber S3, has a portion where the PCV valve 22 is mounted. Each intake manifold 19 of the upper wall (bottom wall of the surge tank 16) 15a of the cylinder head cover 15 bulges upward into the surge tank 16 avoiding the PCV valve 22.
Surge tank communication holes 23, 24, 25, 26 are formed at positions corresponding to the centers of the openings # 1 to # 4, respectively. In addition, each surge tank communication hole 23-26 is PCV
As the distance from the valve 22 increases, the diameters d ₁ , d ₂ , d ₃ ,
d ₄ is set to increase. That is, the diameter d
_The diameter d ₁ ≒ d ₂ <d ₃ <between ₁ , d ₂ , d ₃ and d ₄
the magnitude relationship of d ₄ is established.

On the other hand, as shown in FIG. 2, a flow path 27 is formed at one end of the cylinder head cover 15 between the side wall of the surge tank 16 and the flow path 27.
The two channels 27A and 27B are partitioned by the plate 8 and the plate 29, and the two channels 27A and 27B communicate with each other through a communication hole 28a formed in the partition wall 28. The flow path 27A is formed in a maze shape by a plurality of baffle plates 30.

When the engine 1 is started and the intake valve 5 is opened during an intake stroke in which a piston (not shown) of each cylinder descends in each cylinder, fresh air sucked from an air cleaner (not shown) is released. The measured fresh air is supplied to the cylinder head 2 through the intake manifold 19 through the surge tank 16, and a predetermined amount of fresh air is supplied from an injector (not shown) while flowing through the intake passage 3 of the cylinder head 2. Fuel is injected to form a mixture having a required air-fuel ratio (A / F). The air-fuel mixture flows from the intake passage 3 into the cylinder of a cylinder block (not shown). In this intake stroke, the exhaust valve 6 is closed.

Thereafter, when the piston moves to a compression stroke in which the piston starts rising after passing through the bottom dead center (BDC), the intake valve 5 is closed, and the air-fuel mixture in the cylinder is compressed by the piston. Immediately before reaching (TDC), the air-fuel mixture is ignited and burned by an unillustrated spark plug, and the piston receives a high combustion pressure generated by the combustion of the air-fuel mixture on its top surface, and in the explosion stroke in which the piston descends in the cylinder, the intake air is taken. The valve 5 and the exhaust valve 6 are both closed. When the piston reaches the vicinity of the bottom dead center, the exhaust valve 6 is opened, and the high-temperature and high-pressure exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber S is discharged from the exhaust port 4a through the exhaust port 4a during the exhaust stroke in which the piston rises. The exhaust gas is discharged to the atmosphere through an exhaust manifold (not shown) connected to the exhaust passage 4.

Thereafter, the same operation as described above is repeated, and the engine 1 is continuously operated. However, blow-by gas leaking from between the piston and the cylinder wall is pulled by the intake negative pressure and the intake air of the cylinder head cover 2 is sucked. It is introduced into the side cam chamber S1, flows through the labyrinthine flow path 27A as shown by the arrow in FIG. 2, and flows through the communication hole 28a to the flow path 27B. The blow-by gas flows into the PCV distribution chamber S3 after the flow rate is controlled by the PCV valve 22, and is introduced from the PCV distribution chamber S3 into the surge tank 16 through the surge tank communication holes 23 to 26. Almost evenly distributed to the intake manifold 19 and the intake manifold 1 with fresh air
9 and is supplied to the cylinders of the respective cylinders, and is supplied to the combustion chamber S together with the air-fuel mixture.

Thus, in the engine 1 according to the present embodiment, the cylinder head cover 15 and the surge tank 1
6 is integrated, so no gap is formed between the two.
A sufficient ventilation volume can be ensured in the cylinder head cover 15, and it is not necessary to provide a separate ventilation case.

Further, the integrated cylinder head cover 1
5 and the surge tank 16 incorporate the PCV valve 22, so that the PCV valve 22 and the surge tank 16
It is not necessary to connect the hose and the hose, and the hose can be eliminated to reduce the number of parts, improve the appearance of the engine 1, eliminate the problem of freezing in the hose, and the like.

Further, in the present embodiment, a PCV distribution chamber S3 is defined in the intake side cam chamber S1 in the cylinder head cover 15, and the PCV valve 22 faces the PCV distribution chamber S3. Since the passed blow-by gas is introduced into the surge tank 16 through the surge tank communication holes 23 to 26 of each cylinder, the blow-by gas is substantially equally distributed by the surge tank communication holes 23 to 26 and supplied to each cylinder. Therefore, no imbalance occurs in the output between the cylinders. In particular, in the present embodiment, as described above, the surge tank communication hole 22
26 is the diameter d as the distance from the PCV valve 22 increases.
₁ , d ₂ , d ₃ , and d ₄ are set to be large (d ₁ ≒ d ₂ <d ₃ <d ₄ ), so that blow-by gas is supplied to each cylinder through 23 to 26 in these surge tank communication holes. It is evenly distributed.

Here, a modification of the present embodiment is shown in FIG. 3. As shown in FIG. 3, a PCV distribution chamber S3 is defined in the surge tank 16 by a separate partition wall 31, and the partition wall 31 is formed. May be formed with surge tank communication holes 22 to 26.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 4 shows a DOHC 4 according to this embodiment.
FIG. 5 is a partial sectional view of the cycle engine, and FIG.
FIG. 3 is a cross-sectional view, in which the same elements as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted below.

In the engine 1 according to the present embodiment, the cylinder head cover 15 and the surge tank 16 are integrated, but in the present embodiment, the integrated cylinder head cover 15 and the PCV distribution chamber in the surge tank 16 are formed. Not provided, cylinder head cover 15 and surge tank 1
The PCV valve 22 is attached to the upper wall (bottom wall of the surge tank 16) 15 a of the cylinder head cover 15 which defines the PCV 6 and the PCV valve 22. The PCV valve 22 is opened in the surge tank 16. The flow path 27B is formed by a plurality of baffle plates 15a-1 protruding integrally with the upper wall (bottom wall of the surge tank 16) 15a of the cylinder head cover 15 and a plurality of baffle plates 29a protruding from the plate 29. It is configured in a shape.

In the engine 1 according to the present embodiment, the flow rate of the blow-by gas flowing from the flow path 27A to the flow path 27B through the communication hole 28a is controlled by the PCV valve 22,
6, and is distributed to the intake manifolds 19 of the respective cylinders as indicated by arrows in FIG.
To be burned.

Thus, also in this embodiment, the cylinder head cover 15 and the surge tank 16 are integrated, and the integrated cylinder head cover 15 and the surge tank 1 are integrated.
Since the PCV valve 22 is built in the sixth embodiment, the same effects as in the first embodiment can be obtained.

[0038]

As is apparent from the above description, claim 1
According to the invention described in (2), since the cylinder head cover and the surge tank are integrated, no gap is formed between them and a sufficient ventilation volume can be secured in the cylinder head cover, and a separate bench is provided. This has the effect of eliminating the need for a translation case.

According to the third aspect of the present invention, since the PCV valve is built in the integrated cylinder head cover and surge tank, it is not necessary to connect the PCV valve and the surge tank with a hose as in the related art. It is possible to reduce the number of parts, improve the appearance of the engine, and eliminate the problem of freezing in the hose.

According to the fourth aspect of the present invention, a PCV distribution chamber is defined in the integrated cylinder head cover and the surge tank, and a PCV valve faces the PCV distribution chamber, and a surge tank for each cylinder is provided. Since the communication holes are formed, the blow-by gas is substantially equally distributed by the surge tank communication holes and supplied to the respective cylinders, so that the effect that the output of each cylinder can be maintained substantially equal is obtained.

According to the fifth aspect of the present invention, since the surge tank communication hole is made larger as being farther from the PCV valve, the effect that the blow-by gas can be more evenly distributed to each cylinder by the surge tank communication hole is obtained. Can be

[Brief description of the drawings]

FIG. 1 is a partially broken sectional view of a four-stroke engine according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view similar to FIG. 2, showing a modification of the four-stroke engine according to Embodiment 1 of the present invention.

FIG. 4 is a partially broken sectional view of a four-stroke engine according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

[Explanation of symbols]

 1 4-cycle multi-cylinder engine 2 Cylinder head 15 Cylinder head cover 16 Surge tank 19 Intake manifold 22 PCV valve 23-26 Surge tank communication hole S1 Intake side cam chamber S2 Exhaust side cam chamber S3 PCV distribution chamber

Claims (5)

[Claims] 1. A four-cycle multi-cylinder engine for supplying intake air passing through an air cleaner from a surge tank to each cylinder via an intake manifold, and introducing blow-by gas into the surge tank via a cylinder head cover. And a surge tank integrated with a DOHC four-cycle multi-cylinder engine. 2. A DOHC engine having two cam chambers in said cylinder head cover, wherein blow-by gas is taken out from one cam chamber and introduced into said surge tank. The four-cycle multi-cylinder engine according to claim 1, wherein the surge tank and the surge tank are integrated. 3. The four-cycle multi-cylinder engine according to claim 1, wherein a PCV valve is incorporated in the integrated cylinder head cover and surge tank. 4. A PCV distribution chamber is defined in the integrated cylinder head cover and the surge tank, and the PCV valve faces the PCV distribution chamber, and a surge tank communication hole for each cylinder is formed. The four-cycle multi-cylinder engine according to claim 3, wherein: 5. The four-stroke multi-cylinder engine according to claim 4, wherein the surge tank communication hole is increased as the distance from the PCV valve increases.