JP2982681B2 - Cylinder head of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head for an internal combustion engine mounted on an automobile or the like, and more particularly to a technique for reducing the size of the cylinder head.

[0002]

2. Description of the Related Art In a multi-cylinder DOHC engine mounted on an automobile, it is required to reduce the width of the upper part of the engine as much as possible in order to improve mountability in an engine room and reduce weight. In particular, when the cylinder arrangement is V-type or mounted horizontally, the extra space in the engine room is reduced by the wide cylinder head and the intake and exhaust manifold connected to it, and the layout of auxiliary equipment It was often difficult to expand the crushable zone. Therefore, conventionally, attempts have been made to reduce the width of the cylinder head by reducing the interval between the intake and exhaust camshafts and by preventing the intake manifold from projecting from the side surface of the cylinder head. For example, Japanese Patent Application Laid-Open No. 5-457
No. 61, etc., an inner pivot type swing arm is interposed between the intake / exhaust camshaft and the intake / exhaust valve, thereby keeping the included angle of the intake / exhaust valve and the valve lift at appropriate values. However, the distance between the camshafts and the cam lift are reduced. Also, Japanese Patent Application Laid-Open No. 61-261644
In this publication, an upright intake port (hereinafter, referred to as an upright intake port) is disposed between intake and exhaust camshafts, whereby an intake manifold (or
(Intake pipe) is connected to the upper surface of the cylinder head.

[0003]

When the inner pivot type swing arm and the upright intake port are used together, it is conceivable to make the width of the cylinder head smaller. In addition to the plug, the intake / exhaust pivot and the upright intake port concentrate on the upper portion of the combustion chamber, and there has been a problem that the layout of the portion becomes extremely difficult. In particular, if the valve system is a four-valve system with excellent intake and exhaust efficiency, a pair of intake and exhaust pivots and upright intake ports are required, and if a hydraulic lash adjuster that does not require adjustment of the intake and exhaust pivots is used, Such a tendency is further increased because the diameter of the mounting boss is increased. As a result, the cross-sectional area and the shape of each part of the upright intake port are undesired, and the deterioration of the intake efficiency and the intake flow shape has necessitated a decrease in output and an increase in harmful exhaust gas components.

[0004] The present invention has been made in view of the above situation,
An object of the present invention is to provide a cylinder head of an internal combustion engine in which deterioration of intake efficiency and intake flow shape is suppressed as much as possible while employing an inner pivot type swing arm and an upright intake port together.

[0005]

According to claim 1 of the present invention,
To achieve this object, an intake valve that shuts off communication between the intake port and the combustion chamber, an exhaust valve that shuts off communication between the exhaust port and the combustion chamber, an intake camshaft that drives the intake valve to open and close, An exhaust camshaft for driving the exhaust valve to open and close, a swing arm interposed at least between the intake camshaft and the intake valve or between the exhaust camshaft and the exhaust valve, and swinging the swing arm A freely supporting pivot, wherein the intake port is an upright port along a cylinder axis of the combustion chamber, and the pivot is disposed as an inner pivot between the intake camshaft and the exhaust camshaft. In the cylinder head of the internal combustion engine, the upright port may include:
In order to secure an interval with the inner pivot, a camshaft that is curved in the axial direction of the camshaft is proposed.

As for the positional relationship between the pivot and the upright port, the swing arm is a swing arm on the intake side,
A pivot is provided between the upright port and the intake camshaft, or between the upright port and the exhaust camshaft,
Also, the swing arm is a swing arm on the exhaust side, and the pivot is between the upright port and the exhaust cam shaft,
Alternatively, it may be provided between the upright port and the intake camshaft.

According to a second aspect of the present invention, there is provided the cylinder head according to the first aspect, wherein the upright port is flat in the direction perpendicular to the axis of the camshaft at the curved portion. According to a third aspect, in the cylinder head according to the first or second aspect, two of the intake valves are provided in the axial direction of the camshaft with respect to the combustion chamber, and two of the intake valves are respectively provided in the two intake valves. A swing arm and the pivot are provided, and the upright port is bifurcated from the lower end to the upper end to at least an intermediate position so that the intake valve is interposed therebetween, and the upright ports are separated from each other. The one that is curved in the direction is proposed.

According to a fourth aspect of the present invention, there is provided the cylinder head according to the first to third aspects, wherein the inner pivot is a hydraulic lash adjuster. Claim 5
In the cylinder head according to any one of claims 1 to 4, the inner pivot is both the intake-side pivot and the exhaust-side pivot, and the upright port has the intake port in a direction orthogonal to the axes of the two camshafts. It is proposed to be arranged between the side pivot and the exhaust side pivot.

According to a sixth aspect of the present invention, there is provided the cylinder head of the third aspect, wherein the upright ports are independently formed up to the upper surface of the cylinder head. Claim 7 proposes the cylinder head according to claims 1 to 6, which is a direct injection internal combustion engine including a fuel injection valve for directly injecting fuel into the combustion chamber.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a direct injection gasoline engine to which the present invention is applied.
1 shows an in-line four-cylinder engine body (hereinafter simply referred to as engine) in which an R device and the like are designed exclusively for in-cylinder injection.

In this embodiment, an electromagnetic fuel injection valve 4 is mounted on a cylinder head 2 of the engine 1 together with a spark plug 3 for each cylinder, and fuel is directly injected into a combustion chamber 5. . A hemispherical cavity 8 is formed on the top surface of the piston 7 slidably held up and down by the cylinder 6 at a position where the fuel spray from the fuel injection valve 4 reaches in the latter stage of the compression stroke. The theoretical compression ratio of the engine 1 is set higher (about 12 in the present embodiment) than that of the intake pipe injection type. A DOHC 4-valve valve mechanism is adopted as the valve operating mechanism. An intake camshaft 11 and an exhaust camshaft 12 are rotatably held above the cylinder head 2 to drive the intake and exhaust valves 9 and 10, respectively. ing.

The cylinder head 2 has two camshafts 1.
1 and 12 so that the upright intake port 13
Is formed, and the intake air flow passing through the upright intake port 13 generates a reverse tumble flow described later in the combustion chamber 5. Further, the exhaust port 14 is formed in a substantially horizontal direction similarly to a normal engine, but a large-diameter EGR port (not shown) branches obliquely downward. The upright intake port 13 has a surge tank 23 connected to a throttle body (not shown) via an intake manifold 21.
Is connected. On the other hand, an exhaust pipe (not shown) including a three-way catalyst, a muffler, and the like is connected to the exhaust port 14 via an exhaust manifold 31. The EGR port is connected to the upstream of the intake manifold 21 via a large-diameter EGR pipe 32, and a stepper motor type EGR valve 33 is provided in the pipeline. In the figure,
Reference numeral 34 denotes a high-pressure fuel pump driven by the exhaust camshaft 12, and the high-pressure fuel pump 50 to
Generates a discharge pressure of kg / cm ² or more.

As shown in FIG. 2, between the intake and exhaust valves 9, 10 and the intake and exhaust camshafts 11, 12, hydraulic lash adjusters (hereinafter, referred to as HLA) 51, 52 swing freely. The supported intake side swing arm 53 and exhaust side swing arm 54 are interposed. In the case of the present embodiment, both the intake side HLA 51 and the exhaust side HLA 52
An inner pivot is arranged between the intake and exhaust camshafts 11 and 12. Immediately above the combustion chamber 5, a plug hole 60 for inserting the ignition plug 3 is formed at a position slightly inclined toward the exhaust valve 10 with respect to the cylinder axis LC.

Next, referring to FIG. 3 (a perspective view around the upright intake port 13), FIG. 4 (a view taken in the direction of the arrow IV in FIG. 3) and FIG. 5 (a view taken in the direction of the arrow V in FIG. 3), the present embodiment will be described. The shape of the upright intake port 13 in the embodiment will be described. In the description, for the sake of convenience, a direction parallel to the axis of the intake and exhaust camshafts 11 and 12 (left-right direction in FIG. 4) is referred to as front and rear, and a direction orthogonal to this (left-right direction in FIG. 3) is referred to as left and right. .

As shown in FIGS. 3 to 5, the upright intake port 13 is connected to a pair of left and right independent ports (hereinafter referred to as left and right ports) 13A and 13B from the upper end surface of the cylinder head 2 to the combustion chamber 5. Has become. These left and right ports 13A and 13B are formed in a symmetrical shape on the left and right sides, and open on the upper end surface of the cylinder head 2 to the left and right of the plug hole 60, and have an inner peripheral surface for ensuring a sufficient interval with the plug hole 60. It is curved along the plug hole 60.

Now, when viewed from the side (that is, FIG.
Then, after the left and right ports 13A and 13B descend from the upper end surface of the cylinder head 2 along the cylinder axis LC,
It is open to the combustion chamber 5 while smoothly bending backward.
As a result, the intake air flow (indicated by arrows) passing through the left and right ports 13A and 13B flows into the combustion chamber 5 toward the rear of the piston 7, and a strong reverse tumble flows along the cavity 8 on the top surface of the piston 7. A flow (clockwise swirling flow in FIG. 3) is generated.

Also, when viewed from behind (ie, FIG.
Then, the left and right ports 13A, 13B are once bent outward (ie, away from each other) from the upper end surface of the cylinder head 2 to avoid the intake / exhaust side HLAs 51, 52, and then become substantially parallel and open to the combustion chamber 5. doing. And
As shown in FIG. 6, the left and right ports 13A, 13B are formed flat in the front-rear direction in the curved portion, and the interval between the left and right ports 13A, 13B and the intake / exhaust side HLAs 51, 52 is a predetermined value (several mm in this embodiment). While securing the above, a necessary and sufficient passage cross-sectional area is maintained.

On the other hand, as shown in FIG.
3A and 13B are gradually spaced apart from the plug hole 60 in the left-right direction in the lower half thereof. Therefore, as shown in FIGS. 7 and 8, the distance between the left and right ports 13A and 13B is set to a predetermined value (several mm in this embodiment).
While securing the above, it communicates with the combustion chamber 5 without sharp bending back and forth. As a result, as shown in FIG. 4, the intake air flowing through the left and right ports 13A and 13B flows into the combustion chamber 5 in a substantially parallel state, so that the flow is prevented from being disturbed by the collision of the intake air. it can.

As described above, in the cylinder head 2 of the present embodiment, the intake / exhaust side HLAs 51 and 52 and the plug holes 6 are provided.
0 while ensuring the smoothness of the intake air flow.
Can be formed. As a result, a strong reverse tumble flow can be generated in the combustion chamber 5, and an appropriate cross-sectional area of the passage can be secured, so that the thermal efficiency and the output can be improved.

In this embodiment, the upright intake port 1
3 and the intake / exhaust side swing arms 53, 5
By using the inner pivot 4, the interval between the intake and exhaust camshafts 11 and 12 could be reduced. As a result, the width of the cylinder head 2 is reduced, so that the mountability in the engine room and the weight are reduced, and the intake and exhaust camshafts are not reduced without reducing the angle between the intake and exhaust valves 9 and 10. It has become possible to connect 11, 12 with a scissor gear or the like.

In this embodiment, the swing arms 53 and 54 on the intake and exhaust sides are formed as inner pivots.
The mounting angle of the fuel injection valve 4 (the angle formed with respect to the cylinder axis LC) can be reduced, thereby improving the engine performance. The reason will be described below. In the direct injection gasoline engine, fuel is injected into the cavity 8 on the top surface of the piston 7 at a later stage of the compression stroke in a low load operation range such as an idling operation. Therefore, in order to improve the controllability of the fuel injection in the low load operation range, the piston 7
It is desirable to be able to inject fuel into cavity 8 even if is located relatively below. In other words, in this embodiment, the mounting angle of the fuel injection valve 4 is reduced,
Even if the injection timing is advanced or the injection time is extended, the cavity 8
Leakage of fuel spray to the outside was reduced, fuel efficiency could be improved, and harmful exhaust gas components due to incomplete combustion could be reduced.

In the high-load operation range, fuel is injected in the first half of the intake stroke. In this case, it is desirable that the fuel is uniformly mixed in the combustion chamber 5 so that the spray does not adhere to the cylinder as much as possible. In other words, in the present embodiment, the fuel injection valve 4
By reducing the angle of attachment, the spray from the fuel injection valve 4 is less likely to adhere to the cylinder, the output can be improved, and the harmful exhaust gas component caused by incomplete combustion can be reduced. I could do it.

The description of the specific embodiment is finished above, but aspects of the present invention are not limited to this embodiment.
For example, in the above embodiment, the present invention is applied to an in-line four-cylinder four-valve direct injection gasoline engine. However, the present invention is applied to a single-cylinder engine, a V-type six-cylinder engine, and the like in which the number of cylinders and their arrangement are different. The present invention may be applied to a three-valve type, a five-valve type, or the like, or may be applied to an intake pipe injection gasoline engine or the like. Further, in the above embodiment, the upright port is only the intake port, but the exhaust port may be an upright port. In the above embodiment, both the intake and exhaust swing arms are inner pivots, but one may be an outer pivot. Further, the intake side swing arm may be extended, and the intake side inner pivot may be disposed between the exhaust camshaft and the upright intake port. In this case, the upright intake port may interfere with the valve mechanism member (for example, HLA). It is not necessary to lean more than necessary to the exhaust side for prevention,
It is possible to increase the degree of freedom of the layout of the upright intake port for improving the intake characteristics. Furthermore, the upright intake port is less subject to space restrictions due to interference with the valve operating mechanism member (specifically, the swing arm), that is, the degree of curvature of the upright intake port and the bending range in the cylinder axis direction are reduced. The layout can be set to be small, and the layout setting that suppresses the deterioration of the intake characteristics becomes easy. Further, in the above embodiment, the present invention is applied to the case where the ignition plug is disposed at the center of the cylinder head and the fuel injection valve is disposed at the side part, but the positions of the ignition plug and the fuel injection valve are switched. May be applied. Further, the specific configuration of the device, the specific shape of the upright intake port, and the like can be changed without departing from the gist of the present invention.

[0024]

According to the first aspect of the present invention, an intake valve for interrupting communication between an intake port and a combustion chamber, an exhaust valve for interrupting communication between an exhaust port and a combustion chamber, and opening and closing of the intake valve An intake camshaft to be driven; an exhaust camshaft to open and close the exhaust valve; a swing arm interposed at least between the intake camshaft and the intake valve or at least one of the exhaust camshaft and the exhaust valve; A pivot for swingably supporting the swing arm, the intake port being an upright port along a cylinder axis of the combustion chamber, and the pivot being an inner pivot, the intake camshaft and the exhaust camshaft being provided. In the cylinder head of the internal combustion engine arranged between the camshaft and the inner pivot, the upright port is provided with a camshaft. The output is due to the reduction of the cross-sectional area of the upright port and the deterioration of the shape while improving the mountability in the engine room and reducing the weight by reducing the size of the cylinder head because it is curved in the axial direction of the Decline,
Deterioration of intake characteristics and increase of harmful exhaust gas components can be prevented.

According to the second aspect, in the cylinder head according to the first aspect, the upright port is flat in the direction perpendicular to the axis of the camshaft at the curved portion. , And a decrease in cross-sectional area can be prevented. According to the third aspect, in the cylinder head according to the first or second aspect, two of the intake valves are disposed in the axial direction of the camshaft with respect to the combustion chamber, and two intake valves are provided. The swing arm and the pivot are provided, respectively, and the upright port is branched into two from the lower end to the upper end at least to an intermediate position so that the intake valve is interposed therebetween. When the intake air flows (tumble flows) are formed in the combustion chamber because they are curved in the direction in which they are separated from each other, the intake air flows flowing into the combustion chamber from the respective upright ports flow into the exhaust chamber when they flow into the combustion chamber. Components and swirl flow components around the cylinder axis are suppressed, so that the intake air flow (tumble flow) in the combustion chamber is disturbed and the intake efficiency is deteriorated. Prevention was, a suitable upright port shapes can be realized.

According to the fourth aspect, in the cylinder head according to the first to third aspects, the inner pivot is a hydraulic lash adjuster, so that the valve clearance can be properly adjusted without performing a periodic adjustment. Value can be maintained. According to the fifth aspect, in the cylinder head according to the first to fourth aspects, the inner pivot is both the intake-side pivot and the exhaust-side pivot, and in a direction orthogonal to the axes of the two camshafts. Since the upright port is arranged between the intake-side pivot and the exhaust-side pivot, the upright port can be arranged near the cylinder axis while securing an interval between the two pivots, The size and weight of the cylinder head can be further reduced.

According to the sixth aspect, in the cylinder head according to the third aspect, the upright ports are formed independently up to the upper surface of the cylinder head. It becomes easy to secure the interval with the pivot. According to a seventh aspect of the present invention, in the cylinder head according to the first to sixth aspects, the cylinder head is a direct injection internal combustion engine including a fuel injection valve for directly injecting fuel into the combustion chamber. A suitable upright port is provided to ensure that the intake air flow in the combustion chamber, which is important in the engine, can be generated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a direct injection gasoline engine according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a cylinder head and a cylinder according to the embodiment.

FIG. 3 is a perspective view around an upright intake port.

FIG. 4 is a view as viewed from an arrow IV in FIG. 3;

FIG. 5 is a view as seen from the arrow V in FIG. 3;

FIG. 6 is a sectional view taken along line VI-VI in FIG. 3;

FIG. 7 is a sectional view taken along line VII-VII in FIG. 3;

FIG. 8 is a sectional view taken along line VIII-VIII in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 3 Spark plug 4 Fuel injection valve 5 Combustion chamber 6 Cylinder 7 Piston 8 Cavity 9 Intake valve 10 Exhaust valve 11 Intake camshaft 12 Exhaust camshaft 13 Intake port 13A Left port 13B Right port 14 Exhaust port 51,52 Hydraulic rush Adjuster 53, 54 Swing arm 60 Plug hole LC Cylinder axis

Continuation of the front page (56) References JP-A-62-243945 (JP, A) JP-A-61-261644 (JP, A) JP-A-4-31656 (JP, A) JP-A-3-97505 (JP) , A) Japanese Utility Model 3-108837 (JP, U) Japanese Utility Model 3-5218 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02F 1/42 F01L 1/00 F01L 1/24 F01L 1/26 F02B 23/10

Claims (7)

(57) [Claims] An intake valve for interrupting communication between an intake port and a combustion chamber; an exhaust valve for interrupting communication between an exhaust port and a combustion chamber; an intake camshaft for driving the intake valve to open and close;
An exhaust camshaft for driving the exhaust valve to open and close, a swing arm interposed at least between the intake camshaft and the intake valve or between the exhaust camshaft and the exhaust valve, and swinging the swing arm A freely supporting pivot, wherein the intake port is an upright port along a cylinder axis of the combustion chamber, and the pivot is disposed as an inner pivot between the intake camshaft and the exhaust camshaft. A cylinder head for an internal combustion engine, wherein the upright port is curved in an axial direction of the camshaft so as to secure an interval with the inner pivot. 2. The cylinder head for an internal combustion engine according to claim 1, wherein the upright port is flattened in a direction orthogonal to an axis of the camshaft at the curved portion. 3. The intake valve is disposed two in the axial direction of the camshaft with respect to the combustion chamber, and the two intake valves are provided with the swing arm and the pivot, respectively, and the upright port is provided. Is characterized in that the intake valve is bifurcated from the lower end to the upper end to at least the intermediate position so as to be interposed, and the upright ports are curved in a direction away from each other, A cylinder head for an internal combustion engine according to claim 1 or 2. 4. The cylinder head of an internal combustion engine according to claim 1, wherein the inner pivot is a hydraulic lash adjuster. 5. The intake port pivot and the exhaust port pivot, and the upright port is connected to the intake port pivot and the exhaust port pivot in a direction orthogonal to the axes of the camshafts. The cylinder head for an internal combustion engine according to any one of claims 1 to 4, wherein the cylinder head is disposed between the cylinder head and the cylinder head. 6. The cylinder head for an internal combustion engine according to claim 3, wherein the upright ports are formed independently up to an upper surface of the cylinder head. 7. The internal combustion engine according to claim 1, wherein the engine is a direct injection type internal combustion engine including a fuel injection valve for directly injecting fuel into the combustion chamber. cylinder head.