JP2000240506A - Cylinder head for multicylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact fluid passage of an internal combustion engine, which is comparatively easily formed so as not to increase a manufacturing cost and a size. SOLUTION: A groove 15 is formed on an outer surface of a cylinder head 1, continuously in a cylinder line direction. An opening surface of the groove 15 is covered with a lid 1 to form a fluid passage 17. It is thus possible to easily form passages corresponding to cylinders only by forming the grooves 15 on the side surface of the cylinder heads 1. An increase in a manufacturing cost is suppressed.

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 a multi-cylinder engine.

[0002]

2. Description of the Related Art In a gasoline engine, in order to achieve both high levels of exhaust purification and high output, a technique of feeding fresh air into an exhaust passage and reburning unburned components in the exhaust has already been practically used. (See JP-A-5-79325).

[0003] The fresh air sent into the exhaust gas is preferably at a somewhat high temperature in order to activate the catalyst, and its passage is preferably provided at a position where the exhaust gas can be preheated.

[0004]

However, in general, it is desired to further reduce the manufacturing cost and promote the miniaturization of a mass-produced engine. However, it is difficult to form the above passage at a position close to the exhaust port. Not easy,
This has necessitated an increase in engine manufacturing costs and an increase in the size of the cylinder head.

[0005] The present invention has been devised to solve such problems of the prior art, and its main objects are as follows.
An object of the present invention is to provide a cylinder head of a multi-cylinder engine configured so that a fluid passage can be formed relatively easily and compactly without increasing the manufacturing cost and increasing the size.

[0006]

In order to achieve the above object, according to the present invention, a continuous groove 15 is formed in the outer surface of the groove along the direction of the cylinder rows, and the opening surface of the groove is formed. This is attained by providing the cylinder head 1 of the multi-cylinder engine, wherein the fluid passage 17 is formed by closing with the lid 16.

In this way, the fluid passage corresponding to each cylinder 4 can be easily formed only by forming a groove on the side surface of the cylinder head 1, thereby increasing the manufacturing cost and increasing the size of the cylinder head. You don't have to.

In particular, a branch passage (secondary air port 14) to the exhaust port 6 of each cylinder is provided on the bottom surface of the groove, and the sectional area of the fluid passage is gradually reduced toward the downstream side. If it is used as a secondary air introduction passage, the cross-sectional area of the downstream side of the fluid passage decreases as the secondary air port is branched to each cylinder,
It is possible to further reduce the size of the fluid passage while ensuring the amount of secondary air supplied to each cylinder.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a main part of an in-line multi-cylinder engine E to which the present invention is applied. The cylinder head 1 of the engine E has a combustion chamber 5 formed between the cylinder head 2 and an upper surface of a piston 4 that slides on a cylinder 3 provided inside the cylinder block 2, and a combustion chamber 5 extending to the side of the cylinder head 1. An exhaust port 6 and an intake port 7 extending from the And the exhaust port 6 and the intake port 7
An exhaust valve 11 and an intake valve 12 which are opened and closed via a rocker arm 10 by a rotating cam 9 formed on a cam shaft 8 provided above the cylinder head 1 are provided.

The valve operating mechanism including the camshaft 8 and the rocker arm 10 is covered by a head cover 13 joined to the upper surface of the cylinder head 1.

Between the upper surface of the cylinder head 1 and the exhaust port 6, secondary air for introducing unreacted components in the exhaust gas into the exhaust passage including the exhaust port 6 for reburning unburned components. The port 14 is connected to the exhaust valve 11 from the bottom of the groove 15 formed in the side of the cylinder head 1 on the exhaust port 6 side.
It is drilled toward. The opening surface of the groove 15 is closed by a lid 16 formed by pressing a stainless steel plate, for example, and a fluid passage for introducing secondary air is provided between the bottom surface of the groove 15 and the inner surface of the lid 16. 17 are formed.

As shown in FIG. 2, the groove 15 is continuously wavy in the cylinder row direction from the end on the fourth cylinder side of the cylinder head 1 to a position corresponding to the first cylinder. It is recessed. The groove width of the groove 15 is changed from the fluid passage 17 toward the end of the fourth cylinder, that is, from the upstream side of the fluid passage 17 to the end of the first cylinder, that is, the downstream side of the fluid passage 17. As the number of branched secondary air ports 14 decreases, the width gradually decreases.

As shown in FIG. 3, the lid 16 for closing the groove 15 is fixed at its essential parts to the mounting surface of the exhaust manifold 19 in the cylinder head 1 using bolts B. The outer peripheral contour of the flange 18 corresponds to the outer peripheral contour of the flange 20 of the exhaust manifold 19. By minimizing the outer contours of 18, 20 the contours are kept to a minimum.

A gasket (not shown) is sandwiched between the cylinder head 1 and the lid 16, and the gasket is inserted between the cylinder head 1 and the flange 20 of the exhaust manifold 19.
When integrated with a gasket sandwiched between the components, the number of parts does not need to be increased.

The outer peripheral edge of the lid 15 is folded back from the contact surface of the flange 18 with the cylinder head 1. The folded portion 18a not only enhances the rigidity of the lid 15, but also exerts an action of blocking hot air to the seal member S provided between the cylinder head 1 and the head cover 13.

A passage 21 communicating between both side surfaces of the cylinder head 1 is formed at an end of the cylinder head 1 on the side of the fourth cylinder (see FIGS. 2 and 4). The outside air sent from a secondary air control valve 22 provided on the side of the cylinder head 1 opposite to the exhaust manifold (intake manifold) to control the amount of secondary air introduced by an air pump (not shown) is The fluid is distributed to the secondary air ports 14 of the respective cylinders through the fluid passages 17 including the lids 16 and the grooves 15 formed on the exhaust manifold side of the cylinder head 1 via the passages 21. Since the groove 16 forming the fluid passage 17 is directly recessed in the mounting surface of the exhaust manifold 19 in the cylinder head 1, the secondary air is preheated by exhaust heat, which is advantageous for activating the catalyst. . Further, since the secondary air control valve 22 is provided on the intake manifold side, the secondary air control valve 22 is hardly affected by exhaust heat, and no special heat shielding measures are required.

At the end of the cylinder head 1 on the side of the fourth cylinder,
A projection 23 is provided so as to be in contact with the vehicle body when the transmission is attached and detached and to regulate the amount of rearward displacement of the engine E. The protrusion 23 is formed on the outer surface of the passage 21 that communicates between the secondary air control valve 22 and the fluid passage 17, and also serves to protect the passage 21.

As shown in FIG. 5, the secondary air port 14 branched from the fluid passage 17 is deviated from the center of the combustion chamber 24 of each cylinder to the upstream side of the fluid passage 17 and is upstream of the fluid passage 17. Since the secondary air is supplied to the exhaust valve located on the side, the fluid passage 17 can be further shortened. This prevents the fluid passage 17 from increasing in size, in combination with the gradual reduction in its cross-sectional area. In this embodiment, the cylinder head 1
The chain casing portion 25 is integrally formed at the end on the cylinder number side. However, when the fluid passage 17 for introducing the secondary air is shortened as described above, for example, the other components such as the hydraulic control valve 26 This is also advantageous in securing the mounting space.

The fluid passage according to the present invention is not limited to the secondary air introduction passage provided on the exhaust side, but may be a passage mainly provided on the intake side such as an exhaust recirculation (EGR) passage or a crankcase ventilation (PCV) passage. It can also be used as a passage through which not only gas but also liquid such as oil and cooling water flows.

[0021]

As described above, according to the present invention, the passage corresponding to each cylinder can be easily formed only by forming a groove on the side surface of the cylinder head. Thus, a great effect can be achieved in suppressing an increase in engine manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an engine to which the present invention is applied.

FIG. 2 is a left side view of the cylinder head alone.

FIG. 3 is a left side view of the cylinder head with a lid and an exhaust manifold attached.

FIG. 4 is an elevational view on the flywheel side of an engine to which the present invention is applied.

FIG. 5 is a plan view of a cylinder head in a state in which an upper portion is partially cut off along an axis of a secondary air port.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 6 Exhaust port 14 Secondary air port 15 Groove 16 Lid 17 Fluid passage

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiyuki Sato 1-4-1, Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3G024 AA07 AA11 DA10 DA18 FA10 FA14 GA13 HA05 3G091 AA28 BA04 BA07 CA22 HA02

Claims (2)

[Claims] 1. A cylinder head for a multi-cylinder engine, wherein a groove continuous in a cylinder row direction is recessed on an outer surface thereof.
A cylinder head for a multi-cylinder engine, wherein a fluid passage is formed by closing an opening surface of the groove with a lid. 2. A secondary air introduction passage in which a branch path to an exhaust port of each cylinder is provided at a bottom surface of the groove, and a cross-sectional area of the branch path is gradually reduced toward a downstream side. The cylinder head of a multi-cylinder engine according to claim 1, wherein: