JP2002227718A - Cylinder head structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide cylinder head structure formed so that a cooling water temperature on the suction side is kept at a low temperature by suppressing a thermal influence transmitted from a water passage on the exhaust side to a water passage on the suction side. SOLUTION: The cylinder head structure is such that a partition wall 9 to separate a cooling water passage 8 on the inside of an SOHC type cylinder head, having a plug insertion part 5, into the suction side and the exhaust side is inclined (deviated) to the opposite side to the plug insertion part 5, and by forming a water passage 15, newly communicating with a space among cylinders, in a space between a plug insertion part 5 on the suction side and the partition wall 9, a linear water passage 16 continued to spots situated upstream and downstream along the surface part of the partition wall 9 is formed. By cooling water flowing through the water passage 16, heat transmission on the exhaust side from the partition wall 9 to the plug insertion part 5 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylinder head structure having a cooling water passage formed therein.

[0002]

2. Description of the Related Art A water-cooled multi-cylinder engine has a structure in which a cooling water passage called a water jacket is formed inside (solid portion) of a cylinder head in which an intake / exhaust port, an intake / exhaust valve, and a spark plug are incorporated. Can be Then, by flowing cooling water through the cooling water passage, the cylinder head is cooled.

[0003] By the way, the engine is required not only to improve the output but also to quickly raise the catalyst to the activation temperature so that the exhaust gas treatment of the engine is started as quickly as possible.

Therefore, as shown in Japanese Patent Application Laid-Open No. 5-86968, a cooling water passage formed inside the cylinder head is formed by a partition wall provided near a central portion between the intake and exhaust ports. A technique has been proposed in which an intake side having an exhaust port and an exhaust side having an exhaust port are separated so that the exhaust side of the cylinder head has an environment in which the temperature easily rises quickly and the intake side of the cylinder head has an environment in which the temperature does not easily rise.

[0005]

However, the cylinder head has a small gap between the intake and exhaust ports, and a plug insertion portion for inserting a spark plug is formed near the center between the ports. Therefore, when the partition is formed, a portion where a part of the partition and the peripheral wall of the plug insertion portion are integrally connected near the plug insertion portion is formed.

A cylinder head (SOHC structure, etc.) into which a spark plug (not shown) is inserted obliquely from the intake side toward the center between the intake and exhaust ports a and b as shown in FIG. Since c faces obliquely, it is easy to separate between the plug insertion portion c and the partition wall d. However, in the vicinity of the plug insertion portion c, a connection where the peripheral wall of the adjacent plug insertion portion c and a part of the partition wall d are connected. The part e is formed.

For this reason, the heat of the high-temperature water (cooling water) in the water passage g on the exhaust side is transmitted to the plug insertion portion c connected to the intake port a through the connecting portion e, or to the water flow toward the intake port a. It was unavoidable to affect the cooling of the intake port a (temperature rise). Moreover, since the flow of the cooling water on the partition wall d side of the plug insertion portion c cannot be expected, the cooling performance around the ignition plug is easily impaired.

The present invention has been made in view of the above circumstances. It is an object of the present invention to suppress the thermal effect transmitted from the exhaust-side water channel to the intake-side water channel, and to stabilize the intake-side cooling water temperature. To provide a cylinder head structure that is kept at a low temperature.

[0009]

According to a first aspect of the present invention, there is provided a cylinder head structure, wherein a partition separating a cooling water passage is shifted to an exhaust side so as to increase an area of a water passage on an intake side. The plug insertion portion is formed in the water channel on the intake side, and a water channel is formed between the plug insertion portion and the partition wall.

[0010] As a result, the plug insertion portion of each cylinder and the partition are separated with the water channel interposed therebetween.
A continuous flow of the cooling water from the upstream to the downstream of the cooling water passage is formed along the surface of the partition wall. Due to the cooling water flowing along the surface of this partition, the heat from the partition toward the intake side is
Immediately escaped to the outside. Thus, heat transfer from the partition to the plug insertion portion and heat transfer to the water flow toward the intake port can be suppressed.

Therefore, the thermal effect transmitted from the exhaust-side water passage to the intake-side water passage is suppressed, and the cooling water temperature of the intake-side water passage is kept low. Moreover, since the partition wall side of the plug insertion portion is cooled by the cooling water flowing between the plug insertion portion and the partition wall, cooling around the ignition plug is sufficiently expected.

In particular, in the case of a cylinder head in which the plug insertion portion is formed obliquely from the intake side toward the vicinity of the center between the intake side port and the exhaust side port, a partition wall inclined to the opposite side to the plug insertion portion is employed. In this case, it is effective that a water passage having a large passage area is secured between the plug insertion portion and the partition wall with only a slight change.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in FIGS.

FIG. 1A shows a cylinder head of a multi-cylinder engine to which the present invention is applied, for example, a four-cylinder cylinder head to which a SOHC (single overhead valve camshaft) type valve train (not shown) is assembled. Sectional view,
(B) shows a side view of the cylinder head, respectively, in which 1 is a main body of the cylinder head.

The main body 1 is formed of, for example, an elongated cast member. On the lower surface of the main body 1, four combustion chambers 2 are formed along the longitudinal direction according to the arrangement of the cylinders. Also, on both sides of each combustion chamber 2 (both sides in the width direction of the main body 1), a pair (two; plural) of intake ports 3 arranged in the cylinder row direction opened and closed by intake valves (not shown), and exhaust valves ( (Not shown) A pair (two; plural) lined up in the direction of the cylinder row opened and closed
Exhaust port 4 is open. The inlet side of each intake port 3 extends cylindrically to one side in the width direction of the adjacent main body 1 and opens to one side. The outlet of each exhaust port 4 also extends cylindrically to the other side in the width direction of the adjacent main body 1 and opens to the other side. One side in the width direction of the main body 1 having the intake port 3 is an intake side, and the other side in the width direction of the main body 1 having the exhaust port 4 is an exhaust side. Further, a plug insertion portion 5 for inserting a spark plug (not shown) is formed in the main body 1 for each combustion chamber 2. Each plug insertion part 5
The cylindrical shape has an outlet opening at the center of the combustion chamber 2 (near the center between the intake and exhaust ports 3 and 4) and an inlet extending upward (to the left in FIG. 1b) while being inclined toward the intake side. Part. A receiving portion 6 for rotatably receiving a camshaft (one: not shown) incorporated on the upper side of the combustion chamber 2 is formed in each of the upper portions of the main body 1.

Further, inside the main body 1 (solid portion), FIG.
As shown in (b), a cooling water passage 8 (water jacket) is formed so as to continuously surround the intake / exhaust ports 3 and 4. That is, the cooling water passage 8 is formed over both longitudinal ends of the main body 1.

As shown in FIGS. 2 to 5, a partition wall 9 is formed in the cooling water passage 8 near the center of the third group of intake ports and the fourth group of exhaust ports. The partition wall 9 extends along the cylinder row direction while partitioning the inside of the cooling water passage 8 at the same portion. Both ends of the partition wall 9 are in contact with the respective lids 10 (parts for plugging through holes formed at the time of casting) incorporated into both longitudinal end walls of the main body 1. Thus, as shown in FIG. 5B, the cooling water passage 8 is separated into an intake side and an exhaust side,
On the intake port 3 side (intake side) sandwiching the partition wall 9, a water channel 11 a used exclusively for intake cooling is formed, and the opposite exhaust port 4 is formed.
On the side (exhaust side), a water passage 11b used exclusively for exhaust cooling is formed. An upstream side of each of the water channels 11a and 11b is provided with an inlet 12 formed at one end of the main body 1.
a, 13a, and the downstream side communicates with outlets 12b, 13b formed on the other end of the main body 1, respectively. The partitioning of the cooling water passage 8 by the partition wall 9 provides an environment where the temperature on the intake side of the cylinder head is unlikely to rise, and an environment on the exhaust side of the main body 1 where the temperature easily rises quickly.

As shown in FIGS. 2 to 5B, the partition wall 9 is shifted in the direction in which the area of the water channel 11a increases, and more specifically, the angle of inclination of the plug insertion portion 5 in the opposite direction. It is inclined at. By this inclined partition wall 9, the plug insertion portion 5 is accommodated in the region of the increased water channel 11a. Then, by utilizing the angle of the plug insertion portion 6 and the angle of the partition wall 9 formed in the water channel 11a (relative distance), a water channel through which cooling water flows newly between the plug insertion portion 5 and the partition wall 9. 15 [illustrated in FIG. 3 (a cross-sectional view at the position of the plug insertion portion)]. The passage area of the water passage 15 is equal to or larger than the plane sectional area of the spark plug. This waterway 15
As shown in the positions of the intake and exhaust ports 3 and 4 in FIG. 2, the positions between the combustion chambers 2 and 2 in FIG. 4, and other cross-sectional positions,
A straight path following the surface of the partition wall 9 is formed in communication with a water channel portion 16a formed along the surface of the partition wall 9 on the side of the water channel 11a around the other intake and exhaust ports. As shown in FIG. 5 (b), the water passage 15 communicates between the cylinders as well, and crosses from upstream to downstream of the water passage 10a as shown by the cross hatched portion in FIG. 1 (a). Partition wall 9
A continuous straight water channel 16 without obstacles is formed in a region along the surface of the slab. The water channel 1b shown in FIG. 1 (a) is drawn on the water channel 11b side. However, for the sake of drawing, the cross section of the partition 9 is lower than the inclined portion of the partition 9 and is relatively lower than the other cross sections. This is because the lower part of the cylinder head is located on the water channel 11a side in the inclined portion of the partition wall 9.

The environment on the intake side of the cylinder head (the environment where the cooling water can be kept at a low temperature) by the linear water passage 16.
Has been stabilized.

That is, it is assumed that the cooling water from, for example, a water pump (not shown) flows from the respective inlets 12a and 13a of the cylinder head as shown by arrows in FIG.

The cooling water from the inlet 13a flows only to the exhaust side of the cylinder head. Specifically, as shown in FIGS. 2, 3, 5 (a) and 5 (b), the cooling water is supplied to the water passage portion 18 a between the exhaust port 4 and the partition 9, and to the other exhaust ports 4. It flows downstream while flowing through the surrounding water channel portion 18b. By the time the cooling water flows out of the outlet 13b, the temperature of the cooling water rises due to the heat on the exhaust side, and quickly becomes high-temperature water.

On the other hand, the cooling water from the inlet 12a flows only to the intake side of the cylinder head. Specifically, at a portion where the intake port 3 is provided, the cooling water is supplied to the water channel portion 1 between the intake port 3 and the partition 9 as shown in FIGS.
6a, the water flows through a water channel portion 19a formed around the other intake port 3, and in a portion where the plug insertion portion 5 is present, the portion between the plug insertion portion 5 and the partition 9 as shown in FIGS. Flows through the water passage 15 (continuous with the water passage portion 16a) and the other water passage portion 19a formed around the intake port 3, and at a portion between the combustion chambers 2 (between the cylinders), FIG.
And a channel 15 and a channel portion 16a as shown in FIG.
Flows downstream while flowing through a portion 16b where the water flows and a water channel portion 19a formed at other portions.

At this time, as shown in FIG. 1A, the water channel 15 and the water channel portion 16a
Is formed, a continuous linear flow is formed from the upstream to the downstream of the cylinder head.
In addition, since there is no obstacle in the middle of this flow that interrupts the flow or transmits heat of the high-temperature water on the exhaust side from the partition 9 to the intake side, stable flow of the cooling water is ensured.

As a result, the intake port 3 is separated from the partition 9.
And the heat going to the plug insertion part 5 is initially supplied by stable cooling water flowing along the surface of the partition wall 9.
The air is quickly released from the outlet 12b to the outside.

As a result, the heat transfer from the partition wall 9 to the plug insertion portion 5 or the water flow toward the suction port 3 causes the heat transfer of the high-temperature water, which causes the temperature of the cooling water on the suction side (water passage 11a) to rise. Heat can be suppressed. That is, the thermal effect transmitted from the exhaust-side water passage 11b to the intake-side water passage 11a is suppressed, and heat transfer to the intake port 3 becomes difficult.

Therefore, the cooling water temperature of the water channel 11a can be kept relatively low, and the water channel 11a can be maintained in an environment where the temperature hardly rises. That is, the effect provided by the water channel 11a can be sufficiently exhibited.

Moreover, since the partition wall 9 side of the plug insertion section 5 is also cooled by the cooling water flowing between the plug insertion section 5 and the partition wall 9, the surroundings of the spark plug together with the other cooling water flows. Can be cooled sufficiently.

In particular, in the case of an SOHC type cylinder head in which the plug insertion portion 5 is formed obliquely from the intake side toward the vicinity of the center between the intake side port 3 and the exhaust side port 4, the opposite side to the plug insertion portion 5 The use of the partition wall 9 inclined to the (exhaust side) is effective because a water passage 15 having a large passage area can be secured between the plug insertion portion 5 and the partition wall 9 by only slightly changing the shape of the partition wall 9.

It should be noted that the present invention is not limited to the above-described embodiment, and may be implemented with various modifications without departing from the gist of the present invention. For example, in the above-described embodiment, a structure in which the partition wall is inclined to the side opposite to the plug insertion portion is employed. However, the present invention is not limited to this, and the partition wall is shifted to increase the area on the suction side using another structure. The structure may be used. Further, in one embodiment, the present invention is applied to a SOHC type cylinder head. However, the present invention is not limited to this.
The present invention may be applied to a C-type cylinder head, or may be applied to a cylinder head having a plug insertion portion extending linearly in the vertical direction, instead of a plug insertion portion formed obliquely.

[0030]

As described above, according to the first aspect of the present invention, the heat flowing from the partition to the intake port and the plug insertion portion is cooled by the cooling water flowing stably along the surface of the partition. It is possible to escape to the outside immediately from the point.

Thus, the thermal effect transmitted from the exhaust-side water passage to the intake-side water passage can be suppressed, the cooling water temperature of the intake-side water passage can be stably maintained at a low temperature, and the effect of separating the cooling water passage by the partition wall can be sufficiently achieved. Can be demonstrated. In addition, since the partition wall side of the plug insertion portion is cooled by the cooling water flowing between the plug insertion portion and the partition wall, there is an advantage that cooling around the ignition plug can be sufficiently performed.

[Brief description of the drawings]

FIG. 1A is a plan sectional view showing a cylinder head according to an embodiment of the present invention. (B) is a side view of the cylinder head.

FIG. 2 is a side sectional view of the cylinder head crossing an intake / exhaust port along the line AA in FIG. 1 (a).

FIG. 3 is a side cross-sectional view of the cylinder head crossing a plug insertion portion along a line BB in FIG. 1 (a).

FIG. 4 is a side sectional view of the cylinder head crossing between combustion chambers along the line CC in FIG. 1 (a).

FIG. 5A is a perspective view showing a schematic shape of a separation type cooling water passage formed inside a cylinder block. (B) is a sectional plan view showing a water channel structure around an intake / exhaust port and a plug insertion portion along a line DD in FIG.

FIG. 6A is a side sectional view for explaining a water channel structure around a plug insertion portion of a conventional cylinder block. (B)
Is a plan sectional view of the waterway structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main body of a cylinder head 2 ... Combustion chamber 3 ... Intake port 4 ... Exhaust port 5 ... Plug insertion part 8 ... Cooling water path 9 ... Partition wall 11a ... Intake side water path 11b ... Exhaust side water path 15 ... Between plug insertion part and partition wall The waterway 16 ... a straight waterway.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuya Ida 580-16 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa F-term (reference) in Mitsubishi Motors Engineering Co., Ltd. 3G024 AA04 AA05 AA09 AA11 AA14 AA15 AA16 BA05 CA03 CA05 CA11 DA06 DA10 EA01 FA11

Claims (1)

[Claims] 1. A cylinder head structure in which a cooling water channel is separated into a water channel on an intake side and a water channel on an exhaust side by a partition wall, wherein the partition wall is provided on the exhaust side so as to increase an area of the water channel on the intake side. Cylinder characterized by forming a plug insertion portion for inserting a spark plug into the water passage on the intake side, and forming a water passage communicating between the plug insertion portion and the partition wall. Head structure.