DE112015007047T5 - Cylinder head water jacket structure - Google Patents

Abstract

According to the present invention, a vent hole (13f) discharging air bubbles in a lower water jacket (15) of a cylinder head (13) to an upper water jacket (16) is provided on an outlet side of the lower water jacket (15) and further upstream in the flow direction of Cooling water as a connecting portion (13g, 13h), with the interposed exhaust gas collecting section (28), provided, and is a cooling water channel, which from a portion where the vent hole (13f) is provided, after the exhaust gas collecting section (28) falls steeply on the outlet side of the lower water jacket (15) is formed, and therefore, air bubbles contained in the cooling water flowing through the lower water jacket (15) are blocked by the sloping portion of the cooling water passage and retained near the vent hole (13f), and can be prevented from the lower water jacket (15) to the upper water jacket (16) through the vent hole (13f) smoothly dissipated n.

Description

TECHNICAL AREA

The present invention relates to a cylinder head water jacket structure in which, inside a cylinder head, a lower water jacket and an upper water jacket with an exhaust assembly interposed therebetween are formed, with cooling water supplied to an air inlet side of the lower water jacket flowing to the exhaust side, then passes from the exhaust side of the lower water jacket through a communication hole, and is supplied to the upper water jacket.

TECHNICAL BACKGROUND

A cylinder head water jacket structure in which a lower water jacket and an upper water jacket with an exhaust assembly interposed therebetween are formed inside a cylinder head is known from the following Patent Document 1.

RELATED TECHNICAL DOCUMENTS

PATENT DOCUMENTS

Patent Document 1: Japanese Patent Application Laid-Open No. 2014-84736

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

When the lower water jacket and the upper water jacket are formed inside the cylinder head, bubbles contained in the cooling water remain in the lower water jacket, and it may become difficult to discharge them from the lower water jacket to the upper water jacket through a connecting portion. Therefore, one might think of providing a vent hole that shorts the connection portion and provides communication between the lower water jacket and the upper water jacket and dissipates bubbles contained in the cooling water from the lower water jacket to the upper water jacket through the vent hole. But even in this case, it is necessary to ensure the efficient passage of the bubbles contained in the cooling water through the vent hole.

The present invention has been achieved in light of the above circumstances, and its object is to make bubbles contained in the cooling water more easily pass through a vent hole connecting a lower water jacket to an upper water jacket of a cylinder head.

MEANS OF SOLVING THE PROBLEMS

In order to achieve the above object, according to a first aspect of the present invention, there is provided a cylinder head water jacket structure in which a lower water jacket and an upper water jacket with an exhaust assembly disposed therebetween are formed inside a cylinder head, with cooling water being an air inlet side of the lower water jacket, flows to an exhaust side, then flows from the exhaust side of the lower water jacket through a connecting portion, and is supplied to the upper water jacket, with a vent hole for discharging bubbles in the lower water jacket to the upper water jacket on the exhaust side of the lower water jacket and on an upstream side in the flow direction of the cooling water with respect to the connecting portion, with the interposed exhaust gas arrangement is provided, and a flow path for cooling water, which is provided by a portion where the vent hole i st, falls steeply below the exhaust system, is formed on the exhaust side of the lower water jacket.

Further, according to a second aspect of the present invention, in addition to the first aspect, a throat portion having a reduced flow passage sectional area is formed on the exhaust side of the lower water jacket between a portion where the vent hole is provided and a portion below the exhaust gas assembly.

Further, according to a third aspect of the present invention, in addition to the first or second aspect, the vent hole is a hole connecting the lower water jacket with the upper water jacket in the horizontal direction and arranged on a line extending away from an opening. formed in a side surface of the cylinder head and closed by a plug.

EFFECTS OF THE INVENTION

According to the first aspect of the present invention, in the interior of the cylinder head, the lower water jacket and the upper water jacket are formed with the exhaust assembly disposed therebetween, and cooling water supplied on the air inlet side of the lower water jacket flows to the exhaust side, then exits from the exhaust side of the exhaust lower water jacket through the connecting portion, and is supplied to the upper water jacket. Since the vent hole for discharging bubbles in the lower water jacket to the upper water jacket on the exhaust side of the lower water jacket and at the upstream side in the flow direction of cooling water with respect to the connecting portion with the exhaust assembly interposed therebetween, and the flow path for cooling water steeply descending from the portion where the vent hole is provided below the exhaust assembly to the exhaust side of the lower water jacket is formed, it can be prevented by the sloping portion of the flow path for the cooling water that bubbles contained in the cooling water flow through the lower water jacket and accumulate near the vent hole, thereby making it possible that from the lower water jacket to the upper water jacket are smoothly discharged through the vent hole.

Further, according to the second aspect of the present invention, since the restriction portion having a reduced flow path sectional area is formed on the exhaust side of the lower water jacket between the portion where the vent hole is provided and the portion below the exhaust gas assembly, the flow velocity of the cooling water in the Increased near the exhaust gas assembly through the throat portion, thereby improving the cooling effect of the exhaust system, which assumes a high temperature.

Moreover, according to the third aspect of the present invention, since the vent hole is one connecting the lower water jacket to the upper water jacket in the horizontal direction and arranged on a line extending away from the opening formed in the side face of FIG Cylinder head is formed and closed by the plug, it is possible to easily edit the vent hole through the opening in the side surface of the cylinder head.

A first connecting portion 13g and a second connecting portion 13h of one embodiment correspond to the connecting portions of the present invention, a cylinder head-side lower water jacket 15 of the embodiment corresponds to the lower water jacket of the present invention, a cylinder head-side upper water jacket 16 of the embodiment corresponds to the upper water jacket of the present embodiment Invention, and a core tag portion 22 of the embodiment corresponds to the opening of the present invention.

list of figures

• 1 is a diagram showing the shape of a water jacket (core) of a cylinder block and a cylinder head, and the cooling water flow. (first version)
• 2 FIG. 12 is a diagram showing an upper side of the cylinder head, a gasket and a lower side of the cylinder head (views in the direction of arrow 2A, direction of arrow 2B and direction of arrow 2C in FIG 1 ). (first version)
• 3 is a view of the water jacket of the cylinder head from the exhaust side (view in the direction of arrow 3 in FIG 1 ). (first version)
• 4 is a top view of the water jacket of the cylinder head (looking in the direction of arrow 4 in FIG 3 ). (first version)
• 5 is a plan view of the water jacket of the cylinder head (looking in the direction of arrow 5 in FIG 3 ). (first version)
• 6 FIG. 12 is a view showing an upper side of a cylinder head-side lower water jacket and a lower side of a cylinder head-side upper water jacket. FIG. (first version)
• 7 FIG. 12 is a side view of the exhaust side of the cylinder block (looking in the direction of arrow 7 in FIG 1 ). (first version)
• 8th is a sectional view taken along line 8-8 in FIG 7 , (first version)
• 9 is a sectional view taken along line 9-9 in FIG 7 , (first version)
• 10 is a sectional view taken along line 10-10 in FIG 7 , (first version)

LIST OF REFERENCE NUMBERS

13

cylinder head

13f

vent

13g

first connecting section (connecting section)

13h

second connecting section (connecting section)

15

Cylinder head side lower water jacket (lower water jacket)

15c

throat portion

16

Cylinder head side upper water jacket (upper water jacket)

22

Core marking part (opening)

27

Plug

28

exhaust device

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIG 1 to 10 explained. The vertical direction to which the present invention relates is a cylinder axis direction, regardless of the position in which the engine is running is attached, and is defined with the cylinder block side down and the cylinder head side up.

FIRST VERSION

As in 1 and 2 As shown, a water-cooled in-line three-cylinder engine includes a cylinder block 11 and a cylinder head 13 whose bottom is connected to an upper surface of the cylinder block 11 with a gasket 12 interposed therebetween. The cylinder block 11 includes a cylinder block-side water jacket 14 surrounding three cylinder bores arranged in series along the cylinder line), and the cylinder head 13 contains a cylinder head-side lower water jacket 15 and a cylinder head-side upper water jacket 16 which are stacked in the vertical direction with an exhaust manifold (not shown) interposed therebetween. In the upper left section of 1 are separately shown a condition in which only the cylinder head-side water jacket 15 inside the cylinder head 13 is shown, and a condition in which only the cylinder head-side upper water jacket 16 inside the cylinder head 13 is shown. The shape of the water jacket in each figure is also the shape of a core for casting the water jacket.

On the air inlet side of the cylinder block 11, there is formed a partial water jacket 17 extending in the cylinder-row direction, and on one end side (the cylinder # 1 side) there is formed a cooling water inlet 11a to which cooling water from a cooling water pump 18 is supplied. The cylinder block-side water jacket 15 includes a cooling water inlet 11 b at the air inlet side of the cylinder bore of the cylinder # 2, and the cooling water inlet 11 b and the partial water jacket 17 are connected via a thermal valve 19. The thermal valve 19 opens and closes automatically according to the temperature of the cooling water; it closes at low temperature to favor engine warm-up by adding the cooling water supply to the cylinder block-side water jacket 15 is interrupted, and it opens at high temperature to favor the cooling of the engine, passing the cooling water to the cylinder block-side water jacket 15 is left.

The cylinder block-side water jacket 14 includes, on the other end side (the cylinder # 3 side), a cooling water outlet 11c that supplies cooling water to the cylinder head-side lower water jacket 15 leads away. Therefore, the flow path through which the cooling water supplied to the cooling water inlet 11b of the cylinder block side water jacket 14 flows to the cooling water outlet 11c includes a short flow path that reaches the cooling water outlet 11c after being counterclockwise by half of the air inlet side portion of the cylinder block-side water jacket 14 in FIG 2 (A) and a long flow path that reaches the cooling water outlet 11c after flowing clockwise around the other half of the air inlet side portion and the entire exhaust side portion of the cylinder block side water jacket 14. The shorter flow path is provided with a separator 20 which divides the cylinder block-side water jacket 14 and limits the flow of the cooling water.

In this way, only one cooling water outlet 11c, the cooling water from the cylinder block side water jacket 14, the cylinder head side water jacket 15 Cooling water supplied from the cooling water inlet 11b to the cylinder block side water jacket 14 can reach all parts of the cylinder block side water jacket 14 without passing through the cooling water outlet 11c, and the entire cylinder block 11 can be efficiently cooled ,

Further, if the separator 20 did not exist, most of the cooling water supplied from the cooling water inlet 11b to the cylinder block side water jacket 14 would flow through the shorter flow path and reach the cooling water outlet 11c, and the flow rate through the longer flow path flowing cooling water would become small, and therefore, the exhaust side of the cylinder block 11, which attains a high temperature, might not be efficiently cooled. However, according to the present embodiment, since the shorter flow path is provided with the partition member 20 for restricting the flow rate of the cooling water, the flow rate of the cooling water flowing through the longer flow path can be increased to thereby cool the exhaust side of the cylinder block 111 which is high Temperature attains to favor.

In the top of the cylinder block 11, there are formed two groove-shaped cooling water passages 11d and 11d which extend in a direction which traverses between the three cylinder bores. The inlet side of the cooling water passages 11d and 11d communicate with the exhaust side of the cylinder block side water jacket 14, and the outlet side of the cooling water passages 11d and 11d is blocked near the air inlet side of the cylinder block side water jacket 14.

In the gasket 12, three first communication holes 12a, 12b and 12c are formed, a second communication hole 12d and two third communication holes 12e and 12e. Further, in the bottom of the cylinder head 13 three first cooling water inlets 13a, 13b and 13c formed, a second Cooling water inlet 13d and two third cooling water inlets 13e and 13e, each with the cylinder head side lower water jacket 15 keep in touch.

The partial water jacket 17 of the cylinder head 11 communicates with the three first cooling water inlets 13a, 13b and 13c of the cylinder head side lower water jacket 15 via the three first communication holes 12a, 12b and 12c of the gasket 12 in conjunction. In this arrangement, with respect to the first three communication holes 12a, 12b, and 12c of the gasket 12, the first communication hole 12a closest to the cooling water inlet 11a of the sub water jacket 17 has the smallest opening area, the first communication hole 12c is the farthest from the cooling water inlet 11a of the sub-water jacket 17, the largest opening area, and the first communication hole 12b of the sub-water jacket 17 having a middle distance from the cooling water inlet 11a has an opening area therebetween.

If the opening areas of the three first communication holes 12a, 12b and 12c of the gasket 12 were identical, the flow rate of the cooling water flowing through the first communication hole 12a closest to the cooling water inlet 11a of the sub water jacket 17 would become high, and the flow rate of the cooling water flowing through the first communication hole 12c, which is farthest from the cooling water inlet 11a of the sub water jacket 17, would become small; Changing the opening area of the three first communication holes 12a, 12b and 12c according to the distance from the cooling water inlet 11a of the sub-water jacket 17 allows the cooling water to the three first cooling water inlets 13a, 13b and 13c of the cylinder head-side lower water jacket 15 is supplied evenly.

The cooling water outlet 11c of the cylinder block side water jacket 14 communicates with the second cooling water inlet 13d of the cylinder head side lower water jacket 15 via the second communication hole 12d of the seal 12 in conjunction. The blocked end parts on the air inlet side of the two cooling water passages 11d and 11d formed in the upper surface of the cylinder block 11 stand with the two third cooling water inlets 13e and 13e of the cylinder head side lower water jacket 15 via the third communication holes 12e and 12e of the gasket 12 in conjunction. When the thermal valve 19 is opened, the flow rate of the cooling water from that of the sub-water jacket 17 is directly the cylinder head-side lower water jacket 15 is supplied without passing through the cylinder block-side water jacket 14, about 70% of the total flow rate, and is the flow rate of the cooling water, that of the partial water jacket 17, the cylinder head side lower water jacket 15 supplied via the cylinder block side water jacket 14, about 30% of the total flow rate.

The structure of the cylinder head-side lower water jacket 15 and the cylinder head-side upper water jacket 16 will now be regarding 3 to 10 explained.

The cylinder head side upper water jacket 16 has a size that is about half of that of the cylinder head side lower water jacket 15, and is above the exhaust side of the cylinder head side lower water jacket 15 arranged.

The cylinder head side lower water jacket 15 and the cylinder head-side upper water jacket 16 contain six core brand parts 21 to 26, which protrude outward. The core core parts 21 to 26 are protrusions for holding a sand-made core inside a casting mold around the cylinder head-side lower water jacket 15 and the cylinder head-side upper water jacket 16 pour in when the cylinder head 13 is poured. When the core is removed after casting, the core core parts 21 to 26 become openings which are parts of the cylinder head side lower water jacket 15 and the cylinder head side upper water jacket 16 form. Since the ends of the core tag parts 21 to 26 open at the top of the cylinder head 13, they are plugged 27 blocked, to prevent cooling water from leaking through these parts (see 7 to 10 ).

As in 7 and 8th are shown inside the core tag part 22 the cylinder head side lower water jacket and the cylinder head side upper water jacket 16 via a ventilation hole 16f with each other. The ventilation hole 13f is made by inserting a drill in the horizontal direction from the opening of the core tag part 23, which is a space. This prevents drilling of the ventilation hole 13f using the core tag part 22 that an unnecessary borehole in the cylinder head 13 has to be formed, a step for blocking the borehole becomes unnecessary, and becomes the production of the vent hole 13f easy.

As in 4 and 9 shown in the interior of the core mark part 23 of the cylinder head side lower water jacket 15 and the cylinder head-side upper water jacket 16 via a first connecting section 13g in contact with each other. Further stand, as in 4 and 10 shown inside the core tag part 24, the cylinder head-side lower water jacket 15 and the cylinder head-side upper water jacket 16 above a second connecting portion 13h in contact with each other.

As from the comparison of 3 With 7 2, both views being from the exhaust side, an exhaust manifold 48 of the exhaust manifold extends from between a recessed portion 15a at the top of the exhaust side of the cylinder head side lower water jacket 15 and a recessed portion 16a on an underside on the exhaust side of the cylinder head-side upper water jacket 16 outward. The core brand part 22 in which the ventilation hole 13f is formed, is adjacent to the exhaust system 28 is arranged on the side of the cylinder # 3 in the cylinder row direction, the core punch part 23, in which the first connecting portion 13g is formed adjacent to the exhaust system 28 is disposed on the side of the cylinder # 1 in the cylinder row direction, and further, the core punch part 24 in which the second connecting portion 13h is formed adjacent to the core mark portion 23 on the cylinder # 1 side in the cylinder row direction.

As the core brand part 22 (the ventilation hole 13f ) and the core punch part 23 (the first connecting portion 13g ) disposed on opposite sides of the recessed portion 15a have a high position with respect to the recessed portion 15a of the cylinder head-side lower water jacket 15 have, is the flow path for the cooling water on the exhaust side of the cylinder head-side lower water jacket 15 so kinked that he got to the ventilation hole 13f rises, then drops below the recessed portion 15a and further from below the recessed portion 15a to the first connecting portion 13g rises again.

Volume expansion sections 15b and 16b (see 3 and 5 ), which protrude triangular outward, are on the cylinder head-side lower water jacket 15 and the cylinder head-side upper water jacket 16 formed adjacent to the core tag portion 23. Further, a narrowing section 15c (please refer 3 ) narrowed to a small flow path cross-sectional area in a portion from the position of the cylinder head-side lower water jacket 15 away, where the ventilation hole 13f is provided to the position where the flow path for cooling water drops steeply below the recessed portion 15a out.

Now, the operation of the embodiments of the present invention having the above arrangement will be explained.

Cooling water supplied from the cooling water pump 18 to the sub water jacket 17 of the cylinder block 11 flows from the sub water jacket 17 through the thermal valve 19 and is supplied to the cooling water inlet 11 b at the air inlet side of the cylinder block side water jacket 14. Cooling water branching in two directions at the cooling water inlet 11b flows through the inside of the cylinder block side water jacket 14 in clockwise and counterclockwise directions, is united at the cooling water outlet 11c, then flows through the second communication hole 12d of the gasket 12 and is put on the cylinder # 3-side of the cylinder head-side lower water jacket 15 fed.

Further, cooling water flowing through the inside of the sub water jacket 17 from the cylinder # 1 side to the cylinder # 3 side flows through the first communication holes 12a, 12b, and 12c of the gasket 12 and the first cooling water inlets 13a, 13b, and 13c of the cylinder head 13 becomes the air inlet side of the cylinder head-side lower water jacket 15 supplied and flows from there through the interior of the cylinder head-side lower water jacket 15 towards the exhaust side.

The blocked outlet ends of the cooling water passages 11 d and 11 d, whose inlet ends communicate with the exhaust side of the cylinder block side water jacket 14, are connected to the cylinder head side lower water jacket 15 via the third communication holes 12e and 12e of the gasket 12 and the third cooling water inlets 13e and 13e of the cylinder head 13 connected. The third cooling water inlets 13e and 13e of the cylinder head 13 are disposed immediately downstream in the flow direction of the cooling water, as viewed from the first cooling water inlets 13a, 13b and 13c of the cylinder head 13 Therefore, the cooling water flows through the third high-speed cooling water inlets 13e and 13e, and therefore generates a large negative pressure.

Due to the negative pressure generated in the third cooling water inlets 13e and 13e, hot cooling water at the exhaust side of the cylinder block side water jacket 14 through the two cooling water passages 11d and 11d becomes the cylinder head side lower water jacket 15 sucked up. This prevents cooling water from staying on the exhaust side of the cylinder block-side water jacket 14, and makes it possible to efficiently cool the exhaust side of the cylinder block 11 which becomes high in temperature as compared with the air inlet side of the cylinder block 11.

Cooling water, the part of the water jacket 17 directly into the three first cooling water inlets 13 a, 13 b and 13 c of the cylinder head side lower water jacket 15 without passing through the cylinder block-side water jacket 14, it branches in two directions so as to go around the area of each combustion chamber and flow from the air inlet side to the exhaust side. on the other hand That is, cooling water flowing from the cooling water outlet 11c arranged at the cylinder # 3 of the cylinder block side water jacket 14 flows to the second cooling water inlet 13d of the cylinder head 13 is supplied to the cylinder # 1 side and, while being combined with the cooling water that has flowed from the sub water jacket 17 directly to the cylinder head side lower water jacket 15, flows to the cylinder # 1 side of the exhaust side of the cylinder head -side lower water jacket 15 to the first connection section 13 and the second connection portion 13h , Cooling water coming from the cylinder head-side lower water jacket 15 through the first connection section 13g and the second connecting portion 13h Flowed into the cylinder head side upper water jacket 16, flows through the cylinder head side upper water jacket 16 from the side of the cylinder # 1 to the side of the cylinder # 3 and then via a cooling water outlet port 13i of the cylinder head 13 discharged to a cooler, not shown.

Because the ventilation hole 13f arranged so that it is the cylinder head-side lower water jacket 15 and the cylinder head-side upper water jacket 16 short-circuits, bubbles occur in the cylinder head-side lower water jacket 15 flowing cooling water are contained, through the ventilation hole 13f through and become the cylinder head-side upper water jacket 16 dissipated, thereby preventing bubbles in the cylinder head-side lower water jacket 15 stop.

There, how out 3 apparent, the ventilation hole 13f at the highest position of the cylinder head side lower water jacket 15 is arranged, and the recess portion 15 a of the cylinder head-side lower water jacket 15 at the downstream side of the ventilation hole in the flow direction of the cooling water 13f is disposed, the flow path for the cooling water flowing through the exhaust side of the cylinder head-side lower water jacket 15 from the side of the cylinder # 3 to the side of the cylinder # 1 flows steeply after it to the vent hole 13f has risen steeply, and then rises again strongly. As a result, bubbles collect easily under the vent hole 13f On, and bubbles that have stopped, are from the cylinder head-side lower water jacket 15 to the cylinder head-side upper water jacket 16 over the ventilation hole 13f smoothly dissipated.

Further, since the narrowing section 15c where the flow path cross-sectional area decreases (see 3 ), on the exhaust side of the cylinder head-side lower water jacket 15 between a part where the ventilation hole 13f is provided, and a part under the exhaust system 28 is formed, the flow velocity of the cooling water decreases in the vicinity of the exhaust system 28 through the throat section, thereby reducing the effect of cooling the exhaust system 28 , which takes a high temperature, is improved.

Cooling water that passes under the recessed portion 15a flows from the cylinder head-side lower water jacket 15 through the first connection section 13g and the second connecting portion 13h, and becomes the cylinder head-side upper water jacket 16 fed. Because the first connection section 13g at the upstream side in the flow direction of the cooling water, cooling water from a large number of flow paths of the cylinder head side lower water jacket 15 receives, compared to the second connecting portion 13h on the downstream side in the flow direction of the cooling water, the cooling water flow stagnates in the vicinity of the first connection portion 13g , and therefore there is a possibility that the flow velocity of the cooling water in the flow path on the upstream side of the first connecting portion 13g becomes smaller than the flow velocity of the cooling water in the flow path on the upstream side of the second connection portion 13h ,

However, according to the present embodiment, since the volume extension sections 15b and 16b (see FIG 3 to 5 ), which increase the volume of the cooling water flow path, in the vicinity of the first connection portion 13g are provided on the upstream side, the stagnation of the cooling water flow in the vicinity of the first connecting portion 13g is avoided by the volume expansion portions 15b and 16b, and can a sufficient amount of cooling water through the first connecting portion 13g flow. As a result, any decrease in the flow rate of the cooling water in the flow path on the upstream side of the first connection portion becomes 13g prevents and reduces the flow rate of the cooling water flowing through each flow path of the cylinder head-side lower water jacket 15 flows through it, made evenly, whereby the cooling performance is improved.

Further, since the flow path for the cooling water after the first steep drop then under the Recess portion 15a of the cylinder head-side lower water jacket 15 is steeply increased, there is a possibility that the smooth flow of cooling water is affected, but since the volume expansion portions 15b and 16b, which increase the volume of the flow path formed on the downstream in the direction of the cooling water flow side of the recessed portion 15a, the cooling water smoothly among the Recess portion 15a of the cylinder head-side lower water jacket 15 flow to thereby the exhaust system 15 that has a high temperature to cool efficiently.

Above, an embodiment of the present invention has been explained, but the present invention can be modified in numerous ways as long as the modifications do not depart from their idea and scope.

For example, the engine of the embodiment is a series three-cylinder engine, but the number and arrangement of the cylinders of the engine are not limited to those of the embodiment.

Further, in the embodiment, two connecting portions are provided, which are for a connection between the cylinder head side lower water jacket 15 and the cylinder head-side upper water jacket 16 ensure, ie the first connection section 13g and the second connection portion 13h but the number of pit portions is not limited to that of the embodiment.

In addition, the opening for the production of the ventilation hole 13f not on the core brand part 22 limited to the design and may be another opening through the plug 27 is closed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 201484736 [0003]

Claims (3)

A cylinder head water jacket structure in which a lower water jacket (15) and an upper water jacket (16) are formed inside a cylinder head (13) with an exhaust assembly (28) interposed therebetween, cooling water supplied to an air inlet side of the lower water jacket (15 ), flows to an exhaust side, then flows from the exhaust side of the lower water jacket (15) through a connecting portion (13g, 13h), and is supplied to the upper water jacket (16), with a vent hole (13f) for discharging bubbles in the lower water jacket (15) to the upper water jacket (16) on the exhaust side of the lower water jacket (16) and on an upstream side in the flow direction of the cooling water with respect to the connecting portion (13g, 13h), with the exhaust assembly (17) interposed therebetween (16). 28), and a flow path for cooling water provided from a portion where the vent hole (13f) is provided below Exhaust system (28) falls steeply, is formed on the exhaust side of the lower water jacket (15). The cylinder head water jacket structure after Claim 1 wherein a throat portion (15c) having a reduced flow path sectional area is formed on the exhaust side of the lower water jacket (15) between a portion where the ventilation hole (13f) is provided and a portion below the exhaust assembly (28). The cylinder head water jacket structure after Claim 1 or 2 wherein the vent hole (13f) is a hole connecting the lower water jacket (15) with the upper water jacket (16) in the horizontal direction and arranged on a line extending from an opening (22) extending in a Side surface of the cylinder head (13) is formed and closed by a plug (27).

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