JP2000310157A - Cylinder head structure for multiple cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability while coping with the high output of an engine, by increasing the coolingness in the vicinity of a cylinder axis center having a high load, and the rigidity of a cylinder head around a cylinder in particular, in the cylinder head of a series four-cylinder diesel engine having first and second air intake ports as double tangential ports opened within respective cylinders while directed in a cylinder circular peripheral direction, and air intake and exhaust valves alternately and staggeredly arranged in the before and behind direction of the engine (in a cylinder array direction). SOLUTION: The upper surface of the lower deck part 4c of a cylinder head 4 is nearly at regular intervals and parallelly formed of a first reinforcing rib 38 over from the vicinities of two exhaust port opening parts 17a and 17b at every cylinder 2 through the lower parts of the air intake ports 11 and 12 of the adjoining cylinders 2 to an air intake side side wall part 4a, and a second reinforcing rib 39 extending toward a cylinder axis center (x) from the wall part 4a. Cross drill holes 40 and 41 for leading cooling water are provided in both the ribs 38 and 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head structure of a multi-cylinder engine in which two intake valves and two exhaust valves are provided for each cylinder and are alternately arranged in the cylinder row direction.

[0002]

2. Description of the Related Art Conventionally, as a cylinder head structure of a multi-cylinder engine of this kind, for example, Japanese Patent Application Laid-Open No.
No. 8 or JP-A-8-270501, a double tangential port in which two intake ports for each cylinder are opened in each cylinder while being directed in the cylinder circumferential direction. There has been known a technique that achieves both improvement of intake air charging efficiency and enhancement of swirl. In this engine, for example, as shown in FIG. 10, one of the two intake ports a is formed so as to extend greatly along the outer periphery of the cylinder, and the cylinder is located near the exhaust side (front side in the figure) of the engine. The other intake port c is formed to be relatively short while opening linearly in the cylinder b in the circumferential direction, and is similarly opened linearly in the cylinder b near the intake side of the engine. Yes,
Although not shown, two intake valves and two exhaust valves for each cylinder are alternately arranged in the cylinder row direction, and in plan view,
The zigzag arrangement is a so-called zigzag arrangement as a whole in the cylinder row direction. In this specification, "in a plan view" means a state viewed from a direction along the cylinder axis.

[0003]

Generally, the maximum thermal stress of the cylinder head is generated between the valve seats of the lower deck (the inter-valve bridge portion). It is necessary to enhance the cooling performance of the lower deck portion above the cylinder without reducing the rigidity.

[0004] However, in the case of the cylinder head structure as in the conventional example, at least one of the intake and exhaust ports is formed so as to surround the periphery of each cylinder. When viewed, the flow of the cooling water is hindered by the peripheral wall of the port, and it becomes difficult to sufficiently enhance the cooling performance above the cylinder.

For example, in the case of a direct-injection diesel engine in which fuel injection nozzles are arranged along the cylinder axis, as shown in FIG. In addition, it is difficult to reach near the cylinder axis, and there is a boss of the injection nozzle. Cannot be secured, coupled with the particularly large heat load in this area,
There is a possibility that cracking may occur due to plastic fatigue.

In the case of the double tangential port shown in FIG. 10, the intake and exhaust ports are twisted in the cylinder circumferential direction above each cylinder, so that the rigidity of the cylinder head becomes uneven. There is a concern that the stress concentration may cause a decrease in durability or a decrease in sealing performance with the cylinder block. This means
This is a particularly serious problem in recent diesel engines that are equipped with a supercharger or the like to improve the intake charging efficiency and improve the combustibility to increase the maximum in-cylinder pressure (Pmax).

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a multi-cylinder engine in which two intake valves and two exhaust valves are alternately arranged in the cylinder row direction for each cylinder. Focusing mainly on the flow of cooling water in the water jacket, improve the cooling performance of the cylinder head around the cylinder, and increase its rigidity to improve reliability while responding to higher engine output. It is in.

[0008]

In order to achieve the above object, according to a first solution of the present invention, a ridge is formed so as to reinforce a lower deck portion near an exhaust port opening having a high heat load. , A cooling water passage is provided in this ridge,
The cooling water is led directly to the bridge between the exhaust port openings.

Specifically, according to the first aspect of the present invention, the intake and exhaust ports for each of a plurality of cylinders are alternately arranged in the cylinder row direction on the cylinder head of the engine, and the downstream end of each of the intake ports is 2 on the left and right sides of the cylinder axis when viewed from the cylinder row direction
Each of the exhaust ports is opened in the cylinder at one of the positions, while the upstream end is opened on one of the left and right intake side walls of the cylinder head. The cylinder is opened at two locations on both sides, respectively, while the downstream end is opened at the exhaust side wall of the cylinder head opposite to the intake side wall, and a water jacket surrounds the intake and exhaust ports. It is assumed that the cylinder head structure is formed. Then, on the upper surface of the lower deck portion of the cylinder head facing the inside of the water jacket, a first portion extending from the vicinity of the two upstream end openings of the exhaust port of each cylinder to the intake side wall portion through the lower portion of the intake port of the adjacent cylinder. A projection is formed, and a cooling water passage is provided along the first projection so as to guide cooling water between the two upstream end openings of the exhaust port inside the first projection. I do.

[0010] With the above arrangement, in the cylinder head of this engine, as a result of the layout of the intake and exhaust ports,
Although the cooling of the lower deck above the cylinder tends to be low,
In particular, since the cooling water is directly guided through the cooling water passage in the first ridge between the upstream openings of the exhaust port having a large heat load, the cooling performance of this portion can be sufficiently improved. Further, since the first ridge is formed between two adjacent cylinders, the rigidity of the entire cylinder head can be increased, and the sealing performance with the cylinder block can be improved.
That is, the rigidity of the cylinder head can be increased, and the cooling performance can be improved. Therefore, the reliability can be improved while coping with the high output of the engine.

According to the second aspect of the present invention, the first ridge is formed substantially linearly so as to be oblique with respect to the cylinder row direction in a plan view, and is adjacent to the exhaust port peripheral wall portion of each cylinder in the water jacket. The cylinder is connected to the peripheral wall of the intake port of the cylinder. In this case, since the port peripheral wall near the upstream end opening of the exhaust port has high rigidity, the port peripheral wall and the intake port peripheral wall are connected by the first ridge, so that the rigidity of the lower deck is effective. To be increased.

According to the third aspect of the present invention, the two downstream end openings of the intake port and the two upstream end openings of the exhaust port of each cylinder are arranged along the direction in which the first ridge extends in plan view. It was arranged as follows. This facilitates the layout of the intake / exhaust port and the first ridge on the upper surface of the lower deck.

According to the fourth aspect of the present invention, the downstream end opening of the intake port for each cylinder is arranged on the upstream side of the flow of the cooling water in the water jacket with respect to the upstream end opening of the exhaust port. The one ridge is configured such that the cooling water passage therein is formed such that the cooling water flows in a direction substantially opposite to the flow of the cooling water in the water jacket.

In this configuration, since the downstream end opening of the intake port is located on the upstream side of the cooling water flow from the upstream end opening of the exhaust port for each cylinder, heat is generated at the bridge between the upstream openings of the exhaust port. The load tends to be particularly large. Therefore, in such a configuration, the ability to improve the cooling performance of the cylinder head as in the first aspect of the invention has a particularly effective effect.

According to the fifth aspect of the present invention, the cooling water flowing from the cooling water passage in the first ridge into the water jacket is directed to the lower deck near the upstream end opening of the exhaust port so as to be directed toward the cylinder axis. A cooling water guide section to be provided is provided. With this, the cooling water guided between the exhaust valves through the cooling water passage in the first ridge is directed toward the cylinder axis by the cooling water guide portion, so that the cooling performance above the cylinder is effectively improved. Can be improved.

In the invention of claim 6, the lower deck portion near the first ridge is provided with an introduction hole for introducing cooling water from the cylinder block side in the water jacket of the cylinder head, and at least in the vicinity of the introduction hole, The first ridge and the intake port peripheral wall portion above the first protrusion are separated from each other, and the intake port peripheral wall portion is provided with a cooling water guide portion extending inside the water jacket to above the introduction hole.

According to this structure, the flow of the cooling water guided into the water jacket from the cylinder block through the introduction hole is directed to the lower side in the water jacket by the cooling water guide portion above the introduction hole. The high-temperature lower deck can be effectively cooled by the cooling water flow. Also,
Since the first ridge and the intake port peripheral wall portion above the first ridge are separated near the introduction hole, the cooling water flows therebetween, thereby improving the cooling performance of the intake port and improving the intake filling efficiency. Is achieved. This means that in a supercharged engine in which the intake air temperature after supercharging is about 120 ° C or more,
Particularly effective effects are achieved.

According to a seventh aspect of the present invention, the introduction hole according to the sixth aspect of the present invention is arranged on the upstream side of the flow of the cooling water in the water jacket with respect to the intake port. Thereby, the cooling water flowing out from the introduction hole flows between the first ridge and the port peripheral wall portion in accordance with the flow of the cooling water in the water jacket, so that the function and effect of the invention of claim 6 can be sufficiently obtained. be able to.

According to the invention of claim 8, an introduction hole for introducing cooling water from the cylinder block side to the cooling water passage in the first ridge is provided below the intake port. This cools the periphery by the cooling water guided from the introduction hole to the cooling water passage in the first ridge, so that the cooling performance of the intake port located above the introduction hole is enhanced, which also increases the intake air. Filling efficiency can be improved.

According to the ninth aspect of the present invention, a second ridge is formed on the upper surface of the lower deck portion and extends from the intake side wall to the cylinder axis for each cylinder, and the intake ridge is formed inside the second ridge. A cooling water passage is formed along the second protrusion so as to guide cooling water between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located closer to the side wall portion. A configuration is provided.

According to this configuration, the rigidity of the lower deck portion is increased also on the outer periphery of the cylinder near the intake side wall portion by the second projection in addition to the first projection. Further, in addition to the cooling water passage in the first ridge, the cooling water can be guided toward the cylinder axis by the cooling water passage in the second ridge, so that the cooling performance above the cylinder is further enhanced. be able to.

According to a tenth aspect of the present invention, the second ridge in the ninth aspect of the invention is inclined in the same direction as the first ridge with respect to the cylinder row direction in plan view. This makes the first
The second ridge can be easily laid out on the upper surface of the lower deck. In addition, if the cooling water passages in each of the ridges are provided in parallel with each other, the number of steps for drilling the cooling water passages during the manufacture of the cylinder head can be reduced.

In the eleventh aspect of the present invention, the first and second ridges of the tenth aspect are formed at substantially equal intervals in the cylinder row direction. In this case, the rigidity of the cylinder head can be substantially uniformly increased as a whole.

In the twelfth aspect of the present invention, the first and second ridges in the ninth aspect of the invention are formed such that at least a part of each of the first and second ridges is located above the outer peripheral edge of the cylinder. In this case, the lower deck portion can be strengthened at the outer peripheral edge of the cylinder by each protrusion, and the sealing performance around the cylinder can be effectively improved.

According to a thirteenth aspect of the present invention, in the ninth aspect of the present invention, between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located closer to the exhaust side wall. A configuration is provided in which a connection reinforcing portion that connects the respective peripheral wall portions within the water jacket is provided. Thus, the lower deck portion on the outer periphery of the cylinder on the side closer to the exhaust gas side wall portion is strengthened by the reinforcing connection portion, and the sealing performance around the cylinder can be substantially uniformly improved on both the intake side and the exhaust side.

According to a fourteenth aspect of the present invention, in the ninth aspect of the present invention, between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located closer to the intake side wall portion. It is assumed that a glow plug hole for accommodating the glow plug is open. In this case, since the rigidity of the lower deck portion becomes particularly low near the opening of the glow plug hole, it is particularly effective to improve the rigidity and cooling performance of the lower deck portion as in the invention of claim 9.

According to the fifteenth aspect of the present invention, the thickness of the lower deck portion corresponding to each cylinder axis is made smaller than that of the portion corresponding to the cylinder outer peripheral edge. This makes it possible to increase the rigidity with respect to the combustion pressure acting from the lower combustion chamber side while increasing the cooling performance by making the lower deck portion above the cylinder as thin as possible.

In the sixteenth aspect of the invention, the upper surface of the lower deck portion above each cylinder has a spherical shape. As a result, claim 1
The operation and effect of the fifth invention can be sufficiently obtained.

Next, a second solution of the present invention provides a case where a glow plug hole is provided for each cylinder so as to open into the cylinder between the intake and exhaust port openings close to the intake side wall. Focusing on the fact that the rigidity of the lower deck becomes particularly low in the vicinity of the opening of the glow plug hole, a ridge is formed in the vicinity thereof, and a cooling water passage is provided in the ridge to directly supply cooling water. I was trying to lead.

Specifically, in the invention of claim 17, intake and exhaust ports for each of a plurality of cylinders are provided alternately in the cylinder row direction in the cylinder head of the engine, and the downstream end of the intake port is provided in the cylinder row. 2 on the left and right sides of the cylinder axis
Each of the cylinder heads is opened in the cylinder at one of the positions, while the upstream end is opened on one of the left and right intake side walls of the cylinder head, and the upstream end of the exhaust port is on the left and right sides of the cylinder axis when viewed from the cylinder row direction. Each of the cylinder heads is opened in the cylinder at the two positions, while the downstream end is opened on the exhaust side wall of the cylinder head opposite to the intake port, and a water jacket is formed so as to surround the intake and exhaust ports. Cylinder head structure. A glow plug hole for accommodating a glow plug is opened between a downstream end opening of an intake port and an upstream end opening of an exhaust port of each cylinder located closer to the intake side wall portion, On the upper surface of the lower deck portion of the cylinder head facing the water jacket, a ridge extending from the intake side wall portion toward the cylinder axis is formed for each cylinder, and an opening of the glow plug hole is formed inside the ridge. A cooling water passage is provided along the second protrusion so as to guide the cooling water to the vicinity of the portion.

That is, in the cylinder head of the engine, as a result of the layout of the intake and exhaust ports, the cooling performance of the lower deck portion above the cylinder tends to be low, and the intake port of each cylinder located closer to the intake side wall portion. Since the glow plug hole is opened between the downstream end opening and the upstream end opening of the exhaust port, the rigidity near the opening is reduced, which may cause cracking due to plastic fatigue. On the other hand, according to the above configuration, the cooling water is directly guided to the vicinity of the opening of the glow plug hole through the cooling water passage in the ridge, so that the cooling performance of this portion is sufficiently enhanced, Heat load can be reduced. In addition, the projections can effectively reinforce the lower deck portion on the outer periphery of the cylinder closer to the intake side wall portion, thereby effectively increasing the rigidity near the opening of the glow plug hole and improving the cooling performance. , Reliability can be improved.

[0032]

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

FIG. 2 shows a four-cylinder direct-injection diesel engine 1 according to an embodiment of the present invention.
This engine 1 has a cylinder block 3 made of cast iron having four cylinders 2, 2,... (See FIG. 5), a cylinder head 4 made of an aluminum alloy mounted thereon, and a cylinder mounted on the upper surface of the cylinder head 4. Head cover 5
And an oil pan 6 attached to the lower surface of the cylinder block 3. A piston 8 that defines a combustion chamber and is connected to a crankshaft 7 is reciprocally fitted into each cylinder 2, and fuel is directly injected from a fuel injection nozzle 9 into the combustion chamber in each cylinder 2. It is supposed to be.

An intake manifold 10 is attached to an intake side (right side in the figure) side wall 4a of the cylinder head 4. The intake air flows from the intake manifold 10 through an intake port 12 of the cylinder head 4, and an intake valve 13 is provided. , 13
The air is supplied to the combustion chamber in each of the cylinders 2 (see FIG. 3).
A fuel injection pump 1 is located next to the intake manifold 10.
4 is driven by a crankshaft 7 through a timing belt (not shown) to supply high-pressure fuel to a fuel injection nozzle 9 corresponding to each cylinder 2 through a fuel supply pipe 15. I have.

On the other hand, an exhaust manifold 16 is attached to the exhaust-side (left side in the figure) side wall portion 4b of the cylinder head 4, and the exhaust manifold 16 is connected to the inside of each cylinder 2 through exhaust ports 18 through exhaust valves 18 and 18. The combustion chamber is in communication with the combustion chamber and discharges combustion gas from the combustion chamber. A turbocharger 19 is attached to the exhaust manifold 16, and intake air compressed by the turbocharger 19 is sent to the intake manifold 10 via an intercooler (not shown). Further, in a range extending from the upper surface of the cylinder head cover 5 to above the fuel injection pump 14, a sound insulation cover 20 made of resin for covering the range and attenuating noise and vibration is provided.

In this specification, for convenience of description, the longitudinal direction of the cylinder block 3, that is, the direction in which the four cylinders 2, 2,... The side where the output end of the shaft 7 is located is called the rear side of the engine 1, and the opposite side (the front side in the figure) is the engine 1
Will be called the front side of

As shown in FIGS. 3 and 4, the engine 1 has two intake and exhaust valves 13 and 18 for each cylinder.
The intake and exhaust valves 13 and 18 are driven by a single camshaft 21.
It has a valve train with an OHC layout. The camshaft 21 is arranged so as to be deviated to the exhaust side (left side in FIG. 3 and upper side in FIG. 4) at the upper part of the cylinder head 4 and extend in the front-rear direction of the engine (left-right direction in FIG. 4). Six bearings 22, 2 spaced apart
It is rotatably supported by 2,.

A rocker shaft 23 is disposed obliquely above the camshaft 21 in parallel with the camshaft 21.
(Shown only in FIG. 3). The rocker shaft 23 has rocker arms 24, 25,... Having different lengths on the intake side and the exhaust side, which are swingably supported. The camshaft 21 is synchronized with the rotation of the crankshaft 7.
Are rotated at predetermined timings for each of the cylinders 2 so that the rocker arms 24, 25,... Are depressed to push down the intake and exhaust valves 13, 18 via the rocker bridge 26, respectively.

That is, as shown in FIG. 3, for example, the rocker bridge 26 bridged over the valve shaft ends of the two intake valves 13, 13 reciprocates up and down along the mandrel between the intake valves 13, 13. And the two intake valves 1
The rocker arm 2 on the intake side at the center position between the axes 3 and 13
4 and is slidably contacted with the intake valve 4, and is pushed down by the intake side rocker arm 24, whereby the two intake valves 13, 13 are pushed and opened simultaneously. Similarly, the two exhaust valves 18 are simultaneously opened by the exhaust-side rocker arm 25.

The intake and exhaust valves 13, 18,
Are so-called staggered arrangements alternately arranged in the cylinder row direction and zigzag as a whole in plan view as shown in FIG. In other words, the two intake valves 13 for each cylinder 2 are positioned such that the midpoint of the line connecting the axes thereof, that is, the contact position between the intake side rocker arm 24 and the rocker bridge 26 is the exhaust side rocker arm. 25 is located closer to the camshaft 21 than the contact position between the rocker bridge 25 and the rocker bridge 26 (the midpoint of the line connecting the axes of the two exhaust valves 18, 18). 24
The leverage is longer than the exhaust side. With this,
The lift amount of the intake valves 13, 13 naturally increases, and the intake efficiency is improved.

(Configuration of Cylinder Head) Next, the configuration of the cylinder head 4 of the engine 1 will be described in detail.

As shown in FIGS. 4 and 5, the cylinder head 4 has a total of 10 cylinders 2, 2,... So as to surround each of the four cylinders 2, 2,.
Head bolt holes 29, 29, ... are formed,
A head bolt (not shown) is inserted into each of the head bolt holes 29 and screwed into the bolt hole of the cylinder block 3 so that the cylinder block 3 and the cylinder head 4 are firmly connected. It has become. The three head bolt holes 29, 2 on the exhaust side
, Through holes 28, 28,... For discharging blow-by gas in the crankcase are provided, and the through holes 28, 28,. It also has a function of an oil pit for dropping engine oil into the oil pan 6.

A nozzle hole 31 for accommodating and holding the fuel injection nozzle 9 is formed along the cylinder axis x, and the four openings 11a, 11a,
A glow plug housing hole 32 (glow plug hole), not shown, which is surrounded by 12a, 17a, and 17b and opened at the center thereof and assists ignition of fuel when the engine 1 is cold, is provided with a second intake port. The opening is provided in the cylinder 2 between the opening 12a of the exhaust port 17 and the first opening 17a of the exhaust port 17, that is, between the port opening closer to the camshaft 21.

Further, two intake ports 1 for each cylinder 2
1, 12 and one exhaust port 17 are provided,
As shown in FIG. 5, the first intake port 11 is formed so as to extend greatly from the intake side wall 4a toward the exhaust side and along the cylinder outer periphery, and is located closer to the exhaust side than the cylinder axis x. And opens in the cylinder 2 in the circumferential direction of the cylinder. On the other hand, the second intake port 12 is formed shorter than the first intake port 11, and opens into the cylinder 2 in a cylinder circumferential direction at a position closer to the intake side than the cylinder axis x.

That is, the two intake ports 11, 12
Is a double tangential port that is twisted in the circumferential direction above each cylinder 2 so that the opening direction is directed to the cylinder circumferential direction.
2a is about 7 in the circumferential direction for a general four-valve engine.
It is located at a position that is rotated about 5 °. With such a shape of the intake port, the intake swirl can be sufficiently enhanced while the intake filling efficiency of each cylinder 2 is increased.

Then, such an intake port opening 11
Along with the arrangement of a and 12a, the two openings 17a and 17b of the exhaust port 17 are also arranged so as to be rotationally displaced in the circumferential direction. That is, the first opening 17a of the exhaust port 17 is located closer to the intake side than the cylinder axis x, and the second opening 17b is located closer to the exhaust side than the cylinder axis x. And extends toward the exhaust side wall portion 4b. In other words, the intake and exhaust ports 11, 12, and 17 of the engine 1 open into the cylinder 2 at two locations on both the left and right sides of the cylinder axis x when viewed from the cylinder row direction. As shown in FIG. 4, two intake valves 13 and 13 and two exhaust valves 18 and 1 for each cylinder 2 are provided.
Reference numeral 8 denotes a so-called zigzag arrangement, which is alternately arranged in the front-rear direction of the engine and zigzag as a whole.

A water jacket W is formed from the front end to the rear end of the cylinder head 4 so as to surround the intake and exhaust ports 11, 12, and 17, as shown in FIG. This water jacket W
Are connected to a water jacket (not shown) of the cylinder block 3 through a number of water holes (introduction holes) 33, 33,... Penetrating through the lower deck portion 4c of the cylinder head 4, and are introduced from the cylinder block 3 side. The cooling water flows toward the front end of the engine as indicated by an arrow in the drawing, and is discharged from a cooling water outlet 34 opened in a wall portion on the front end side.

Further, on the front end face of the cylinder head 4,
Although not shown, a high-temperature side cooling water pipe is attached so as to communicate with the cooling water outlet 34, and the high-temperature cooling water discharged from the water jacket W of the cylinder head 4 is sent to a radiator of the vehicle. The radiator and the cylinder block 3 are connected by a low-temperature-side cooling water pipe, and cooling water cooled by the radiator and cooled to a low temperature is returned to the cylinder block 3.

Here, when viewed in the cylinder row direction within the water jacket W, the first and second cylinders 2 are located above the respective cylinders 2.
The peripheral wall portions of the intake ports 11 and 12 rise from the upper surface of the lower deck portion 4c along the cylinder outer periphery and extend to the intake side wall portion 4a obliquely upward, while the peripheral wall portion of the exhaust port 17 similarly has the upper surface of the lower deck portion 4c. And extends to the exhaust side wall 4b (see FIG. 10). For this reason, the flow of the cooling water flowing from the rear end side of the engine to the front end side in the water jacket W is hindered by the peripheral wall of the first intake port 11 and is difficult to reach the center of the cylinder. May be reduced.

Further, at the center of the four port openings of each cylinder 2, a boss 36 having a nozzle hole 31 therein is provided.
Are erected along the cylinder axis x (see FIG. 8), so that the exhaust port opening 17
In the bridge portion between a and 17b, it is extremely difficult to secure a sufficient flow rate of the cooling water despite the extremely large thermal load. Further, as described above, the intake side wall portion 4a
Since the glow plug hole 32 is opened between the intake and exhaust port openings 12a and 17a closer to the opening, there is a concern that the rigidity near the opening is reduced.

Therefore, in the engine 1, as a characteristic part of the present invention, as shown in FIGS. 1 and 6 to 8, first and second reinforcing ribs (protrusions) are provided on the upper surface of the lower deck portion 4 c facing the water jacket W. ) 38, 39 are formed, and cross drill holes (cooling water passages) 4 are formed in the reinforcing ribs 38, 39.
0 and 41 are provided to directly guide the cooling water to the vicinity of the exhaust side valve bridge and the glow plug hole 32.

More specifically, as shown in FIG. 6, the base end side (the lower side in the figure) of the first reinforcing rib 38 is provided with a head bolt hole 2 adjacent to the opening 12 a of the second intake port 12 of each cylinder 2.
9 and is integrally formed so as to connect the peripheral wall of the second intake port 12 and the boss 29 a of the head bolt hole 29. On the other hand, the tip end side (upper side in the figure) of the first reinforcing rib 38 is connected to the exhaust port 17 of the adjacent cylinder 2.
It is located near the two openings 17 a and 17 b and is formed so as to be connected to the peripheral wall of the exhaust port 17.

In other words, the first reinforcing ribs 38 are provided obliquely with respect to the front-rear direction of the engine in plan view so as to face the cooling water flow in the water jacket W, and the first reinforcing ribs 38 of the exhaust port 17 between the adjacent cylinders 2. The peripheral wall of the opening 17a and the peripheral wall of the opening 12a of the second intake port 12 are connected to each other. In this way, the peripheral walls near the highly rigid port openings are connected to each other, The rigidity of the lower deck portion 4c is effectively increased. Are formed so as to extend in the direction in which the intake port openings 11a, 12a and the exhaust port openings 17a, 17b are lined up for each cylinder 2. As a result, the first reinforcing ribs 38, 38,. The first reinforcing ribs 38 can be formed sufficiently long between the cylinders 2 without interfering with the port openings.

On the other hand, the second reinforcing ribs 39, 39,... Are formed substantially in parallel with the first reinforcing ribs 38, at substantially equal intervals in a plan view, and respectively extend from the intake side wall portion 4a to the cylinder shaft center. It extends to the vicinity of the opening of the glow plug hole 32 toward x. As described above, the first reinforcing ribs 38, 38,... And the second reinforcing ribs 38, 39 are arranged substantially in parallel and at substantially equal intervals in the cylinder row direction.
In addition to being able to increase the rigidity of the
They can be easily laid out on the lower deck 4c.

Moreover, the first reinforcing ribs 38, 38,...
Are arranged above the outer peripheral edge of each cylinder 2 at both ends in the front-rear direction of the engine.
Are arranged so as to be located above the outer peripheral edge of the cylinder closer to the intake side wall 4a of each cylinder 2. In addition to this, the exhaust side wall 4b is provided for each cylinder 2. The lower deck 4c is connected between the intake and exhaust port openings 11a and 17b on the near side so as to connect the peripheral walls of the ports.
The third reinforcing rib 42 (connection reinforcing portion) is formed on the upper side. That is, the lower deck portion 4 is reinforced at four locations surrounding each cylinder 2 by the first to third reinforcing ribs 38, 39, and 42, thereby improving the sealing performance around the cylinders substantially uniformly. Can be done.

The first and second reinforcing ribs 38,
Cross drill holes (cooling water passages) 40 and 41 for guiding the cooling water toward the axis x of each cylinder 2 are provided in 39. More specifically, the cross drill hole 40 in the first reinforcing rib 38 is formed along the first reinforcing rib 38 from outside the intake side wall 4a of the cylinder head 4 as shown in FIG. Two exhaust port openings 17a, 1
7b is open at an intermediate position. This cross drill hole 4
As shown in FIG. 8, a wall-shaped cooling water guide portion 44 extending from the peripheral wall portion of the exhaust port 17 to the lower deck portion 4 c is formed in the vicinity of the outlet side opening portion 0. By directing the guided cooling water toward the cylinder axis x as indicated by the arrow in the figure, the cooling performance above each cylinder 2 can be further improved.

Further, as shown in the figure, on the upper surface of the lower deck portion 4c, a portion corresponding to the upper side of each cylinder 2 has a spherical shape, and a portion corresponding to the cylinder axis x corresponds to a portion corresponding to the cylinder outer peripheral edge. Since it is thinner, it is possible to enhance the heat transfer from the lower combustion chamber to improve the cooling performance and to have sufficiently high rigidity against the combustion pressure acting from the combustion chamber side. Can be.

On the other hand, on the upstream side of the cross drill hole 40 near the intake side wall 4a, an introduction hole 45 penetrating through the lower deck portion 4c is opened, and the introduction hole 45 allows the water jacket on the cylinder block 3 side. Is supplied with cooling water. Since this introduction hole 45 is located just below the first intake port 11 (see FIG. 1).
By cooling the surrounding water jacket W with the cooling water from the introduction hole 45, the first intake port 11 above the water jacket W is also cooled, thereby improving the intake filling efficiency. Incidentally, 46, 46,
... are plugs for closing the upstream end of the cross drill hole.

As shown in FIG. 8, the cooling water flow in the water jacket W with respect to the first reinforcing rib 38 is located above the water hole 33 adjacent to the upstream side (right side in the figure).
A tongue-shaped cooling water guide portion 47 is provided so as to extend from the peripheral wall portion of the first intake port 11 into the water jacket.
The cooling water flows through the peripheral wall of the intake port 11 while being separated therefrom. Therefore, the cooling water flowing from the cylinder block 3 side through the water hole 33 is directed downward by the cooling water guide portion 47 above the cooling water as shown by an arrow in FIG. In accordance with the flow of the cooling water, the cooling water passes between the first reinforcing rib 38 and the port peripheral wall portion and flows around the boss portion 36 along the cylinder axis x.

As a result, the lower deck portion 4 above the cylinder 2
c can be effectively cooled, and the cooling performance of the intake ports 11 and 12 is also improved. In particular, the engine 1 of this embodiment is equipped with a turbocharger 19,
Since the intake air temperature after supercharging reaches about 120 ° C. or more, the cooling performance of the intake ports 11 and 12 is improved as described above,
The ability to improve the intake filling efficiency has a particularly effective effect.

On the other hand, as shown in FIG. 9, the cross drill hole 41 in the second reinforcing rib 39 is
It is perforated along the second reinforcing rib 39 like 0,
The cooling water introduced from the cylinder block 3 side is guided to the vicinity of the opening 32a of the glow plug hole 32 by the introduction hole 45 penetrating through the lower deck portion 4c. That is, as described above, the glow plug hole 32 is provided so as to open between the opening 12a of the second intake port 12 and the first opening 17a of the exhaust port 17, so that the vicinity of the opening 32a Although there is a concern that the rigidity may decrease, in this embodiment, the cooling water is directly guided to the vicinity of the opening 32a by the cross drill hole 41 so as to enhance the cooling performance. The heat load can be reduced, and the reliability can be sufficiently improved.

Further, the first and second reinforcing ribs 38, 3
The cross-drill holes 40 and 41 in 9 are respectively drilled in parallel, so that the number of man-hours for drilling the cross-drill holes 40, 41,... .

Therefore, according to the cylinder head structure of the engine 1 according to this embodiment, as shown in FIG.
Although the intake and exhaust ports 11, 12, and 17 are laid out in a complicated manner, and as a result, the cooling performance around the cylinder tends to be low, the cross drill holes 40,
The coolant and the coolant guides 44 and 47 direct the coolant toward the axis x of each cylinder 2 as shown by the arrows in FIG.

In particular, in the water jacket W of the cylinder head 4, the cooling water flows from the rear end side of the engine toward the front end side (see FIG. 5), and the exhaust port opening 17a having a high heat load is provided. , 17b, and the vicinity of the opening 32a of the glow plug hole 32 where the rigidity is likely to be reduced, all of which are shaded by the intake ports 11, 12 and the like. In addition, since the cooling water is directly guided by the cross drill holes 40 and 41 in the second reinforcing ribs 38 and 39 to ensure a sufficient flow rate of the cooling water, it is possible to reliably prevent a decrease in reliability.

The lower deck portion 4 of the cylinder head 4
forming first and second reinforcing ribs 38, 39,... on the upper surface to increase the rigidity of the entire cylinder head 4, and further forming third reinforcing ribs to form a lower deck above the outer peripheral edge of each cylinder 2. By increasing the rigidity of the portion 4c substantially evenly, the sealing performance between the cylinder head 4 and the cylinder block 3 can be improved, and in addition to the above-described improvement of the cooling performance, the high output of the engine 1 is supported. Meanwhile, reliability can be improved.

It should be noted that the present invention is not limited to the above-described embodiment, but includes other various embodiments. That is, the engine 1 according to the embodiment is
Although the two intake ports 11 and 12 for each cylinder 2 are both tangential ports, the invention is not limited to this. For example, one of them may be a helical port. Further, the present invention can be applied not only to a diesel engine but also to a gasoline engine.

Further, in the cylinder head 4 of the above-described embodiment, the first and second two types of reinforcing ribs 3 are provided on the lower deck portion.
8 and 39 are formed, but only one of the reinforcing ribs may be provided.

[0068]

As described above, according to the cylinder head structure of the multi-cylinder engine according to the first aspect of the present invention, the cooling arrangement above the cylinder tends to be reduced due to the layout of the intake and exhaust ports. However, the cooling water can be guided directly through the cooling water passage between the two upstream end openings of the exhaust port having a particularly large heat load, so that the cooling performance can be sufficiently improved. By forming the first ridge extending over the entire length of the cylinder head to increase the rigidity of the entire cylinder head, the sealing performance of each cylinder can be improved. Therefore,
By improving the rigidity and cooling performance of the cylinder head, it is possible to improve reliability while responding to an increase in engine output.

According to the second aspect of the invention, the port peripheral wall near the upstream end opening of the exhaust port and the intake port peripheral wall are connected by the first ridge, so that the rigidity of the lower deck can be effectively increased. .

According to the third aspect of the present invention, the layout of the intake / exhaust port and the first ridge on the upper surface of the lower deck can be easily performed.

According to the fourth aspect of the invention, when the upstream end opening of the exhaust port is disposed downstream of the cooling water flow for each cylinder, the effect of the first aspect of the invention is particularly effective.

According to the fifth aspect of the present invention, the cooling water flowing out of the cooling water passage in the first ridge is directed toward the cylinder axis by the cooling water guide, so that the cooling performance above the cylinder is effectively improved. Can be improved.

According to the sixth aspect of the invention, the cooling water supplied through the introduction hole is directed to the lower side in the water jacket by the cooling water guide portion above the cooling water.
The high-temperature lower deck can be effectively cooled. According to the invention of claim 7, the above-mentioned effect can be sufficiently obtained.

According to the eighth aspect of the present invention, the introduction hole for introducing cooling water into the cooling water passage is provided below the intake port, so that the cooling of the intake port is promoted and the intake filling efficiency can be improved.

According to the ninth aspect of the present invention, the sealability around the cylinder on the side closer to the intake side wall can be enhanced by the second ridge, and the cooling water passage in the second ridge also cools. Water can be directed toward the cylinder axis,
The cooling performance can be further improved.

According to the tenth aspect, the first and the second
The layout of the ridges can be easily performed, and the number of steps for drilling the cooling water passage can be reduced.

According to the eleventh aspect, the rigidity of the cylinder head can be substantially uniformly increased as a whole.

According to the twelfth aspect of the invention, the sealing performance around the cylinder can be effectively improved by the ridge.

According to the thirteenth aspect of the present invention, the sealing performance around the cylinder can be enhanced on the side closer to the exhaust side wall by the connection reinforcing portion, so that the sealing performance is substantially uniformly improved on both the intake side and the exhaust side. it can.

According to the fourteenth aspect, the rigidity and cooling performance of the lower deck can be improved near the glow plug hole opened in the cylinder.

According to the fifteenth aspect, it is possible to increase the rigidity with respect to the combustion pressure while enhancing the cooling performance of the lower deck portion above the cylinder, and according to the sixteenth aspect, the above effects are sufficiently obtained. be able to.

According to the cylinder head structure of the multi-cylinder engine according to the seventeenth aspect of the present invention, the layout of the intake / exhaust ports tends to lower the cooling performance above the cylinders, and in addition to the vicinity of the opening of the glow plug hole. Even in the premise configuration in which the reliability may be deteriorated, the rigidity of the portion is increased by the ridge, and the cooling water is directly guided through the cooling water passage in the ridge, so that the cooling performance is sufficiently improved. Therefore, cooling performance and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a partial plan sectional view showing a cylinder head structure according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an overall configuration of a diesel engine according to the embodiment.

FIG. 3 is a longitudinal sectional view of a cylinder head showing an arrangement of intake and exhaust ports and a configuration of a valve train.

FIG. 4 is a plan view showing a configuration of a cylinder head in a state where a rocker shaft and the like are omitted.

FIG. 5 is a plan sectional view of a cylinder head showing an arrangement of intake and exhaust ports and a configuration of a water jacket.

FIG. 6 is a plan sectional view of the cylinder head having a section different from that of FIG. 5;

FIG. 7 is a longitudinal sectional view taken along line AA of FIG. 6;

FIG. 8 is a longitudinal sectional view taken along line BB of FIG. 6;

FIG. 9 is a longitudinal sectional view taken along line CC of FIG. 6;

FIG. 10 is an explanatory view showing an arrangement of intake and exhaust ports of an engine having a double tangential port.

[Explanation of symbols]

 W Water jacket of cylinder head 1 4-cylinder diesel engine 2 cylinder 3 cylinder block 4 cylinder head 4a intake side wall 4b exhaust side wall 4c lower deck 9 injection nozzle 11,12 intake port 11a, 11b intake port opening 17 exhaust port 17a, 17b Exhaust port opening 32 Glow plug hole 32a Glow plug hole opening 33 Water hole (introduction hole) 38 First reinforcement rib (first protrusion) 39 Second reinforcement rib (second protrusion) 40, 41 Cross drill hole (cooling water passage) 42 Third reinforcing rib (connection reinforcing part) 44, 47 Cooling water guide part 45 Inlet hole x cylinder axis

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02F 1/40 F02F 1/40 BA (72) Inventor Naoyuki Yamagata 3-1, Fuchu-cho, Fuchu-cho, Aki-gun, Hiroshima Prefecture No. Mazda Co., Ltd. F-term (reference) 3G024 AA06 AA09 AA11 AA71 BA05 CA03 CA05 CA26 DA02 DA06 DA09 DA18 FA01 FA05

Claims (17)

[Claims] An intake port and an exhaust port for each of a plurality of cylinders are alternately arranged in a cylinder row direction on a cylinder head of an engine, and a downstream end of each of the intake ports has a cylinder axis as viewed from the cylinder row direction. The upper end is opened in either the left or right intake side wall of the cylinder head, and the upstream end of each exhaust port is viewed from the cylinder row direction. The cylinder head is opened in the cylinder at two locations on both the left and right sides of the cylinder axis, while the downstream end is opened on the exhaust side wall of the cylinder head opposite to the intake side, surrounding the intake and exhaust ports. In the cylinder head structure in which the water jacket is formed, the upper surface of the lower deck portion of the cylinder head facing the water jacket is provided with two exhaust ports for each cylinder. First ridge leading to the intake side wall portion from the vicinity of the upstream end opening through an intake port below the adjacent cylinders are formed in the interior of the first ridge, 2 cooling water of the exhaust port
A cylinder head structure for a multi-cylinder engine, wherein a cooling water passage is provided along the first projecting shape so as to guide between the two upstream end openings. 2. The first ridge according to claim 1, wherein the first ridge is formed in a substantially linear shape so as to be oblique to the cylinder row direction in a plan view, and is adjacent to an exhaust port peripheral wall portion of each cylinder in the water jacket. A cylinder head structure for a multi-cylinder engine, wherein the cylinder head structure connects an intake port peripheral wall of a cylinder. 3. The two downstream end openings of the intake port and the two upstream end openings of the exhaust port of each cylinder are arranged along the direction in which the first ridge extends in plan view. A cylinder head structure for a multi-cylinder engine, wherein the cylinder head structure is arranged as follows. 4. The cooling water flow in the water jacket according to claim 1, wherein a downstream end opening of the intake port of each cylinder is closer to an upstream end opening of the exhaust port than a flow of the cooling water in the water jacket. The first ridge is formed so that the cooling water flows in a cooling water passage in the cooling water passage in a direction substantially opposite to the flow of the cooling water in the water jacket. Cylinder head structure. 5. A cooling device according to claim 1, wherein the cooling water flowing out of the cooling water passage in the first ridge into the water jacket is directed to the cylinder axis in the lower deck portion near the upstream end opening of the exhaust port. A cylinder head structure for a multi-cylinder engine, wherein a cooling water guide portion for directing is provided. 6. The lower deck portion in the vicinity of the first ridge is provided with an introduction hole for introducing cooling water from a cylinder block side into a water jacket of a cylinder head, at least in the vicinity of the introduction hole. The first ridge and the intake port peripheral wall portion above the first ridge are separated from each other, and the intake port peripheral wall portion is provided with a cooling water guide portion extending inside the water jacket to above the introduction hole. The cylinder head structure of a multi-cylinder engine characterized by the following. 7. The cylinder head structure for a multi-cylinder engine according to claim 6, wherein the introduction hole is arranged upstream of the intake port in the flow of the cooling water in the water jacket. 8. The multi-purpose air conditioner according to claim 1, wherein an inlet hole for introducing cooling water from a cylinder block side to a cooling water passage in the first ridge is provided below the intake port. The cylinder head structure of a cylinder engine. 9. A cylinder according to claim 1, wherein a second ridge is formed on the upper surface of the lower deck portion, the second ridge extending from the intake side wall portion toward the cylinder axis for each cylinder. The second cooling water is introduced between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located closer to the intake side wall.
A cylinder head structure for a multi-cylinder engine, wherein a cooling water passage is provided along a projection. 10. The cylinder head structure for a multi-cylinder engine according to claim 9, wherein the second ridge is inclined in the same direction as the first ridge in the cylinder row direction in a plan view. 11. The cylinder head structure for a multi-cylinder engine according to claim 10, wherein the first and second ridges are formed at substantially equal intervals in the cylinder row direction. 12. The cylinder head structure for a multi-cylinder engine according to claim 9, wherein at least a part of each of the first and second ridges is located above an outer peripheral edge of the cylinder. 13. The water supply system according to claim 9, wherein each of the peripheral walls is water-connected between a downstream end opening of an intake port and an upstream end opening of an exhaust port of each cylinder located closer to the exhaust side wall. A cylinder head structure for a multi-cylinder engine, characterized in that a connection reinforcing portion for connection within a jacket is provided. 14. The glow plug according to claim 9, wherein the glow plug is housed between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located on the side closer to the intake side wall. A cylinder head structure for a multi-cylinder engine, characterized in that the hole is open. 15. The cylinder head structure for a multi-cylinder engine according to claim 1, wherein a thickness of a portion corresponding to each cylinder axis of the lower deck portion is thinner than a portion corresponding to an outer peripheral edge of the cylinder. 16. The cylinder head structure for a multi-cylinder engine according to claim 15, wherein an upper surface of a lower deck portion above each cylinder is formed in a spherical shape. 17. An intake port and an exhaust port for each of a plurality of cylinders are provided alternately in a cylinder row direction on a cylinder head of an engine, and a downstream end of the intake port is provided on a left and right side of a cylinder axis when viewed from the cylinder row direction. The cylinder head is opened at two locations on both sides, and the upstream end is opened at one of the left and right intake side walls of the cylinder head. The upstream end of the exhaust port is located at the cylinder axis when viewed from the cylinder row direction. The cylinder is opened in the cylinder at two locations on the left and right sides of the cylinder, while the downstream end is opened on the exhaust side wall of the cylinder head opposite to the intake port. A water jacket surrounds the intake and exhaust ports. In the formed cylinder head structure, between the downstream end opening of the intake port and the upstream end opening of the exhaust port of each cylinder located on the side close to the intake side wall portion. A glow plug hole for accommodating a glow plug is opened, and a projection extending from the intake side wall toward the cylinder axis is formed for each cylinder on an upper surface of a lower deck portion of the cylinder head facing the water jacket, A cylinder for a multi-cylinder engine, wherein a cooling water passage is provided along the second protrusion so as to guide cooling water near an opening of the glow plug hole. Head structure.