JPH0218307Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine cooling device that heats intake air using engine cooling water.

(Prior Art) In a reciprocating engine in which a combustion chamber is defined by a cylinder block, a cylinder head, and a piston inserted into the cylinder block,
Intake air is supplied to this combustion chamber via an intake passage in an intake pipe and a cylinder head. In such an engine, a cooling water passage is formed in the cylinder head, as shown in Japanese Utility Model Application Publication No. 58-35645, and the engine cooling water flowing through this cooling water passage is used to cool each engine. I try to cool the parts.

(Problems to be Solved by the Invention) Incidentally, it is common practice to effectively utilize the heat of engine cooling water in the cylinder head to promote vaporization and atomization of fuel.

However, it is difficult to form a cooling water passage for heating the intake air over a wide area along the flow direction of the intake passage in the head and the intake pipe, and effective intake air heating is achieved using engine cooling water. was not necessarily sufficient. That is, bubbles, that is, air, tend to accumulate in the cooling water passage at a high position, and when this air remains partially, the heat transfer effect of this air collecting area becomes extremely poor. If the cooling water passage for heating the intake air is simply formed along the intake passage, this air retention portion will be formed.

On the other hand, a cooling water passage is formed in the cylinder head to cool the area around the exhaust passage in the head, but due to restrictions due to the height positional relationship with this exhaust side cooling water passage (exhaust passage side cooling The water passage is
In order to cool the exhaust passage, which becomes extremely hot, air cannot be allowed to stagnate, so it is strongly required that the cooling water passage be located at a lower position than other cooling water passages. In reality, it is difficult to set the height to an absolutely low position where air does not accumulate.

Therefore, the purpose of the present invention is to effectively heat the intake passage within the head with engine cooling water over almost the entire length of the intake passage, without placing any restrictions on the cooling of the exhaust passage. The intake passage in the intake pipe located on the upstream side of the passage is also effectively heated by engine cooling water to vaporize the fuel.
An object of the present invention is to provide an engine cooling device that can further promote atomization.

(Means and actions for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration. That is, a combustion chamber is defined by a cylinder block, a cylinder head, and a piston fitted into the cylinder block, and an intake passage formed in the cylinder head and opened to the combustion chamber is connected to the cylinder head. In an engine that is connected to an intake passage in an intake pipe installed in the engine, the intake passage in the cylinder head and in the intake pipe is inclined upward in a substantially straight line as it goes upstream, at least when the engine is installed. an in-head extending portion for heating the intake air is formed in the cylinder head and extends linearly upward from the cooling water passage in the cylinder head along the intake passage in the cylinder head; An intake pipe cooling water passage for heating the intake air is formed in the pipe and extends linearly upward along the intake passage in the intake pipe, continuous with the in-head extension part, and each of the intake pipe cooling water passages is formed in the pipe. A communication passage communicating between the uppermost parts is formed in the intake pipe, and the communication passage communicates with the radiator at an end in the cylinder arrangement direction.

With the above configuration, it is possible to arrange the in-head extending portion and the cooling water passage in the intake pipe extremely close to the intake passage in the head and the intake pipe in order to overheat the intake air. The linearly inclined shape of the cooling water passage in the pipe itself makes it difficult for air to accumulate in the part extending in the head and in the middle of the cooling water passage in the intake pipe, and furthermore, the cooling water in the part extending in the head and in the intake pipe becomes difficult to accumulate. The flow of engine cooling water is generated by connecting the tops of the cooling water passages in each intake pipe with each other through a communication passage due to the linearly inclined shape of the passage, and by communicating the communication passage with the radiator at the end in the cylinder arrangement direction. In addition, it is possible to prevent the occurrence of drifting, and the active flow of engine cooling water can be effectively utilized to ensure air discharge. Therefore, it is possible to effectively superheat the intake air.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIG. 1, a cylinder head 3 is mounted and fixed on a cylinder block 1 via a gasket 2, and the cylinder block 1 and cylinder head 3 are connected to each other.
A combustion chamber 5 is defined by a piston 4 and a piston 4 slidably inserted into the cylinder block 1.

As shown in FIG. 2, two intake ports 6 and 7 and one exhaust port 8 formed in the cylinder head 3 are opened to the combustion chamber 5, and the intake ports 6 and 7 are connected to an intake valve. 6A or 7
A, the exhaust port 8 is opened and closed by an exhaust valve 8A and a camshaft 9 at known timings. The two intake ports 6 and 7 are formed adjacent to each other in the crankshaft direction (vertical direction in Figure 2), and the exhaust port 8 is formed in the engine width direction (horizontal direction in Figure 2) with respect to one intake port 6. A spark plug mounting hole 10 is formed adjacent to the other intake port 7 in the engine width direction.

In the cylinder head 3, the intake passage A of the engine described above has its upstream portion serving as a common intake passage 11, while its downstream end portion has a pair of left and right branched intake passages connected to the intake port 6 or 7. 11A and 11B. The two branched intake passages 11A and 11B, that is, the two intake ports 6, 7, are defined by a partition wall 3a integrally formed on the cylinder head 3. Further, the intake pipe 12 connected to the cylinder head 3 has a main intake passage 12A connected to the common intake passage 11, and a shutter valve 13 is disposed in the downstream end of the main intake passage 12A. is closed at low loads, that is, fully closed or slightly opened at low loads, and opened at high loads.

A low-load intake passage 14 that bypasses the shutter valve 13 is located below each of the common and branched intake passages 11, 11A, and 11B, and is formed within the pipe wall of the intake pipe 12 and within the cylinder head 3. . This low-load intake passage 14 has a small effective opening area to increase the intake flow rate.
Its upstream end is opened as an inlet 14a in the bottom wall of the intake pipe 12 immediately upstream of the shutter valve 13. Further, the downstream end of the low-load intake passage 14 serves as the outlet 14b, and one of the intake ports 7
(One intake valve 7A) is opened immediately upstream.
This low-load intake passage 14 is connected to the combustion chamber 5.
The combustion chamber 5 is oriented substantially tangentially to the combustion chamber 5 so as to generate a swirl of intake air.

With the above-described intake passage configuration, the shutter valve 13 is closed during low loads, so that all or almost all of the intake air passes through the low-load intake passage 14, which has a small effective opening area, and is transferred to one intake air. It is supplied from port 7 to combustion chamber 5. As a result, stable combustion is ensured, especially at low load, by improving the intake flow velocity and generating swirl. Also, when the load is high, the shutter valve 13 is opened, so the intake pipe 1
Intake air introduced into the common intake passage 11 from the main intake passage 12A in the main intake passage 12A is distributed by the partition wall 3a, and is introduced from the intake port 6 into the combustion chamber 5 through the branch intake passage 11A. Intake passage 11
It will be introduced into the combustion chamber 5 from the intake port 7 through B. This improves charging efficiency during high loads and ensures sufficient output.

On the other hand, fuel is supplied from a fuel injection valve I provided at the connection between the cylinder head 3 and the intake pipe 12. This fuel injection valve I
The (injection port) is oriented toward (the upstream end surface of) the partition wall 3a, and as a result, the fuel injected from the fuel injection valve I is diffused into both intake ports 6, 7 ( Both branch intake passages 11A, 11B)
will be distributed and supplied to.

Engine cooling water passages 15, 16, and 17 are formed within the cylinder head 3. Of these cooling water passages 15, 16, and 17, the cooling water passages 15 and 16 are located at the peripheral portion of the cylinder head 3 and at the bottom of the cylinder head 3 (the cylinder block 3).
The cooling water passage 15 is located below the partition wall 3a from the common intake passage 11, and the cooling water passage 16 is formed so as to extend in the crankshaft direction.
is located below the exhaust passage 18 that connects to the exhaust port 8. The remaining cooling water passage 17 is formed at a high position in the center of the cylinder head 3 so as to extend in the direction of the crankshaft, and is arranged in a relationship with the cooling water passage 15 such that the partition wall 3a is sandwiched therebetween. There is. The cooling water passages 15 and 16 are connected to the cylinder block 1 through communication ports 19 and 20 opened on the lower surface of the cylinder head 3, respectively.
It communicates with the cooling water passage 21 inside, and communicates with the cooling water passage 17 at its end in the crankshaft direction.

As mentioned above, the cooling water passage 1 in the upper center
7 and a cooling water passage 15 located below the partition wall 3a are communicated with each other through a through hole 22 formed in the partition wall 3a, as shown in FIG. 3 (see FIG. 4). That is, the through hole 22 is linear,
One end thereof opens into a cooling water passage 15, and the other end opens into a cooling water passage 17. In the embodiment, such a through hole 22 is formed from the mating surface side of the cylinder head 3 with respect to the cylinder block 1, as shown by the arrow It is formed by drilling (by drilling diagonally upward from the mating surface toward the center of the combustion chamber 5), and the unnecessary lower surface side opening 23 of the cylinder head 3 formed by this drilling is formed. When this cylinder head 3 is assembled to the cylinder block 1, it will be closed by the cylinder block 1 via the gasket 2.

Here, the horizontal line when the engine is installed (for example, when mounted on a vehicle) is indicated by the symbol l in Figure 1, and as is clear from this horizontal line l, the intake air inside the cylinder head 3 and the intake pipe 12 is Passage 1
1, 11A, 11B, 12A, and 14 are inclined upward as they go upstream. In the case of a V-type engine, such an inclined relationship can be obtained as is by the relationship of the V bank angle, and in the case of an in-line engine, it can be obtained by slightly inclining the entire engine.

As mentioned above, the intake passages 11, 11A, 11B, 12 in the cylinder head 3 and in the intake pipe 12
A, 14 have a predetermined inclination relationship, but in order to more actively heat the intake air at low loads where fuel vaporization and atomization are a problem, in addition to the above-mentioned cooling water passage 15, An extended portion 24 for heating intake air extending along the low-load intake passage 14 is connected to the cooling water passage 15 . As shown in FIG. 5, this extended portion 24 for heating the intake air extends along the bottom wall of the low-load intake passage 14 and covers the side wall portion thereof except for the vicinity of the upstream end (the fifth (see broken line in the figure). Further, an intake pipe cooling water passage 25 is formed in the intake pipe 12 and covers the bottom wall and both side walls of the low-load intake passage 14.
(See also FIG. 6) Each cooling water passage 25 extends along the low-load intake passage 14 to the vicinity of its inlet 14a. The upper end of the extension 24 communicates with the lower end of the cooling water passage 25 via a communication hole 26 . The extended portion 24 for heating intake air and the cooling water passage 25 of the intake pipe 12 are provided for each cylinder, that is, for each low-load intake passage 14 for each cylinder. The passages 25 are communicated with each other at the top thereof by a communication passage 27 formed in the intake pipe 12, as shown in FIG. And this communication path 2
The end portion in the cylinder arrangement direction of No. 7 merges with a collective outlet 28 of another cooling water passage in the cylinder head 3 and is connected to a radiator (not shown). The collective outlet 28 also communicates with the cooling water passage 17 and opens to the outside at the top of the water jacket within the cylinder head 3.

In the above configuration, the cooling water rises from the cooling water passage 21 in the cylinder block 1 to the cooling water passages 15 and 16 in the cylinder head 3, passes through the cooling water passage 17, and finally reaches the position shown in the figure. After being cooled by the radiator, the above-mentioned circulation is repeated. At the same time, the cooling water passage 15 flows to the extension part 24 for heating the intake air, and then to the cooling water passage 25 in the intake pipe 12, but these extension parts 24 and the cooling water passage 25, because of the inclination relationship along the intake passage 14, air does not accumulate in the middle part up to the top of the cooling water passage 25, and the communication passage 27 prevents air from accumulating between the tops of the cooling water passage 25. Since they are connected to each other and engine cooling water circulates, air will not accumulate at the top.
As a result, the intake air flowing through the low-load intake passage 14 is sufficiently warmed by the cooling water in the intake air heating extension part 24 and the cooling water passage 25 of the intake pipe 12, and the fuel is vaporized. , which is preferable in terms of promoting atomization.

In the embodiment, the partition wall portion 3a is also sufficiently warmed by the engine cooling water circulating through the through hole 22, thereby further vaporizing and atomizing the fuel. Further, since the end of the communication passage 27 joins the collection outlet 28 to form a circulation path to the radiator, this is more preferable in terms of preventing the air from stagnation.

FIG. 7 shows another embodiment of the present invention, in which the same components as in the previous embodiment are given the same reference numerals, and their explanation will be omitted. In this embodiment, the low-load intake passage 14 is also eliminated, and accordingly, the shutter valve 13 is also eliminated. Of course, the extension part 2 for heating the intake air inside the cylinder head 3
4 and the cooling water passage 25 in the intake pipe 12 are formed along the common and branched intake passages 11, 11A, 11B and along the intake passage 12A in the intake pipe 12.

In the above embodiments, an engine with two intake ports has been described, but it goes without saying that the invention can be similarly applied to an engine with one intake port, which is the most common type of engine. Further, a vaporizer may be used as the fuel supply device, and in this case, since fuel always flows into the intake passage heated by the extension portion 24, it is more advantageous in terms of promoting vaporization and atomization. It is.

(Effects of the invention) As is clear from the above, the invention has the following effects:
The intake passage in the cylinder head and the intake air connected to the intake passage in the cylinder head are reliably prevented from forming air pockets without imposing restrictions on the height position of the cooling water passage for the exhaust passage formed in the cylinder head. It is possible to effectively heat the intake passage in the pipe and is extremely effective in promoting vaporization and atomization of fuel.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the present invention.
2 is a plan sectional view taken along the intake passage and exhaust passage of FIG. 1; FIG. FIG. 3 is a plan sectional view at a lower position than FIG. 2. FIG. 4 is a sectional view of the main part along the through hole. FIG. 5 is a sectional view taken along the line shown in FIG. 1. FIG. 6 is a sectional view taken along the line of FIG. 1. FIG. 7 shows another embodiment of the present invention, and is a side sectional view corresponding to FIG. 1. A: Intake passage, l: Horizontal line, I: Fuel injection valve, 1: Cylinder block, 3: Cylinder head, 4: Piston, 5: Combustion chamber, 6, 7: Intake port, 8: Exhaust port, 11: Common Intake passage, 1
1A, 11B: Branch intake passage, 12: Intake pipe, 1
3: Shutter valve, 14: Low load intake passage, 14
a: Inlet, 14b: Outlet, 15, 16, 1
7, 21: Cooling water passage, 19, 20: Communication port, 2
4: Extension part for intake air heating inside the cylinder head, 2
5: Cooling water passage for heating intake air in the intake pipe, 26: Communication hole, 27: Communication path.

Claims (1)

[Claims for Utility Model Registration] A combustion chamber is defined by a cylinder block, a cylinder head, and a piston fitted into the cylinder block, and an intake air formed in the cylinder head and opened to the combustion chamber. In an engine in which a passage communicates with an intake passage in an intake pipe attached to the cylinder head, the intake passage in the cylinder head and the intake pipe extends upward in a substantially straight line as it goes upstream, at least when the engine is installed. an in-head extending portion for heating intake air that extends linearly upward from the cooling water passage in the cylinder head along the intake passage in the cylinder head; is formed in the intake pipe, and an intake pipe cooling water passage for heating the intake air is formed in the intake pipe, and extends upward in a straight line along the intake passage in the intake pipe, and is continuous with the in-head extending portion; An engine cooling device, characterized in that a communication path is formed in the intake pipe and communicates the uppermost parts of the cooling water passages in the intake pipe, and the communication path communicates with a radiator at an end in a cylinder arrangement direction.