JPH039287B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field> The present invention relates to a so-called boiling-cooled multi-cylinder internal combustion engine that uses the latent heat of vaporization of a refrigerant to cool the cylinders and the outer wall of a combustion chamber. This invention relates to a steam manifold that guides boiling steam to the outside.

<Background technology> For example, the boiling-cooled internal combustion engine is
This will be explained with reference to FIG. 1.

That is, the water jacket 2 of the engine 1 is filled with a liquid phase refrigerant L that occupies most of its volume, and the liquid phase refrigerant L is heat exchanged with the cylinders.
It is boiled and vaporized to generate steam (vapor phase refrigerant V).

After the generated steam is collected in the upper space within the cylinder head of the water jacket 2, it is led to the condenser 4 via the steam passage 3, where it is radiated and condensed to be returned to liquid refrigerant.

The liquefied refrigerant is returned to the water jacket 2 via the refrigerant passage 5 by the feed pump 6.

Such boiling cooling systems use the latent heat of vaporization of the refrigerant to cool the engine, so they have high cooling efficiency, and the condenser has excellent heat dissipation effects because it exchanges heat with a large temperature difference between high-temperature steam and the outside air. ing. Further, since the boiling of the refrigerant starts from parts that tend to become high temperature, such as the walls of the combustion chamber, uniform cooling can be achieved.

For these reasons, boiling cooling allows the wall temperature of the combustion chamber to be as high as possible within a range that does not affect the durability and knock resistance of the material, resulting in extremely favorable results in terms of thermal efficiency. can be obtained.

By the way, in the refrigerant cycle of the evaporative cooling system which has such a characteristic effect, the vapor passage 3 is pipe-shaped and simply connected to the end of the cylinder head in the cylinder row direction, as shown in the figure. Generally, the structure is such that vapor is drawn to the outside from the outermost end of the refrigerant V layer. Furthermore, since the liquid phase refrigerant L occupies most of the water jacket 2 and is configured to cover the cylinder wall and the combustion chamber wall, the actual situation is that the volume occupied by the gas phase refrigerant V is relatively small. be.

Therefore, the steam generated from the water jacket around the cylinder near the steam outlet is smoothly drawn into the condenser 4, but on the other hand, the steam generated in the water jacket at the opposite end, which is far away from the steam outlet, is The vapor phase refrigerant tends to stagnate in the V layer, and the heat dissipation of the stagnant vapor is not performed smoothly, resulting in cylinders becoming locally heated, and especially when the pipe diameter of the steam passage 3 is small, the passage resistance increases. Due to this effect, there is a risk that parts of the water jacket 2 such as the exhaust port wall and the combustion chamber wall may locally overheat.

<Object of the Invention> In view of the above, an object of the present invention is to enable steam to be smoothly led out from the water jackets of all cylinders.

<Structure of the Invention> In order to achieve the above object, the present invention provides a dedicated steam manifold, and stores the steam above the water jacket of each cylinder through an inlet port formed to communicate independently with the top of the water jacket. The steam manifold is arranged so that the steam is smoothly guided and collected in a steam collector having a large capacity and low passage resistance without flowing, and the steam is smoothly guided to the outside from an outlet port provided at the top of the steam collector. Configured.

<Example> Examples of the present invention will be described below based on FIGS. 2 to 4.

2A to 2D show the present invention applied to a multi-cylinder diesel engine, in which a sub-combustion chamber 12 facing a glow plug and an injection valve is formed in the cylinder head 11, and injection is supplied to the sub-combustion chamber 12. The fuel is ignited by the compression action of the piston 13 and flows into the nozzle 1.
4 and is ejected into the main combustion chamber 15 as flame and unburned components. A water jacket 17 in the cylinder head 11 facing the outer wall 16 of the auxiliary combustion chamber 12 and the main combustion chamber 15 communicates with a water jacket 21 surrounding each cylinder wall 20 of the cylinder block 19 via a communication passage 18. There is. The liquid phase refrigerant then fills the water jacket 21 of the cylinder block 19 and further fills the lower part of the cylinder head 11 to form the cylinder wall 20 and each combustion chamber 15, 12.
It covers the outer wall 16 of the tank, absorbs heat from this, and boils and vaporizes. The boiling vapor collects in the vapor phase refrigerant space above the water jacket 17. In the figure, 26 is an injection nozzle mounting hole, 27 is a glow plug mounting hole, 28 is an intake manifold, and 29 is an exhaust manifold.

On the other hand, a steam manifold 30 according to the present invention, which is cast from aluminum, is attached to the side end surface of the cylinder head 11 via a mounting flange 31 by fixing means such as bolting. The inlet port 32 provided in the steam manifold 30 at a rate of one per cylinder is a gas phase refrigerant space above the water jacket 17 of the cylinder head 11, and is a communication port located above the outer wall 16 of the main combustion chamber 15. They each independently communicate with the section 17A. The communication port portion 17A has an inner surface shape that guides the vapor in the vapor phase refrigerant space of the water jacket 17 directly upward, and then smoothly guides it to the inlet port 32 of the steam manifold 30. They have equal passage areas and communicate with a steam collector 33 located higher than the inlet port 32 with smooth curved walls.

Therefore, the steam in the water jacket 17 can be smoothly guided into the higher-level steam collector 33 in substantially equal amounts for each cylinder independently, thereby improving the ventilation of the vapor phase refrigerant space above the water jacket 17. This improves performance and prevents steam stagnation.

Here the steam collector 33 is connected to the inlet port 3
2, the steam collector 33
This provides a draining effect that causes droplets condensed therein to flow under their own weight into the water jacket 17 through the inlet port 32.

The steam collector 33 is a generally cylindrical body extending parallel to the cylinder row, and both ends thereof are closed by Welch plugs 34. Therefore, its shape is compact, manufacturing is extremely easy, and furthermore, it is easy to layout near the intake manifold 28. An outlet port 35 is provided at the upper part of the steam collector 33, such as near the upper end of the center in the longitudinal direction.
Connect them continuously. The passage areas of the outlet port 35 and the steam collector 33 are set to be sufficiently large to prevent the steam flows flowing in from each inlet port 32 from interfering with each other and locally stagnation in the water jacket 17. It has become like never before. The vapor thus smoothly guided is sent to a condenser (not shown) via the outlet port 35 (see FIG. 1).

Note that a water inlet 36 is provided at a part of the upper end of the steam collector 33.
is provided. Therefore, the steam manifold 30 becomes the highest position in the cooling system, and air can be easily vented from the system through the water inlet 36 at its upper end.

A ring groove 38 is provided on the end face of the flange 31 of the inlet port 32 and the flange 37 of the outlet port 35 for mounting a sealing structure using an "O" ring. It is also possible to prevent air from entering when the inside of the water jacket 17 and steam manifold 30 become negative pressure.

In the above embodiment, the outlet port 35 is located approximately at the center of the steam collector 33 in the longitudinal direction. As a result, each inlet port 32
There is no long distance between the cylinders, that is, the ventilation resistance is averaged, and a substantially uniform amount of steam can be extracted from each cylinder to the outside.

In this sense, if it is necessary to make the passage resistance from each inlet port 32 to the outlet port 35 more uniform, the longer the distance from the inlet port 32 to the outlet port 35, the larger the passage area of the inlet port 32 or the longer the passage resistance. Just make it shorter. An example thereof is shown in FIG. In this embodiment, exit port 35
A is provided at the longitudinal end of the steam collector 33, and the inlet port 32 and outlet port 35A
An example is shown in which the length of the inlet port 32 is shortened as the distance from the inlet port 32 is longer.

Furthermore, in the case of the steam collector 33, increasing the passage cross-sectional area according to the steam flow rate reduces passage resistance. Therefore, as shown in FIG. 4, the cross-sectional area of the steam collector section through which the steam led only from a single inlet port 32a flows, allows the steam led from the other inlet port 32b to join with the above steam flow. In order to increase the cross-sectional area of the steam collector section, if the top wall of the steam collector 33A is inclined by α toward the outlet port 35, the inlet ports 32a and 32b
It is possible to equalize the flow of steam flowing through the ceiling wall, and in this case, it is possible to promote a smooth flow of steam along the ceiling wall.

<Effects of the Invention> As described above, according to the present invention, each cylinder has a plurality of inlet ports each independently communicating with the vapor phase cooling space above the water jacket, and a plurality of inlet ports disposed at a higher position than the inlet ports. A steam manifold is provided, which includes a steam collector that collects steam flowing in from an inlet port, and an outlet port that guides steam to the outside from the upper part of the steam collector. By drawing an equal amount of steam to the outside for each cylinder, local stagnation of steam can be prevented. This makes it possible to generate vapor from the liquid phase refrigerant uniformly in each cylinder, preventing local overheating of the cylinder wall and combustion chamber wall, and preventing thermal deformation and damage to the cylinder head. In addition to this, together with the smooth induction of steam, the cooling performance of the engine can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic system diagram showing a conventional example of a boiling-cooled multi-cylinder internal combustion engine, Fig. 2 shows an embodiment of the present invention, A is a longitudinal sectional view, and B is a side view of a single steam manifold used in the above. In the figure, C is a cross-sectional view taken along the line CC of B, D is a cross-sectional view of the outlet port portion of B, and FIGS. 3 and 4 are side views of a single steam manifold showing other embodiments of the present invention. be. 11... Cylinder head, 17, 21... Water jacket, 30... Steam manifold, 3
2, 32a, 32b...Inlet port, 33, 33
A...Steam collector, 35, 35A...Exit port.

Claims (1)

[Claims] 1 A steam manifold that is connected to the cylinder head of a boiling-cooled multi-cylinder internal combustion engine and draws boiling vapor of a refrigerant to the outside from the upper part of the water jacket, and the number of cylinders that independently communicate with the upper part of the water jacket of each cylinder. a steam collector that communicates with the inlet port and is disposed at a higher level than the inlet port to collect steam, and an outlet port that guides the steam to the outside from the upper part of the steam collector. Features a steam manifold for boiling-cooled multi-cylinder internal combustion engines.