JPH0144767Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a cooling water passage structure for an engine.

FIG. 1 shows a conventional engine cooling water system. The crankcase 11 supports a cylinder liner 12 and has a cylinder head 40 on the top. The inner surface of the cylinder liner 12 is connected to the piston 1.
4 slides. A combustion chamber 15 is formed by the cylinder head 40, cylinder liner 12, and piston 14. Cooling water pump P21 driven by the crankshaft
After passing through the inlet pipe into the crankcase 11, the cooling water discharged from the cylinder enters the cylinder cooling water reservoir 22 surrounded by the cylinder liner 12 and the crankcase 11, and cools the outer surfaces of the crankcase 11 and the cylinder liner 12. It is cooled and flows into the cylinder head 40 through the communication hole 23 in the upper part. Figure 2 is the first
FIG.

An intake valve 31, an exhaust valve 32, and a fuel injection valve 33 are provided on the surface of the cylinder head 40 that is in contact with the combustion chamber 15.
An exhaust passage 35 is connected to each. Furthermore, partition walls 41 and 42 are provided in the cooling water reservoir to divide it into an intake side cooling water reservoir 43 surrounding the intake passage 34 and an exhaust side cooling water reservoir 44 surrounding the exhaust passage 35. Furthermore, the partition walls 41 and 42 have holes 4 through which cooling water flows.
5,46 are provided. The cooling water flowing into the cylinder head 40 from the aforementioned communication hole 23 first enters the intake side cooling water reservoir 43.

Next, the cooling water passes through the holes 45 and 46 and flows out from the cooling water outlet pipe 25 attached to the upper part of the exhaust side cooling water reservoir 44 to the piping 26. Cylinder head 4 in Figure 1
The 0 section is a - sectional view of FIG. Furthermore, in Fig. 1, the cooling water in pipe 26 is connected to thermostat V27.
A part of it passes through radiator R28 and pipe 29,
The remainder passes through the bypass pipe 31 and directly reaches the suction port of the cooling water pump P21.

Next, FIG. 3 shows a cross-sectional view taken along the line -- in FIG. 2. The end of the intake passage 34 on the combustion chamber 15 side is an intake valve seat 51, and the end of the exhaust passage 35 is an exhaust valve seat 52. The space between the intake valve seat 51 and the exhaust valve seat 52 is an intake/exhaust valve space 53. The partition wall 42 is present above the space 53 between the intake and exhaust valves.

Next, the operation of the conventional example will be explained.

As shown in FIG. 3, an intake passage 34 and an exhaust passage 3
5 are close to each other, and there is a partition wall 42 between them, so even though the space between the intake and exhaust valves 53 is in contact with the combustion chamber 15, the distance from the cooling water is large, and the space between the intake and exhaust valves 53 is in contact with the combustion chamber 15. temperature increases.

As a result, a large thermal stress is generated between the intake and exhaust valves 53, causing a crack, causing cooling water to leak into the combustion chamber 15, and making the engine unusable.

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine cooling water passage structure that eliminates the above-mentioned problems and prevents cracks between intake and exhaust valves.

For this reason, the present invention provides a cooling water passage only in the lower part of the partition wall that separates the intake side cooling water reservoir and the exhaust side cooling water reservoir of the cylinder head, so that the cooling water flows from the cylinder cooling water reservoir to the intake side cooling water reservoir through the communication hole. It is characterized in that the entire amount of the cooling water is configured to flow through the cooling water passage to the exhaust side cooling water reservoir.

Embodiments of the engine cooling water passage structure according to the present invention will be described below with reference to FIGS. 4 to 6.

Here, the same or equivalent components as those of the conventional device will be described using the same reference numerals.

FIG. 4, which corresponds to the above-mentioned FIG. 2, shows a cross-sectional structure of the cylinder head 61 of the present invention. In the present invention, the holes 45 and 46 in the partition walls 41 and 42 are eliminated.

Further, a partition wall 42 between the intake valve 31 and the exhaust valve 32
A cooling water passage 62 communicating from the intake side cooling water reservoir 43 to the exhaust side cooling water reservoir 44 is provided at the lower part of the cooling water reservoir 43 .

FIG. 5 shows a - cross section of FIG. 4. The cooling water passage 62 is provided between the intake passage 34 and the exhaust passage 35 and immediately above the intake/exhaust valve gap 63.

Next, the operation of the above embodiment will be explained.

In FIG. 4, the entire amount of cooling water that has flowed into the intake side cooling water reservoir 43 from the communication hole 23 is transferred to the partition wall between the intake side cooling water reservoir 43 and the exhaust side cooling water reservoir 44, except for the cooling water passage 62. Therefore, the entire amount flows to the exhaust side cooling water reservoir 44 through the cooling water passage 62. Therefore, as shown in FIG. 5, the area immediately above the intake/exhaust valve gap 63 can be sufficiently cooled with cooling water, and the temperature rise in the intake/exhaust valve gap 63 is reduced.

Therefore, the thermal stress in the portion 63 is reduced, and cracks do not occur between the intake and exhaust valves 63.

The cooling water passage 62 shown in Fig. 5 is a first embodiment in which the cooling water passage 62 is formed of a cast core, but the one shown in Fig. 6 is a second embodiment in which the cooling water passage 64 is bored by machining. . The effects of the second embodiment are exactly the same as those of the first embodiment.

Next, a third embodiment will be described. As mentioned above, in the first and second embodiments, the cooling water passage 62 or 64 was provided between the intake valve 31 and the exhaust valve 32, but in the third embodiment, the cooling water passage 62 or 64 was provided between the exhaust valve 32 and the fuel valve 33 or the intake valve 3.
1 and the fuel valve 33, and its operation and effect are the same as in the first embodiment.

As mentioned above, the engine cooling water passage structure according to the present invention has a cooling water passage provided only in the lower part of the partition wall that partitions the intake side cooling water reservoir and the exhaust side cooling water reservoir at a position close to the combustion chamber above the intake and exhaust valves. Since the entire amount of cooling water is made to pass through the cooling water passage, the large thermal stress generated between the intake and exhaust valves is eliminated, and cracks occurring in this area can be prevented.

[Brief explanation of the drawing]

Figure 1 is a diagram of a conventional engine cooling water system.
FIG. 2 is a cross-sectional view taken from FIG. 1, and FIG. 3 is a cross-sectional view taken from FIG. 2. 4 to 6 show embodiments of the present invention, FIG. 4 is a drawing corresponding to the - sectional view of FIG. 2, and FIGS. 5 and 6 are respectively - sectional views of FIG. Figure 5 shows the cooling water passage 6.
2 is a casting hole, and FIG. 6 shows the case where the hole 62 is machined. 34...Intake passage, 35...Exhaust passage, 42...
...Bulkhead, 61...Cylinder head, 62, 64...
...Cooling water passage.

Claims (1)

[Scope of utility model registration request] A partition wall installed in the cylinder head that divides the cylinder head into an intake side cooling water reservoir surrounding the intake passage and an exhaust side cooling water reservoir surrounding the exhaust passage; only at the lower part of the partition located between the intake valve and the exhaust valve. a cooling water passage bored through and communicating the intake side cooling water reservoir and the exhaust side cooling water reservoir; a cylinder cooling water reservoir formed surrounding a cylinder liner in the crankcase;
A communication hole that communicates the cylinder cooling water reservoir with the intake side cooling water reservoir, an inlet pipe that communicates the outlet of the cooling water pump with the inlet of the cylinder cooling water reservoir, and an outlet that communicates the exhaust side cooling water reservoir with the thermostat. A pipe is provided to allow cooling water to flow from the cylinder cooling water reservoir to the intake side cooling water reservoir through the communication hole, and to direct the entire amount of cooling water that has flowed into the intake side cooling water reservoir to the exhaust side through the cooling water passage. A cooling water passage structure for an engine, characterized in that the cooling water is configured to flow into a cooling water reservoir.