JPH0681647A - Cooling system for internal combustion engine - Google Patents

Abstract

PURPOSE:To lower the temperature of cooling water flowing in a water pipe so as to improve a cooing effect on the discharge side of the water pipe by providing a cooling means for radiating the heat of cooling water, at the intermediate part of the water pipe for communicating the parts, having pressure difference, of a cooling water passage. CONSTITUTION:A cooling system for an internal combustion engine is provided with a water pipe 16 with one end thereof disposed in a cooling water passage 13a and with the other end thereof disposed at the other part of the cooling water passage, that is, at a part where cooling water pressure difference is generated in relation to the part where one end is positioned. Cooling fins 17 are provided at the part, exposed outside of a cylinder head 13, of the water pipe 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an internal combustion engine, and more particularly, it is possible to control the wall surface temperature of any part of the cooling passage part of the internal combustion engine by means of a water pipe connecting the parts of the cooling water passage having a pressure difference. Regarding a cooling device.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine, a cooling water passage is provided inside the engine, and a cooling water pump circulates the cooling water in the cooling water passage to cool the cylinder and the combustion chamber wall surface. In this case, the heat transfer coefficient on the wall surface of the cooling water passage increases as the cooling water flow velocity increases, that is, the cooling water flow rate increases, and the cooling effect improves. For this reason, the cooling water pump is usually driven from the crankshaft of the internal combustion engine by using an appropriate means to obtain a cooling water flow rate substantially proportional to the engine speed. As a result, when the engine is operated at high speed and the amount of heat generated increases, the flow rate of cooling water also increases, and the heat transfer coefficient on the wall surface of the cooling water passage also increases, so that a large cooling effect is obtained and the wall temperature of the combustion chamber, etc. is reduced. Can be kept.

However, since the cooling water passage inside the engine generally has a complicated shape, the flow velocity on the wall surface does not increase uniformly even if the cooling water flow rate increases, and depending on the shape of the cooling water passage. May cause a portion where the flow velocity does not increase even if the flow rate increases. In such a portion, there is a portion where the wall temperature locally rises because the heat transfer coefficient on the wall surface of the cooling water passage does not increase even if the amount of heat generated during high-speed operation of the engine increases.

Recently, in order to improve the engine performance, the compression ratio and the number of valves of the engine have been increased, so that the shape of the cooling water passage tends to be complicated near the engine combustion chamber and near the upper part of the cylinder wall. Further, especially when the number of exhaust valves is increased, the cooling water passage in the part sandwiched between the exhaust port and the exhaust port of each cylinder is structurally difficult to increase the flow velocity. Causes a problem that the temperature rises easily.

For this reason, at the time of high speed rotation, the temperature of the combustion chamber wall in this portion may rise transiently, causing problems such as knocking and preignition. In order to prevent this problem, it is necessary to increase the flow velocity of this part to some extent by greatly increasing the cooling water flow rate. To this end, a large-capacity cooling water pump is used to provide extra cooling. It is necessary to flow water, which causes problems such as deterioration of fuel efficiency due to cost increase and pump drive loss increase.

Further, since the shape of the cooling water passage is not the same in each cylinder and the cooling water flow velocity is also different, the combustion chamber wall temperature is 1
Not only is there a non-uniform portion within one cylinder, but there is also a difference between each cylinder. If the cooling water flow rate is increased as described above in such a state, the thermal conductivity increases more than necessary and the temperature decreases in the portion where the flow velocity of the cooling water passage tends to increase. There is a possibility that the chamber wall temperature becomes uneven and the wall temperature difference between the cylinders further expands, and the engine durability deteriorates due to an increase in thermal strain.

Therefore, the present applicant filed Japanese Patent Application No.
-68399, a cooling device for an internal combustion engine capable of increasing the cooling effect of an arbitrary portion of the cooling water passage without increasing the capacity of the cooling water pump or increasing the temperature difference in each portion (hereinafter referred to as the prior application example). I said).

FIG. 4 is a simplified diagram for explaining the overall configuration of the prior application example. In the figure, arrows indicate the flow of cooling water. The cooling device 11 of the prior application example is a so-called intake preceding cooling type, and cooling water circulates in the flow cooling device as described below.

The cooling water that has radiated heat by the radiator 12 and has a low temperature first flows into the preceding cooling passage 13b which is a cooling water passage in the cylinder head 13. Here, the vicinity of the intake port of the cylinder head 13 is cooled by this low-temperature cooling water and maintained at a low temperature, so that the intake efficiency to the combustion chamber is enhanced. After that, the cooling water flows into the water pump 14, is pressurized, and then flows into the cylinder block 15. The cooling water that has flowed into the cylinder block 15 cools each cylinder and then passes through the cooling water passage on the exhaust port side of the cylinder head 13 and returns to the radiator 12 again.

FIG. 5 is a view showing a water pipe 16 which is a main part of the prior application example. One end of the water pipe 16 is the cylinder head 13
The cooling water passage 13a is arranged near the wall surface, and the other end is arranged near the wall surface inside the preceding cooling passage 13b. Since the pressure of the cooling water in the cooling water passage 13a is higher than the pressure in the preceding cooling passage 13b, the cooling water flows in the water pipe 16 as shown by the arrow in the figure. In the prior application example, the action of suction and discharge of the cooling water flowing through the water pipe 16 increases the speed of the cooling water near the opening end of the water pipe 16 to remove the temperature boundary layer of the cooling water, This is a configuration in which a part of the wall surface of the cooling water passage in the cylinder head 13 is selectively cooled.

[0011]

However, in the above-mentioned prior application example, the cooling water in the cooling water passage 13a through which the cooling water flows into the water passage has already passed through the preceding cooling passage 13b and the cylinder block to generate heat. It is absorbing, and its temperature is high. When such a high-temperature cooling water is sucked into the water pipe 16 and discharged into the preceding cooling passage 13b, the cooling water is already high in temperature, so the preceding cooling passage 13b.
The cooling effect of the inner wall surface may not be improved so much.
Further, depending on the temperature of the discharged cooling water, if the temperature is extremely high, the wall surface temperature may rise.

Therefore, the present invention has been made in view of the above problems, and the cooling means for radiating the heat of the cooling water is provided in the middle of the water passage to reduce the temperature of the cooling water flowing through the water passage, and the discharge side of the water passage. It is an object of the present invention to provide a cooling device having an improved cooling effect.

[0013]

In order to solve the above-mentioned problems, the cooling device of the present invention is provided in an internal combustion engine having a cooling water passage formed therein, and one end of which is provided with a predetermined distance between the cooling water passage and a wall surface of the cooling water passage. Cooling of an internal combustion engine having a water pipe arranged so as to secure a cooling water flow passage area, and the other end of the cooling water passage having a cooling water pressure difference from the other portion of the cooling water passage In the device, the water pipe has a cooling means for radiating the heat of the cooling water flowing therein to the outside.

[0014]

In the structure in which the water pipe has the cooling means, the heat of the high-temperature cooling water that has flowed into the water pipe is released to the outside of the water pipe by the cooling means, and is discharged from the discharge side end of the water pipe to provide the cooling water passage. Lower the temperature of the cooling water that cools the wall surface of.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The first embodiment of the present invention has the same configuration as the prior application example shown in FIGS. 4 and 5, and the same reference numerals are given to the same components. FIG. 1 is a diagram showing a main part of a first embodiment of a cooling device of the present invention. The difference between this embodiment and the prior application is that the water pipe 16 of this embodiment has a cooling fin 17 in the middle thereof. It is in the middle of being.

The cooling fins 17 are made of a metal having good heat conductivity such as aluminum, and are provided at the exposed portions of the water pipe 16 between the both ends of the water pipe 16 inserted into the cylinder head 13. .

At the end of the water passage 16 located inside the cooling water passage 13a, the cooling water near the wall surface inside the cooling water passage 13a is sucked into the water passage 16. At this time, the temperature boundary layer of the cooling water formed near the wall surface is removed, and the cooling effect is improved. The cooling water in the cooling water passage 13a is
In the state where the heat is absorbed by passing through the preceding cooling passage 13b of No. 3 and the cooling water passage in the cylinder block 15, the cooling water temperature is rising. Therefore, relatively high temperature cooling water flows into the water pipe 16.

The cooling water that has flowed into the water pipe 16 is the water pipe 1.
1, and flows in the direction of the arrow in FIG. 1, and the heat of the cooling water is transferred to the water pipe 16. The heat transferred to the water pipe 16 is conducted through the water pipe 16 and is released from the surface of the water pipe 16. Most of the heat is transferred to the cooling fins 17 and released to the atmosphere.

Due to the cooling effect of the cooling fins 17, the cooling water flowing through the water pipe 16 is supplied to the preceding cooling passage 1 on the discharge side.
Before being discharged into 3b, it is cooled to be low-temperature cooling water. Therefore, from the end of the water pipe 16 to the preceding cooling passage 13b.
The cooling water discharged to the inner wall surface becomes low-temperature cooling water cooled at the ambient temperature, and a sufficient cooling effect can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment of the present invention has a configuration similar to that of the prior application example shown in FIGS. 4 and 5, and the same components are designated by the same reference numerals. FIG. 2 is a diagram showing a main part of the first embodiment of the cooling device of the present invention. The difference between this embodiment and the previous application is
The water passage 18 of this embodiment has a bellows portion 18a.

The bellows portion 18a is located between both end portions of the water pipe 18 inserted into the cylinder head 13, and the water pipe 1 is provided.
8 is provided in a portion exposed to the outside, and has the same cooling function as that of the first embodiment. That is, each stage of the bellows portion 18 a functions as a cooling fin and radiates heat of the cooling water flowing inside the water pipe 18 to the outside of the water pipe 16.

Here, both ends of the water flow pipe 18 are the above-mentioned first
Similar to the embodiment, the wall surfaces in the cooling water passage 13a and the preceding cooling passage 13b are cooled by the action of sucking and discharging the cooling water.

In addition to the cooling effect similar to that of the first embodiment described above, this embodiment has an effect that an excessive force is not applied to the fixed portion of the water pipe 18 due to the flexibility of the bellows portion 18a. That is, the water pipe 18 has both ends at the cylinder head 1.
3 is inserted and fixed, and the vibration due to the operation of the internal combustion engine is transmitted to the fixed portion. Further, a force acts on the fixed portion due to the linear expansion of the water pipe 18 due to the temperature rise during operation. Further, the cylinder head 13 is generally formed of an aluminum alloy, and the water passage 18 is made of stainless steel (SUS) because of its strength and resistance to corrosion. Thermal stress is applied to the part. Due to its flexibility, the bellows portion 18a has a water passage 18
This has the effect of alleviating the force applied to the fixed part of the water tank and preventing the water pipe 18 from being damaged.

Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment of the present invention has the same configuration as that of the prior application shown in FIGS. 4 and 5, and the same components are designated by the same reference numerals. FIG. 3 is a view showing the essential parts of a third embodiment of the cooling device of the present invention. The difference between this embodiment and the previous application is that the water pipe 16 of this embodiment is provided with a heat exchanger 19. There is something to do.

The high temperature cooling water passing through the water pipe 16 is
The preceding cooling passage 13b after being cooled by the heat exchanger 19
Since it is discharged inside, the effect of cooling the wall surface of the preceding cooling passage 13b is improved.

In the present embodiment, various cooling media can be considered as the cooling medium to be supplied to the heat exchanger 19, and various secondary effects can be obtained. For example, when the fuel of the internal combustion engine is supplied to the heat exchanger 19 as a cooling medium, atomization of the fuel is promoted and the combustion efficiency of the internal combustion engine is improved. Also,
When the engine oil is supplied to the heat exchanger 19 as a cooling medium when the internal combustion engine is cold, the temperature rise of the engine oil is promoted, and the fuel efficiency can be improved when the engine is cold. Further, if the cooling medium is air, it can be used as a heat source for a heater of a vehicle. Furthermore, if a throttle body is used instead of the heat exchanger 19, it is possible to also use the throttle body for hot water heating.

[0027]

As described above, according to the present invention, the heat of the high-temperature cooling water flowing into the water pipe is discharged to the outside of the water pipe by the cooling means and discharged from the discharge side end of the water pipe. Since the temperature of the cooling water for cooling the wall surface of the passage becomes low, the cooling effect by providing the water passage pipe is further improved, and an efficient cooling device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a first embodiment of the present invention.

FIG. 2 is a diagram showing a main part of a second embodiment of the present invention.

FIG. 3 is a diagram showing a main part of a third embodiment of the present invention.

FIG. 4 is a simplified diagram illustrating an overall configuration of a prior application example.

FIG. 5 is a diagram showing a main part of a prior application example.

[Explanation of symbols]

 11 Cooling Device 12 Radiator 13 Cylinder Head 13a Cooling Water Passage 13b Preceding Cooling Passage 14 Water Pump 15 Cylinder Block 16, 18 Water Pipe 17 Cooling Fin 18a Bellows 19 Heat Exchanger

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryuichi Matsushiro 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute, Inc.

Claims (1)

[Claims] 1. An internal combustion engine having a cooling water passage formed therein, one end of which is arranged so as to secure a predetermined cooling water passage area between the cooling water passage wall surface and the other end of the cooling water passage. Is a cooling device for an internal combustion engine having a water pipe arranged in a portion that causes a cooling water pressure difference with a portion where the one end is located, the water pipe being a heat of the cooling water flowing therein. A cooling device for an internal combustion engine, which is configured to have a cooling means for discharging the air to the outside.