JPS5813120A - Cooling device for engine - Google Patents

Abstract

PURPOSE:To prevent ocurrence of negative pressure at the suction side by putting the reserver tank in communication with the cooling water flow-in part of a water pump through a cooling water supplying passage, which is equipped with a check valve designed to allow the cooling water to flow only in the direction from the reserve tank to water pump. CONSTITUTION:A reserver tank 22 in communication with the radiator cap 21 of a radiator 3 is put in communication with the suction side of a water pump 2 through a cooling water supplying passage 26. This cooling water supplying passage 26 is equipped with a check valve 27, which allow the cooling water to flow only in the direction from the reserver tank 22 to the suction side of water pump 2. Accordingly, the check valve 27 is opened when the negative pressure in the suction passage 25 for the water pump 2 exceeds a certain set value, and then the check valve 27 is opened and the cooling water is supplied from the reserver tank 22 to the passage 25. Thus negative pressure at the suction side is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine cooling system, and more particularly to a forced circulation cooling system.

Generally, forced circulation type cooling equipment uses a pressurized cooling method in combination. This is because if the cooling system is sealed, the boiling point of the cooling water will rise corresponding to the internal pressure, making overheating less likely to occur, and at the same time increasing the temperature difference with the outside air, improving heat dissipation effectiveness. be. In this pressurized cooling method, a pressure of 0.3 to 0.9 kq/cd is usually found in the cooling system.

A conventional engine cooling system is usually configured as shown in Figure 1 (Book 4, Sankaido, Gasoline Engine 17: Nimen'$,
Published in near month). In FIG. 1, (1) shows a quarter jacket which is a cooling water passage for a clear engine, and cooling water is supplied into this water jacket (1) from a water pump (2). (3) is a radiator consisting of an upper tank (4), a lower tank (5), and a core (6) that communicates these.Aha, this four-tube tank (4) and water jacket (1) are communicated by a waterway (7). ing. Further, a radiator cap (8) is attached to the upper tank (4), and this radiator cap (8) is communicated with the reservoir tank Ql through an overflow tube (9). The core (6) consists of water pipes and fins for flowing cooling water from the upper tank (4) toward the lower tank (5), and performs heat exchange. The lower tank (5) is connected to the water pump (2) through a passage (11), and this passage aD and the water channel (7)
) is in communication with the bypass passage (13). A3 is a thermostat provided in the passage (11) and opens and closes the entrance to the passage αB of the bypass passage r1z. This thermostat Q31 The flow of cooling water to the radiator (3) is controlled using The cooling water circulates as shown by the solid line, and since the thermostat (13) closes when the cooling water temperature is low, the cooling water circulates via the bypass path (12+) as shown by the broken line in the figure.

FIGS. 2 and 3 are diagrams for explaining the operating state of the radiator cap (8). Figure 2 shows a state in which the cooling water pressure in the cooling system is increased by opening the pressurizing valve A4, and at this time, the cooling water flows out and overflows as shown by the arrow in the figure. This indicates that the reservoir cooling water pressure becomes negative pressure through the tube (9) and the negative pressure valve aη biased by the negative pressure valve spring (161) of the radiator cathode (8) is opened. □ Cooling water flows from the reservoir tank Ql to the radiator (3) as shown by the arrow in the figure.

Therefore, in a forced circulation cooling system that uses this type of pressurized cooling method, the cooling system is always kept full of cold water, which not only makes it easy to maintain the amount of cooling water. , 1 cooling system is always maintained at a predetermined pressure (0
, 3 to 0.9 (9/d), so 1. The boiling point of the cooling water is higher, making it less likely to cause overheating, and the temperature difference between the cooling water and the outside air is increased, improving the heat dissipation effect. Furthermore, since the inside of the cooling system is always maintained at a predetermined pressure, cavitation is less likely to occur in the water pump.

However, even with such a cooling system, the flow path resistance from the radiator's upper tank to the lower tank is large in the flow path that circulates through the radiator, and the pressure adjustment of the cooling system is provided in the upper tank of the two radiators. Since this was done only in the radiator cap, the cooling water pressure on the discharge side of the quarter pump may become high and the cooling water pressure on the suction side may become negative pressure. As a result, the hose in the suction side passage of the water pump is crushed, which not only causes a decrease in the amount of circulating water, but also causes cavitation due to negative pressure. Therefore, there are problems in that cavitation erosion occurs in the water pump and the cooling performance deteriorates.

This invention was made by focusing on the above-mentioned conventional problems, and provides a forced circulation type cooling system that uses a pressurized cooling method. The purpose of the present invention is to solve the above-mentioned problems by providing a check pulp in the cooling water passage between the reservoir tank and the water pump that allows the cooling water to flow only in the direction from the reservoir tank to the water pump.

The present invention will be explained below based on the drawings.

Note that the same reference numerals are given to the same parts as those in the conventional example. FIG. 4 is a diagram showing an embodiment of the present invention.

First, to explain the configuration, (l) is a water jacket which is a cooling water passage for the engine, and cooling water is supplied into the water jacket (1) from a water pump (2). (3) is a hot tank (4).

The radiator is composed of a lower tank (5) and a core (6) that communicates these with each other, and the horn link (4) and water jacket (1) are communicated through a waterway (7). Radiator cap C for upper tank (4)
When D is attached, the radiator cap υ is communicated with the reservoir tank which is open to the atmosphere through an overflow tube (9).

This radiator cap Q11 is as shown in FIG.
It has a pressure valve (to) and a pressure spring (goods),
Cooling water pressure is pressurized spring c! When the elastic force becomes larger than 4, the cooling water flows out as shown by the arrow in Fig. 1. Again, in Fig. 4, the core (6) consists of a water pipe and fins for flowing the cooling water from the upper tank (4) toward the lower tank (5), and is connected to the cooling water heated by the water jacket (1). The lower tank (5
) is communicated with the water pump (2) through a passage C15 (for example, a rubber tube), and this passage (to) is communicated with the upper front distribution channel (7) through a bypass passage α2. There is. 0 is a small bypass (
This is the thermostat that opens and closes the entrance to passage 120 (c).This thermostat a3 is connected to the water jacket (
Radiator (3) depending on the temperature of the cooling water heated in 1>
Controls the flow of cooling water to. Cooling water is supplied from the reservoir tank (c) through the cooling water supply passage (to) to the passage (c) between this thermostat 0 and the water pump (2), that is, the cooling water inlet of the water pump (2). This cooling water supply passage c! Q1 In particular, a check valve is provided in the cooling water supply passage (c) on the connecting end side with the passage (c).
As shown in Fig. 6, there is a check ball (7) that divides the cooling water supply passage (c) into a water pump side supply passage (c) and a reservoir tank side supply passageway, and this check ball It has a check spring OD that biases the tank side supply passage in four directions.

Next, the effect will be explained. ``When the engine is started, the water pump (2) is activated and cooling water is supplied to the quarter jacket (1). The temperature of this cooling system is the temperature at which the engine starts■.

When the temperature is below a predetermined temperature, the thermostat α3 is closed. As a result, the cooling water flows from the water jacket (1) to the water pump (2) via the radiator (3), the water channel (7), and the % bypass passage α2, as shown by the broken line arrow in Fig. 4. circulate.

Next, the temperature of the cooling water increases due to the heat from the engine, and when it reaches a predetermined temperature or higher, the thermostat a3 is activated and the valve opens, so that the cooling water flows into the water as shown by the solid line arrow in Figure 4. It circulates from the jacket (1) to the water pump (2) via the waterway (7) and one passage of the walking kneader (3). However, since the water pipe of the radiator (3) has a large flow resistance, the passage (on the suction side of the water pump (2))
c) Negative pressure is generated. When this negative pressure becomes more than a predetermined negative pressure, that is, more than the elasticity of the check spring 61) that urges the check ball (7) toward the reservoir tank, cooling water flows from the reservoir tank to the passage ( C)
K is replenished and the negative pressure is eliminated. As a result, a large negative pressure is not generated in the passage (c), so that the tube in the passage αυ is not crushed and cavitation does not occur.

Furthermore, when the temperature of the cooling water increases due to acceleration of the engine, etc., the pressure of the cooling water in the cooling system increases. The pressure of this cooling water is a predetermined pressure, that is, the radiator cap Q11
When the elastic force of the pressure spring Q4 becomes larger, the cooling water flows out of the radiator cap Qυ and flows into the reservoir tank through the overflow tube (9).

As mentioned above, when the negative pressure in the passage (c) exceeds a predetermined value, the cooling water that has flowed into the reservoir tank (a) opens the "check pulp penalty" and is supplied to the water pump (c). ).As a result, the pressure in the cooling system can always be maintained at a predetermined pressure, and the cooling water can be kept in a full state.Therefore, maintenance of the amount of water flow is reduced. Not only is this easy, but the boiling point of the cooling water is high, making overheating less likely to occur, and the large temperature difference with the outside air improves the heat dissipation effect.

FIG. 7 is a diagram showing another embodiment of the invention. In this embodiment, the thermostat is installed on the outlet side of the water jacket in the embodiment shown in FIG.
Components that are the same as those of the embodiment shown in the drawings are denoted by the same reference numerals, and their explanations will be omitted. 021 is waterway (7)
This thermostat Φ opens and closes the valve depending on the temperature of the cooling water that has passed through the water jacket (1).

In this embodiment, since a thermostat (C33) is provided at the outlet of the water jacket (1), it is possible to switch the flow path in accordance with the temperature condition of the engine.

Furthermore, when water is injected into a new engine on an assembly line or when the coolant is replaced, air remains in the cooling system, and removing this air has traditionally been time-consuming. However, in the cooling device of the present invention, air can be easily vented by installing a radiator cap with the pressurizing valve removed instead of the radiator cap shown in the above two embodiments and operating one engine. Since there is no pressure valve, the cooling water circulated by the water pump flows from the radiator cap to the reservoir tank, the cooling water supply passage, and the water pump. At this time, since the reservoir tank is open to the atmosphere, air and water are separated here, and air can be easily removed without waiting for warm-up operation.

As explained above, the present invention has a structure including a water jacket, a radiator that communicates with the water jacket and dissipates the heat received by the cooling water to the outside, and a water jacket that supplies waste water to the water jacket. pump and
In the engine cooling system, the engine cooling system includes a thermostat that changes the path of the cooling water depending on the temperature of the cooling water, a radiator cap that is attached to the radiator and applies pressure to the cooling system, and a reservoir tank that communicates with the radiator. The reservoir tank and the water pump's inflow port are communicated through a cooling water supply passage, and a check valve is installed in this cooling water supply passage to allow continuous cooling to flow only from the reservoir tank to the water pump. Therefore, it is possible to take advantage of the advantages of a single forced circulation cooling system that uses an electric cooling method, and to overcome the disadvantages. Namely.

By reducing the pressure difference throughout the cooling system, it is possible to prevent the occurrence of cavitation and the collapse of the tube on the suction side of the water pump, as well as simplify maintenance of the amount of cooling water and reduce overheating. This has the advantage of being able to prevent the heat dissipation and improve the heat dissipation effect.

[Brief explanation of the drawing]

Figure 1 is a schematic overall diagram showing a conventional engine cooling system;
Figures 2 and 3 are enlarged sectional views of the radiator cap of the cooling device in Figure 1, Figure 2 is a diagram showing cooling water flowing out from the radiator, and Figure 3 is a diagram showing cooling water flowing into the radiator. FIG. 4 is a schematic overall view showing an embodiment of the engine cooling device according to the present invention, and FIG.
4 is an enlarged sectional view of the radiator cap of the cooling device shown in FIG. 4, FIG. 6 is an enlarged sectional view of the check valve of the cooling device shown in FIG. 4, and FIG. 7 is a schematic overall view showing another example of the present invention. It is a diagram. (,1)...Water jacket (2)...Water pump (3)...Radiator (13c33...Thermostat (21+-...Radiator cap)...Reservoir tank Kan...Cooling water supply Passage (a)... Check valve patent applicant Nissan Motor Co., Ltd. agent Patent attorney Ariwa Army - Department 2 Figure 3/13

Claims (1)

[Claims] A water jacket formed in the engine body, a radiator that communicates with the water jacket and dissipates the heat received by the cooling water to the outside, a water pump that supplies cooling water to the water jacket, and the temperature of the cooling water from the water jacket. In an engine cooling system, the engine cooling system includes a thermostat that changes the cooling water passage area according to the cooling water, a radiator cap that is attached to the radiator and applies pressure to the cooling system, and a reservoir tank that communicates with the radiator.
The reservoir tank and the cooling water inlet of the water pump are communicated through a cooling water supply passage, and the cooling water supply passage is provided with a check pulp that allows the cooling water to flow only in the direction from the reservoir tank to the water pump. ENGIZO's cooling system.