JPH0557315U - Sub tank structure of engine - Google Patents

Abstract

(57) [Object] To provide an engine sub-tank structure that can be positioned relatively downward. [Constitution] A sub-tank 40 connected to a cooling water circuit of an engine 10 includes a separation chamber 42 that constitutes a steam separation space,
It includes an expansion chamber 44 which is isolated from the separation chamber and constitutes an expansion space for compensating for volume changes of cooling water and air, and a communication pipe 46 which connects the expansion chamber and the separation chamber to each other. It is located below the chamber.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an engine sub-tank structure, and more particularly to an engine sub-tank structure that can be positioned relatively downward.

[0002]

[Prior Art]

 BACKGROUND ART A water-cooled cooling device for an engine is known that includes a closed cooling water circuit including a radiator. In such a cooling device, cooling water as a heat medium is circulated in the cooling water circuit, and heat generated by the engine is radiated by the radiator. Generally, the cooling water of the engine reaches a considerably high temperature, so bubbles are mixed in the cooling water due to cavitation and vibration of the cylinder block.

In order to surely perform air bubble separation or air-water separation, it is known that a down-flow radiator upper tank is connected with a sub-tank having a water-water separation function (Japanese Patent Publication No. 62-191612, actual). (Kaisho 60-57736, etc.). Further, in a cooling device equipped with a cross flow type radiator, one in which such a sub-tank is connected to an upstream side tank and / or a downstream side tank of the radiator is proposed (Japanese Patent Application No. 3-249756 by the present applicant ( Application on September 27, 1991)).

Such a sub-tank must be arranged at a position where air bubbles contained in the cooling water are separated from the cooling water to enhance the cooling efficiency of the cooling device and sufficient cooling water can be supplied to the cooling water circuit. .. For this reason, in the cooling device described in JP-A-62-191612, the liquid level of the sub tank is positioned higher than the liquid level of the water jacket of the engine.

[0005]

[Problems to be solved by the device]

 However, in recent body design, there is a tendency to design the height of the bonnet lower, and the allowable height of the equipment installation space in the engine room is set relatively low. For this reason, if a vehicle body design that emphasizes the outer shape of the vehicle body is adopted, the sub tank cannot be installed at a desired height, while if the height of the sub tank is secured, the desired vehicle body shape cannot be achieved.

The present invention has been made in view of the above points, and an object thereof is to provide an engine sub-tank structure that can be positioned comparatively downward, whereby a low bonnet of a vehicle body can be achieved. It is necessary to secure the desired arrangement of sub tanks.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a sub-tank connected to a cooling water circuit of an engine, the sub-tank includes a water-air separation space for air-water separation of cooling water and a water-air separation space. In an engine sub-tank structure having an expansion space that compensates for volume changes of cooling water and air, the sub-tank forms a separation chamber that forms the air-water separation space and the expansion space that is isolated from the separation chamber. And a communication means for communicating the expansion chamber with the separation chamber, and the expansion chamber is arranged below the separation chamber. To serve.

[0008]

[Action]

 According to the above configuration of the present invention, the expansion space for compensating for the pressure fluctuations of the cooling water and the air in the separation chamber is formed by the expansion chamber disposed below the separation chamber. Therefore, the expansion space formed above the cooling water can be reduced, and the upper end of the sub tank can be set low.

[0009]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of an engine cooling device having a sub-tank structure according to the present invention. The engine 10 includes a cooling device 12. The cooling device 12 includes a radiator 14 that cools high-temperature cooling water that has flown out of a water jacket (not shown) of the engine 10, a thermostat 18 that bypasses the cooling water that flows toward the radiator 14, and a forced circulation of the cooling water. And a water pump 16.

The radiator 14 includes an upstream tank 20 into which cooling water flows, a radiator core 22 that cools the cooling water, and a downstream tank 24 that receives the cooling water that has passed through the radiator core 22. The radiator core 22 cools the cooling water by a heat exchange action between the cooling water and the blast air formed by traveling air or a cooling fan (not shown).

A cooling water inlet pipe 26 is arranged between the upstream tank 20 and the water jacket of the engine 10, and a cooling water return pipe 28 is arranged between the downstream tank 24 and the water pump 16. A bypass pipe 30 is arranged between the cooling water inflow pipe 26 and the cooling water return pipe 28. The thermostat 18 is arranged at the connection between the cooling water return pipe 28 and the bypass pipe 30, and the amount of cooling water flowing into the upstream tank 20 (indicated by the arrow a) and the radiator 14 bypassing the radiator 14 are returned to the engine 10. The cooling water amount (shown by arrow b) is adjusted to adjust the cooling water temperature.

The cooling device 12 also includes a sub-tank 40 for separating water and water. The sub-tank 40 includes a separation chamber 42, an expansion chamber 44 disposed below the separation chamber 42, and a communication pipe 46 that connects the separation chamber 42 and the expansion chamber 44 to each other. An air passage 48 is connected to the separation chamber 42, and the air passage 48 is connected to the branch passages 32 and 34 via a switching valve 36. The branch passage 32 is connected to the upstream tank 20, the branch passage 34 is connected to the downstream tank 24, and the switching valve 38 connects the air passage 48 to the branch passage 32 and / or the air passage 48 depending on the operating state of the engine 16. It selectively communicates with the branch passage 34. The return pipe 38 is connected to the separation chamber 42, and the return pipe 38 joins the cooling water return pipe 28 on the downstream side of the thermostat 18.

FIG. 2 is a vertical cross-sectional view showing the structure of the sub-tank 40 arranged in the vehicle, and FIG. 3 is a plan view of the sub-tank 40. The sub-tank 40 is arranged in the engine room of the vehicle and is located below the vehicle's bonnet 60 (shown in phantom). The sub tank 40 is a resin tank integrally formed so as to form the separation chamber 42 and the expansion chamber 44, and the separation chamber 42 and the expansion chamber 44 are separated by a partition wall 43. A plurality of brackets 40a are provided in the lower portion of the sub tank 40, and the sub tank 40 is supported by a vehicle body (not shown) by these brackets 40a.

The separation chamber 42 is arranged above the water jacket of the engine 10 and is defined by a top wall 42 a, a side wall 42 b, and a partition wall 43. A substantially cylindrical protrusion 52 is formed on the top wall 42 a, and the lower end of the protrusion 52 communicates with the separation chamber 42. A cap 54 is attached to the upper end of the protrusion 52, and the separation chamber 42 and the protrusion 52 form a continuous sealed space. An inflow pipe 56 is provided adjacent to the protruding portion 52, and the inflow pipe 56 projects upward from the top wall 42a and is bent forward of the vehicle body. The air passage 48 formed of a flexible pipe is connected to the inflow pipe 56. Further, the outflow pipe 58 is connected to the side wall 42b, and the outflow pipe 58 projects rearward from the side wall 42b and is bent downward. The return pipe 38 communicating with the water pump 16 of the engine 10 is connected to the outflow pipe 58.

The expansion chamber 44 is disposed below the separation chamber 42 and constitutes a sealed space defined by the partition wall 43, the bottom wall 44a and the side wall 44b. Further, the bottom wall 44a is provided with a step portion 44c that forms a liquid reservoir. A communication port 52a is formed on the side surface of the projecting portion 52, and the upper end of the communication pipe 46 is connected to the communication port 52a. The communication pipe 46 extends substantially vertically downward, and the lower end of the communication pipe 46 is connected to the lower end portion of the side wall 44b of the expansion chamber 44, that is, the side wall 44b forming the liquid reservoir. ing. Thus, the upper end portion of the separation chamber 42 and the lower end portion of the expansion chamber 44 communicate with each other via the communication pipe 46.

As shown in FIG. 2, the liquid level of the cooling water in the separation chamber 42 is always located on the liquid level WL between the highest liquid level HL and the lowest liquid level LL. Cooling water containing bubbles or air flows into the separation chamber 42 from the radiator 14 via the air passage 48 and the inflow pipe 56. The cooling water from which air bubbles or air has been separated in the separation chamber 42 is returned to the engine 10 via the outflow pipe 58 and the return pipe 38.

When the temperature of the cooling water rises and the liquid level WL of the cooling water in the separation chamber 42 rises, or when excess air accumulates in the separation chamber 42, the air above the liquid level WL is transferred to the expansion chamber 44. While increasing the gas pressure inside, the gas flows out from the communication pipe 46 into the expansion chamber 44. Further, when the cooling water temperature drops, the cooling water surface level WL in the separation chamber 42 drops, or the air pressure in the separation chamber 42 decreases, the air in the expansion chamber 44, which has a relatively high pressure, flows into the communication pipe 46. Reflux to the separation chamber 42. Thus, the expansion chamber 44 acts as a means for compensating for volume changes of the cooling water and the air in the separation chamber 42, and ensures a smooth vapor-water separation action of the cooling water in the separation chamber 42.

As described above, the sub-tank 40 connected to the engine 10 and the radiator 14 includes a separation chamber 42 for separating the cooling water from water, and a communication pipe 46 connected to the top of the separation chamber 42 and extending downward. The expansion chamber 44 is provided below the separation chamber 42 and communicates with the lower end portion of the communication pipe 42. According to the sub-tank 40 having such a configuration, the sub-tank can be designed without securing an expansion space for compensating for pressure fluctuations of the cooling water and the air in the separation chamber 42 above the cooling water, so that the upper end of the sub-tank is set low. it can . Therefore, in a vehicle in which the effective height of the engine room is limited, for example, a so-called low bonnet type vehicle, the sub tank can be easily installed in the engine room. In other words, the structure of the sub-tank 40 can improve the degree of freedom in vehicle body design.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various changes and modifications can be made, which are also described in the scope of utility model registration claims. Needless to say, the present invention is included in the range described above. For example, in the above-mentioned embodiment, the separation chamber and the expansion chamber are formed by integrally molded sub tanks, but the separation chamber and the expansion chamber are formed by separate molded tanks, and both tanks are formed. May be connected by a communication pipe.

Further, in the above embodiment, the sub-tank is described as a resin molded product, but a metal sub-tank may be used, for example. Further, although the sub-tank is of a type that does not include a pressure-type cap for adjusting pressure, the present invention may be applied to a cooling device of a type including such a pressure-type cap or a pressure valve.

Further, in the above embodiment, the cooling device is provided with the cross flow type radiator, but the present invention is also applicable to the cooling device provided with the down flow type radiator.

[0022]

[Effect of the device]

 As described above, according to the present invention, there is provided an engine sub-tank structure which can be positioned relatively downward, and thereby, it is possible to achieve both a low bonnet of the vehicle body and a desired sub-tank arrangement. Becomes

[Brief description of drawings]

FIG. 1 is a circuit diagram of an engine cooling device having a sub-tank structure according to the present invention.

FIG. 2 is a vertical cross-sectional view showing the structure of a sub tank arranged in a vehicle.

FIG. 3 is a plan view of the sub tank shown in FIG.

[Explanation of symbols]

 10 Engine 12 Cooling Device 14 Radiator 40 Sub-tank 42 Separation Chamber 44 Expansion Chamber 46 Communication Pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Seiji Namba 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (1)

[Scope of utility model registration request] 1. A sub-tank connected to a cooling water circuit of an engine, the sub-tank having a gas-water separation space for separating the cooling water from the water, and a change in volume of the cooling water and the air in the water-water separation space. In a sub-tank structure of an engine having an expansion space for compensating for the sub-tank, the sub-tank comprises a separation chamber forming the steam separation space, an expansion chamber forming the expansion space isolated from the separation chamber, and the expansion chamber. And a communication unit that communicates the separation chamber with each other, and the expansion chamber is disposed below the separation chamber.