JP2013072359A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability and reliability of an engine by forming a flow passage through which cooling water which has cooled an engine flows by using reinforcing ribs in a surge tank, to prolong a time (route) in which the cooling water is exposed with air in the surge tank so as to separate bubbles from the cooling water and so as to restrict the generation of cavitation in a cooing water system.SOLUTION: The engine cooling device includes: a water jacket 1a through which cooling water 1 for an engine 1 flows; a radiator 2 which cools the cooling water; and a surge tank 3 positioned higher relative to the radiator 2 and the water jacket 1a to separate bubbles mixed in the cooling water. One end side of the surge tank 3 is formed with: a flow-in part 31b for the cooling water; a discharge part 31a to a water pump; a flow-in passage 35 which makes the cooling water which flows from the flow-in part 31a flow nearly straight; and a reinforcing rib 31e extending to a vicinity of the other end side to distribute the cooling water in the vicinity in the surge tank 3.

Description

  The present invention relates to an engine cooling apparatus for removing bubbles contained in surge tank type cooling water disposed in a cooling water system of an internal combustion engine.

The engine cooling system is provided with a cooling water circulation system for circulating cooling water between the engine and the radiator so as to cool the engine. In addition, bubbles generated in the cooling water cause a reduction in cooling capacity or cause metal corrosion due to cavitation.
Therefore, as described in Japanese Patent No. 2667317 (Patent Document 1), a surge tank system using a surge tank is known.

  In a surge tank type engine cooling system, a surge tank is connected to an engine or a radiator, bubbles generated in cooling water are separated by a surge tank, and cooling water from which bubbles are removed is returned to the engine. Further, the surge tank is maintained at a pressure equivalent to the pressure in the radiator, and the pressure drop of the cooling water sucked by the water pump can be prevented.

  According to Patent Document 1, a reservoir tank that is higher than the cooling water level in the engine and stores replenishing cooling water is communicated with the pressure in the header tank (surge tank), and the cooling water system suddenly increases when the engine starts. Has been made possible by the air in the expansion space being absorbed, and the technical disclosure has been made that can prevent the deterioration of each component constituting the cooling water system of the engine.

  Further, according to JP-A-8-200063 (Patent Document 2), it comprises a branch pipe that guides intake air to the intake port, and a flange for mounting the branch pipe provided at the intake port side end of the branch pipe, There is disclosed a technique in which a groove communicating with a water jacket provided in a cylinder head and communicating with a cooling water discharge portion is opened on a mounting surface of the flange that is in close contact with the cylinder head.

Therefore, since the passage through which the cooling water reaches the water discharge portion is provided on the mounting surface of the flange, the branch pipe through which the intake air flows is not heated. That is, since the cooling water flows through the flange, the branch pipe is not directly heated, and since the heat conduction from the flange is small, the heat is indirectly reduced as much as possible.
For this reason, it is supposed that the bubble at the time of water injection can be extracted efficiently.

Japanese Patent No. 2667317 (Patent Document 1) JP-A-8-200063

In Patent Document 1, the pressure increase of the cooling water system at the time of engine start is moderated, the pressure fluctuation range of the cooling water system during engine operation is reduced, and the frequency of opening and closing the pressure cap attached to the surge tank is reduced. This extends the interval of replenishing the preliminary cooling water to the reservoir tank, and each tank in which the cooling water flowing from the cooling water system to the reservoir tank is stored is filled with the cooling water, There is a problem that the bubbles contained in the cooling water cannot be positively separated by touching.
Further, in Patent Document 2, the technical content is that an air vent structure when an engine cylinder is inclined and cooling water is injected into an engine mounted on a vehicle, and a bubble mixed in the cooling water is separated by a surge tank. Different.

  In view of the problems of the prior art, the present invention forms a flow path through which cooling water that has cooled the engine flows using cooling ribs in the surge tank, and the cooling water in the surge tank is in contact with air. The purpose is to improve the durability and reliability of the engine by lengthening the (path) and separating bubbles from the cooling water to suppress the occurrence of cavitation in the cooling water system.

  In order to achieve such an object, the present invention includes a water jacket that communicates with an engine cooling water system and through which cooling water that cools the engine flows, a radiator that cools cooling water that has flowed through the water jacket and has been heated, and the radiator And a surge tank having a rectangular shape in a plan view in the gravitational direction for separating air bubbles contained in the cooling water and located above the water jacket in the gravitational direction, the engine cooling device comprising: An inflow part into which cooling water from the cooling water system side flows in, an outflow part from which cooling water in the surge tank flows out to the cooling water system, and an inflow part from the inflow part are inserted into one end of the tank in the longitudinal direction In addition to forming an inflow path for flowing cooling water in a substantially straight line, it extends to the vicinity of the other end in the longitudinal direction of the rectangular shape, and the cooling water flows in the surge tank in the vicinity thereof Characterized in that a and that the partition wall.

According to this invention, the time (path) exposed to the air can be reduced by forming the inflow path through which the cooling water flowing into the surge tank from the inflow part disposed on the one end side flows to the other end side by the partition wall. By making the length longer, the separation of bubbles from the cooling water can be easily promoted, and the partition wall can prevent the cooling water flowing into the surge tank from returning to the cooling water system from the state where the bubbles are not sufficiently separated.
Therefore, metal corrosion can be prevented by suppressing the occurrence of cavitation in the cooling water system, and the reliability and durability of the cooling water system, particularly the engine, can be improved.

  In the present invention, it is preferable that the partition wall is formed by a first reinforcing rib inside the surge tank.

By adopting such a structure, since the partition wall is formed by the first reinforcing rib in the surge tank, a separate material for the partition wall is not required, the structure is simplified, and the cost and weight increase can be suppressed. .

  Preferably, in the present invention, in the surge tank, a main outflow path formed by a second reinforcing rib of the surge tank that guides cooling water discharged from the inflow path to the outflow portion in a substantially straight line, It is preferable that the flow path width be narrower than that of the main outflow path and a sub outflow path formed by the third reinforcing rib of the surge tank.

By adopting such a structure, the cooling water outflow path in the surge tank is separated into the main and the sub, and in the main flow path, the cooling water is prevented from being disturbed by flowing in a straight line to promote the separation of bubbles. At the same time, the flow width of the sub-outflow passage is narrowed, the flow of cooling water is made gentle, and the separation of fine bubbles is promoted.
In addition, by providing the main and sub-channels, the flow resistance of the cooling water in the surge tank is reduced, and the driving force for the water pump to suck in the cooling water in the surge tank is reduced, contributing to the improvement of engine output. can do.

  In the present invention, preferably, a cooling water level detection sensor for detecting a cooling water level in the surging tank is disposed in the auxiliary outflow passage.

  By adopting such a structure, the flow of the cooling water in the secondary outflow passage is gentler than that of the main outflow passage, so that the amount of fluctuation of the cooling water level is small and the measurement accuracy can be improved.

  According to the present invention, the time (path) exposed to the air can be reduced by forming the inflow path through which the cooling water that has flowed into the surge tank from the inflow portion disposed on the one end side flows to the other end side by the partition wall. By making it longer, it is easier to promote bubble separation from the cooling water, thereby suppressing cavitation in the cooling water system to prevent metal corrosion and improving the reliability and durability of the cooling water system, especially the engine Can be achieved.

1 shows a cooling water system configuration diagram of an engine mounted on a vehicle in which the present invention is implemented. FIG. The explanatory view of the pressure cap which adjusts the pressure of a surge tank is shown. The external appearance perspective view of the surge tank of this invention is shown. AA sectional drawing of FIG. 3 is shown. Fig. 4 is a perspective view of the Roissier BB section in Fig. 3. The schematic of flow-path description in Roachiel is shown.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.
In general, water or a liquid having antifreezing and rust prevention effects is used as the cooling medium. In the present embodiment, these are collectively referred to as “cooling water”.
In addition, up, down, left, and right are described as up and down (gravity direction) and left and right (vehicle width direction) based on the seated state in the driver's seat.

An overall configuration in which the present invention is applied to an engine mounted on a vehicle will be described with reference to FIGS.
FIG. 1 is a configuration diagram of a cooling water system of an engine mounted on a vehicle, 1 is an engine mounted on the vehicle, 2 is a radiator that cools cooling water discharged from the engine 1, and 3 is a surge tank of the present invention. The surge tank 3 is positioned above the water jacket 1a and the radiator 2 through which the cooling water for cooling the engine 1 flows in order to separate bubbles mixed in the cooling water, and has the same pressure as the cooling water system. A pressure cap 10 is attached to maintain the pressure. 7 is a thermostat that senses the temperature of the cooling water and changes the flow path of the cooling water, and 8 is a water pump that is driven along with the operation of the engine 1 to flow the cooling water in the cooling water system. Reference numeral 9 denotes a radiator fan that sucks air, which has been heated by heat exchange between cooling water and air in the radiator 2, from the heat exchanging portion of the radiator 2.
PC is a pipe connector for joining the cooling water flowing from the radiator 2 through the pipe P2 to the pipe P1.

When the engine 1 is started and the engine 1 is not sufficiently warmed (when cold), the cooling water flows from the engine 1 through the pipe P4 to the thermo stud 7 and from the thermo stud 7 through the pipe P6 to the water pump 8. The water pump 8 is pumped again into the water jacket 1a of the engine 1 and the circulation is repeated until the engine 1 is sufficiently warmed up.
Then, when the warm air of the engine 1 advances and the temperature of the cooling water rises above a specified level, the thermostud 7 stops the cooling water from the pipe 4 from flowing to the pipe 6 side, and flows to the pipe 7 side, so that the radiator 2 The cooling water is cooled by the above, and the engine 1 is cooled by being fed into the water jacket 1 a of the engine 1 by the water pump 8 through the pipe 5.

Further, when the engine 1 is operated at a high speed, a high load, etc., the temperature of the cooling water rises as the temperature rises. The expanded cooling water flows into the surge tank 3 through the pipe P1 and the pipe P2.
The cooling water flowing into the surge tank 3 is cooled in the surge tank 3 and air bubbles mixed in the cooling water are removed and sucked into the water pump 8 via the pipe P3. The pump 8 is pumped to the water jacket 1a and circulates in the cooling water system in a state where the occurrence of cavitation is suppressed.

As shown in FIGS. 2A and 2B, the pressure cap 10 includes a pressure valve and a vent valve, and always maintains the pressure of the cooling water system in an appropriate state.
This is maintained above atmospheric pressure in order to raise the boiling temperature of the cooling water and enhance the cooling effect of the cooling water.
As the cooling water temperature in the cooling water system rises, the pressure also rises. When the pressure in the surge tank 3 exceeds a specified value, the pressure valve 101 presses and compresses the pressure valve spring 105 to reduce the pressure.
On the other hand, when the cooling water temperature falls, the inside of the surge tank 3 and the inside of the radiator 2 become negative pressure, the vent valve spring 106 of the vent valve 102 is pushed and compressed to introduce outside air, and the pressure inside the surge tank 3 is increased and regulated. To keep the value.

FIG. 3 is an external perspective view of the surge tank 3. The surge tank 3 is manufactured by separately manufacturing the lower shell 31 and the upper shell 32 on the lower side of the BB line, and welding the upper side of the upper side 32, respectively. Is formed.
In particular, the surge tank 3 is provided with a driver's seat floor (not shown) on the upper side of the engine 1 such as a cab over type truck or a small cab over type front engine bus, and a space between the engine 1 and the floor is provided. Flatness with a small height direction (gravity direction) and a relatively large width direction (vehicle width direction) (size that can secure the required cooling water capacity of the surge tank) in order to adapt to a vehicle with a structure that cannot be secured sufficiently The plan view of the shape is formed in a substantially rectangular shape.
When the direction of the surge tank is indicated, the long side direction of the rectangular shape is described as “longitudinal direction” and the short side direction is described as “width direction” for easy explanation.

In the lower shell 31 of the surge tank 3, an outlet 31a for returning the cooling water of the surge tank 3 to the water pump 8 through the pipe 3, and cooling water from the water jacket 1a of the radiator 2 and the engine 1 through the pipe P1. Inflow port 31b is provided.
The upper shell 32 of the surge tank 3 is provided with a pressure cap mounting portion 32b on which the pressure cap 10 serving as a cooling water supply port is mounted while maintaining the pressure of the cooling water system at a specified value.

The inside of the surge tank 3 will be described with reference to FIGS. 4, 5 and 6. 4 is a vertical sectional view of the surge tank 3 taken along the line AA in FIG. 3, and FIG. 5 is a perspective view of the lower shell 31 taken along the line BB in FIG. Shows a schematic diagram of the flow path inside Roasiel.
As shown in FIG. 4, the upper shell 32 and the lower shell 31 are welded along the line AA in FIG. 3 to form a tank structure in which the inside is sealed.
One end side of the lower shell 31 is formed with an inclined portion 31r whose width direction in plan view is gradually reduced to a trapezoidal shape.
The trapezoidal inclined portion 31r is provided with an outflow portion 31a through which cooling water in the surge tank 3 flows out to the water pump 8 side, and an inlet 31b through which cooling water from the cooling water system enters.
The outflow portion 31a is disposed on the bottom side of the lower shell 31, the inflow port 31b is disposed on the upper position of the outflow portion 31a, and the flow is blocked by the reinforcing ribs 31e.
Each of the outflow portion 31 a and the inflow port 31 b is attached at a substantially right angle to the longitudinal axis of the surge tank 3.

Cooling water from the water jacket 1a enters from the inlet 31b provided at one end in the longitudinal direction of the lower shell 31 and flows to the other end of the lower shell 31 through the inflow passage 35. It flows while diffusing toward the center in the width direction of the lower shell 31 through the space between the reinforcing ribs 31h.
The inflow passage 35 is formed by a first reinforcing rib extending to the vicinity of the other end in the longitudinal direction of the lower shell 31 along the side wall on the side where the inflow portion 31b of the lower shell 31 is attached. Yes.

The first reinforcing rib protrudes from the wall surface 31r (the surface constituting the outer wall of the surge tank 3) to which the inflow portion 31b on one end side is attached to the flow channel side, continues in the vertical direction, and extends in the direction along the inflow channel 35. Reinforcing ribs 31c arranged intermittently, and reinforcing ribs 31e extending (continuous) from the wall surface on which the inflow portion 31b is attached to the vicinity of the other end side with an interval in the width direction from the reinforcing ribs 31c. It consists of and.
The other end side of the reinforcing rib 31e is formed in a closed cross-sectional structure integrally coupled with the reinforcing rib 31f, and the rigidity of the other end side portion of the reinforcing rib 31e is reinforced.
4 and 6 show the closed section space S of the closed section structure. The closed section space S is formed continuously with the upper shell 32 and the lower shell 31.
These reinforcing ribs 31c and 31e, as shown in part in FIG. 4, are arranged on the upper shell 32 so as to be continuous with the reinforcing ribs arranged at positions facing the reinforcing ribs 31c and 31e. When the upper shell 32 and the lower shell 31 are joined along the line BB, they are joined in the same manner so that the rigidity can be maintained.

Cooling water from the inflow passage 35 flows between the reinforcing ribs 31f and the reinforcing ribs 31h while diffusing toward the center in the width direction of the lower shell 31, and most of the cooling water flows through the main outflow passage 36 (FIGS. 4 and 6). The remainder flows into the sub outflow passage 37.
The main outflow passage 36 is formed by a second reinforcing rib at the substantially center in the width direction of the lower shell 31 from the other end side to the one end side.
In the second reinforcing rib, the reinforcing rib 31f, the reinforcing rib 31i, and the reinforcing rib 31g are intermittently arranged substantially linearly on one side in the width direction of the main outflow passage 36.
On the other hand, the other side in the width direction is intermittently and substantially linearly arranged by the reinforcing ribs 31k, the reinforcing ribs 31m, and the reinforcing ribs 31n.
Further, a guide member 31q is provided on one end side of the main outflow passage 36 to guide the cooling water flowing through the main outflow passage 36 so as to smoothly flow toward the outflow portion 31a.
These reinforcing ribs 31f, 31i, etc. are continuous with the reinforcing ribs disposed on the upper shell 32 at positions facing the reinforcing ribs 31f, 31i, etc., as shown in part in FIG. When the upper shell 32 and the lower shell 31 are joined along the line BB, they are joined in the same manner so that the rigidity of the surge tank 3 can be maintained.

The sub outflow passage 37 is formed by a third reinforcing rib from the other end side to the one end side on the opposite side to the width direction of the lower shell 31 with respect to the inflow passage 35.
In the auxiliary outflow passage 37, a part of the cooling water that passes between the reinforcing rib 31f and the reinforcing rib 31h and between the reinforcing rib 31h and the reinforcing rib 31u that reinforces the outer wall on the other end of the lower shell 31 is provided with the reinforcing rib 31j. And the reinforcing rib 31u and between the reinforcing rib 31j and the reinforcing rib 31k.
The flow path area of the sub outflow path 37 is smaller than that of the main outflow path 36.
In the third reinforcing rib, one side in the width direction of the sub outflow passage 37 has a reinforcing rib 31j, a reinforcing rib 31k, a reinforcing rib 31m, and three (in the case of FIG. 6) reinforcing ribs 31n intermittently arranged in a substantially straight line. Yes.
The other side in the width direction of the sub outflow passage 37 is formed by reinforcing ribs 31p disposed intermittently along the outer wall on the surface constituting the outer wall in the longitudinal direction of the lower shell 31.
The cooling water of the sub outflow passage 37 passes through between the plurality of reinforcing ribs 31n intermittently arranged on one side, merges with the cooling water flowing through the main outflow passage 36, and flows out from the outflow portion 31a to the water pump 8 side.
These reinforcing ribs 31j, 31k, etc. have a structure in which the ribs of the upper shell 32 and the lower shell 31 are continuous and joined in the same manner as the reinforcing rib of the main outflow passage 36.

A cooling water level sensor mounting portion 31t is formed at the intermediate portion in the longitudinal direction of the sub outflow passage 37.
The sub outflow passage 37 has a smaller flow passage area than the main outflow passage 36 and is less affected by suction from the water pump 8 side. Therefore, the flow becomes gentle with respect to the main outflow passage 36, and the water level fluctuation of the water level sensor mounting portion Is small and the detection accuracy can be increased.

By adopting such a configuration, the inflow path 35 for flowing the cooling water flowing into the surge tank 3 from the inflow portion disposed on one end side to the other end side by the partition wall α, the main outflow path 36, and the sub outflow By forming the flow path exposed to the air in the surge tank 3 so as to flow through the path 37, the bubble separation from the cooling water is easily promoted, and the cooling water flowing into the surge tank 3 is sufficient. It is possible to prevent the reinforcing rib 31e from returning from the discharge portion 31a to the cooling water system in a state where the bubbles are not separated.
Therefore, metal corrosion can be prevented by suppressing the occurrence of cavitation in the cooling water system, and the reliability and durability of the cooling water system, particularly the engine, can be improved.
Further, by providing the main outflow passage 36 and the sub outflow passage 37, the flow resistance can be reduced, and by reducing the suction driving force of the water pump 8, the output of the engine 1 can be improved.
Furthermore, since the surge tank 3 has a flat shape, the water level change is small even if the cooling water in the surge tank 3 decreases. Therefore, the cooling water level sensor 31t is disposed in the sub outflow passage 37 where the water level change is small due to the flow of the cooling water. Thus, the cooling water level can be detected with high accuracy, the cooling water management can be ensured, and the maintainability of the engine 1 is improved.

  The present invention can be applied to a surge tank structure that removes bubbles contained in a surge tank type cooling water disposed in a cooling water system of an internal combustion engine to prevent insufficient cooling that occurs in the cooling water system and metal corrosion due to cavitation.

DESCRIPTION OF SYMBOLS 1 Engine 1a Water jacket 3 Surge tank 8 Water pump 10 Pressure cap 31 Roastiel 31a Outflow part 31b Inflow part 31e Reinforcement rib (partition wall)
31q guide member 32 upper shell 35 inflow portion 36 main outflow portion 37 sub outflow portion

Claims (4)

A water jacket that communicates with the engine cooling water system and through which cooling water for cooling the engine flows;
A radiator that cools the cooling water heated through the water jacket;
A surge tank that is located above the radiator and the water jacket in the gravitational direction, and has a surge tank having a rectangular shape in a plan view in the gravitational direction for separating bubbles contained in the cooling water,
On the long side direction one end side of the rectangular shape of the surge tank, an inflow portion into which cooling water from the cooling water system side flows,
A discharge part for flowing out the cooling water in the surge tank to the cooling water system, an inflow path for flowing the cooling water flowing in from the inflow part in a substantially straight line, and the vicinity of the other end in the longitudinal direction of the rectangular shape A cooling device for an engine, characterized by having a partition wall extending in the vicinity of which the cooling water flows in the surge tank.   The engine cooling device according to claim 1, wherein the partition wall is formed by a first reinforcing rib inside the surge tank.   In the surge tank, the main outflow passage formed by the second reinforcing rib of the surge tank that guides the cooling water flowing in from the inflow passage to the outflow portion in a substantially straight line, and the flow passage width is narrower than the main outflow passage. The engine cooling device according to claim 1, further comprising a sub outflow passage formed by a third reinforcing rib of the surge tank.   4. The engine cooling apparatus according to claim 3, wherein a cooling water level detection sensor for detecting a cooling water level in the surging tank is disposed in the sub outflow passage.

Images