JPH08226322A - Cooling device for engine - Google Patents

Abstract

PURPOSE: To enable a cooling device for an engine to have enhanced cooling efficiency on the suction side of a cylinder head at high-load operation. CONSTITUTION: A water jacket formed within a cylinder head 3 is separated into an exhaust-side water jacket 6 and a suction-side water jacket 7. The exhaust side water jacket 6 and time suction side water jacket 7 are placed, respectively, upstream and downstream of a radiator 9. A portion of an upper hose 8 is diverged and connected to near the inlet port of a water pump 16 by means of first and second auxiliary passages 21, 22. A control valve 24 is placed in the first auxiliary passage 21. A closed storage tank 23 having an air chamber 23b is placed between the first and second auxiliary passages 21, 22. An ECU 25 drives the control valve 24 for opening or closing, on the basis of input signals from a throttle opening sensor 26 and an engine speed sensor 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cooling device for cooling an engine with cooling water.

[0002]

2. Description of the Related Art Hitherto, as a cooling device of this type, an invention association publication technical report 87-12661 (issue date: 1987 1
There is one disclosed on 20th October. As shown in FIG. 4, in this apparatus, a plurality of water jackets are formed inside the cylinder block 52 and the cylinder head 53 of the engine 51. Further, a radiator 54 for cooling the cooling water is arranged in front of the engine 51 (on the left side in FIG. 4). The upstream side of the radiator 54 has an exhaust side water jacket 5 disposed on the exhaust port (not shown) side in the cylinder head 53.
Connected to 5. The downstream side of the radiator 54 is connected to an intake side water jacket 56 arranged on the intake port (not shown) side in the cylinder head 53. The intake side water jacket 56 is connected to the water jacket 59 of the cylinder block 52 via a thermostat 57 and a water pump 58, and is also connected to the exhaust side water jacket 55 by a bypass passage 60 branched from the thermostat 57.

In the apparatus having the above structure, the thermostat 57 is closed when the temperature of the cooling water is low, such as during warm-up operation, so that the cooling water does not circulate on the radiator 54 side. There is. Therefore, the cooling water forms the flow path indicated by the dotted arrow in FIG.
The cooling water discharged from the water pump 58 is returned to the water pump 58 through the water jacket 59 of the cylinder block 52, the exhaust side water jacket 55, the bypass passage 60 and the thermostat 57 in order. Since the cooling water does not circulate on the radiator 54 side, its temperature rises quickly. Therefore, the warm-up operation ends in a short time.

On the other hand, when the temperature of the cooling water rises above a predetermined value, the thermostat 57 is opened,
The cooling water circulates on the radiator 54 side.
Therefore, the cooling water forms the flow path indicated by the solid line arrow in the figure, and the cooling water discharged from the water pump 58 is introduced into the radiator 54 via the water jacket 59 of the cylinder block 52 and the exhaust side water jacket 55. It After that, the cooling water passes through the water jacket 56 on the intake side and the thermostat 57, and the water pump 5 is cooled.
Returned to 8.

As described above, in this apparatus, the engine 51 is cooled by forcibly circulating the cooling water in the engine 51. In particular, in this device, since the intake water jacket 56 is provided on the downstream side of the radiator 54,
The cylinder head 53 on the intake port (not shown) side is cooled by the cooling water that has passed through the radiator 54 and has a low temperature. That is, the same device uses the intake air pre-cooling method to improve the charging efficiency.

[0006]

By the way, the engine 5
When 1 becomes a high load state, the cooling efficiency is further increased,
It is required to cool the engine 51. However, in the cooling device according to the conventional technique, the cooling capacity thereof is determined by the flow rate of the cooling water, in other words, the discharge capacity of the water pump 58, so that the cooling is further promoted when the high load state occurs. Was impossible.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an engine cooling device having an improved cooling capacity during high load operation.

[0008]

In order to achieve the above object, the present invention provides a cylinder block water jacket provided in a cylinder block of an engine and an exhaust port side in a cylinder head. An exhaust side water jacket that communicates with the water jacket, a radiator that communicates with the exhaust side water jacket through a first passage, and an intake port side inside the cylinder head that communicates with the radiator through a second passage. On the other hand, a cylinder block water jacket, an exhaust side water jacket, a first side water jacket provided with an intake side water jacket communicating with the cylinder block water jacket through a third passage, and arranged in the middle of the third passage. 1 passage, LA In an engine cooling device for forcibly circulating cooling water in the order of the air, the second passage, the intake water jacket, and the third passage, one end is downstream of the exhaust water jacket and upstream of the intake water jacket. Side passage, the other end of which is connected to the upstream side position of the water pump in the third passage, and an operating state for detecting whether or not the operating state of the engine is a high load state A detection means, a control valve disposed in the auxiliary passage, which opens or closes the auxiliary passage based on a detection signal from the operating state detection means, and an auxiliary passage disposed downstream of the control valve,
The gist of the present invention is to provide a closed type storage tank having an air chamber.

[0009]

According to the present invention, the cooling water is supplied by the water pump to the cylinder block water jacket, the exhaust side water jacket, the first passage, the radiator, the second passage,
The intake side water jacket and the third passage are forcedly circulated in this order. The cooling water absorbs the heat generated in the cylinder block and the cylinder head of the engine in the circulation process and cools them, while radiating the heat absorbed in the radiator to the outside. Further, since the intake side water jacket is provided on the downstream side of the radiator, the intake port side of the cylinder head is cooled by the cooling water having a low temperature.

When the operating condition of the engine is not the high load condition, the control valve opens the auxiliary passage based on the detection signal of the operating condition detecting means. When the auxiliary passage is opened, part of the cooling water is returned to the water pump through the auxiliary passage without passing through the intake water jacket.

On the other hand, when the operating condition of the engine becomes a high load condition, the control valve is closed based on the detection signal of the operating condition detecting means to shut off the auxiliary passage. Therefore, the cooling water returned to the water pump through the auxiliary passage flows into the intake side water jacket side. As a result, the flow rate of the cooling water passing through the intake water jacket increases and the flow velocity thereof also increases. The cooling water in the auxiliary passage downstream of the storage tank is sucked by the water pump, but no cooling water flows in the auxiliary passage because the control valve is closed. Therefore, the internal pressure of the air chamber provided in the storage tank is reduced. As a result, the pressure in the auxiliary passage on the downstream side of the storage tank decreases, and the pressure in the third passage and the intake water jacket decreases accordingly. Then, when the pressure in the intake-side water jacket decreases, the cooling water in the intake-side water jacket enters a boiling cooling state and absorbs heat of vaporization from the wall surface of the intake-side water jacket.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is embodied in a cooling device for an automobile engine will be described below with reference to FIGS.

FIG. 1 is a diagram schematically showing a schematic configuration of a cooling device in this embodiment. The engine 1 includes a cylinder block 2 and a cylinder head 3 arranged above the cylinder block 2. In the cylinder head 3, a space through which cooling water flows is formed inside a side (hereinafter, referred to as a cylinder head exhaust side 4) on which an exhaust side camshaft, an exhaust valve and an exhaust port (neither is shown) are arranged. It is the exhaust side water jacket 6. A cylinder block water jacket 2a is formed inside the cylinder block 2 so as to communicate with the exhaust side water jacket 6. On the other hand, the intake side camshaft, intake valve and intake port (none are shown)
A space through which cooling water flows is also formed in the cylinder head on the side on which is arranged (hereinafter referred to as the cylinder head intake side 5) to form an intake side water jacket 7. The cylinder block water jacket 2a and the exhaust side,
The intake side water jackets 6 and 7 absorb heat generated in the cylinder block 2 and the cylinder head 3 by the cooling water therein and cool them. As the cooling water, a long-life coolant in which an antifreeze solution containing ethylene glycol as a main component and a rust preventive agent are mixed with soft water is used.

The water jacket 6 on the exhaust side is communicated with an upper tank 10 of a radiator 9 by an upper hose 8. The radiator 9 is arranged in front of the engine 1 (on the left side in FIG. 1) and has a structure in which a core 12 is provided between the upper tank 10 and the lower tank 11. The core 12 includes an upper tank 10 and a lower tank 1.
A plurality of tubes 13 for connecting 1 are provided, and a large number of cooling fins 14 are formed in the tubes 13 in order to improve heat radiation efficiency. The cooling water that has absorbed the heat of the cylinder block 2 and the cylinder head 3 in the cylinder block water jacket 2a, the exhaust side and intake side water jackets 6 and 7 is discharged from the cooling fins 14 in the process of passing through the core 12 of the radiator 9. The heat is radiated to the outside. At this time, the radiator 9 is cooled by the traveling wind or the air blown from a cooling fan (not shown) provided behind the radiator 9 (on the right side in FIG. 1), so that the heat radiation efficiency thereof is improved.

The intake-side water jacket 7 is connected to the lower tank 11 and the lower hose 15 while being connected to the water pump 16 attached to the cylinder block 2 by a first return passage 17 and a second return passage 18. ing. Here, the first return passage 17 and the second return passage 17
A thermostat 19 is arranged between the return passages 18. The water pump 16 is composed of a centrifugal pump, is drivingly connected to a crankshaft (not shown), and its discharge pressure changes according to the rotation speed of the engine 1. The cooling water in the second return passage 18 is sucked by the water pump 16 and discharged into the cylinder block water jacket 2a in the cylinder block 2.

Incidentally, the upper hose 8 and the lower hose 15
Respectively constitute the first passage and the second passage in the present invention. The first return passage 17 and the second return passage 18 form the third passage of the present invention.

The thermostat 19 is a temperature-sensitive valve which operates in accordance with the temperature of the cooling water. In this embodiment, the wax enclosed therein expands and contracts in accordance with the temperature change of the cooling water. A wax-type thermostat that opens and closes the valve is used. A bypass passage 20 is connected to the thermostat 19, and the bypass passage 20 communicates with the exhaust side water jacket 6.

A first auxiliary passage 21 is opened and connected in the middle of the upper hose 8. Further, a second auxiliary passage 22 is opened and connected near the suction port of the water pump 16 in the second return passage 18. The first and second auxiliary passages 21 and 22 are connected to each other via a closed storage tank 23. The first auxiliary passage 21
The second auxiliary passage 22 constitutes the auxiliary passage in the present invention.

The storage tank 23 is provided with a storage chamber 23a for absorbing the expanded portion of the cooling water when the cooling water expands due to a temperature rise, and an air chamber 23b is formed in the upper portion thereof. The first auxiliary passage 21 is connected to the storage tank 23 in the same air chamber 23b, while the second auxiliary passage 22 is connected to the storage chamber 23a.

A control valve 24, which is an electromagnetic valve, is disposed in the middle of the first auxiliary passage 21. Control valve 2
The ECU 4 is opened and closed by an ECU 25 (Electronic Control Unit) and operates so as to allow or block the flow of the cooling water in the first auxiliary passage 21.
That is, the ECU 25 controls the control valve 24 to open when the engine 1 is not in the high load state and to close the control valve 24 when the engine 1 is in the high load state. . The ECU 25 detects the operating state of the engine 1 based on input signals from the throttle opening sensor 26 and the engine speed sensor 27 connected to the ECU 25. The throttle opening sensor 26 detects the amount of rotation of a rotary shaft of a throttle valve (not shown), and is arranged in a throttle body (not shown) provided in an engine intake system (not shown). The engine rotation speed sensor 27 detects the rotation speed of a crankshaft (not shown) and is arranged in a distributor (not shown). In the above configuration, E
The CU 25, the throttle opening sensor 26, and the engine speed sensor 27 constitute an operating state detecting means.

The operation and effect of this embodiment having the above configuration will be described. When the engine 1 is in the warm-up operation state, that is, when the temperature of the cooling water is lower than the predetermined value, the thermostat 19 is in the closed state.
The passage from the first return passage 17 to the second return passage 18 is blocked. On the other hand, the second return passage 18 is in communication with the bypass passage 20. The cooling water discharged from the water pump 16 is the cylinder block water jacket 2a and the exhaust side water jacket 6
It circulates in the bypass passage 20 and the thermostat 19.
Through the second return passage 18. Then, the cooling water is again discharged from the water pump 16 into the cylinder block water jacket 2a. Therefore, the cooling water does not flow into the radiator 9 side, but circulates in the flow path indicated by the arrow in FIG. Since the cooling water does not pass through the radiator 9, its temperature rises quickly and the warm-up operation ends in a short time.

When the warm-up operation is completed and the temperature of the cooling water rises above a predetermined value, the thermostat 19 opens.
When the thermostat 19 is opened, the first return passage 17 is opened.
And the 2nd return passage 18 will be in a communication state. Therefore,
The cooling water flows into the radiator 9 side and circulates through the flow path indicated by the arrow in FIG. That is, the cooling water discharged from the water pump 16 first circulates in the cylinder block water jacket 2a and the exhaust side water jacket 6, and absorbs heat from the cylinder block 2 and the cylinder head exhaust side 4 which have high temperatures. . Subsequently, the cooling water flows into the radiator 9 via the upper hose 8 and the upper tank 10. Here, a part of the cooling water is branched from the upper hose 8 and the first auxiliary passage 2
It is also introduced on the 1st side. The cooling water flowing into the radiator 9 radiates its heat from the cooling fins 14 to the outside in the process of passing through the tube 13 provided in the core 12. As a result, the temperature of the cooling water is lowered, and the cooled cooling water flows into the intake side water jacket 7 via the lower tank 11 and the lower hose 15. Then, the cooling water absorbs heat on the intake side 5 of the cylinder head and cools it. Further, the cooling water returns from the intake side water jacket 7 to the water pump 16 through the first return passage 17, the thermostat 19 and the second return passage 18, and is circulated again.

As described above, the cooling system of this embodiment uses the intake pre-cooling method. That is, the water jacket for cooling the cylinder head 3 is separated into the exhaust side and intake side water jackets 6 and 7, the cooling water passing through the radiator 9 first cools the cylinder head intake side 5, and then the cylinder head. The exhaust side 4 is designed to be cooled.

The cooling device of this embodiment to which the intake precooling method is applied has the following features. That is, since the cylinder head intake side 5 is cooled by the cooling water that has passed through the radiator 9 and has a low temperature, the cooling efficiency in this portion is extremely high. Therefore, in the cooling device of the present embodiment, the temperature of the intake air passing through the intake port (not shown) in the cylinder head intake side 5 can be lowered. As a result, the density of the intake air is increased and the filling efficiency is improved. Further, knocking can be prevented by suppressing the temperature rise on the intake side 5 of the cylinder head. In addition, since the water jackets 6, 7 of the cylinder head 3 are separated into the intake side and the exhaust side, the volume of each water jacket 6, 7 is reduced. As a result, the flow velocity of the cooling water passing through the water jackets 6 and 7 is increased, and the cooling effect is further improved.

A signal corresponding to the rotation amount of the rotary shaft of the throttle valve is input from the throttle opening sensor 26 to the ECU 25, and a signal corresponding to the rotation speed of the crankshaft is input from the engine speed sensor 27. ing. Then, when both the rotation amount and the rotation speed calculated by the input signal are less than a predetermined value,
The control valve 24 is kept open by the ECU 25. As a result, a part of the cooling water flowing through the upper hose 8 flows into the storage tank 23 from the first auxiliary passage 21 via the control valve 24. Then, the cooling water is once mixed with the cooling water in the storage chamber 23a, and then the second auxiliary passage 22
Flows into. The cooling water flowing into the second auxiliary passage 22 is the second
It merges with the cooling water in the return passage 18 and is circulated again by the water pump 16.

On the other hand, when either one of the rotation amount and the rotation speed increases above a predetermined value, that is, when the operating state of the engine 1 becomes a high load state, the ECU 2
The control valve 24 is controlled by 5 to be in a closed state. Therefore, the circulation of the cooling water in the first auxiliary passage 21 is blocked. Then, the cooling water that has returned to the water pump 16 after sequentially passing through the first auxiliary passage 21, the control valve 24, the storage tank 23, and the second auxiliary passage 22 comes to flow into the radiator 9 side. It circulates through the flow path indicated by the arrow. As a result, the flow rate of the cooling water passing through the intake water jacket 7 increases and the flow velocity also increases, so that cooling of the cylinder head intake side 5 is promoted.

The second auxiliary passage 22 is the second return passage 18
Since it is connected in the vicinity of the suction port of the water pump 16, the cooling water in the second auxiliary passage 22 is sucked by the water pump 16 together with the cooling water in the second return passage 18. At this time, the flow of the cooling water in the first auxiliary passage 21 is blocked by the control valve 24. The internal pressure of the air chamber 23b formed in the storage tank 23 is reduced as the cooling water in the second auxiliary passage 22 is sucked by the water pump 16. As a result, the second auxiliary passage 22 and the second return passage 18 communicating with the second auxiliary passage 22.
The internal pressure of the inside is reduced, and the insides of the first return passage 17 and the intake side water jacket 7 are also reduced. And
The internal pressure in the intake water jacket decreases, and the boiling point of the cooling water flowing inside decreases. The cooling water having the lowered boiling point boils on the wall surface of the intake water jacket 7 and, at the same time, absorbs a large amount of heat of vaporization from the wall surface. That is, the cylinder head intake side 5 is in a boiling cooling state, and the cooling is promoted.
Therefore, even when the engine 1 is in a high load state and a large amount of heat is generated on the cylinder head intake side 5, the cooling device of the present embodiment can suppress the temperature rise of the cylinder head intake side 5, and the cylinder head intake side 5 can be suppressed. There is no danger that 5 will overheat. In addition, knocking can be prevented by suppressing the temperature rise on the intake side 5 of the cylinder head. Further, in the cylinder head intake side 5, the inside of the intake side water jacket 7 is boiled and cooled effectively, so that the density of the intake air passing through the intake port (not shown) is reduced and the charging efficiency is improved. I will. Therefore, according to the cooling device of the present embodiment, it is possible to increase the output during high load operation.

Although the embodiment embodying the present invention has been described above, the embodiment can be implemented by changing the configuration as follows. (1) Although the first auxiliary passage 21 is connected in the middle of the upper hose 8, it may be connected to the lower hose 15.

(2) Although the throttle opening sensor 26 and the engine speed sensor 27 are used as the means for detecting that the engine 1 is in the high load state in the above embodiment, only one of them may be used.

(3) The throttle opening sensor 26 may be replaced with another sensor such as an intake pressure sensor or an air flow sensor. Further, other technical ideas which are not described in the claims and which are grasped by the above-described embodiments will be described below together with their effects.

(A) In the invention described in claim 1 or 2, the operating state detecting means includes a throttle opening sensor for detecting a rotation amount of a rotary shaft of a throttle valve, and an engine for detecting a rotation speed of a crankshaft. An engine cooling device comprising a rotation speed sensor and an ECU.

According to this structure, the operating state of the engine is determined by the amount of rotation of the rotary shaft of the throttle valve and the number of rotations of the crankshaft, so that it can be reliably detected that the engine is in a high load state. it can.

[0033]

According to the engine cooling device of the present invention, it is possible to improve the cooling effect on the intake port side of the cylinder head when the engine is in a high load state.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a cooling device according to an embodiment of the present invention, showing a flow of cooling water during warm-up operation.

FIG. 2 is a diagram showing the flow of cooling water during normal operation as well.

FIG. 3 is a diagram showing a flow of cooling water during high load operation.

FIG. 4 is a diagram showing a schematic configuration of a cooling device in the related art and showing a flow of cooling water during warm-up operation and normal operation.

[Explanation of symbols]

1 ... Engine, 2 ... Cylinder block, 2a ... Cylinder block Water jacket, 3 ... Cylinder head, 6
... Exhaust side water jacket, 7 ... Intake side water jacket, 8 ... Upper hose (first passage), 9 ... Radiator, 15 ... Lower hose (second passage), 16 ... Water pump, 17 ... First return passage (third passage) ), 18 ... Second return passage (third passage), 21 ... First auxiliary passage (auxiliary passage), 22 ... Second auxiliary passage (auxiliary passage), 23 ... Storage tank, 23b ... Air chamber, 24 ... Control valve , 25 ... ECU
(Operating state detecting means), 26 ... Throttle opening sensor (operating state detecting means), 27 ... Engine speed sensor (operating state detecting means).

Claims (1)

[Claims] 1. A cylinder block water jacket provided in a cylinder block of an engine, an exhaust side water jacket provided on an exhaust port side in a cylinder head and communicating with the cylinder block water jacket, and the exhaust side water jacket. A radiator communicated with the jacket through a first passage, and a radiator provided in the cylinder head on the intake port side and communicated with the radiator through a second passage, while being communicated with the cylinder block water jacket through a third passage. An intake side water jacket is provided, and a cylinder block water jacket, an exhaust side water jacket, a first passage, a radiator, a second passage, an intake side water jacket, and a water pump disposed in the middle of the third passage. In the cooling apparatus for an engine for forcibly circulating cooling water in the order of the third passage, one end is the downstream side of the exhaust side water jacket,
Whether the engine is in a high load state, and an auxiliary passage connected to an upstream side position of the intake side water jacket and the other end of which is connected to an upstream side position of the water pump in the third passage. An operating state detecting means for detecting whether or not the control valve is provided in the auxiliary passage and opens or closes the auxiliary passage based on a detection signal from the operating state detecting means; and a downstream side of the control valve. And a closed storage tank having an air chamber, which is disposed in the auxiliary passage of the engine cooling device.