JPH0586970A - Cooling device for engine - Google Patents

Abstract

PURPOSE:To simplify the structure, in a cooling device to independently control a cooling water circulating system for a cylinder head and a cooling water circulating system for a cylinder block. CONSTITUTION:Two delivery ports 32 and 33 through which cooling water delivered from a water pump 30 is guided to water jackets 5 and 4 on the head side and the block side respectively are formed in a branched state. An on-off valve 40 for opening and closing a delivery port on the block side according to an operation state is provided. Meanwhile, a communicating hole 6 through which the water jackets 4 and 5 are mutually intercommunicated is formed, and an outlet 7 of the water jacket on the head side is formed in the vicinity of the communicating hole 6. A rib for intercoupling right and left head bolt boss parts is formed in a protruding state in the interior of the water jacket 5 on the head side in a manner to front on the outlet 7. The communicating hole 6 connected to the water jacket 4 on the block side is opened to a rib. Delivery ports 32 and 33 are formed in a branched state in the pump housing 31 of a water pump and the on-off valve 40 and an actuator are provided thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for a water-cooled engine.

[0002]

2. Description of the Related Art In automobile engines,
The cooling water circulation system for the cylinder head and the cooling water circulation system for the cylinder block are independently formed to prevent knocking and the like by keeping the combustion chamber wall of the cylinder head at a relatively low temperature. By keeping the temperature relatively high, friction was reduced, and higher output and lower fuel consumption were achieved.

However, as this type of cooling device,
For example, in the one disclosed in Japanese Utility Model Laid-Open No. 60-102422, two water jackets for circulating cooling water are formed in a cylinder block and a cylinder head, and a thermostat valve is provided at the outlet of each water jacket. Therefore, there is a problem that the number of thermostat valves and cooling water pipes increases and the structure becomes complicated.

Further, since the one disclosed in Japanese Patent Laid-Open No. 57-97014 has a structure in which five valve bodies are attached to a single thermostat valve to open and close each port, the cooling water piping is complicated. There was a problem of inviting.

In view of the above points, the present invention has an object to simplify the structure of a cooling device which independently controls a cooling water circulation system for a cylinder head and a cooling water circulation system for a cylinder block.

[0006]

SUMMARY OF THE INVENTION According to the present invention, two water jackets for circulating cooling water are formed in a cylinder block and a cylinder head respectively, and a discharge port for guiding cooling water discharged from a water pump to each water jacket. The block side discharge port is provided with an on-off valve that opens and closes according to the operating state, while a communication hole that communicates between the water jackets is formed, and the cooling water outlet of the head side water jacket is connected to the communication hole. A bypass that guides the cooling water from the outlet to the suction side of the water pump by bypassing the radiator and forming a cooling passage by connecting the outlet to the suction side of the water pump via a radiator. A thermostat valve that forms a passage and opens and closes the cooling passage according to the temperature of the cooling water is provided.

Further, a rib connecting the left and right head bolt bosses is formed in the inside of the head-side water jacket so as to face the outlet, and the communicating hole for connecting to the block-side water jacket is opened in this rib.

Further, the two discharge ports are formed in a branch in a pump housing for accommodating the water pump, and the opening / closing valve and an actuator for driving the opening / closing valve are also attached to the pump housing.

[0009]

[Function] When the cooling water temperature is lower than the specified value, the thermostat valve is closed, and the entire amount of the cooling water discharged from the water pump flows into the head side water jacket and flows out from the head side water jacket. While water circulates through the bypass passage and heat dissipation from the radiator is stopped, while the on-off valve closes the block-side discharge port, circulation of cooling water in the block-side water jacket is stopped and the cylinder temperature rises. Is promoted and the amount of HC emission is reduced.

When the temperature of the cooling water rises above a predetermined value and the thermostat valve opens and the opening / closing valve opens the block side discharge port, the cooling water discharged from the water pump is discharged to the head side and the block side. The cooling water that diverted to each water jacket and circulated in the head side water jacket flows out from the outlet, and the cooling water that circulates in the block side water jacket merges with each other through the communication hole via the head side water jacket and then from the outlet. It flows out and circulates in the radiator to radiate heat.

By forming a communication hole for communicating the water jackets with each other in the vicinity of the outlet through which the cooling water from the water jacket on the head side flows out, the cooling water which circulates through the water jacket on the block side and has a high temperature is circulated. Since it is possible to avoid circulating the water jacket, the flow of cooling water in the water jacket on the head side and the water jacket on the block side can be independently controlled via the on-off valve, and each can be controlled to an optimum temperature.

Further, since the rib connecting the left and right head bolt boss portions is formed, the rigidity of the cylinder head can be enhanced, and the communication hole can be sufficiently close to the outlet by opening the communication hole in the rib. This makes it possible to effectively prevent the cooling water, which has become high temperature by circulating through the block side water jacket, from circulating through the head side water jacket, which enhances the cooling performance of the cylinder head and prevents knocking.

Further, by mounting the on-off valve, the diaphragm actuator and the like together with the water pump in the pump housing to form a unit, the apparatus can be made compact and the work of assembling these parts to the engine can be simplified. ..

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a four-cylinder engine 1 has a water jacket 4 formed in a cylinder block 2.
And a water jacket 5 formed on the cylinder head 3. The block-side water jacket 4 circulates cooling water around each cylinder 19 that houses the piston 9, while the head-side water jacket 5 circulates cooling water around the combustion chamber wall 18.

A water pump 30 for supplying cooling water to each water jacket 4, 5 is provided. As shown in FIG. 2, the front surface 29 of the cylinder block 2 is formed with a mounting surface 21 for the pump housing 31 of the water pump 30, and an inlet 22 for guiding the cooling water to the head-side water jacket 5 and a block inside the mounting surface 21. An inlet 23 for guiding cooling water is formed in the side water jacket 4.

As shown in FIGS. 3, 4, and 5, the pump housing 31 has two discharge ports 32 and 33 formed in a branched manner. The head side discharge port 32 guides cooling water to the head side water jacket 5 via the inlet 22 of the cylinder block 2, and the block side discharge port 33 flows to the block side water jacket 4 via the discharge port 23 of the cylinder block 2. Guide

The water pump 30 is a pump housing 3
The blades 34 are housed in the inside of the nozzle 1, and the cooling water sucked from the suction port 24 by the rotation of the blades 34 is discharged to the discharge ports 32 and 33. The blade 34 has a belt 37 wound around a pulley 35 connected coaxially and a pulley 36 connected to the crankshaft side to transmit the engine rotational force.

The pump housing 31 has a partition wall 3 for partitioning a discharge port 32 communicating with the block-side water jacket 4.
8 is formed, and an opening / closing valve 40 for opening / closing the opening 39 of the partition wall 38 is provided. The on-off valve 40 is rotatably supported by the pump housing 31 via an arm 41 and a shaft 42, and the shaft 42 is connected to a rod 45 of a diaphragm actuator 44 via an arm 43. The diaphragm actuator 44 is fixed to the pump housing 31 via a bracket 46, and when atmospheric pressure is introduced via a pressure switching valve (not shown), the opening / closing valve 40 is held at a position to close the discharge port 33 as shown in the figure. When intake negative pressure of the engine is introduced through the pressure switching valve, the opening / closing valve 40 is rotated to open the discharge port 33.

The control unit 50 provided as a control means for the on-off valve 40 has a cooling water temperature, an engine speed,
The boost pressure and knocking detection signals are input, the pressure switching valve is controlled according to the operating state, and the opening / closing valve 40 is opened / closed via the diaphragm actuator 44.

As shown in FIGS. 6 and 7, an outlet 7 for discharging the cooling water of the head side water jacket 5 is formed in the rear wall 16 of the cylinder head 3, and a head side water jacket is provided in the vicinity of the outlet 7. A communication hole 6 is formed to connect the block water jacket 4 and the block side water jacket 4 to each other.

In the cylinder head 3, a spark plug boss portion 53 is formed at the center of the combustion chamber wall 18, and two intake ports 54 and two exhaust ports 55 are connected around the boss portion 53 to form a combustion chamber. The water jacket 5 is defined between the lower deck 57 including the wall 18 and the upper deck 56.

In the cylinder head 3, head bolt boss portions 17 are formed around each cylinder 19 at a predetermined interval, and a head bolt (not shown) penetrating each head bolt boss portion 17 is screwed into the cylinder block 2 for fastening. It

On the lower deck 57 of the cylinder head 3,
A rib 15 is formed to connect the left and right head bolt boss portions 17 connected to the rear wall 16 in a beam shape, and the communication hole 6 is formed at the center of the rib 15. The rib 15 projects from the lower deck 57 to a position facing the side of the outlet 7, and the communication hole 6 is formed to face the outlet 7.

As shown in FIG. 1, the outlet 7 of the water jacket 5 on the head side is connected to the suction port 24 of the water pump 30 via the radiator 14 to form the cooling passage 10, and the cooling water from the outlet 7 is also supplied to the radiator. Bypass passage 11 that bypasses 14 and leads to the suction port 24 of the water pump 30
To form. In this case, a heater core 12 for heating the passenger compartment is provided in the middle of the bypass passage 11, and the water passage resistance of the bypass passage 11 is formed larger than the water passage resistance of the cooling passage 10 at a predetermined ratio. The radiator 1 is a thermostat valve 13 that opens and closes the cooling passage 10 according to the temperature of the cooling water.
4 located between the water pump 30 and the bypass passage 1
The thermosensitive valve 13 is provided on the upstream side of the confluence point of 1, and the temperature sensing portion of the thermostat valve 13 is provided so as to face the bypass passage 11.

Next, the operation will be described.

When the cooling water temperature is lower than a predetermined value, the thermostat valve 13 is closed, and the opening / closing valve 40 closes the block side discharge port 33 based on the output from the control unit 50. As a result, the water pump 30
The entire amount of the cooling water discharged from the cooling water circulates in the bypass passage 11 without flowing into the radiator 14, while the cooling water circulation is stopped in the block side water jacket 4.
As a result, the temperature rise of the cylinder 19 and the combustion chamber wall 18 during cold is promoted, and the HC emission amount is reduced.

During a warm period when the temperature of the cooling water rises above a predetermined value, the thermostat valve 13 opens and the opening / closing valve 40 opens the block side discharge port 33 based on the output from the control unit 50. As a result, the water pump 30
The cooling water discharged from the head side and the block side is divided into the water jackets 5 and 4, the cooling water circulating in the head side water jacket 5 flows out from the outlet 7, and the cooling water circulating in the block side water jacket 4 is It flows from the communication hole 6 to the outlet 7 via the head-side water jacket 5, merges with each other, and then circulates in the radiator 14 to radiate heat. At this time, the flow of the cooling water in each of the water jackets 5 and 4 on the head side and the block side can be independently controlled via the opening / closing valve 40, and each can be controlled to an optimum temperature. Actually, the thermostat valve 13 has a cooling water temperature of 80.
When the temperature exceeds 90 ° C, the valve opens, and the on-off valve 40 controls the cooling water temperature to 10
When the temperature exceeds about 0 ° C., the block side discharge port 33 is set to open, and the temperature of the cylinder block 2 is kept relatively high.

By forming a communication hole 6 in the vicinity of the outlet 7 through which the cooling water from the head side water jacket 5 flows out, the block side water jacket 4 is circulated to a high temperature. It is possible to prevent the cooling water that has become circulated in the head-side water jacket 5, and in the head-side water jacket 5, only the relatively low-temperature cooling water that is discharged from the water pump 30 circulates to heat the combustion chamber wall 18. Since the cylinder head 3 is carried away, knocking or the like is prevented by keeping the cylinder head 3 at a relatively low temperature, while friction is reduced by keeping the cylinder 19 at a relatively high temperature, and high output and low fuel consumption are achieved.

A rib 1 protruding so that the communicating hole 6 faces the outlet 7.
5, the communication hole 6 can be brought sufficiently close to the outlet 7, and the cooling water that has become hot by circulating through the block side water jacket 4 circulates through the head side water jacket 5. Can be effectively suppressed. By thus joining the cooling water flowing out from the outlet 7 with the cooling water flowing out from the communication hole 6, the piping connected to the radiator 14 can be made single, and the piping can be simplified.

The rib 15 connects the left and right head bolt bosses 17 provided so as to be connected to the rear wall 16 of the cylinder head 3 in a beam shape to enhance the rigidity of the cylinder head 3 and a communication hole penetrating the rib 15. 6 and cylinder block 2
It is possible to prevent the cooling water from leaking out from the joint with the water jacket 4.

The head side discharge port 3 is provided in the pump housing 31.
2 and the block side discharge port 33 are integrally formed, and the opening / closing valve 40, the diaphragm actuator 44 and the like are assembled into the pump housing 31 to form a unit, whereby the device can be made compact and the assembling work can be performed. Can be simplified.

[0033]

As described above, according to the present invention, the cooling water is circulated in the cylinder block and the cylinder head.
Each water jacket is formed by branching the discharge port that leads cooling water discharged from the water pump to each water jacket, and the block side discharge port is provided with an on-off valve that opens and closes according to the operating condition. By forming a communication hole that communicates with each other, the cooling water outlet of the head side water jacket is formed in the vicinity of the communication hole, which simplifies the piping arranged between the radiator and the engine and reduces the head side when cold. Since the cooling water is circulated between the water jacket and the water pump to stop the circulation of the cooling water to the block side water jacket and the radiator, the temperature rise of the cylinder and the combustion chamber wall is promoted and the HC emission amount is reduced. After the temperature rises, the flow of cooling water for each water jacket on the head side and block side is independently controlled via the on-off valve. And you can control, can be controlled to the optimum temperature, respectively.

Further, a rib connecting the left and right head bolt bosses is formed to project inside the head side water jacket so as to face the outlet, and a communicating hole for connecting to the block side water jacket is opened in this rib, so that the cylinder head of the cylinder head is opened. The rigidity can be increased, and the communication hole can be brought sufficiently close to the outlet, and the cooling water that has become high temperature by circulating through the block side water jacket can be effectively suppressed from circulating through the head side water jacket.

Further, since each discharge port is formed in the pump housing in a branched manner and the on-off valve and its actuator are attached, the device can be made compact and the work of assembling these parts to the engine can be simplified. ..

[Brief description of drawings]

FIG. 1 is a circuit diagram of a cooling system showing an embodiment of the present invention.

FIG. 2 is a front view of a cylinder block of the same.

FIG. 3 is likewise a front view of the pump housing.

FIG. 4 is a plan view of the pump housing of the same.

FIG. 5 is a rear view of the pump housing.

FIG. 6 is a cross-sectional view of a cylinder head of the same.

7 is a longitudinal sectional view of the cylinder head, which is also taken along the line AA of FIG.

[Explanation of symbols]

 4 Block side water jacket 5 Head side water jacket 6 Communication hole 7 Outlet 10 Cooling passage 11 Bypass passage 13 Thermostat valve 14 Radiator 15 Rib 17 Head bolt boss portion 30 Water pump 31 Pump housing 32 Head side discharge port 33 Block side discharge port 40 Open / close valve 44 Diaphragm actuator 50 Control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location F01P 5/10 C 9246-3G 7/16 502 P 6848-3G 505 D 6848-3G (72) Invention Person Ryoji Goto 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.

Claims (3)

[Claims] 1. A cylinder block and a cylinder head are each provided with two water jackets for circulating cooling water, and a discharge port for guiding the cooling water discharged from a water pump to each water jacket is formed in a branched manner. An opening / closing valve that opens and closes according to the operating state is provided on the other hand, and a communication hole that communicates between each water jacket is formed, and an outlet for cooling water of the head side water jacket is formed in the vicinity of the communication hole. Is connected to the suction side of the water pump via a radiator to form a cooling passage, and a bypass passage for guiding cooling water from the outlet to the suction side of the water pump by bypassing the radiator is formed. A cooling device for the engine, characterized in that a thermostat valve that opens and closes according to the temperature of the cooling water is installed. Place 2. A rib connecting the left and right head bolt bosses is formed in the inside of the head side water jacket so as to face the outlet, and the communication hole connecting to the block side water jacket is opened in this rib. The engine cooling device according to claim 1, wherein: 3. A pump housing for accommodating the water pump, wherein the two outlets are formed in a branched manner, and an opening / closing valve and an actuator for driving the opening / closing valve are also attached to the pump housing. The engine cooling system described.