JPH07189694A - Engine cooling system - Google Patents

Abstract

(57) [Summary] [Purpose] To effectively utilize the available space to shorten the total engine length. In a V-type engine having left and right banks 21 and 22, a water pump 23 is arranged in a vacant space at the end of one bank 21 offset by a bank, and the discharge side of the water pump 23 is located at the left and right banks 21 and 22. And the left and right banks 2 in the empty space at the end of the other bank 22 which is connected to the cooling water passage of
Cooling water return passage 39 that joins the cooling water passages 1 and 22
The cooling water return passage 39 downstream of the merging portion 60 is branched and connected to the water pump 23 side and the radiator 40 side through the outer periphery of the bank 22.

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.

[0002]

2. Description of the Related Art In a V-type engine, cooling water is sent from a water pump to cooling water passages provided in left and right banks (cylinder head, cylinder block).

The cooling water that has cooled the left and right banks is returned to the radiator and the water pump through the cooling water return passage. In this case, the cooling water is discharged from the left and right banks on the outlet side of the cooling water passage of one bank. Combine the cooling water of
Some have been put back (Japanese Utility Model Publication No. 63-96227, etc.).

On the other hand, in order to control the temperature of the cylinder block, there is a thermostat valve for closing the cooling water passage of the cylinder block when the cooling water temperature is below a predetermined value.

This is to improve the warm-up performance by interrupting the flow of cooling water in the cylinder block when the engine is cold, and to keep the temperature in the cylinder block at a predetermined value during normal operation. By cutting off the flow of cooling water,
While accurately cooling the cylinder head, overcooling of the cylinder block is suppressed to reduce friction with the piston (Japanese Patent Laid-Open No. 162716/58, etc.).

[0006]

However, the former type is a V-type because a converging portion for converging cooling water from the left and right banks is formed at the bank end which is bank offset and protrudes in the engine axial direction. It is unavoidable that the total length of the engine becomes long.

Further, since the merging portion has to have a large cross-sectional area of the passage, there is a problem that the structure has a more protruding structure.

On the other hand, in the latter, the temperature sensing portion of the thermostat valve is provided in the cooling water outlet passage of the cylinder block in order to open and close the thermostat valve by the cooling water temperature in the cylinder block. When the thermostat valve is closed, the flow of cooling water does not occur around the temperature-sensing part, and the temperature is stagnant, so the temperature inside the cylinder block cannot be sensed accurately.

Therefore, there is a problem that the opening of the thermostat valve is delayed, the temperature in the cylinder block deviates from the proper temperature, and the temperature around the cylinder liner becomes too high.

An object of the present invention is to provide a cooling device which can solve such problems and is suitable for a V-type engine.

[0011]

According to a first aspect of the present invention, in a V-type engine having left and right banks, a water pump is arranged in an empty space at one bank end which is bank offset, and the discharge side of the water pump is A cooling water return passage that connects to the cooling water passages of the left and right banks and joins the cooling water passages of the left and right banks in the empty space at the other bank end offset by a bank is provided. The passage is branched and connected to the water pump side and the radiator side through the outer circumference of the bank.

According to a second aspect of the present invention, in a V-type engine having left and right banks, the cooling water passage of the cylinder head of one bank is connected upstream of the passage and the cooling water passage of the cylinder head of the other bank is connected midway in the passage. A first cooling water return passage is formed, a second cooling water return passage that joins the cooling water passage of the cylinder block is formed in the first cooling water return passage, and an outflow resistance is provided in the first cooling water return passage. A thermostat valve for detecting the temperature of the cooling water from the cooling water passage of the cylinder head upstream of the large cooling water passage and opening the second cooling water return passage.

[0013]

In the first aspect of the present invention, the merging portions of the cooling water return passages for returning the cooling water from the water pump and the left and right banks are provided in the empty spaces at the left and right bank ends which are offset by the bank, so that the entire length of the engine is reduced. Can be shortened.

Further, since the flow rate is small on the upstream side of the merging portion of the cooling water return passage and the passage cross-sectional area can be reduced, the cooling water return passage can be moved closer to the engine side.

In the second aspect of the invention, since the thermostat valve is provided in the first cooling water return passage through which the cooling water that has passed through the cooling water passage of the cylinder head flows, the thermostat valve is opened and closed with good response by the cooling water temperature.

In this case, the cooling water temperature from the cooling water passage of the cylinder head connected upstream of the first cooling water return passage,
That is, since the thermostat valve is opened / closed by the cooling water temperature from the cooling water passage of the cylinder head, which has a large outflow resistance and a relatively high temperature, the second on the cylinder block side is opened.
The cooling water return passage is accurately opened and closed.

[0017]

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

FIG. 1 is a plan view of a V-type 6 cylinder engine, FIG.
4 is a cooling path diagram thereof. The right bank 22 of the engine 20 is on the front side of the engine (front side of the vehicle), and the left bank 21 is
Is bank offset to the rear of the engine.

On the front end side of the engine 20, a water pump 23 is installed in an empty space at the front end of the left bank 21 offset by a bank, and the discharge side of the water pump 23 is located on the left and right banks 21, 22 of the cylinder block 24 from the center of the bank. Are connected to the inlet portions 27, 28 of the cooling water passages 25, 26 formed in the above and the inlet portions 33, 34 of the cooling water passages 31, 32 formed in the left and right cylinder heads 29, 30.

The cooling water passage 25 of the cylinder block 24,
26 pass around each of the cylinders 35 and are joined at an outlet 36 at the rear of the block.

Cooling water passage 3 of cylinder heads 29, 30
1, 32 pass through the respective combustion chambers, intake ports, exhaust ports, etc., and outlets 37, 38 are formed at the rear of the head.

A first cooling water return passage 39 is connected to the outlet portions 37, 38 of the cooling water passages 31, 32 of the cylinder heads 29, 30.

The first cooling water return passage 39 is bent toward the center of the bank immediately from the outlet 37 side of the cooling water passage 31 of the cylinder head 29 of the left bank 21 which is bank offset to the rear side of the engine. The converging portion 60 with the outlet portion 38 is extended to the outlet portion 38 side of the cooling water passage 32 of the cylinder head 30 of the right bank 22 that is bank-offset to the front side and is located at the empty space at the rear end of the right bank 22. It is formed.

The passage area of the first cooling water return passage 39 is smaller on the outlet portion 37 side of the cooling water passage 31 located upstream, and gradually expands to the inside (engine side) to remove the position of the cylinder head 29. It is formed so as to enlarge the downstream. FIG. 5 shows the structure of the first cooling water return passage 39.

A downstream side of the first cooling water return passage 39 is extended along the outer periphery of the right bank 22 to the front side of the engine, and an inlet passage of a radiator 40 installed on the suction side of the water pump 23 and on the front side of the engine. 55, and the outlet passage 56 of the radiator 40 is connected to the suction side of the water pump 23.

On the other hand, a second cooling water return passage 41 is connected to the outlet portions 36 of the cooling water passages 25 and 26 of the cylinder block 24, and the second cooling water return passage 41 is connected to the first cooling water return passage 39. In addition, the cooling water passages 31 and 32 of the cylinder heads 29 and 30 are joined between the outlet portions 37 and 38.

A thermostat valve 43 is interposed in the confluence portion 42. 5 to 9 show the structures of the confluence portion 42 and the thermostat valve 43.

The first cooling water return passage 39 of the confluence portion 42 has a predetermined volume portion 44 formed by expanding the passage 39 to the engine side and offsetting the center thereof.
An opening is provided on the upper surface of the. A cover 46 having a pipe port 45 is attached to this opening, and the second cooling water return passage 41 is connected to the pipe port 45.

In the thermostat valve 43, a first valve 47 and a second valve 48 are assembled to a support frame 49, and a wax case 50 filled with wax, a piston 51, and a wax case 50 are provided. Integrated valve 52
And a spring 53.

In the thermostat valve 43, the wax case 50 side serving as a temperature sensing portion is inserted into the volume portion 44 of the first cooling water return passage 39, and the flange portion 54 of the support frame 49.
Is applied to the periphery of the opening of the volume 44, and the cover 46
It is fixed by attaching.

The first valve 47 of the thermostat valve 43 is
When the temperature of the cooling water flowing through the first cooling water return passage 39 reaches a predetermined temperature (a temperature higher than the valve opening temperature of the radiator thermostat valve 57 described later), the wax in the wax case 50 begins to expand and presses the tip. Piston 51
The valve 52 is opened by pressing down the wax case 50 against the spring 53. The second valve 48 of the thermostat valve 43 is for safety, and the valve 52 is opened when the cooling water temperature rises to the upper limit temperature.

The first valve 47 is arranged upstream of the second valve 48 in the first cooling water return passage 39 (cylinder head 29 side).

A thermostat valve 57 is provided in the outlet passage 56 of the radiator 40 connected to the suction side of the water pump 23, and when the cooling water temperature on the suction side of the water pump 23 is below a reference temperature (for example, 82 ° C.). The outlet passage 56 is closed, and when the reference temperature is reached, the outlet passage 56 is opened.

Numeral 58 designates a line for a passenger compartment heater
Reference numeral 9 indicates a line for the oil cooler.

As described above, the water pump 23 is provided in the empty space at the front end of one bank 21 which is bank-offset to the rear side of the engine, and the first empty space is provided at the rear end of the other bank 22 which is bank-offset to the front side of the engine. Since the merging portion 60 of the cooling water return passage 39 is provided, the installation space is small and the total length of the engine can be shortened.

On the upstream side of the first cooling water return passage 39, only the cooling water from the cooling water passage 31 of one cylinder head 29 flows and the flow rate is small, so the passage area on the upstream side is made small. Therefore, the cooling water return passage 39 can be moved closer to the engine side by that amount, and the installation space can be reduced and the total length of the engine can be further shortened.

Further, although the first cooling water return passage 39 has a passage area increased toward the downstream side, it does not project to the outside of the engine because it has a structure that expands to the engine side.

On the other hand, good temperature control of the cylinder block 24 becomes possible. That is, when the cooling water temperature is low, such as when the engine is cold, the thermostat valve 43 in the confluence portion 42 of the first and second cooling water return passages 39 and 41 and the thermostat valve 5 in the outlet passage 56 of the radiator 40.
7 is closed.

At this time, the cooling water discharged from the water pump 23 flows through the cooling water passages 31 and 32 of the left and right cylinder heads 29 and 30, and circulates to the water pump 23 through the first cooling water return passage 39. At the same time, the flow of cooling water in the cooling water passages 25, 26 of the cylinder block 24 is blocked. Therefore, the temperature inside the cylinder block 24 rises quickly.

When the temperature of the cooling water passing through the inside of the first cooling water returning passage 39 reaches a predetermined temperature, the second cooling water returning passage 4
Thermostat valve 43 of the merging portion 42 (first valve 4
7) is opened, but when the temperature is lower than this, the thermostat valve 57 of the outlet passage 56 of the radiator 40 is opened, and the cooling water is cooled through the radiator 40.

As a result, the cylinder heads 29 and 30 are accurately cooled, while the cylinder block 24 is not overcooled, and the temperature inside the cylinder block 24 is maintained at the required temperature.

Then, when the temperature of the cooling water flowing through the cooling water passage 31 of the cylinder head 29 and passing through the inside of the first cooling water return passage 39 reaches a predetermined temperature, the thermostat of the confluence portion 42 of the second cooling water return passage 41. The valve 43 (first valve 47) is opened, the second cooling water return passage 41 is opened to the first cooling water return passage 39, and the cooling water from the water pump 23 is the cooling water passage of the cylinder block 24. It will be distributed to 25 and 26.

Since the temperature sensitive portion of the thermostat valve 43 exists in the cooling water flowing from the cooling water passage 31 of the cylinder head 29 to the first cooling water return passage 39, the temperature of the cooling water causes the thermostat valve 43 to open and close with good response. Also,
Since the cooling water passage 31 of the cylinder head 29 is located on the upstream side of the first cooling water return passage 39, the outflow resistance is larger than that of the cooling water passage 32 of the cylinder head 30, and therefore the relative flow. Due to the temperature of the cooling water from the cooling water passage 31 of the cylinder head 29 which becomes extremely high, the second cooling water return passage 41 is opened / closed exactly according to the set temperature.

Therefore, while the high warm-up performance is ensured, the temperature inside the cylinder block 24 is maintained at an appropriate temperature, so that the friction with the piston is sufficiently reduced and good combustibility is obtained. It is possible to improve fuel efficiency and reduce emissions. Further, when the temperature of the cooling water after cooling the cylinder head 29 becomes equal to or higher than a predetermined temperature, the cylinder block 24 is cooled, so that the temperature of the cylinder liner or the like is prevented from rising excessively, and the reliability is high. can get.

FIG. 10 shows the circulating flow rate of the cooling water in each part when the thermostat valves 43 and 57 are open. The amount of cooling water in the right cylinder head 30 is larger than that in the left cylinder head 29 because the outflow resistance to the first cooling water return passage 39 is large. Further, if the cooling water of the cylinder block 24 is cut off, the amount of cooling water of the cylinder heads 29, 30 increases accordingly.

When the cooling water temperature rises to the upper limit temperature, the safety valve 48 of the thermostat valve 43 is opened and high safety is obtained.

In this embodiment, the cylinder heads 29, 30 are
Although the outlets 37 and 38 of the cooling water passages 31 and 32 are provided at the rear end of the head, they may be provided inside the rear portion of the head or the like. In this case, the connection shape with the outlet of the first cooling water return passage 39 By changing the position of the merging portion 60.

[0048]

As described above, according to the first aspect of the invention, in a V-type engine having left and right banks, a water pump is arranged in an empty space at one bank end which is bank offset, and the discharge side of this water pump is A cooling water return passage that connects to the cooling water passages of the left and right banks and joins the cooling water passages of the left and right banks in the empty space at the other bank end offset by a bank is provided. Since the passage is branched and connected to the water pump side and the radiator side through the outer circumference of the bank, the total length of the engine can be shortened.

According to a second aspect of the present invention, in a V-type engine having left and right banks, the cooling water passage of the cylinder head of one bank is connected upstream of the passage and the cooling water passage of the cylinder head of the other bank is connected in the middle of the passage. A first cooling water return passage is formed, a second cooling water return passage that joins the cooling water passage of the cylinder block is formed in the first cooling water return passage, and an outflow resistance is provided in the first cooling water return passage. Since a thermostat valve for detecting the cooling water temperature from the cooling water passage of the cylinder head upstream of the large passage for opening the second cooling water return passage is provided, the cooling water of the cylinder block can be accurately cut off and distributed by the thermostat valve. Therefore, it is possible to perform appropriate temperature control of the cylinder block such as improvement of warm-up performance, reduction of friction, and improvement of combustibility.

[Brief description of drawings]

FIG. 1 is a plan view of an engine according to an embodiment.

FIG. 2 is a cooling path diagram of the embodiment.

FIG. 3 is a cooling path diagram on the front side of the engine.

FIG. 4 is a cooling path diagram on the rear side of the engine.

FIG. 5 is a plan view of a first cooling water return passage.

FIG. 6 is a plan view of a cover of a merging portion.

FIG. 7 is a plan view in which a thermostat valve is incorporated in a merging portion.

8 is a cross-sectional view taken along the line AA of FIG.

9 is a cross-sectional view taken along the line BB of FIG.

FIG. 10 is a flow rate characteristic diagram.

[Explanation of symbols]

 20 Engine 21 Left Bank 22 Right Bank 23 Water Pump 24 Cylinder Block 25,26 Cooling Water Passage 29,30 Cylinder Head 31, 32 Cooling Water Passage 36-38 Outlet 39 First Cooling Water Return Passage 40 Radiator 41 Second Cooling water return passage 42 Confluence part 43 Thermostat valve 44 Volume part 46 Cover 47 First valve 48 Second valve 50 Wax case 60 Confluence part

Claims (2)

[Claims] 1. In a V-type engine having left and right banks, a water pump is arranged in an empty space at one bank end offset by a bank, and the discharge side of this water pump is connected to the cooling water passages of the left and right banks. With
A cooling water return passage that joins the cooling water passages of the left and right banks is provided in the empty space at the other bank end that is offset by a bank, and the cooling water return passage downstream of this joining portion is passed through the outer circumference of the bank to the water pump side and radiator side. An engine cooling device characterized by being branched and connected. 2. In a V-type engine having left and right banks, a cooling water passage of a cylinder head of one bank is connected upstream of the passage, and a cooling water passage of a cylinder head of the other bank is connected in the middle of the passage. Forming a water return passage, forming a second cooling water return passage that joins the cooling water passage of the cylinder block with the first cooling water return passage, and
The cooling water return passage is provided with a thermostat valve for detecting the cooling water temperature from the cooling water passage of the cylinder head upstream of the passage having a large outflow resistance and opening the second cooling water return passage. apparatus.