JPS6323539Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cooling device for a water-cooled engine, and more particularly to a cooling device in which a thermostat is provided in the middle of a suction waterway from a radiator to a water pump.

Generally, as a cooling system for a water-cooled engine, cooling water from the engine body is returned to the engine body through a bypass passage during warm-up operation, and cooling water is returned to the engine body through a radiator after warm-up. It has been known. (Reference Bibliography Special Publication 1977-
Publication No. 26653) Whether the cooling water from the engine body is to flow to the radiator or to the bypass passage is determined by, for example, the first
By switching the pellet type thermostat as shown in the figure, it is selectively determined according to the cooling water temperature.

FIG. 1 shows the operating state of the thermostat during warm-up operation. In the figure, 1 indicates the thermostat housing, and 2 indicates the housing 1 via the gasket 6.
3 is a main valve; 4 is a temperature sensing section that opens and closes the main valve 3; and 5 is a bypass valve that operates in conjunction with the temperature sensing section 4.

In this state, the cooling water temperature is low, so the temperature sensor 4
The wax stored in the main valve 3 contracts and overcomes the biasing force of the spring 7, closing the main valve 3.

At this time, the bypass valve 5 is open, so
Cooling water (low temperature) from the engine body (not shown)
is drawn through the thermostat and into the water pump through a bypass passage.

As the temperature of the cooling water gradually rises, the wax in the temperature sensing part 4 expands, and eventually this expansion force overcomes the urging force of the spring 7 and the pressing force from the piston 8 causes the main valve 3 to open. At the same time, the bypass valve 5 attached to the bottom of the temperature sensing section 4 closes to block the bypass passage.

In this way, during warm-up operation, the cooling water from the engine body bypasses the radiator and is returned to the engine body via the water pump while maintaining the heated water temperature. This results in
Efforts are being made to warm up the vehicle.

When the warm-up is completed, the cooling water is returned to the water pump through the radiator, and the bypass passage is closed by the bypass valve 5, so that all the cooling water is cooled by the radiator and set so that the water temperature does not exceed a predetermined temperature. Maintain water temperature at appropriate temperature.

However, in such a conventional cooling device, the bypass valve 5 of the thermostat is formed in the shape of a disk, and the disk portion 8 opens and closes the inlet 9 of the bypass passage. In the open state, the cooling water flows around the outer circumference of the disc portion 8 and then flows to the water pump outlet 10 on the side.

Therefore, at this time, only a part of the cooling water from the bypass passage passes through the temperature sensing part 4 in the center of the thermostat, so the thermal response of the thermostat is poor, and even if the cooling water temperature rises to a certain degree, However, since the cooling water still bypassed the radiator, the engine tended to overheat.

In addition, in order to solve such problems, the second
As shown in the figure, a guide wall 1 is placed between the inlet 9 of the bypass passage and the outlet 10 of the water pump.
1 and configured so that all the cooling water flowing into the thermostat passes through the temperature sensing part 4 in the center, but according to this, the cooling water flow path to the outlet 10 is narrowed and the water channel is The disadvantage is that the resistance increases.

The present invention was developed by focusing on the problems of the conventional example.The bypass valve of the thermostat is formed into a bell-shaped cylinder, and an opening is formed on the side of the cylinder in the direction in which the cooling water should be guided. By providing a window section, all the cooling water from the bypass passage passes smoothly around the temperature sensing part through the window section, and then is sent under pressure to the water pump outlet, increasing the thermal response of the thermostat. The purpose is to

Embodiments of the present invention will be described below with reference to the drawings, and the same components as in FIGS. 1 and 2 will be denoted by the same reference numerals.

FIG. 3 shows an embodiment of the present invention, showing a schematic configuration of an engine cooling system, and FIG. 4 showing an enlarged cross-sectional view of a thermostat in the engine cooling system.

A is the engine body, 12 is the cylinder block,
13 is a cylinder head, 14 is an intake waterway, 15 is a radiator, 16 is an outlet waterway, 17 is a thermostat, and 18 is a water pump. In Figure 3,
→ and 〓 indicate the flow directions of high-temperature cooling water and low-temperature cooling water, respectively.

The housing 1 of the thermostat 17 is formed with cooling water inlets 21 , 9 , and 23 for guiding cooling water from the radiator 15 , bypass passage 19 , and heater 20 , and sending the inflow cooling water to the water pump 18 . Cooling water outlet 10
is formed.

A thermostat main body 2 is housed inside the housing 1, and the thermostat main body 2 is fastened to a water inlet 24 with a bolt or the like via a gasket 6.

The thermostat main body 2 includes a main valve 3 through which cooling water from a radiator 15 flows in, a temperature sensing section 4 that opens and closes the main valve 3, and a bypass valve that opens and closes a cooling water inlet 9 from a bypass passage in conjunction with the temperature sensing section 4. It consists of a valve 25. Note that the cooling water inlet 23 from the heater 20 is always open.

A portion 8a of the piston 8 fixed to the thermostat main body 2 and wax 27 filled around the portion 8a are housed inside the temperature sensing portion 4.

When the temperature of the cooling water that comes into contact with the outer periphery of the temperature sensing part 4 reaches a predetermined value or higher, the expansion of the wax 27 pushes the piston 26 upward, and the temperature sensing part 4 moves downward against the spring 7. . At this time, the main valve 3 integrated with the temperature sensing section 4 moves downward to close the inlet 9.

Bypass valve 2, which is a characteristic part of this embodiment
5 is located coaxially and downwardly with the piston 8 and is formed into a bell-like cylindrical shape, and is located above the opening center axis of the inlet 9.

The outer circumferential diameter of the bypass valve 25 substantially matches the inner diameter of the inlet 22, and the bypass valve 2
5 moves downward, the outer periphery of the cylinder slips into the inlet 22 and blocks the inlet 9, as shown in FIG.

The inside of the bypass valve 25 is formed hollow, and a plurality of windows 26 are opened on the cylindrical side surface (the outer periphery of the cylinder).

In this case, the window 26 is provided on the opposite side of the outflow port 10 to the water pump 18, and almost all of the cooling water that has passed through the window 26 from the inflow port 9 passes around the temperature sensing section 4. The water is then sent from the outlet 10 to the water pump 18.

In FIG. 3, 28 is a heater operated by high-temperature cooling water from the engine main body A, and 29 is a throttle chamber that similarly utilizes the residual heat of the high-temperature cooling water to promote fuel vaporization.

Next, the effect will be explained.

During engine warm-up, the cooling water temperature is low, the main valve 3 of the thermostat 17 is closed, and at the same time the bypass valve 25 is open as shown in FIG.

Therefore, the hot water heated by the engine body 11 attempts to flow into the housing 1 through the window 26 of the bypass valve 25.

At this time, the inflow cooling water is forcibly led to the opposite side of the outflow port 10, sandwiching the temperature sensing part 4, so most of the cooling water flows around the temperature sensing part 4 as shown by arrow B. It is discharged from exit 10. Thereafter, the cooling water is returned to the engine body A by the suction action of the water pump 18.

In this way, the cooling water flow path is formed so that the hot water from the bypass passage 19 always hits the periphery of the temperature sensing portion 4 of the thermostat 17, so that the temperature sensing characteristics of the thermostat 17 are improved.

As a result, the thermostat 17 responds sensitively to the coolant temperature and appropriately opens and closes the valve, thereby preventing the coolant from flowing into the engine body A without going through the radiator 15 even when the coolant temperature is sufficiently high. This prevents the engine from overheating.

When the engine warm-up is completed, the main valve 3 opens, and at the same time, the bypass valve 25 fits into the inlet 9 as shown in FIG. 5, stopping the flow of cooling water from the bypass passage 19.

In this way, the engine coolant circulates through the radiator 15, so the coolant temperature is always maintained below a certain temperature.

As described above, according to the present invention, the bypass valve of the thermostat is formed into a bell-like cylindrical shape, and a window portion is provided on the side surface of the cylinder (the outer periphery of the cylinder) so that the cooling water is guided in an appropriate direction. The cooling water that flows into the housing through this window sensitively captures the cooling water temperature, which reliably improves the temperature sensing characteristics of the thermostat while the engine is warming up, thereby avoiding engine overheating. Get the effect of being able to.

[Brief explanation of drawings]

1 and 2 are sectional views showing a conventional thermostat, FIG. 3 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 4 is a sectional view showing a thermostat of an embodiment of the present invention. FIG. 5 is an explanatory diagram of the main part of FIG. 4. 1...Thermostat housing, 3...Main valve, 17...Thermostat, 25...Bypass valve, 26...Window section.

Claims (1)

[Scope of utility model registration request] In a water-cooled engine cooling system, a thermostat is installed in the middle of a cooling water passage that circulates between the engine body and the radiator, and the thermostat is switched so that the cooling water flows through a bypass passage that bypasses the radiator. A cooling device for a water-cooled engine, characterized in that a bypass valve is formed into a bell-like cylindrical shape, and a window portion is provided on the side surface of the cylinder to guide cooling water through a temperature-sensing section.