JPH0444817Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of an engine cooling device.

(Prior art) Conventionally, there has been a main cooling water passage for circulating cooling water pumped by a water pump into the engine via a radiator, and a first cooling water passage interposed in the main cooling water passage.
a first bypass passage that allows cooling water to bypass the radiator and circulate into the engine when the thermostat valve is closed; and a second bypass passage that bypasses a portion of the engine and guides a portion of the cooling water to the first thermostat valve. and a second thermostat valve that closes the second bypass passage when the cooling water temperature exceeds a predetermined value.
28703), and by guiding the cooling water that cooled the inside of the engine and the cooling water that has bypassed the engine through the second bypass passage to the first thermostat valve, hunting due to changes in water temperature when the engine is cold can be prevented. There are things that can be done to prevent this phenomenon.

However, in the conventional system described above, when the engine is operated at high speed and high load when the engine is cold, such as immediately after starting, the second thermostat valve installed in the second bypass passage is open. In this case, the amount of cooling water supplied to the engine is insufficient, causing the engine temperature to rise rapidly.However, the second thermostat valve is supplied with the warm cooling water that cooled the engine, and the cold cooling water that bypassed the engine through the second bypass passage. Since the cooling water is mixed with water and supplied, there is a problem in that the amount of cooling water cannot be controlled in a responsive manner in response to requests from the engine, resulting in engine damage.

(Purpose of the invention) The present invention was made in view of the above-mentioned conventional problems, and maintains the conventional hunting phenomenon function while controlling the amount of cooling water according to the demands of the engine with a simple configuration. The purpose is to provide a possible engine cooling system.

(Structure of the invention) In order to achieve the above object, the present invention includes a main cooling water passage that circulates the cooling water pumped by the water pump into the engine via the radiator, and a main cooling water passage that is interposed in the main cooling water passage. When the first thermostat valve is closed, the first bypass passage bypasses the radiator and circulates the cooling water into the engine; 2 bypass passages;
and a second thermostat valve that closes the bypass passage when the cooling water temperature exceeds a predetermined value, the main valve of the second thermostat valve comprising:
A pressure responsive means is provided that operates in the closing direction when the cooling water pressure reaches a predetermined value or higher.

(Effects of the invention) Since the present invention is constructed as described above, the second bypass passage and the second thermostat valve maintain the hunting prevention function due to water temperature changes when the engine is cold, and the pressure-responsive With a simple configuration of providing a means, engine damage can be avoided by controlling the amount of cooling water according to the demands of the engine.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, an engine cooling device 1 includes:
A main cooling water passage 5 that circulates cooling water pumped by a water pump 2 that rotates in synchronization with the output shaft into the engine 4 via a radiator 3, and a first cooling water passage interposed in the main cooling water passage 5. thermostatic valve 6
A first bypass passage 7 that circulates cooling water into the engine 4 bypassing the radiator 3 when the valve is closed.
and a second bypass passage 8 which bypasses the engine 4 and leads a portion of the cooling water to the first thermostat valve 6; The second thermostatic valve 9 starts closing operation at about 90°C, which is higher than the valve temperature of 80°C.

Further, the second thermostat valve 9 used in the engine cooling device 1 will be explained in detail with reference to FIG. As the wax material expands, a piston 9d whose tip is supported by a stopper 9c is made to protrude, thereby controlling the opening and closing of the main valve 9e located at the other end of the temperature sensing portion 9b. This main valve 9e
is in contact with a spring 9f as a pressure responsive means that contracts with a water pressure of 2 kg, one end of which is supported by a stopper 9g. Furthermore, this second thermostatic valve 9 is operated when the main valve 9e has reached its maximum stroke in the closing direction due to the expansion of the wax material.
Specified distance A (approximately 2 mm to 5 mm) to the valve seat side 10
It is installed with the remaining parts. Note that 11 is a return spring.

Since the configuration is as described above, the engine 4 is controlled by the second bypass passage 8 and the second thermostat valve 9.
If the engine 4 is operated at high speed and high load when it is cold, such as immediately after starting, the discharge pressure of the water pump 2 will increase, but the In the main valve 9e of the thermostatic valve 9, when the water pressure exceeds 2 kg, the spring 9f contracts and moves toward the valve seat 10, increasing the amount of cooling water on the engine 4 side. Damage to the engine 4 (thermal damage) can be prevented by simply taking some measures. In addition, in this embodiment, in the maximum stroke state of the second thermostat valve 9 in the closing direction, the valve seat 10 is
By interposing the second thermostat valve 9 in the second bypass passage 8 so as to form a gap of about 5 mm, not only is the effect achieved when the engine 4 is cold, but also the cooling water is heated to a high temperature (second thermostat). When the temperature is 90 degrees Celsius or higher when the valve 9 closes, and when the engine 4 is running at low speed and the water pressure has not reached 2 kg), the time taken into consideration when installing the second thermostat 9 is as follows:
As more cooling water is relieved to the radiator 3 side, the amount of cooling water to the radiator 3 side increases.
As a result, it becomes possible to lower the cooling water temperature, and it is possible to solve the problem of insufficient cooling of the engine 4, which is a resistor.

[Brief explanation of the drawing]

1 and 2 disclose an embodiment of the present invention, in which FIG. 1 is an overall view of an engine cooling system, and FIG. 2 is a view of the second thermostatic valve 9 disclosed in FIG. 1. This is an overall diagram. 2...Water pump, 3...Radiator, 4
...Engine, 5...Main cooling water passage, 6...1st
Thermostat valve, 7...first bypass passage, 8
...Second bypass passage, 9...Second thermostat valve, 9e...Main valve, 9f...Spring (pressure responsive means).

Claims (1)

[Scope of Claim for Utility Model Registration] Closing of a main cooling water passage that circulates cooling water pumped by a water pump into the engine via a radiator, and a first thermostat valve installed in the main cooling water passage. a first bypass passage that bypasses the radiator and circulates the cooling water into the engine; a second bypass passage that bypasses the engine and guides a portion of the cooling water to the first thermostatic valve; and a second thermostat valve that closes the bypass passage when the cooling water temperature exceeds a predetermined value, the main valve of the second thermostat valve comprising:
An engine cooling device characterized in that it is provided with a pressure response means that operates in the closing direction when the cooling water pressure reaches a predetermined value or more.