JPS6095126A - Engine coolant temperature control device - Google Patents

Abstract

PURPOSE:To change the setting temp. of a coolant to any desired value by furnishing two or more openings on a bypass, leading from between the engine thermostat to coolant passage, arranged along the flowing direction of the coolant, and by switching them selectively. CONSTITUTION:In the downstream of No.1 coolant passage 3 leading from engine 1 to radiator 2 about a wax type thermostat 6, the passage 3 is in communication with No.2 coolant passage 4, leading from radiator 2 to water pump 5, through a bypass 7. Between the engine 1 and thermostat 6, openings 9a, 9b of said bypass 7 leading to No.1 coolant passage 3 are provided at two points along the flowing direction of the coolant in such an arrangement as switchable by a selector valve 10. The opening at the top 9a gives a lower setting of coolant temp., while the other 9b at the bottom a higher setting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling water temperature control device for an engine cooling system.

(Prior art) In general, engine cooling is achieved by installing a thermostat in the cooling water passage that connects the engine cooling water outlet and the radiator cooling water inlet, and also by connecting the radiator cooling water outlet and the engine cooling water inlet. This is done by installing a water pump in the cooling water passage and controlling the temperature of the cooling water to a constant level using the thermostat.

By the way, when the engine is under low load, it is necessary to improve the combustion efficiency of the air-fuel mixture in the combustion chamber, and when the outside temperature is low or when the heater is in use, it is necessary to improve the heater performance. It is effective to set the temperature of the cooling water high in order to

Therefore, as a conventional cooling water temperature control device for a water-cooled engine, as described in Japanese Utility Model Application No. 5/1-142722, a Guitflam device is installed above the wax type thermostat in the cooling water passage. By placing a control piece operated by the thermostat in close opposition to the shaft of the thermostat, and automatically adjusting the lift amount of the shaft according to the engine load, the valve opening temperature of the thermostat is raised at low loads, and the temperature at which the thermostat opens at high loads is increased. There are some that control the valve opening temperature to a low level.

However, this cooling water temperature control device has a problem in that a powerful diaphragm device is provided and a control piece is introduced into the cooling water passage, making the configuration complicated and expensive.

(Object of the Invention) The present invention has been made in order to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a cooling water temperature control device that has an extremely simple configuration and can appropriately control the temperature according to various conditions. With the goal. - (Structure of the Invention) A feature of the structure is that a plurality of openings of the bypass passage to the cooling water passage between the engine and the thermostat are arranged in parallel along the flow direction of the cooling water, and By installing a switching valve in the cooling water, the plurality of openings mentioned above can be switched, and by bypassing the opening on the downstream side near the thermostat, the cooling water temperature can be set low, and bypassing from the opening on the upstream side far from the thermostat. As a result, the cooling water temperature was set higher.

(Effects of the Invention) Since the present invention is configured as described above, the opening of the bypass path is increased and the switching valve is inserted in the bypass path without changing the thermostat, so the configuration is simplified and can be implemented at low cost. Moreover, it can be easily applied to existing engines.

(Example) Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, the cooling water circulation system of the water-cooled engine 1 is such that the cooling water that has been pumped in the engine 1 is introduced into the radiator 2 through the first cooling water passage 3, cooled, and then transferred to the radiator 2. The water is pressurized by a water pump 5 installed in a second cooling water passage 4 located one side of the engine, and is circulated into the engine 1. Furthermore, from engine 1 to radiator 2
Wax type thermostat 6 of first cooling water passage 3 leading to
The first cooling water passage 3 is connected to the second cooling water passage 4 between the radiator 2 and the water pump 5 through a bypass passage 7 on the downstream side of the cooling water, and when the cooling water temperature is lower than the set temperature of the thermostat 6, the first cooling water The passage 3 is closed by the valve 8 of the thermostat 6 and circulated via the bypass passage 7, and when the temperature of the cooling water exceeds the set temperature, the valve 8 of the thermostat 6 is opened to circulate most of the cooling water to the radiator 2. It has become.

Here, the first
As the openings of the bypass passage 7 to the cooling water passage 3, two openings 9a and 9b are opened vertically separated by a predetermined interval along the flow direction of the cooling water, and each opening 9a=9b is opened as each inlet of the switching valve IO. It is connected to the boats lla and 11b by bypass passages 7a and 7b, and the outlet port 11c of the switching valve 10 is connected to the second cooling water passage 4 between the radiator 2 and the water pump 5 by the bypass passage 7c, and the upper opening 9a is connected to the boats lla and 11b. and the lower opening 9b are configured to be switched by a switching valve lO.

The above-mentioned upper opening 9a is provided in the pipe wall 13 of the first cooling water passage 3 at a side position of the spring receiving case 12 of the thermostat 6, and when the valve 8 of the thermostat 6 is closed, the main flow of cooling water flows into the thermostat. 1 and 6, and flows from inside the spring receiver case 12 into the opening 9a. Thereby, when bypassing from the upper opening 9a, the temperature of the thermostat 6 rises to the same temperature as the cooling water temperature.

On the other hand, the lower opening 9b is provided in the pipe wall 13 at a location below the thermostat 1-6, and the main flow of cooling water flows into this opening 9b before reaching the thermostat 6, cooling it. Only the side stream of water reaches the vicinity of the thermostat 6 and gradually flows into the opening 9b while remaining there.As a result, when bypassing from this opening 9b, the cooling water temperature reaches the setting of the thermostat 6. The cooling water near the thermostat 6 rises to the set temperature only when the temperature becomes higher than the predetermined temperature, and each time the thermostat 6 is opened.

Therefore, hereinafter, the upper opening 9a will be referred to as a (warm temperature opening L1), and the lower opening 9b will be referred to as a high temperature opening [].

Here, as shown in FIGS. 2 and 3, the switching valve 1
0 is a three-way valve in which a valve body 14 is provided with two inlet ports 11a and 11b and one outlet port IIC, and a valve shaft 15 having a communication passage is rotatably inserted into the valve body 14. By rotating the valve shaft 15 with the solenoid 16 via the link 16a, the low temperature opening 9a and the high temperature opening 9b are opened.
Bypass path 7 on the downstream side of the switching valve 10
It is designed to be connected to C.

The solenoid 16 has a circuit configuration in which an outside temperature switch 19 and a heater switch 20 are connected in parallel between the ignition switch 18 and the solenoid 16 in a series circuit from the pantry 17 to the solenoid 16 via the ignition switch 18. When the solenoid 16 is not energized, the switching valve IO connects the low-temperature opening 9a, whereas when the outside temperature switch 19 and/or the heater switch 20 are turned on and the solenoid 16 is energized, the switching valve IO connects the low temperature opening 9a. A valve 10 is adapted to connect to a high temperature outlet 9b.

Of course, a low load switch may be connected in parallel to the outside temperature switch 19 and the heater switch 2°.

In addition to this, a spool valve or other various valves may be used as the switching valve 1O (and the switching operation may be performed manually without using the solenoid 16).

Furthermore, the bypass passages 7a, 7b, and 7C are two parallel bypass passages extending from the low-temperature opening 9a and the high-temperature opening 9b to the second cooling water passage 4 between the radiator 2 and the water pump 5. In addition, a switching valve may be interposed in each bypass path.

In addition, the thermostat 6 may be of a bellows type instead of a wax type.

Next, the operation of the above configuration will be explained.

In normal operating conditions, both the outside temperature switch 19 and the heater switch 20 are OFF and the solenoid F' 16 is not energized, so the bypass paths 7a and 7C from the low temperature opening 9a are
Since it communicates with the cooling water passage 4, the thermostat 6 correctly detects the cooling water temperature as described above.

When the set temperature of the thermostat 6 is, for example, 82°C, the cooling water temperature is controlled as shown by curve A and maintained at 82°C on average, as shown in FIG.

On the other hand, when the outside air temperature is low or when using a heater in a cold region, it is desirable to set the cooling water temperature high. Therefore, when the outside temperature switch 19 is turned on when the outside air temperature is below a certain value, or when the heater switch 20 is turned on when the heater is in use, the solenoid 16 is energized and the switching valve 10 is switched.
Since the bypass passages 7b and 7C from the high-temperature opening 9b communicate with the second cooling water passage 4, the thermostat 6 does not correctly follow the ever-changing cooling water temperature as described above, and responds with a time delay. Assuming that the valve 8 of the thermostat 6 is closed during the process of increasing the cooling water temperature, the main flow of the cooling water is bypassed from the high temperature opening 9b, so even if the cooling water temperature reaches 82°C, The cooling water temperature near thermostat 6 is considerably lower than that, and
As shown by curve B in the figure, only when the cooling water temperature rises to, for example, 95° C., the cooling water near the thermostat 6 reaches 82° C., and the valve 8 outside the thermostat 1-6 opens forcefully. Then, the cooling water flows through the sir mosque'y l' 6 to the radiator 2, and the thermostat 6 becomes approximately the same temperature as the cooling water, so while being cooled by the radiator 2, the cooling water temperature force < When the temperature drops below 82°C, the valve 8 of the thermos valve 6 will close. In this way, since the cooling water temperature changes back and forth in a substantially sinusoidal manner between approximately 95°C and 82°C, its 31-poor average value is approximately 88.
It will be kept at 5℃・

[Brief explanation of the drawing]

The drawings show embodiments of the present invention. FIG. 1 is an overall configuration diagram of an engine cooling water temperature control device. FIG. 2 is a longitudinal sectional front view of a switching valve. ! A circuit configuration diagram for controlling valve A, and FIG. 4 is an explanatory diagram of the operation of cooling water temperature control. l...Engine, 2...Radioconita, 3, 4...
・Cooling water passage, 5...meter pump, 6...
Thermostat, 7... Bypass path, 9a/91)
・・Opening of Ino gas l/8, 10...Switching valve.

Claims (1)

[Claims] (1) A thermostat is installed in the cooling water passage that connects the engine cooling water outlet and the radiator cooling water inlet, and a cooling water passage that connects the radiator cooling water outlet and the engine cooling water inlet. In an engine in which a water pump is disposed in the engine, and a cooling water passage between the engine and the thermostat and a cooling water passage between the radiator and the water pump are communicated via a bypass passage,
A plurality of bypass passage openings to the cooling water passage between the engine and the thermostat are arranged in parallel along the flow direction of the cooling water, and a switching valve for switching the plurality of openings is interposed in the bypass passage. Engine cooling water temperature control device