JPS6020563B2 - Engine cooling water temperature control device for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In controlling the cooling water temperature of an internal combustion engine for an automobile, a single thermostat is generally used to control the cooling circulation flow.

Therefore, the temperature ranges from around -2500 in the winter to around 140 o0 in the summer.
A nearly constant temperature over a wide range up to (generally about 80
oo). Essentially, engine water temperature control should provide the optimum water temperature no matter what the air temperature or engine operating conditions are. Controlling the high temperature of the cooling water is effective as an improvement measure, but this condition setting is expected to cause problems such as a decrease in the engine cooling effect in the summer and an increase in the temperature of the engine lubricating oil. The present invention provides two means for solving the above-mentioned problems.
The use of two thermostats doubles the conditions for cooling water temperature control, maintains more favorable engine operating conditions than prior art devices, and allows the other to assist in the event of one thermostat failure. The purpose is to provide a blind eye that ensures driving.

That is, the gist of the present invention is that, in an engine cooling system of an internal combustion engine, two thermostats having different operating temperatures are installed at a cooling water engine outlet part so as to set independent cooling water circuits, and one of the circuits is equipped with two thermostats having different operating temperatures. An engine cooling water temperature control device for an internal combustion engine, characterized in that a cooling water circulation flow control valve is provided.

The present invention will be explained below with reference to the accompanying drawings.

The figure is an explanatory diagram of the operation of the engine cooling water temperature control device for an internal combustion engine according to the present invention.
A first thermostat 3 and a second thermostat 4 are installed at the outlet from the cooling water, forming two cooling water circuits sharing a radiator 5, a water pump 6 and a water bypass 7.

In addition, one of the circuits has a thermostat (in this example, 4
) and the radiator 5. A flow control valve 8 is provided between the radiator 5 and the radiator 5. A control valve 8 is provided in a circuit including the thermostat 4, with the higher opening temperature (for example, about 930 C) of the two thermostats designated as 3, and the lower one (for example, 8.0 C) as 4.

In an environment where the outside air temperature is low, the system water temperature is controlled at a high temperature (approximately 9yo) by closing the control valve 8, and in an environment where the outside air temperature is high, the system water temperature is controlled at a low temperature (approximately 8℃) by opening the valve. can be implemented. In other words, the controlled water temperature can be divided into winter and summer. Although the opening and closing settings of the flow control valve can be performed manually prior to engine operation, an electrical control method using a solenoid valve can be adopted.

An automatic control method based on cooling water temperature sensing can also be adopted.
This provides a smooth transition in the event that control valve switching is required due to thermostat failure. Since the present invention is constructed as described above, when the outside air temperature is low, the control valve is closed, so that the cooling water is sent to the radiator only through the high temperature thermostat after reaching the barrier temperature of the high temperature thermostat. The cooling water temperature is maintained at a high temperature because the
As the heater performance improves, the blade oil temperature also rises, reducing friction loss and improving fuel consumption.

When the outside temperature is low, the entire engine, including the radiator, is cooled by the cold outside air, so the cooling efficiency is good and the cooling performance is not insufficient. When the outside temperature is high, the control valve is open, so when the cooling water reaches the opening temperature of the low-temperature thermostat, it flows to the radiator via the low-temperature thermostat. When the valve temperature is reached, it also flows through the high temperature thermostat.

In general, a thermostat acts as a restrictor for the cooling water passage, but since both thermostats are installed in parallel, not only does it not act as a two-stage restriction at high temperatures, but it also restricts the flow rate to a larger amount than if a single thermostat were used. can be flushed out of the Rajee. When the outside temperature is high, the cooling efficiency of the entire engine, including the radiator, is reduced by the outside air, so if the cooling water temperature is not kept low by flowing it to the radiator from a relatively low temperature, the lubricating oil temperature will rise too much and the engine There is a risk that the lubricating effect of the sliding parts of the cooling water will decrease, but this problem can be prevented.Also, when the temperature of the cooling water becomes high and the flow rate through one thermostat is not sufficient, the flow rate through two thermostats is used. This has the effect of ensuring a sufficient flow rate and improving cooling performance.

[Brief explanation of drawings]

The accompanying drawing is an explanatory diagram of the operation of the engine cooling water temperature control device for an internal combustion engine according to the present invention, and the lower part of the drawing shows an embodiment of the same device in which flow control valves are provided in both circuits.

Claims (1)

[Claims] 1 In the engine cooling system of an internal combustion engine, a low-temperature thermostat and a high-temperature thermostat are installed at the cooling water engine outlet, and at least a part of the cooling water passage that communicates the engine and the radiator of the internal combustion engine is branched into two. do,
Two cooling water passages are formed in parallel, one cooling water passage is provided with the low-temperature thermostat and the control valve, the other cooling water passage is provided with the high-temperature thermostat, and the control valve is connected to the outside temperature. An engine cooling water temperature control device for an internal combustion engine, characterized in that a valve is opened when the temperature is high and closed when the temperature is low.