JP2707792B2 - Internal combustion engine cooling system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a cooling device for cooling an internal combustion engine such as an automobile driving engine.

(Prior art)

Generally, as shown in FIG. 5, a cooling device for an internal combustion engine for driving a vehicle includes an internal combustion engine 94, a heat exchanger 91 for cooling the cooling water of the internal combustion engine 94, and a high-temperature It comprises a first water channel 7 for leading cooling water to the heat exchanger 91 and a second water channel 8 for introducing cooling water cooled by the heat exchanger 91 to the internal combustion engine 94. Also,
A water pump 93 for circulating cooling water is provided in the middle of the second water conduit 8. The water pump 93 is an internal combustion engine.
94 rotating pulleys and belts, etc.
It rotates with the operation of 94.

Then, in cooling the internal combustion engine 94, cooling water is circulated between the internal combustion engine 94 and the heat exchanger (radiator) 91 by the water pump 93.

When the temperature of the cooling water is low, such as when the internal combustion engine 94 is started, the thermostat 92 is closed, and a bypass pipe 71 is used to prevent the cooling water from circulating through the heat exchanger 91. Let it.

On the other hand, when the cooling water temperature rises with the operation of the internal combustion engine 94 and cooling becomes necessary, the thermostat 92 is closed. Thereby, the cooling water circulates between the internal combustion engine 94 and the heat exchanger 91 and is cooled.

In the cooling device, usually, as shown in FIG. 5, the hot water passage 81 and the heater core 96 are arranged in parallel with the internal combustion engine 94.
Is provided. When the temperature of the cooling water increases due to the operation of the internal combustion engine 94, the vehicle interior is heated by the hot water flowing through the hot water passage 81 and the heater core 96. The hot water exiting the heater core 96 passes through the hot water channel 81, the second water channel 8, and the water pump 93, and enters the internal combustion engine 94 again.

[Problem to be solved]

In recent years, there has been a strong demand for improving the cooling performance of an automobile internal combustion engine. As one of the methods, there is a method of increasing the flow rate of cooling water circulating to a heat exchanger. Conventionally, as a means, a method has been proposed in which, in addition to the water pump 93, a sub water pump is additionally provided in the circulation path.

For example, in the internal combustion engine cooling apparatus disclosed in Japanese Patent Application Laid-Open No. 63-16122, a sub-water pump circuit is provided in parallel with the water pump 93 (not shown) in FIG. And also with this sub-water pump,
Cooling water is fed into the internal combustion engine. However, since the cooling water path inside the internal combustion engine originally has a high water flow resistance, the effect of installing the sub water pump is small, and an increase in the total circulation flow rate to the heat exchanger 91 can hardly be expected. .

The internal combustion engine cooling device disclosed in Japanese Utility Model Laid-Open Publication No. 63-190520 has a sub-water pump connected to the rear of the internal combustion engine in addition to the water pump 93 shown in FIG. , Connected in series (not shown). However, even in this case, when the internal combustion engine is operated at a high speed and the discharge flow rate of the water pump 93 increases, the sub-water pumps connected in series rather become flow resistance. Therefore, when the flow rate of the water pump 93 is high, a bypass is required for the sub-water pump,
A control valve such as a check valve is also required.

In addition, the space of the entire cooling device becomes large, and it is difficult to mount the cooling device in a narrow engine room. In addition, the cost increases. Further, although the total circulation flow to the heat exchanger increases with the series connection of the water pump 93 and the sub water pump, a large amount of cooling water is naturally circulated in the internal combustion engine. Therefore, when the internal combustion engine is rotating at a low speed, the cooling of the internal combustion engine is promoted too much, and the heat loss of cooling water increases. As a result, an adverse effect such as a decrease in the output of the internal combustion engine occurs.

Further, in the internal combustion engine cooling device disclosed in Japanese Patent Application Laid-Open No. 63-268912, an engine bypass is provided between the first water passage 7 and the second water passage 8 shown in FIG. In addition, a second thermostat different from the thermostat 92 is provided to adjust the flow rate. However, even in this method, only the water temperature of the internal combustion engine is controlled, and the circulation flow rate to the heat exchanger cannot be increased, and the cooling capacity of the heat exchanger cannot be improved accordingly.

The present invention has been made in view of the above-mentioned conventional problems, and can increase an amount of cooling water circulating to a heat exchanger without causing an increase in heat loss of cooling water of an internal combustion engine. It is intended to provide a device.

[Solutions to solve the problem]

The present invention provides a heat exchanger for cooling cooling water of an internal combustion engine, a first water conduit for leading cooling water flowing out of the internal combustion engine to a heat exchanger, and cooling by the heat exchanger. A second headrace for introducing cooling water into the internal combustion engine;
A main circulation unit for cooling water circulation provided in the middle of the second water conduit, a bypass water channel provided between the second water conduit and the first water conduit on a downstream side of the main circulation unit,
An internal combustion engine, comprising: a sub-circulation means provided in the bypass water passage; and a control device for detecting a cooling water temperature near a cooling water outlet of the internal combustion engine and controlling operation of the sub-circulation means. In the cooling device.

The most remarkable point in the present invention is that a main circulation means for circulating cooling water is interposed in the second water conduit,
A sub-circulation means is provided between the downstream side of the main circulation means and the first headrace, and the control device for controlling the sub-circulation means is provided.

That is, the sub-circulation means is connected in series with the main circulation means between the second water conduit and the first water passage, and is bypassed in parallel with the internal combustion engine on the downstream side of the main circulation means. They are connected.

The main circulation means is a main circulation means for circulating cooling water between the heat exchanger and the internal combustion engine. As the main circulating means, there is a water pump which rotates by utilizing a driving force of an internal combustion engine by belt hanging or the like as in the related art. There are also electric and hydraulic water pumps. Further, a dual water pump can be used to improve the discharge capacity of the water pump.

The sub-circulation means is for short-circuiting a part of the circulating cooling water discharged from the main circulation means directly to the first headrace. By controlling the sub-circulation means, the flow rate of the cooling water sent from the main circulation means to the internal combustion engine is adjusted, and the heat loss of the cooling water of the internal combustion engine is reduced. As such a sub-circulation means, there are water pumps of an electric type, a hydraulic type and the like. Further, the above-described dual water pump can also be used. There is also a water pump that uses the driving force of an internal combustion engine by a belt hook, an electromagnetic clutch, or the like.

Next, the control device is a control unit that detects the temperature of the cooling water at the outlet of the internal combustion engine by a temperature sensor and, when the temperature of the cooling water reaches a set temperature or higher, issues a signal for operating the sub-circulation means. That is, when the load on the internal combustion engine increases and the coolant temperature at the outlet of the internal combustion engine becomes higher than a predetermined set temperature, the sub-circulation means is operated. The set temperature is the operation start temperature of the sub-circulation means.

[Action]

In the present invention, when the internal combustion engine is started, the cooling water does not flow to the heat exchanger due to the operation of the thermostat as in the related art. When the temperature of the cooling water rises, the thermostat operates, the cooling water is circulated between the internal combustion engine and the heat exchanger, and the cooling water is cooled by the heat exchanger. At this time, the entire discharge flow rate of the main circulation means is introduced into the internal combustion engine.

Next, when the load on the internal combustion engine increases and the temperature of the cooling water at the outlet of the internal combustion engine further rises and reaches a set value or more, the temperature sensor of the control device detects this and activates the sub circulation means. . As a result, a part of the discharge flow rate of the main circulation means is directly discharged to the first water conduit by the sub circulation means, and the remaining cooling water is introduced into the internal combustion engine. Therefore, the flow rate of the cooling water flowing into the internal combustion engine decreases.

Since the flow rate of the cooling water into the internal combustion engine is small as described above, the internal combustion engine is not supercooled when the internal combustion engine is rotating at a low speed such as idling or traveling uphill. Therefore, the heat loss of the cooling water of the internal combustion engine does not increase, which contributes to the improvement of the output of the internal combustion engine.

Further, even during a high heat load operation, the characteristics of the main circulation means are improved by reducing the water flow resistance behind the main circulation means as compared with the conventional case. Therefore, there is no problem due to a decrease in the flow rate to the internal combustion engine.

Also, even when the internal combustion engine rotates at a high speed during high-speed operation and the main circulation means has a high flow rate, the flow resistance of the sub-circulation means is lower than that of the conventional art because the main flow path of the cooling water is the cooling water path in the internal combustion engine. It doesn't matter like technology. Also,
Therefore, it does not require a check valve and is inexpensive.

〔effect〕

Therefore, according to the present invention, it is possible to increase the cooling water circulation flow rate to the heat exchanger without causing an increase in the cooling water loss heat quantity of the internal combustion engine, and to provide an inexpensive internal combustion engine cooling device. be able to.

〔Example〕

First Embodiment An embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the internal combustion engine cooling device according to the present embodiment includes a first water passage 7 and a second water passage 8 connecting the heat exchanger 91 and the internal combustion engine 94, and a midway of the second water passage. The main circulation means 1 for circulating cooling water provided, and a bypass water passage 22 provided between the second water passage 8 and the first water passage 7 on the downstream side of the main circulation means 1 (on the side of the internal combustion engine 94). And a sub-circulation means 2 provided in the bypass water passage 22, and a control unit 3 as a control device for controlling the operation of the sub-circulation means.

Then, the bypass water channel 22 provided with the sub-circulation means is provided.
Is connected by a T-tube 221 in the second water conduit 8 between the main circulation means 1 and the internal combustion engine 94. The downstream side of the bypass channel 22 is connected to the first water channel 7 by a T-shaped pipe 222. In addition, sub circulation means 2
Has an electric motor 21 for driving. The above T-tube
Either of the 221 and 222 may have a three-way valve function.

Further, a temperature sensor 31 for detecting the temperature of the cooling water derived from the internal combustion engine 94 is provided near the outlet of the internal combustion engine 94 in the first water conduit 7. The temperature sensor 31
Are electrically connected to the control unit 3. The electric motor 21 of the sub-circulation means 2 is electrically connected to the control unit 3.
The main circulating means 1 is connected to a rotating pulley of the internal combustion engine 94 by a belt.

The rest is the same as the cooling device shown in FIG.

 Next, the operation and effect will be described.

First, when the internal combustion engine 94 is started, the thermostat 92 is closed, and the cooling water circulates between the internal combustion engine 94 and the short-circuit pipe 71 by the main circulating means 1 (hatched arrow in the figure), and the heat exchanger Does not flow to 91. Then, when the temperature of the cooling water increases as the operation of the internal combustion engine 94 continues (for example, 80 to 9).
0 ° C), the thermostat 92 opens, and the cooling water is supplied to the internal combustion engine 9
It circulates between 4 and the heat exchanger 91 (white arrow in the figure). Thereby, the cooling is cooled by the heat exchanger.

During the operation of the internal combustion engine, the main circulation means 1
All of the cooling water discharged from the first water passage is circulated to the heat exchanger 91 from the first water conduit 7 through the cooling water path inside the internal combustion engine 94. That is, the cooling water does not pass through the bypass water passage 22.

Next, when the load of the internal combustion engine 94 increases, the water temperature at the outlet of the internal combustion engine 94 increases. Therefore, when this temperature reaches a set value (for example, 90 ° C.) or more, the control unit 3 detects this by the temperature sensor 31 and drives the electric motor 21 of the sub-circulation means 2.

Therefore, a part of the amount of cooling water discharged from the main circulating means 1 is directly discharged to the first water channel 7 by the sub-circulating means 2 via the bypass water channel 22 (black arrow in FIG. 1). Therefore, the amount of cooling water introduced into the internal combustion engine 94 decreases.

More specifically, when the rotation speed of the internal combustion engine is low to medium rotation (during idling, uphill running, etc.), the circulation flow rate of the main circulating means 1 is also low to medium flow rate. Therefore, the cooling water flows in the cooling water path and the bypass water path 22 in the internal combustion engine 94 in parallel, and a larger flow rate flows to the heat exchanger 91 than in the case where only the main circulation means 1 is operated. However, a part of the discharge flow rate of the main circulation means 1 is directly discharged to the first headrace channel by the sub circulation means 2. Therefore, the internal combustion engine 94
The flow rate of cooling water introduced into the internal combustion engine is small and does not cause an increase in heat loss of cooling water of the internal combustion engine.

Therefore, the flow rate of the cooling water to the heat exchanger 91 increases, and the cooling performance improves. On the other hand, since the internal combustion engine is not supercooled, the output can be improved.

In the cooling water circulation, the cooling water passage inside the internal combustion engine has a larger flow resistance than the bypass water passage of the sub-circulation means, and thus has a function as a check valve. Therefore, it is not necessary to newly install a control valve such as a check valve.

Further, when the rotation speed of the internal combustion engine 94 becomes high due to high speed running of the automobile or the like, the main circulating means 1 also rotates at high speed. Therefore, the discharge flow rate of the main circulation unit 1 increases. At this time, the sub circulation means 2 serves as a downstream flow resistor. However, since the cooling water path in the internal combustion engine, which is the main circuit, performs a bypass function for the sub-circulation means 2, it is possible to prevent a reduction in the total circulation flow rate.
Of course, at this time, the operation of the sub-circulation means 2 may be stopped by the control unit 3 for power saving.

Next, when the temperature of the cooling water at the outlet of the internal combustion engine drops and becomes lower than the above set value, the control unit 3 stops driving the electric motor 21 of the sub-circulation means 2.

FIG. 2 shows a flowchart relating to the above operation. In the figure, "E / G" is "internal combustion engine"
And “sub W / P” indicates a “sub water pump” as sub circulation means.

That is, in the figure, when the load on the internal combustion engine increases in step (hereinafter abbreviated to 301) 301, the outlet water temperature of the internal combustion engine increases in 302. Then, at 303, the water temperature is
If it is detected at 31 and it is determined at 304 that the control unit 3 is at or above the set temperature, the sub-circulation means 2 is operated at 305. Therefore, the circulation flow rate to the heat exchanger increases (306).

When it is determined in 304 that the cooling water is below the set temperature, the detection of the water temperature is continued in 303.

FIG. 3 shows the relationship between the rotation speed NE of the internal combustion engine 94 and the cooling water circulation flow rate VR of the heat exchanger. The solid line A shows that the sub circulation means does not operate and only the main circulation means 1 operates. Is shown. Dotted line B is the main circulation means 1
And a case where the sub-circulation means 2 is operating.

As is known from the figure, when only the main circulation means 1 is used, the circulation flow rate of the heat exchanger increases in proportion to the rotation speed of the internal combustion engine as shown by the solid line A.

However, when the main circulating means 1 and the sub-circulating means 2 are operated, the circulating flow rate to the heat exchanger is increased even when the internal combustion engine is rotating at a low speed, and the heat exchange capacity of the heat exchanger can be effectively used. At this time, the flow rate of the cooling water introduced into the internal combustion engine decreases.

Second Embodiment As shown in FIG. 4, this embodiment is an example in which a thermostat 92 is interposed on the first headrace 7 side in the cooling device of the first embodiment.

 Others are the same as the first embodiment.

In this embodiment, the same effect as in the first embodiment can be obtained.

[Brief description of the drawings]

1 to 3 show a first embodiment, FIG. 1 is an overall explanatory view of a cooling system of an internal combustion engine, FIG. 2 is a flowchart showing a main part of operation of the cooling system, and FIG. FIG. 4 is a diagram showing the relationship between the cooling water flow rate of the heat exchanger and FIG. 4 is an explanatory diagram of a main part of the cooling device of the second embodiment, and FIG. 5 is an overall explanatory diagram of a conventional internal combustion engine cooling device. DESCRIPTION OF SYMBOLS 1 ... Main circulation means, 2 ... Sub circulation means, 21 ... Electric motor, 3 ... Control unit, 31 ... Temperature sensor, 7 ... First water passage, 8 ... Second water passage, 91 ... …Heat exchanger,
94 ... internal combustion engine, 96 ... heater core,

Claims (1)

(57) [Claims] 1. A heat exchanger for cooling cooling water of an internal combustion engine, a first water conduit for leading cooling water flowing out of the internal combustion engine to a heat exchanger, and a cooling water cooled by the heat exchanger. A second water conduit for introducing the cooling water into the internal combustion engine, a main circulation device for cooling water circulation provided in the middle of the second water conduit, and the second water conduit on the downstream side of the main circulation device. Operating the sub-circulation means by detecting a cooling water temperature near a cooling water outlet of the internal combustion engine by detecting a cooling water temperature near a cooling water outlet of the internal combustion engine. And a control device for controlling the temperature of the internal combustion engine.