JPH06257430A - Cooling system for engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption by reconciling the promotion of temperature-up and the restrain of overheating of lubricating oil in an engine having an oil cooler, etc., for performing heat exchange with cooling water. CONSTITUTION:This device is provided with a first cooling water path, which is set in low temperature and in which cooling water, supplied to a cylinder head 1 from a water pump 4, is returned to a water pump 4 via a radiator 7 or detouring around the radiator 7; and a second cooling water path, which is set in high temperature and in which cooling water supplied to a cylinder block 2 from the water pump 4, is returned to the water pump 4 via the radiator 7 or a heater 10 and detoured the radiator 7. Also an oil cooler 3 is arranged in a path, in which cooling water is returned from the cylinder head 1 while detouring the radiator 7. An electromagnetic valve 16 is arranged on the oil cooler 3 upstream of the path. Cooling water from the cylinder heat 1 side and that from the cylinder block 2 side are selectively introduced according to water temperature and an engine load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid cooling two-system engine cooling device for cooling a cylinder head and a cylinder block by separate paths.

[0002]

2. Description of the Related Art Conventionally, it has been practiced to construct a cooling liquid passage of an engine into two systems so as to cool a cylinder head more strongly than a cylinder block. JP-A-60
The cooling device disclosed in Japanese Patent Laid-Open No. 43119 is an example, and the cylinder head is cooled by a normal cooling water path including a radiator, while the cylinder block is cooled by circulating lubricating oil. Depending on the oil temperature, the oil circulation path is switched between heat exchange with the cooling water and heat exchange with the cooling water, thereby speeding up the oil temperature and promoting warm-up. After the machine, the temperature of the cooling water for cooling the cylinder head is made lower than the temperature of the lubricating oil for cooling the cylinder block, so that the cylinder head side is cooled more strongly.

Separately from the above, an engine equipped with an oil cooler for cooling the lubricating oil of the engine by heat exchange with the engine cooling water has been conventionally known.

[0004]

Generally, in an engine equipped with an oil cooler for cooling the lubricating oil by heat exchange with the engine cooling water as described above, the temperature of the cooling water rises slowly, so It takes time for the temperature to rise to the optimum temperature, which slows warm-up, and because the viscosity of the lubricating oil continues to be high for a long time, friction resistance inside the engine parts and the oil cooler increases and fuel consumption performance increases. There was a problem of getting worse.

In the case of an engine in which the cylinder head is cooled by cooling water and the cylinder block is cooled by lubricating oil, the above-mentioned JP-A-60-431 is used.
By providing a means for switching the circulating oil path between a path for exchanging heat with the cooling water and a path for not exchanging heat with the cooling water as in the apparatus described in Japanese Patent Publication No. 19 publication, in the warming-up process, the cylinder head side relatively The oil temperature is accelerated by heat exchange with high-temperature cooling water, and after warming up, the heat exchange with cooling water is stopped to raise the oil temperature above the water temperature, and when the oil temperature rises above a certain temperature. Then, heat exchange with the cooling water can be performed again to suppress overheating of the lubricating oil. But,
In an engine equipped with an oil cooler that exclusively cools each part of the engine including the cylinder block with cooling water, and also cools the lubricating oil with the cooling water, the means described in the above publication cannot be applied, and the oil temperature rise It was difficult to achieve both acceleration and suppression of overheating.

The same problem may occur not only in the oil cooler but also in other heat receiving members that exchange heat with the engine cooling water.

The present invention has been made in view of the above problems, and enhances fuel efficiency by promoting both the temperature rise of engine lubricating oil that exchanges heat with cooling water and the suppression of overheating. The purpose is to

[0008]

According to the present invention, the temperature of the cooling water supplied to the cylinder head side is set to the cylinder block side when the cooling water path is constituted by two systems so as to cool the cylinder head more strongly to the cylinder block. Focusing on setting the temperature lower than the temperature of the cooling water to the side, by utilizing this two-system type cooling device, promotion of temperature rise of the lubricating oil flowing through the heat receiving member such as the oil cooler and suppression of overheating It has been found that it is possible to achieve both.
Then, the configuration is such that the water temperature of the first cooling water path for supplying the cooling water to the cylinder head, the second cooling water path for supplying the cooling water to the cylinder block, and the water temperature of the first cooling water path after the engine is started. First water temperature adjusting means for raising the temperature to a first set temperature and maintaining the first set temperature, and a second setting for setting the water temperature of the second cooling water path after engine start is higher than the first set temperature. In a two-system engine cooling device comprising a second water temperature adjusting means for raising the temperature to a second set temperature and maintaining the second set temperature, the cooling water from the first cooling water passage after passing through the cylinder head via the switching means. And a heat receiving path for selectively introducing cooling water from the second cooling water path after passing through the cylinder block to the heat receiving member.

[0009] The switching means, when the water temperature of the first cooling water passage after passing through the cylinder head and the water temperature of the second cooling water passage after passing through the cylinder block are equal to or lower than a predetermined temperature, are from the first cooling water passage. Second cooling water is introduced into the heat receiving member, and when the water temperature of the first cooling water passage after passing through the cylinder head and the water temperature of the second cooling water passage after passing through the cylinder block exceed a predetermined temperature, the second cooling is performed. The cooling water from the water passage is operated according to the water temperature so as to be introduced into the heat receiving member, whereby the temperature rise of the lubricating oil or the like flowing through the heat receiving member can be promoted and fuel efficiency can be improved.

Further, the switching means is configured such that, when the water temperature of the first cooling water passage after passing through the cylinder head and the water temperature of the second cooling water passage after passing through the cylinder block are equal to or lower than a predetermined temperature, the first cooling water passage is cold. Cooling water from the first cooling water path after passing through the cylinder head and the water temperature of the second cooling water path after passing through the cylinder block exceed a predetermined temperature, and the engine load reaches a predetermined load. During the following warm low load, the cooling water from the second cooling water path is introduced into the heat receiving member, and the first cooling water is passed through the first head.
The cooling water from the first cooling water passage receives heat when the temperature of the cooling water passage and the water temperature of the second cooling water passage after passing through the cylinder block exceed a predetermined temperature and the engine load exceeds a predetermined load during a warm high load. It should be operated according to the water temperature and load so as to be introduced into the member, thereby realizing precise control that keeps the lubricating oil or the like at a high temperature while suppressing overheating of the lubricating oil or the like flowing through the heat receiving member. It is possible to improve fuel efficiency.

Here, the first water temperature adjusting means is, for example,
A thermostat that operates according to the radiator and the water temperature and switches the first cooling water path to a path that bypasses the radiator when the temperature is below the first set temperature, and switches to the path that passes through the radiator when the first set temperature is exceeded. Consists of a valve, etc. Further, the second water temperature adjusting means switches, for example, a radiator, an electric heater, and a second cooling water path to a path that bypasses the radiator and passes through the heater when the temperature is equal to or lower than the second set temperature. When the set temperature of 2 is exceeded, it is composed of another thermostat valve or the like that bypasses the heater and switches to a path that passes through the radiator.

[0012]

The first water temperature adjusting means is suitable for cooling the cylinder head because the water temperature of the first cooling water passage for supplying the cooling water to the cylinder head after the engine is started is received by the engine as the warming-up process proceeds. To the first set temperature by suppressing further increase in the water temperature. In addition, the second water temperature adjusting means receives the water temperature of the second cooling water path for supplying the cooling water to the cylinder block after the engine is started, by the heat received from the engine accompanying the warming-up process, at a temperature higher than the first set temperature. Then, the temperature is raised to the second set temperature suitable for cooling the cylinder block, and further increase of the water temperature is suppressed to maintain the second set temperature. At this time, the cooling water in the first cooling water path receives heat from the cylinder head, which is hotter than the cylinder block, so that the water temperature rises relatively quickly,
It stabilizes at the first set temperature on the low temperature side. In contrast,
The water temperature rises relatively gently by receiving heat from the cylinder block whose temperature is not higher than that of the second cooling water passage cylinder head, but is stabilized at the second set temperature on the high temperature side by the second water temperature adjusting means.

The heat receiving path for introducing the cooling water to the heat receiving member such as an oil cooler is provided from a path for introducing the cooling water from the first cooling path after passing through the cylinder head and a second cooling water path after passing through the cylinder block. It is possible to switch to the path for introducing the cooling water, which makes it possible to adjust the rate of temperature rise of the lubricating oil or the like flowing through the heat receiving member and suppress overheating. When the switching means operates according to the water temperature,
By introducing the cooling water from the first cooling water passage, which has a rapid temperature rise during cold, to the heat receiving member, the temperature rise of the lubricating oil and the like flowing through the heat receiving member is promoted, and at the time of warming, the temperature is stable at a high temperature. (2) By introducing the cooling water from the cooling water path to the heat receiving member, the lubricating oil and the like are kept at a high temperature.
Further, when the switching means operates in accordance with the water temperature and the load, the cooling water from the first cooling water path, which has a rapid temperature rise during cold, is introduced into the heat receiving member, so that the temperature rise of the lubricating oil or the like is promoted. The second, which is stable at high temperature when the load is warm and low
Lubricating oil is kept at a high temperature by introducing cooling water from the cooling water path to the heat receiving member, and cooling water from the first cooling water path that is stable at low temperature is introduced to the heat receiving path during warm high load. As a result, overheating of the lubricating oil or the like flowing through the heat receiving member is suppressed. Especially in this case, since the high-temperature cooling water is introduced from the second cooling water path only when the load is low and there is no fear of overheating even during warming, it is possible to increase the set temperature on the cylinder block side. It is possible to further increase the temperature setting of lubricating oil and the like, and to realize further improvement in fuel consumption.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of an engine cooling device according to an embodiment of the present invention. In the figure, 1 indicates an engine cylinder head, and 2 indicates the same cylinder block. Further, 3 indicates an oil cooler for cooling the engine lubricating oil.

In the engine cooling apparatus of this embodiment, the first conduit 5 connecting the discharge port of the water pump 4 and the cooling water passage in the cylinder block 2 and the water branched from the first conduit 5 are provided. The discharge port of the pump 4 is the cylinder head 1
A second conduit 6 connected to a cooling water passage inside the cylinder head, a third conduit 8 connecting an outlet of the cooling water passage inside the cylinder head 1 to a suction port of the water pump 4 via a radiator 7, and a cylinder block 2 Inside the cooling water passage, the radiator 7
A fourth conduit 9 connecting upstream to the third conduit 8
And a fifth conduit 11 that branches from the fourth conduit 9 and connects the discharge port of the cylinder block 2 to the third conduit 8 downstream of the radiator 7 via an electric heater 10.
A first thermostat valve 12 arranged at a connection portion between the fifth conduit 11 and the third conduit 8 and a first thermostat valve 12 arranged at a branch portion between the fifth conduit 11 and the fourth conduit 9. Two
Of the thermostat valve 13 of the third conduit 8 and the fourth conduit 9 of the third conduit 8 are branched from the upstream side, pass through the oil cooler 3, bypass the radiator 7 and the first thermostat valve 12, and are connected to the water pump. A sixth conduit 14 which joins the third conduit 8 again before the suction port 4;
A seventh conduit 15 branching from the second thermostat valve 13 upstream of the fifth conduit 11 and connecting to the sixth conduit 14 upstream of the oil cooler 3;
An electromagnetic valve 16 is provided at a connection portion between the conduit 15 and the sixth conduit 14.

The first thermostat valve 12 is
It operates at a first set temperature (A in FIG. 2) on a relatively low temperature side, and below the set temperature, the conduction from the upstream side of the third conduit 8 is cut off and the fifth conduit 11 is opened. It is connected to the downstream side of the third conduit 8, and when the set temperature is exceeded, the fifth conduit
The third conduit 8 itself also conducts the upstream side and the downstream side while keeping the conduit 11 and the third conduit 8 communicating with each other. In addition, the second
The thermostat valve 13 operates at a second set temperature (B in FIG. 2) that is higher than the first set temperature, and at the set temperature or lower, the thermostat valve 13 is connected to the downstream side of the fourth conduit 9. The conduction is cut off so that the upstream side of the fourth conduit 9 is communicated with the fifth conduit 11, and when the set temperature is exceeded, the communication with the fifth conduit 11 is cut off and the upstream side of the fourth conduit is connected. Conducts electrical connection with the downstream side. Further, the solenoid valve 16 is controlled according to the water temperature and the load of the engine, and when it is cold, the communication with the seventh conduit 15 is cut off and the sixth conduit 1 is cut off.
4 is electrically connected to the upstream side and the downstream side, and when the engine load is a low load equal to or lower than a predetermined load at the time of warming, the sixth conduit 14 is disconnected from the upstream side so that the seventh conduit 15 is connected to the sixth conduit 15. The sixth conduit 14 is connected to the downstream side of the sixth conduit 14 by cutting off the communication with the seventh conduit 15 again when the engine load is high and the load exceeds a predetermined load during warm time. Let

In the above engine cooling device, the water pump 4 is connected to the cooling water passage in the cylinder head 1 via the first conduit 5 and the second conduit 6, and the third conduit 8 or the radiator via the radiator 7 is connected. The path that returns to the water pump 4 via the sixth conduit 14 that bypasses 7 constitutes the first cooling water path that supplies the cooling water to the cylinder head 1, and the path from the water pump 4 to the first conduit 5 is formed. After that, connect to the cooling water passage in the cylinder block 2,
A path for returning to the water pump 4 from the fourth conduit 9 via the third conduit 8 via the radiator 7 or the fifth conduit 11 via the heater 10 is a second cooling water path for supplying cooling water to the cylinder block 2. Make up.

FIG. 2 shows the first cooling water path () on the cylinder head 1 side and the second cooling water path on the cylinder block 2 side.
3 shows the water temperature transition of the cooling water path () after the engine is started, and FIGS. 3 to 6 show the operating state of the device of this embodiment.

As shown in FIG. 2, the water temperature in the first cooling water path () rises relatively quickly due to the large amount of heat received from the cylinder head 1. And this first
When the water temperature exceeds the first set temperature (A), the cooling water path () is switched to a path passing through the radiator 7 as described later, and the water temperature is maintained at the set temperature (A). On the other hand, the second cooling water path () receives heat from the cylinder block 2 whose temperature is lower than that of the cylinder head 1, so that the water temperature rises relatively slowly. And this second
When the water temperature exceeds the second set temperature (B), which is higher than the first set temperature (A), the cooling water path () becomes a path that bypasses the heater 10 and passes through the radiator 7 as described later. The water temperature is switched to the set temperature (B). Then, as will be described later, when the water temperature of the second cooling water passage () reaches the water temperature level of the first cooling water passage () during the cold state, after the passage of the cylinder head 1 of the first cooling water passage (). When the cooling water is guided to the oil cooler 3 and the water temperature of the second cooling water path () exceeds the water temperature level of the first cooling water path (), the cooling water path to the oil cooler 3 is operated by the engine. The cooling water is switched according to the load, the cooling water after passing through the cylinder head 1 of the first cooling water path () is guided to the oil cooler 3 when the load is low, and the second cooling water is supplied when the load is high.
The cooling water after passing through the cylinder block 2 of the cooling water path () is guided to the oil cooler 3.

FIG. 3 shows the flow of the cooling water in the cold state until the water temperature reaches the first set temperature (A) (a in FIG. 2). At this time, the solenoid valve 16 bypasses the radiator 7
And the fifth thermostat valve 12 blocks the conduction of the third conduit 8 via the radiator 7 and the fifth conduit 11 via the heater 10.
Is connected to the downstream side of the third conduit 8, and the second thermostat valve 13 cuts off the conduction of the fourth conduit 9 bypassing the heater 10 so that the upstream side of the fourth conduit 9 is connected to the heater 10. By communicating with the fifth conduit 11 via
As shown in the figure, the first cooling water path on the cylinder head 1 side is a path that bypasses the radiator 7, and the second cooling water path on the cylinder block 2 side is a path that bypasses the radiator 7 through the heater 10. Become. Further, the cooling water in the first cooling water passage after passing through the cylinder head 1 is introduced into the oil cooler 3.

FIG. 4 shows the flow of the cooling water after the water temperature reaches the first set temperature (A) in the cold state (b in FIG. 2).
At this time, the first thermostat valve 12 makes the third conduit 8 passing through the radiator 7 electrically conductive, the fifth conduit 11 passing through the heater 10 communicates with the downstream side of the third conduit 8, and the solenoid valve 16 becomes The sixth conduit 14 which also bypasses the radiator 7 is electrically connected to the upstream side and the downstream side, and the second thermostat valve 13 also interrupts the conduction of the fourth conduit 9 which also bypasses the heater 10 to close the fourth conduit. The upstream side of 9 is connected to the fifth conduit 11 via the heater 10. As a result, as shown in the figure, the first cooling water path on the cylinder head 1 side becomes a path passing through the radiator 7, and the second cooling water path on the cylinder block 2 side passes through the heater 10 and bypasses the radiator 7. Become a route. Further, the cooling water in the first cooling water passage after passing through the cylinder head 1 is still introduced into the oil cooler 3.

FIG. 5 shows a period during which the water temperature reaches the second set temperature (B) during warm time (c in FIG. 2), and
The flow of cooling water when the engine load is a low load below a predetermined load is shown. At this time, the first thermostat valve 12 conducts the third conduit 8 via the radiator 7 and the fifth conduit 11 via the heater 10 to the third conduit 8.
The solenoid valve 16 blocks the conduction from the upstream side of the sixth conduit 14 that bypasses the radiator 7, and connects the seventh conduit 15 on the cylinder block 2 side to the oil cooler 3 side. The second thermostat valve 13 bypasses the heater 10 and cuts off the conduction of the fourth conduit 9 communicating with the radiator 7 side so that the upstream side of the fourth conduit 9 communicates with the fifth conduit 11 passing through the heater 10. . As a result, as shown in the figure, the first cooling water path on the cylinder head 1 side becomes a path passing through the radiator 7, and the second cooling water path on the cylinder block 2 side passes through the heater 10 and bypasses the radiator 7. The cooling water in the second cooling water path after passing through the cylinder block 2 is introduced into the oil cooler 3.

FIG. 6 shows the cooling water after the water temperature reaches the second set temperature (B) during warm time (d in FIG. 2) and when the engine load exceeds a predetermined load at high load. Shows the flow of. At this time, the first thermostat valve 12 conducts the third conduit 8 passing through the radiator 7, the solenoid valve 16 conducts the sixth conduit 14 bypassing the radiator 7, and the second thermostat valve 13 operates the heater 10. And the fourth conduit 9 that bypasses to the radiator 7 side is conducted. As a result, as shown in the figure, the first cooling water path on the cylinder head 1 side becomes a path passing through the radiator 7, and the second cooling water path on the cylinder block 2 side also becomes a path passing through the radiator 7. Further, cooling water is introduced into the oil cooler 3 from the first cooling water path set at a low temperature.

FIG. 7 shows the period until the water temperature reaches the second set temperature (B) during warm time (c in FIG. 2), and
Fig. 7 shows the flow of cooling water when the engine load exceeds a predetermined load and is high. At this time, the first thermostat valve 12
Makes the third conduit 8 passing through the radiator 7 conductive, and makes the fifth conduit 11 passing through the heater 10 communicate with the downstream side of the third conduit 8, and the solenoid valve 16 makes the sixth conduit bypassing the radiator 7. 14, the second thermostat valve 13 bypasses the heater 10 and cuts off the conduction of the fourth conduit 9 that communicates with the radiator 7, and the upstream side of the fourth conduit 9 passes through the heater 10. It communicates with the conduit 11. As a result, as shown in the figure, the first cooling water path on the cylinder head 1 side becomes a path passing through the radiator 7, and the second cooling water path on the cylinder block 2 side passes through the heater 10 and bypasses the radiator 7. The cooling water is introduced into the oil cooler 3 from the first cooling water path set at a low temperature.

FIG. 8 shows the cooling water after the water temperature reaches the second set temperature (B) (d in FIG. 2) during warm time and when the engine load is under a predetermined load or a low load. Show the flow. At this time, the first thermostat valve 12 brings the third conduit 8 through the radiator 7 into conduction, and the solenoid valve 16 shuts off the conduction of the sixth conduit 14 bypassing the radiator 7 from the upstream side. Side seventh conduit 15
Is communicated with the oil cooler 3 side, and the second thermostat valve 13 bypasses the heater 10 and conducts the fourth conduit 9 leading to the radiator 7 side. As a result, as shown in the figure, the first cooling water path on the cylinder head 1 side becomes a path passing through the radiator 7, and the second cooling water path on the cylinder block 2 side also becomes a path passing through the radiator 7 to the oil cooler 3. The cooling water in the second cooling water passage after passing through the cylinder block 2 is introduced.

In the above embodiment, the solenoid valve is used to switch the cooling water introduction path to the oil cooler, but a thermostat valve may be used instead of the solenoid valve. However, when a thermostat valve is used, switching cannot be performed due to engine load. Therefore, the set temperature of the cooling water on the cylinder block side may have to be lowered somewhat so that the lubricating oil will not be overheated at the time of high load.

In the above embodiment, the oil cooler for cooling the lubricating oil with the cooling water is provided. However, the present invention is not limited to the oil cooler, and heat exchange with the engine cooling water is performed. It is also applicable to the heat receiving member of.

[0029]

Since the present invention is constructed as described above, it promotes the temperature rise of the lubricating oil flowing through the heat receiving member such as the oil cooler that exchanges heat with the cooling water and suppresses overheating. It is possible to suppress the increase in frictional resistance due to the viscosity of the lubricating oil and improve the fuel efficiency.

Further, the switching of the heat receiving path for introducing the cooling water to the heat receiving member such as an oil cooler can be realized by a simple structure such as a thermostat valve which operates simply according to the water temperature, and the water temperature can be changed by using an electromagnetic valve or the like. And realize precise switching according to the engine load, and raise the set temperature on the cylinder block side by introducing cooling water from the cylinder block side that is set to a high temperature only when the load is low and there is no concern of overheating. It is possible to achieve high oil temperature and further improve fuel efficiency.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention

FIG. 2 is a characteristic diagram of water temperature transition in one embodiment of the present invention.

FIG. 3 is an operation state explanatory diagram of an embodiment of the present invention (No. 1)

FIG. 4 is an operation state explanatory diagram of the embodiment of the present invention (No. 2)

FIG. 5 is an explanatory diagram of the operating state of the embodiment of the present invention (No. 3).

FIG. 6 is an explanatory view of the operating state of the embodiment of the present invention (No. 4).

FIG. 7 is an explanatory view of the operating state of the embodiment of the present invention (No. 5).

FIG. 8 is an operational state explanatory diagram (6) of the embodiment of the present invention.

[Explanation of symbols]

 1 Cylinder Head 2 Cylinder Block 3 Oil Cooler 4 Water Pump 5 1st Conduit 6 2nd Conduit 7 Radiator 8 3rd Conduit 9 4th Conduit 10 Heater 11 5th Conduit 12 1st Thermostat Valve 13 2nd Thermostat valve 14 sixth conduit 15 seventh conduit 16 solenoid valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F01M 5/00 M 7443-3G

Claims (3)

[Claims] 1. A first supply of cooling water to a cylinder head
Cooling water path, a second cooling water path for supplying cooling water to the cylinder block, and the water temperature of the first cooling water path after engine start up to a first set temperature to reach the first set temperature. The first water temperature adjusting means for holding and the water temperature of the second cooling water path after engine start up to a second set temperature higher than the first set temperature and held at the second set temperature. In a two-system engine cooling device including a second water temperature adjusting means, cooling water from the first cooling water passage after passing through a cylinder head and second cooling after passing through a cylinder block via a switching means. An engine cooling device comprising a heat receiving path for selectively introducing cooling water from a water path to a heat receiving member. 2. The switching means is configured such that when the water temperature of the first cooling water passage after passing through a cylinder head and the water temperature of the second cooling water passage after passing through a cylinder block are equal to or lower than a predetermined temperature, the first means is provided. The cooling water from the cooling water path is introduced into the heat receiving member, and the water temperature of the first cooling water path after passing through the cylinder head and the second temperature after passing through the cylinder block.
2. The engine according to claim 1, wherein when the water temperature of the cooling water passage exceeds the predetermined temperature, the cooling water from the second cooling water passage is operated according to the water temperature so as to be introduced into the heat receiving member. Cooling system. 3. The switching means is configured such that when the water temperature of the first cooling water passage after passing a cylinder head and the water temperature of the second cooling water passage after passing a cylinder block are equal to or lower than a predetermined temperature, the first means is provided. The cooling water from the cooling water path is introduced into the heat receiving member, and the water temperature of the first cooling water path after passing through the cylinder head and the second temperature after passing through the cylinder block.
When the water temperature of the cooling water passage exceeds the predetermined temperature and the engine load is a warm low load equal to or less than the predetermined load, the cooling water from the second cooling water passage is introduced into the heat receiving member, and the cooling water passes through the cylinder head. When the water temperature of the subsequent first cooling water passage and the water temperature of the second cooling water passage after passing through the cylinder block exceed the predetermined temperature and the engine load exceeds the predetermined load during warm high load, the first cooling water The engine cooling device according to claim 1, wherein the cooling device operates according to a water temperature and a load so as to introduce the cooling water from the path to the heat receiving member.