JP2007291927A - Engine cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cooling system capable of quickly raising temperature of lubrication oil in an engine cold state with a simple construction, without deteriorating engine cooling performance. <P>SOLUTION: The engine cooling system comprises a water pump 1 for pressure-feeding cooling water into an engine, a radiator passage 2 for leading the cooling water flowed through the engine to the water pump via a radiator 10, a bypass passage 4 for leading the cooling water flowed through the engine to the water pump, a heat exchanger passage 6 for leading the cooling water flowed through the engine to the water pump via a heat exchanger 11 which exchanges heat between the lubrication oil supplied to the engine and the cooling water, and a wax type thermostat 3 for opening and closing the radiator passage. The engine cooling system further comprises a relief valve 5 for opening and closing the bypass passage according to pressure of the cooling water in the bypass passage and a thermostat passage 8 for leading a part of the cooling water in the bypass passage to a temperature sensing portion of the thermostat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling system for an engine, and more particularly to adjustment of oil temperature of lubricating oil.

  In a water-cooled engine, when the temperature of the cooling water flowing through the engine reaches a predetermined temperature, the cooling water is guided to the radiator. When the temperature does not reach the predetermined temperature, the cooling water is returned to the water pump through the bypass passage without passing through the radiator. Water temperature is managed. The return path of the cooling water to the water pump is generally switched by a wax type thermostat. This thermostat incorporates a wax that expands and contracts due to temperature changes, and opens and closes the valve by the expansion and contraction of the wax. The thermostat is opened and closed according to the temperature of the cooling water by flowing the cooling water that has circulated through the engine to the temperature sensing part that contains the wax, and the cooling water that has generally passed through the bypass passage is flowed to the temperature sensing part. .

  On the other hand, the temperature of the engine cooling water and the lubricating oil are generally adjusted to each other via a heat exchanger (oil cooler or oil warmer), and the cooling water does not contain the lubricating oil when the engine is cold, such as during warm-up operation. It functions as a medium for raising the temperature early. Since the viscosity of the lubricating oil decreases as the oil temperature rises, the early temperature rise of the lubricating oil reduces the frictional resistance of the sliding parts to be lubricated at an early stage and contributes to improving the fuel efficiency of the automobile. In other words, by raising the temperature of the coolant early when the engine is cold, the temperature of the lubricating oil is raised quickly, and the fuel efficiency of the vehicle is improved.

  In Patent Document 1, the cooling water passage to the oil cooler is switched, and during warm-up operation, the engine is circulated and heated, and the cooling water is supplied to the oil cooler to promote the temperature rise of the lubricating oil. Later, an apparatus is disclosed in which cooling water before flowing through the engine is supplied to an oil cooler to suppress the temperature rise of the lubricating oil.

JP 2001-271644 A

  However, the apparatus of Patent Document 1 requires a plurality of three-way valves and electronic control thereof. Therefore, the engine cooling system is complicated and expensive.

  An object of the present invention is to provide an engine cooling device that can increase the temperature of lubricating oil early when the engine is cold, with a simpler configuration, without impairing the cooling performance of the engine.

  According to the present invention, the water pump that pumps the cooling water into the engine, the radiator passage that guides the cooling water that has circulated through the engine to the water pump via the radiator, and the cooling water that has circulated through the engine A bypass passage that leads to the water pump, and a heat exchanger that leads the cooling water flowing through the engine to the water pump via a heat exchanger that performs heat exchange between the lubricating oil supplied to the engine and the cooling water. An engine cooling device comprising: a passage; and a wax-type thermostat that opens and closes the radiator passage. A relief valve that opens and closes the bypass passage according to the pressure of cooling water in the bypass passage; and the bypass passage And a thermostat passage for guiding a part of the cooling water inside the thermostat to the temperature sensing part of the thermostat. Cooling system for an engine is provided.

  In the engine cooling device of the present invention, when the temperature of the cooling water is low, such as when the engine is cold, the cooling water does not flow to the radiator, and the temperature is increased. Further, the relief valve works to close the bypass passage when the pressure of the cooling water is low, such as when the engine is cold, and increase the flow rate of the cooling water flowing to the heat exchanger. Thereby, early temperature rise of lubricating oil can be aimed at.

  Further, when the pressure of the cooling water rises while the thermostat is closed, the bypass passage is opened by the action of the reel valve, thereby preventing the water flow resistance of the cooling water from increasing. By providing the thermostat passage, when the cooling water reaches a predetermined temperature, the thermostat is opened, the cooling water flows to the radiator, and the temperature rise of the cooling water and the lubricating oil is suppressed. Therefore, the cooling performance of the engine is maintained. Furthermore, the above-described effects can be obtained with a simple configuration in which the relief valve and the thermostat passage are added as compared with the conventional cooling device.

  Therefore, it is possible to quickly raise the temperature of the lubricating oil when the engine is cold with a simpler configuration without impairing the cooling performance of the engine.

  In the present invention, a cooling water reflux chamber is formed in the engine and communicates with an outlet of the heat exchanger passage and the water pump, and the reflux chamber has a housing portion for the thermostat. A configuration may be adopted in which the outlet of the heat exchanger passage is disposed closer to the water pump than the temperature sensing portion of the thermostat. According to this configuration, the cooling water flowing through the heat exchanger passage does not necessarily flow to the temperature sensing portion of the thermostat. However, in the present invention, by providing the thermostat passage, the feeling of the thermostat is provided. Cooling water flow to the warm zone is ensured. That is, the outlet of the heat exchanger passage can be disposed closer to the water pump than the temperature sensing part of the thermostat without considering the cooling water flow to the temperature sensing part, and the degree of freedom in design is improved. To do.

  Further, in the present invention, an outlet of the bypass passage communicates with the reflux chamber, the relief valve is disposed on a movable shaft of the thermostat that is movable by expansion / contraction of wax of the thermostat, and A valve body for releasably closing the outlet of the bypass passage, wherein the thermostat passage leaks the cooling water in the bypass passage from the outlet of the bypass passage closed by the valve body to the temperature sensing portion; A configuration that is a passage can be employed. According to this structure, the said thermostat and the said relief valve are unitized, and assembly | attachment property can be improved. In addition, by configuring the thermostat passage as described above, cooling water can be supplied from the bypass passage to the temperature sensing portion of the thermostat at the shortest distance.

  Moreover, in this invention, the structure currently formed in the said valve body can be employ | adopted for the said channel | path for thermostats. According to this configuration, the thermostat passage can be formed without processing the engine wall, and further, the assembly performance is improved by forming the thermostat passage in the valve body. Can do.

  In this case, it is possible to adopt a configuration in which the thermostat passage is a plurality of holes formed in the valve body at an equal pitch on a concentric circle with the movable shaft. According to this configuration, it is possible to avoid the situation where the thermostat passage is blocked and the cooling water is not supplied to the temperature sensing portion of the thermostat, and the cooling water can be more reliably fed to the temperature sensing portion.

  In the present invention, the thermostat passage may be a notch formed in an outlet end surface of the bypass passage that contacts the valve body. According to this configuration, the thermostat passage can be formed with a minimum of processing.

  Further, in the present invention, the heat exchanger passage has a structure in which an outlet thereof is formed on the upper wall of the reflux chamber and has a portion extending upward from the outlet and penetrating the wall portion of the engine. Can do. According to this configuration, it is possible to improve the workability of the wall portion of the engine required for disposing the heat exchanger passage.

  Moreover, in this invention, the structure provided with the channel | path for heaters which guides the cooling water which distribute | circulated the inside of the said engine to the said water pump via a heater is employable. According to this configuration, when the pressure of the cooling water is low, such as when the engine is cold, the bypass passage is closed, and the flow rate of the cooling water flowing to the heater together with the heat exchanger is increased. Early warming can be achieved.

  In the present invention, there is provided a heater passage for guiding the cooling water flowing through the engine to the water pump via a heater, and an outlet of the heater passage communicates with the reflux chamber, and the thermostat The structure arrange | positioned rather than the said temperature sensing part to the said water pump side is employable. While aiming at an early warming in the cabin, it is possible to prevent the cooling water whose temperature has been lowered by the heat exchange by the heater from flowing into the temperature sensing part of the thermostat.

  Further, in the present invention, it is possible to adopt a configuration in which the bypass passage is formed in the wall portion of the engine and has a portion parallel to and adjacent to the passage of the lubricating oil. According to this configuration, in addition to the heat exchanger, heat exchange between the cooling water and the lubricating oil between the passages can be achieved, and early temperature rise of the lubricating oil can be promoted when the engine is cold.

  As described above, according to the present invention, it is possible to provide an engine cooling device that can increase the temperature of the lubricating oil early when the engine is cold, with a simpler configuration, without impairing the cooling performance of the engine.

  FIG. 1 is a block diagram of an engine cooling apparatus A according to an embodiment of the present invention. The cooling device A includes a water pump 1 that cyclically pumps cooling water into the engine 100. The water pump 1 is connected to the crankshaft of the engine 100 via a power transmission mechanism, and operates by rotation of the crankshaft. Therefore, the flow rate of the cooling water pumped by the water pump 1 at the time of high rotation when the engine 100 becomes high temperature increases the cooling performance of the engine 100.

  Cooling water pumped by the water pump 1 passes through the engine 100, such as a water jacket 100a in the cylinder block and a cooling water channel 100b in the cylinder head, and cools a portion to be cooled in the engine 100. The cooling device A includes a radiator passage 2 that guides cooling water flowing through the engine 100 to the water pump 1 via the radiator 10. The radiator 10 is a device for exchanging heat between the traveling wind of the automobile and the cooling water to cool the cooling water.

  A wax-type thermostat 3 for opening and closing the radiator passage 2 is disposed at the outlet of the radiator passage 2. When the thermostat 3 is opened, the cooling water in the radiator passage 2 flows into the water pump 1 through the reflux chamber 20 formed in the engine 100. When the thermostat 3 is closed, the cooling water in the radiator passage 2 is blocked by the thermostat 3 and does not flow into the water pump 1.

  The cooling device A includes a bypass passage 4 that guides cooling water flowing through the engine 100 to the water pump 1. In the case of this embodiment, the bypass passage 4 is formed inside the engine 100, but a part thereof may be formed by piping outside the engine 100. A relief valve 5 is disposed at the outlet of the bypass passage 4. The relief valve 5 opens and closes the bypass passage 4 according to the pressure of the cooling water in the bypass passage 4. More specifically, the opening and closing is performed by a differential pressure between the pressure of the cooling water in the bypass passage 4 and the pressure of the cooling water in the reflux chamber 20.

  When the relief valve 5 is opened, the cooling water in the bypass passage 4 flows into the water pump 1 through the reflux chamber 20. When the relief valve 5 is closed, the cooling water in the bypass passage 4 does not flow into the water pump 1. However, a small amount of cooling water flows into the water pump 1 through a thermostat passage 5 described later. The relief valve 5 is set to open when the engine 100 is at a high speed and the coolant pressure becomes high when the thermostat 3 is closed. Accordingly, the relief valve 5 is in a closed state when the rotational speed of the engine 100 is low and the coolant temperature is low, such as during warm-up operation.

  The cooling device A includes a heat exchanger passage 6 that guides the cooling water flowing through the engine 100 to the water pump 1 through a heat exchanger 11 that performs heat exchange between the lubricating oil supplied to the engine 100 and the cooling water. In the present embodiment, a throttle 12 is also disposed in the middle of the heat exchanger passage 6. The heat exchanger 11 exchanges heat between the lubricating oil that passes through the oil gallery 100 c and the like and is circulated to the engine 100 and the cooling water that flows through the heat exchanger passage 6. The throttle 12 is for adjusting the intake air amount of the engine 100, and the warmed cooling water flowing through the heat exchanger passage 6 is used for preventing freezing and for adjusting the automatic opening when idling.

  The cooling device A includes a heater passage 7 that guides cooling water flowing through the engine 100 to the water pump 1 through the heater 13. The heater 13 performs heat exchange between warm cooling water flowing through the heater passage 7 and air, and supplies warm air to the passenger compartment of the automobile to perform air conditioning. A control valve 14 may be provided in the heater passage 7 as indicated by a broken line. The control valve 14 functions as a regulating means that regulates the flow of the cooling water in the heater passage 7. Its operation will be described later.

  The cooling device A includes a thermostat passage 8 that guides a part of the cooling water in the bypass passage 4 to the temperature sensing portion of the thermostat 3. In the present embodiment, since the bypass passage 4 is closed by the relief valve 5, it is necessary to supply the cooling water circulated through the engine 100 to the temperature sensing portion in order to open and close the thermostat 3 at the cooling water temperature. Therefore, in the present embodiment, a part of the cooling water in the bypass passage 4 circulated in the engine 100 is guided to the thermostat 3 by the thermostat passage 8.

  Next, the operation of the cooling device A will be described with reference to FIGS. FIG. 2 is an explanatory diagram of the operation of the cooling device A during the warm-up operation (when the engine 100 is started and at a low rotation). During the warm-up operation, the temperature of the cooling water is low, and the thermostat 3 is in a closed state. Accordingly, the cooling water does not flow through the radiator passage 2. Further, when the engine 100 is running at a low speed, the relief valve 5 is also closed. Therefore, the cooling water flowing through the engine 100 hardly flows into the bypass passage 4, and a small amount of cooling water flowing through the thermostat passage 8 flows through the bypass passage 4. Accordingly, the cooling water flowing through the engine 100 flows through the heat exchanger passage 6 and the heater passage 7 and returns to the water pump 1.

  Next, FIG. 3 is an operation explanatory diagram of the cooling device A after completion of the warm-up operation. When the temperature of the cooling water reaches the valve opening start temperature (about 80 degrees) of the thermostat 3, the temperature of the cooling water flowing from the thermostat passage 8 to the temperature sensing part of the thermostat 3 acts on the temperature sensing part, and the thermostat 3 is opened. It becomes a valve state. Accordingly, the cooling water flowing through the engine 100 flows through the radiator passage 2, the heat exchanger passage 6, and the heater passage 7 and returns to the water pump 1. When the cooling water passes through the radiator 10, an increase in the cooling water temperature is suppressed. When the thermostat 3 is opened, the difference in the coolant pressure between the recirculation chamber 20 and the bypass passage 4 is reduced, so that the relief valve 5 does not open regardless of the rotational speed of the engine 100. Therefore, the cooling water flowing through the engine 100 hardly flows into the bypass passage 4, and a small amount of cooling water flowing through the thermostat passage 8 flows through the bypass passage 4.

  Next, FIG. 4 is an explanatory view of the operation of the cooling device A when the engine 100 is at a high speed during the warm-up operation. In this case, since the cooling water is low in temperature, the thermostat 3 is in a closed state, and the cooling water does not flow into the radiator passage 2. When the engine 100 rotates at a high speed, the flow rate of the cooling water discharged from the water pump 1 increases, so that the difference in the cooling water pressure between the reflux chamber 20 and the bypass passage 4 increases. As a result, the relief valve 5 is opened, and the cooling water flowing through the engine 100 flows through the bypass passage 4, the heat exchanger passage 6, and the heater passage 7 and returns to the water pump 1.

  Thus, in the cooling device A, when the temperature of the cooling water is low, such as when the engine 100 is cold, by the action of the thermostat 3, the cooling water does not flow to the radiator 10 and the temperature is increased. Further, due to the action of the relief valve 5, when the pressure of the cooling water is low, such as when the engine 100 is cold, the bypass passage 4 is closed, and the flow rate of the cooling water flowing to the heat exchanger 11 is increased (FIG. 2). ). Thereby, early temperature rise of lubricating oil can be aimed at.

  FIG. 9 is a diagram showing changes in the temperature of the cooling water and the lubricating oil during the warm-up operation. As shown in the figure, the temperature of the cooling water rises first in the cooling water and the lubricating oil. When the cooling water reaches the valve opening start temperature of the thermostat 3, the cooling water is cooled by the action of the radiator 10, the temperature rise is suppressed, and the temperature of the lubricating oil becomes higher. The heat exchanger 11 functions as an oil warmer until both temperatures are reversed, and functions as an oil cooler after the reverse. And in this embodiment, since the flow volume of the cooling water which flows into the heat exchanger 11 increases until it reaches the valve opening start temperature of the thermostat 3 (FIG. 2), the temperature rise of the lubricating oil in the meantime can be aimed at.

  Further, when the pressure of the cooling water rises while the thermostat 3 is closed, the bypass passage 4 is opened by the action of the reel valve 5 (FIG. 4), and the water flow resistance of the cooling water is prevented from increasing. The Further, by providing the thermostat passage 8, when the cooling water reaches a predetermined temperature (valve opening start temperature), the thermostat 3 is opened and the cooling water flows to the radiator 10, and the temperature of the cooling water and the lubricating oil increases. It is suppressed. Therefore, the cooling performance of engine 100 is maintained. Furthermore, compared with the conventional cooling device, the above effect can be obtained with a simple configuration in which the relief valve 5 and the thermostat passage 8 are added. Therefore, it is possible to quickly raise the temperature of the lubricating oil when the engine 100 is cold without impairing the cooling performance of the engine 100 with a simpler configuration.

  Further, since the cooling device A includes the heater passage 7, the cooling water flowing through the heater 13 together with the heat exchanger 11 in the cold time such as during the warm-up operation of the engine 100 (FIG. 2). The flow rate is increased and the room can be warmed early. The outlet of the heater passage 7 is disposed in the reflux chamber 20 on the water pump 1 side of the thermostat 3 (FIG. 1). For this reason, it is possible to prevent the cooling water whose temperature has been lowered by the heat exchange by the heater 13 from flowing into the temperature sensing part of the thermostat 3. That is, although the cooling water has reached the valve opening start temperature, the start of opening the thermostat 3 can be prevented from being delayed, and the cooling performance of the engine 100 can be maintained.

  When the control valve 14 is provided as shown in FIGS. 1 to 4, the control valve 14 has a predetermined temperature (for example, about 40 degrees) at which the cooling water is lower than the valve opening start temperature of the thermostat 3. It is desirable to regulate the flow of the cooling water in the heater passage 7 (reducing the flow rate or closing the valve) until it reaches According to this configuration, when the effectiveness of the heater 13 is poor and the cooling water is at a low temperature, the circulation of the cooling water in the heater passage 7 is regulated to increase the temperature of the cooling water at an early stage. Early temperature increase can be achieved. At the same time, unheated air from the heater 13 is prevented from being sent into the cabin.

  Further, in the cooling device A, as shown in FIG. 1, it is desirable that the bypass passage 4 is formed in the wall portion of the engine 100 and has a portion parallel to and adjacent to the lubricating oil passage (oil gallery 100 c). In the cooling device A, a small amount of cooling water flows through the bypass passage 4 even when the engine 100 is cold (FIG. 1). For this reason, if this configuration is adopted, in addition to the heat exchanger 11, heat exchange between the cooling water and the lubricating oil can be achieved between the passages 4 and 100c through the wall portion of the engine 100. In this case, it is possible to promote early temperature rise of the lubricating oil.

  Next, a specific application example of the cooling device A will be described. 5 is a partial side view of a cylinder block showing the main part of the engine 100 to which the cooling device A is applied, FIG. 6 is a cross-sectional view of the main part along the line II in FIG. 5, and FIG. 7 is the line II-II in FIG. FIG. In this example, the water pump 1 is attached to the rear end surface of the cylinder block 110, and the thermostat 3 is attached to the side portion of the cylinder block 110.

  The reflux chamber 20 communicates with the water pump 1. The cooling water flowing into the reflux chamber 20 is sucked by the water pump 1 and is pumped into the cylinder block 110 from the passage 110a (FIG. 7) formed from the rear end surface of the cylinder block 110. The reflux chamber 20 forms a housing portion for the thermostat 3 at the end opposite to the water pump 1. A cover member 120 that covers the thermostat 3 is attached to the housing portion and is sealed.

  As shown in FIG. 6, the thermostat 3 is inserted through a movable shaft 3b integrally formed with a temperature sensing portion 3a containing wax, a valve body 3c fixed to the movable shaft 3b, and a rear end of the movable shaft 3b. A shaft 3d and a spring 3e that urges the movable shaft 3b in the valve closing direction are provided. And the wax incorporated in the temperature sensing part 3a expands and contracts due to the change in the ambient temperature of the temperature sensing part 3a.

  As shown in FIG. 6, the valve body 3c is in a closed state until the temperature sensing part 3a reaches the valve opening start temperature, and when the valve opening start temperature is reached, the shaft 3d is pushed up by the expansion of the wax. Since the shaft 3d is fixed to the case of the thermostat 3, the movable shaft 3b moves upward in FIG. 6, and the valve body 3c is opened. When the temperature sensing portion 3a is cooled again from the valve opening start temperature, the wax contracts, and the valve closing state shown in FIG. 6 is restored by the urging force of the spring 3e.

The relief valve 5 includes a valve body 5a and a spring 5b, and is disposed at the tip of the movable shaft 3b of the thermostat 3. According to this structure, the thermostat 3 and the relief valve 5 are unitized, and assembly | attachment property can be improved. The outlet 4a of the bypass passage 4 opens toward the tip of the movable shaft 3b and communicates with the reflux chamber 20, but is closed by the valve body 5a. The spring 5b constantly urges the valve body 5a in the direction in which the outlet 4a is closed. The outlet 4 a of the bypass passage 4 is formed on a substantially coaxial line with the axis of the movable shaft 3 b and is in a position facing the cover member 120.

The outlet 6 a of the heat exchanger passage 6 is formed on the upper wall of the reflux chamber 20 and communicates with the reflux chamber 20. FIG. 6 shows the position of the outlet 6a in plan view with a broken line. The heat exchanging passage 6 extends upward from the outlet 6a and penetrates the wall portion of the cylinder block 110. As shown in FIG. 5, the external pipe portion (6) is connected to the upper portion of the through hole. According to this configuration, the workability of the wall portion of the cylinder block 110 required for disposing the heat exchanger passage 6 can be improved. That is, the passage portion from the outlet 6a extends upward, so that the direction of punching of the cylinder block 110 coincides with the direction of punching of this passage, and the workability is good in the case of casting. Furthermore, the passage portion from the outlet 6a is a through hole, which is suitable for machining.

  As shown in FIG. 6, the outlet 6 a of the heat exchanger passage 6 is disposed closer to the water pump 1 than the temperature sensing portion 3 a of the thermostat 3. According to this configuration, the cooling water flowing through the heat exchanger passage 6 does not necessarily flow to the temperature sensing part 3a of the thermostat 3, but in this embodiment, the thermostat passage 8 is provided, so that the temperature sensing of the thermostat 3 is achieved. A cooling water flow to the portion 3a is ensured. That is, the outlet 6a of the heat exchanger passage 6 can be disposed closer to the water pump 1 than the temperature sensing part 3a without considering the cooling water flow to the temperature sensing part 3a, and the degree of design freedom is improved.

  The heater passage 7 also communicates with the reflux chamber 20, and its outlet 7 a is disposed on the water pump side 1 relative to the temperature sensing portion 3 a of the thermostat 3. This configuration is also useful for improving the degree of freedom in designing the heater passage 7 and can prevent the cooling water whose temperature has been reduced by the heat exchange by the heater 13 from flowing into the temperature sensing portion 3a of the thermostat 3.

  The radiator passage 2 is connected to the cover member 120 in the form of an external pipe (radiator hose), and communicates with the reflux chamber 20 via the thermostat 3. According to this configuration, the routing of the passage around the thermostat 3 can be simplified in that a part of the radiator passage 2 is not formed in the wall of the cylinder block 110.

  Next, in this example, the thermostat passage 8 is configured as a passage through which cooling water in the bypass passage 4 leaks from the outlet 4a of the bypass passage 4 closed by the valve body 5a to the temperature sensing portion 3a. According to this configuration, the cooling water can be supplied from the bypass passage 4 to the temperature sensing part 3 a of the thermostat 3 at the shortest distance. FIGS. 8A and 8B are explanatory views of the thermostat passage 8.

  In the example of FIGS. 8A and 8B, the thermostat passage 8 is formed as a hole in the valve body 5a. According to this configuration, the thermostat passage 8 can be formed without processing the wall of the cylinder block 110, and the relief valve 5 can be assembled by forming the thermostat passage 8 in the valve body 5a. As a result, the thermostat passage 8 is formed, and the assemblability can be improved. Thus, the cooling water in the bypass passage 4 flows into the reflux chamber 20 through the hole 8 and comes into contact with the temperature sensing portion 3a.

  As shown in FIG. 8B, a plurality of holes 8 are formed, and are formed in the valve body 5a at an equal pitch on a concentric circle with the movable shaft 3a. According to this configuration, even if any one of the thermostat passages 8 is blocked by dust or the like in the cooling water, the other thermostat passages 8 can reliably send the cooling water to the temperature sensing portion 3a of the thermostat 3. The situation where the cooling water is not supplied to the warm part 3a can be avoided.

  FIG. 8C shows another example of the thermostat passage 8, which is formed as a notch on the end surface of the wall portion defining the outlet 4 a of the bypass passage 4 in contact with the valve body 5 a. Also in this example, the cooling water in the bypass passage 4 flows into the reflux chamber 20 through the notch 8 and comes into contact with the temperature sensing portion 3a. According to this configuration, the thermostat passage 8 can be formed with minimum processing. When the notch 8 is formed at a position opposite to the water pump 1 as viewed from the temperature sensing portion 3a as in the example of the figure, the cooling water easily flows to the temperature sensing portion 3a.

It is a block diagram of engine cooling device A concerning one embodiment of the present invention. FIG. 6 is an operation explanatory diagram of the cooling device A. FIG. 6 is an operation explanatory diagram of the cooling device A. FIG. 6 is an operation explanatory diagram of the cooling device A. 2 is a partial side view of a cylinder block showing a main part of an engine 100 to which a cooling device A is applied. FIG. It is principal part sectional drawing in alignment with line II of FIG. FIG. 6 is a partial cross-sectional view (rear end view of a cylinder block) taken along line II-II in FIG. 5. (A) And (b) is explanatory drawing of the channel | path 8 for thermostats, (c) is explanatory drawing of the other example of the channel | path 8 for thermostats. It is a figure which shows the change of the temperature of a cooling water and lubricating oil at the time of warming-up operation.

Explanation of symbols

A Cooling device 1 Water pump 2 Radiator passage 3 Thermostat 4 Bypass passage 5 Relief valve 6 Heat exchanger passage 7 Heater passage 8 Thermostat passage 10 Radiator 11 Heat exchanger 13 Heater

Claims (10)

A water pump that pumps cooling water into the engine;
A radiator passage for guiding cooling water flowing through the engine to the water pump via a radiator;
A bypass passage for guiding cooling water flowing through the engine to the water pump;
A heat exchanger passage that guides the cooling water flowing through the engine to the water pump via a heat exchanger that performs heat exchange between the lubricating oil supplied to the engine and the cooling water;
A wax-type thermostat for opening and closing the radiator passage;
In the engine cooling device with
A relief valve that opens and closes the bypass passage according to the pressure of the cooling water in the bypass passage;
A thermostat passage for guiding a part of the cooling water in the bypass passage to the temperature sensing portion of the thermostat;
An engine cooling system comprising: A cooling water recirculation chamber formed in the engine and in communication with an outlet of the heat exchanger passage and the water pump;
The reflux chamber has a storage portion for the thermostat,
The engine cooling device according to claim 1, wherein an outlet of the heat exchanger passage is disposed closer to the water pump than the temperature sensing portion of the thermostat. An outlet of the bypass passage communicates with the reflux chamber;
The relief valve is movable on the expansion and contraction of the thermostat wax, and is disposed on a movable shaft of the thermostat, and has a valve body that closes the outlet of the bypass passage so as to be openable;
3. The engine according to claim 2, wherein the thermostat passage is a passage through which cooling water in the bypass passage leaks from the outlet of the bypass passage closed by the valve body to the temperature sensing portion. Cooling system.   4. The engine cooling apparatus according to claim 3, wherein the thermostat passage is formed in the valve body.   The engine cooling device according to claim 4, wherein the thermostat passage is a plurality of holes formed in the valve body at a constant pitch on a concentric circle with the movable shaft.   4. The engine cooling device according to claim 3, wherein the thermostat passage is a notch formed in an outlet end face of the bypass passage that contacts the valve body.   3. The engine according to claim 2, wherein an outlet of the heat exchanger passage is formed in an upper wall of the reflux chamber, and has a portion extending upward from the outlet and penetrating the wall of the engine. Cooling system.   The engine cooling device according to claim 1, further comprising a heater passage that guides cooling water flowing through the engine to the water pump via a heater. A heater passage for guiding cooling water flowing through the engine to the water pump via a heater;
3. The engine cooling according to claim 2, wherein an outlet of the heater passage communicates with the reflux chamber and is disposed closer to the water pump than the temperature sensing portion of the thermostat. apparatus.   2. The engine cooling apparatus according to claim 1, wherein the bypass passage is formed in a wall portion of the engine and has a portion parallel to and adjacent to the passage of the lubricating oil.

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