JPH09158725A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a thermosensitive part of a thermostat to respond rapidly to the cooling water temperature by providing a cooling water outflow port side valve element protrusively with a guide part extended toward the valve seat part side so as to lead cooling water, flowing in from a by-pass side inflow port, to the thermosensitive part. SOLUTION: Cooling water having cooled each part of an engine 10 is cooled by a radiator 12 and then passes a thermostat 16 and a water pump 20 so as to flow back to the engine. The thermostat 16 opens a main valve 40 by the upward relative displacement of a thermosensitive part casing caused by the thermal expansion of thermosensitive material of a thermosensitive part 36, and closes a by-pass side inflow port 28 by a by-pass cutoff valve 42. In this case, the by-pass cutoff valve 42 is protrusively provided with a guide part 56 formed into a cylindrical face over almost semi-circumference, facing a cooling water outflow port 26, and a recess 58 for accommodating the guide part 56 is formed at an outside part, facing the cooling water outflow port 26, of a valve seat part 28' to improve responsiveness to temperature change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a water-cooled engine.

[0002]

2. Description of the Related Art As a cooling device for a vehicle engine, a device as shown in the schematic diagram of FIG. 5 has been already proposed. (See Japanese Utility Model Laid-Open No. 58-173722) In FIG. 5, reference numeral 10 conceptually represents a multi-cylinder engine for a vehicle, which flows through cooling water chambers in a crankcase and a cylinder head of the engine 10 and various parts of the engine. After cooling the cooling water by the radiator 12,
It flows from the inlet passage 14 through a thermostat, generally indicated at 16, to the outlet passage 18, through the water pump 20 of the engine 10 and again into the cooling water chamber of the engine 10. In addition, in the cooling water chamber of the engine 10,
A bypass passage 22 is provided which bypasses the radiator 12 and allows the cooling water chamber to communicate with the outlet passage 18 via the thermostat 16.

The thermostat 16 includes a radiator side inlet 24 connected to the inlet passage 14, a cooling water outlet 26 connected to the outlet passage 18, and a bypass side inlet 28 connected to the bypass passage 22. A thermostat housing 30 having The thermostat housing 30 includes an upper housing 30a having the cooling water outlet 26 and the bypass side inlet 28,
Lower housing 3 having the radiator-side inlet 24
0b, the flange 34 of the valve case 32 is sandwiched between the upper and lower housings 30a and 30b, and the spindle 38 of the temperature sensing section 36 is connected to the valve case 32. The temperature sensing section 36 has a casing in which wax pellets and synthetic rubber are enclosed, and the wax pellets as the temperature sensing material are thermally expanded due to a temperature rise, whereby the synthetic rubber is compressed and the spindle 38 is axially outwardly moved. It is configured to project to.

A main valve 40 for controlling the communication between the radiator side inlet 24 and the cooling water outlet 26 is mounted on the temperature sensing section 36, and a disc-shaped member is provided at the end opposite to the spindle 38. The bypass cut valve 42 is attached by a snap ring 44 and a conical coil spring 46. The main valve 40 is always elastically biased in a direction to be seated on a valve seat portion 52 formed on the flange 34 by a valve spring 50 having one end abutted on a case 48 fixed to the flange 34. ing. Further, in the upper housing 30 a, a weir or a guide portion is provided adjacent to the opening end of the cooling water outlet 26.
4 is projected downward.

In the above engine cooling device, when the cooling water temperature of the engine 10 is lower than the set temperature, the wax pellets stored in the temperature sensing section 36 are contracted. The spindle 38 is contracted in the casing of the temperature sensitive portion, the main valve 40 is seated on the valve seat portion 52 of the flange 34, and the communication between the radiator side inlet 24 and the cooling water outlet 26 is cut off. There is. Further, as shown in the drawing, the bypass cut valve 42 attached to the end portion of the temperature sensing portion 36 opposite to the spindle 38 is provided from the valve seat portion 28 ′ formed on the outer periphery of the opening end of the bypass side inlet 28. The bypass side inflow port 28 and the cooling water outflow port 26 are in communication with each other with a sufficient space therebetween.

Therefore, the cooling water of the engine 10 flows from the bypass passage 22 through the bypass side inlet 28 to the outer periphery of the temperature sensing portion 36 of the thermostat 16, and the weir or the guide portion 5 is provided.
The water flows into the cooling water outlet 26 from the inlet opening narrowed by 4, flows into the water pump 20 through the outlet passage 18, and is circulated again in the cooling water chamber of the engine 10. At this time, since the weir or the guide portion 54 is provided downward in the opening portion of the cooling water outlet port 26, the cooling water is exposed to the temperature sensing portion 36.
Since the wax pellets flow along the outer peripheral surface of the same, the wax pellets as the temperature-sensitive material accommodated in the temperature-sensitive portion 36 rapidly respond to the temperature of the cooling water and rise in temperature.

Since the cooling water bypasses the radiator 12 as described above during the cold operation of the engine 10,
The warm-up is performed quickly and the temperature of the cooling water gradually rises.
As the temperature of the cooling water rises, the wax pellets in the temperature sensing portion 36 change to a liquid phase and thermally expand, compressing the built-in synthetic rubber and causing the spindle 38 to project outward in the axial direction. As a result, when the casing of the temperature sensing portion 36 is relatively displaced upward in the drawing and the cooling water temperature reaches the set temperature, the main valve 40 is fully opened and the bypass cut valve 42 is seated on the valve seat portion 28 '. To close the bypass side inlet 28. Therefore, substantially the entire amount of cooling water of the engine 10 passes through the radiator 12, enters the radiator side inlet 24 from the inlet passage 14, flows to the cooling water outlet 26 through the fully opened main valve 40, and further passes through the outlet passage 18. The water is circulated through the water pump 20 to the cooling water chamber of the engine 10.

In the previously proposed device, the cooling water outlet 26
Since the weir or the guide portion 54 is provided so as to project downward near the open end of the cooling water, the cooling water can flow to the outer peripheral portion of the temperature sensing portion 36 during the warm-up period. There is an advantage that it is possible to prevent the thermostat 16 from malfunctioning and causing hunting or overheating. However, after the engine warming up is completed, the weir or the guide member 54 provided near the opening end of the cooling water outlet 26 is removed from the cooling water outlet 2.
Since the opening area of 6 is greatly reduced and the resistance against the circulating flow of the cooling water becomes great, the mechanical loss of the water pump 20 increases. Therefore, there is a problem that the pump capacity required to secure a required cooling water flow rate increases, the output of the engine 10 consumed for driving the pump increases, and eventually the fuel consumption deteriorates. At times, there is a problem that the pressure on the suction side of the water pump 20 decreases and cavitation easily occurs.

[0009]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and the temperature sensitive portion of the thermostat operates responsively to the temperature of the cooling water of the engine during warm-up operation of the engine. By this, warm-up can be performed quickly and reliably, and during normal operation after warm-up, the flow resistance when the engine cooling water flows through the thermostat is small, thus reducing the mechanical loss of the water pump, It is a primary object of the present invention to provide an engine cooling device that can improve the output of the engine and the fuel consumption.

Further, the present invention, when the engine is warmed up,
The cooling water flowing into the thermostat housing from the bypass passage bypassing the radiator can be guided to the outer peripheral portion of the temperature sensing portion more reliably and in a larger amount than the previously proposed device,
Therefore, it is possible to further improve the responsiveness of the temperature sensing part to the cooling water temperature and accurately control the amount of bypass cooling water.
Another object of the present invention is to provide an engine cooling device that can prevent overheat and hunting from occurring more reliably. Further, the present invention effectively prevents the occurrence of cavitation that tends to occur during high speed rotation of the engine by reducing the resistance of the cooling water passage on the suction side of the water pump during normal operation after the engine has finished warming up. To provide an engine cooling device capable of
Yet another purpose.

[0011]

In order to achieve the above object, the present invention provides a thermostat housing with a radiator side inlet into which cooling water from a radiator flows and a bypass side flow into which cooling water bypassing the radiator flows. An inlet and a cooling water outlet through which cooling water flows out to the engine body are provided, and a bypass cut valve that is arranged facing the bypass side inlet and opens and closes the bypass side inlet, and operates on the bypass cut valve Temperature-sensing part that is connected to each other and automatically opens and closes the bypass cut valve by detecting the cooling water temperature, and the bypass cut valve that is formed near the opening end of the bypass side inlet when the engine warms up. And a valve seat portion on which the seat is seated, the valve seat extending toward the valve seat portion on the valve body on the cooling water outlet side of the bypass cut valve. The cooling water flowing from the bypass side inlet at the opening of the bypass-cutting valve is to propose an engine cooling apparatus, wherein a guide portion for guiding the said temperature sensitive portion is protruded.

In the present invention, the guide portion projecting on the valve body of the bypass cut valve is provided in the recess formed in the outer portion of the valve seat portion facing the cooling water outlet when the engine is warmed up. It is preferably configured to be housed, and when the bypass cut valve is separated from the valve seat portion and the bypass side inlet is opened, a guide projecting on the valve body is provided. Preferably, the tip of the part is configured to be located in the recess beyond the valve seat part to form an overlap. Furthermore, the guide portion projecting on the valve body of the bypass cut valve is housed in a recess formed on the inner peripheral surface of the cooling water outlet side of the bypass side inlet at the end of engine warm-up. It may be configured to.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described below with reference to FIGS. (It should be noted that substantially the same members or parts as those of the already proposed device described with reference to FIG. 5 are denoted by the same reference numerals, and overlapping description will be omitted.) According to the present invention, the thermostat 16 is provided. A bypass cut valve 42 that is attached to an end of the temperature sensing unit 36 that faces the bypass-side inlet 28 provided in the upper housing 30a and that opens and closes the bypass-side inlet 28.
As shown in FIGS. 3 and 4, a guide portion 56 extending toward the bypass side inlet 28 is provided in a protruding manner. The guide portion 56 is formed as a cylindrical surface extending over a substantially semicircle facing the cooling water outlet 26 provided on the upper housing 30a.

On the other hand, a valve seat portion 28 'provided at the open end of the bypass side inlet 28 of the upper housing 30a.
2 is a partial perspective view of the cooling water outlet 26 of FIG. 2 (in FIG. 1, a part of the upper housing 30a viewed from the bypass cut valve 42 side and the valve seat portion 28 'is cut out in a disk shape). (As shown in the drawings), a recess 58 for accommodating the guide portion 56 is formed. Further, the bypass cut valve 42 of the guide portion 56 is
As shown in FIG. 1, the height from the upper surface is when the cooling water temperature is low, the spindle 38 of the temperature sensing unit 36 is contracted into its casing, and the bypass cut valve 42 is fully opened. Further, the upper end portion of the guide portion 56 is the valve seat portion 2
It is set so as to go over 8'and still enter the recess 58 by a height h to form an overlap portion.

According to the above construction, since the temperature of the cooling water is sufficiently lower than the set temperature during the cold operation of the engine 10, as described above, the spindle 38 of the temperature sensing section 36 of the thermostat 16 has the temperature sensing section casing. When the bypass cut valve 42 is fully opened, the main valve 40 is seated on the valve seat portion 52 of the flange 34 and is fully closed. Therefore, the cooling water of the engine 10 passes through the bypass passage 22 and the bypass side inlet 28, and flows into the thermostat housing 3.
0, but at this time, since the guide portion 56 on the bypass cut valve 42 closes the passage to the cooling water outlet 26 over a substantially semicircle, almost all of the cooling water is supplied to the bypass cut valve 42. 42 flows downward from the outer peripheral edge portion where the guide portion 56 is not provided, flows along the outer periphery of the temperature sensing portion 36, then flows to the cooling water outlet 26, and circulates again to the cooling water chamber of the engine 10 via the water pump 20. Warm-up is performed.

During the warm-up operation, the guide portion 56 projecting above the bypass cut valve 42 is always in the valve seat portion 2.
In the recess 58 provided in the outer portion of 8 ', at least a high height h is entered to form an overlap portion, so that the short-circuiting cooling from the bypass side inlet 28 to the cooling water outlet 26 is directly performed. There is almost no water, so the temperature sensor 36
Operates quickly and accurately in response to the temperature of the cooling water, and does not cause hunting due to overshooting or overheating, and warms up smoothly and effectively.

When the warm-up is completed as described above, the spindle 38 of the temperature sensing section 36 extends sufficiently outward of the temperature sensing section casing, and the bypass cut valve 42 serves as the opening end of the bypass side inlet 28. Is seated on the valve seat portion 28 ', the inflow port 28 is substantially fully closed, and the main valve 40 is fully opened. At this time, bypass cut valve 4
The guide portion 56 projecting above 2 is housed in the recess 58 as shown by the dotted line in FIG.
Since a cooling water passage having a sufficient height H, which is much wider than the previously proposed device, is formed at the open end of the radiator 12 and the inlet passage 1 from the cooling water chamber during normal operation of the engine.
4 through the main valve 40 of the thermostat 16, further from the cooling water outlet 26 through the outlet passage 18 to the water pump 20 and back to the cooling water chamber, the circulation resistance of the cooling water main circulation circuit is small, and therefore the water pump Since the mechanical loss of the engine 20 is reduced and the output consumed for driving the water pump of the engine 10 is reduced, the engine 1
0 output and fuel efficiency are improved. Further, when the engine 10 rotates at a high speed, that is, when the water pump 20 rotates at a high speed, a large negative pressure due to resistance does not occur on the suction side of the pump, so that cavitation can be effectively prevented. There are advantages.

In the above embodiment, the guide portion 56 projecting from the bypass cut valve 42 is provided inside the recess 58 formed in the outer portion of the valve seat portion 28 'at the opening end of the bypass side inlet 28. However, a recess 58 is provided in the radially inner portion of the valve seat portion 28 ′, that is, the inner peripheral surface near the open end of the bypass side inlet 28, and the guide in the recess is formed. It can be configured so as to accommodate the portion 56, and it is clear that this modified example can also obtain substantially the same operational effects as described above.

[0019]

As described above, according to the engine cooling device of the present invention, the thermostat housing has a radiator side inlet into which cooling water from the radiator flows, and a bypass side flow into which the cooling water bypassing the radiator flows. An inlet and a cooling water outlet through which cooling water flows out to the engine body are provided, and a bypass cut valve which is arranged to face the bypass side inlet and opens and closes the bypass side inlet,
A temperature sensing part that is operatively connected to the bypass cut valve to detect the cooling water temperature and automatically open and close the bypass cut valve, and the warm-up of the engine that is formed near the opening end of the bypass side inlet When a valve seat portion on which the bypass cut valve is seated is provided, the bypass cut valve extends toward the valve seat portion on the valve body on the cooling water outlet side of the bypass cut valve, A guide part for guiding the cooling water flowing from the bypass side inlet to the temperature sensing part when the valve is opened is projected, and during the warm-up operation, the temperature sensing part of the thermostat quickly and cools the temperature of the cooling water. It has the advantage of being able to reliably prevent the occurrence of problems such as hunting and overheating by operating in response accurately, and also guides the cooling water to the suction side of the water pump during normal operation after warming up. This has the advantage of reducing the flow path resistance at the open end of the waste water outlet, reducing the mechanical loss of the water pump, and improving the engine output and fuel consumption.In addition, the negative pressure on the suction side of the water pump at high engine speeds There is an advantage that cavitation caused by the increase can be effectively prevented.

Further, the guide portion projecting on the valve body of the bypass cut valve is housed in the recess formed in the outer portion of the valve seat portion facing the cooling water outlet when the engine is warmed up. Or when the guide portion is configured to be housed in a recess formed in the inner peripheral surface of the bypass side inlet on the cooling water outlet side at the end of warming up, It is possible to secure a sufficiently large passage area in the cooling water inflow portion of the cooling water outlet after the end of the machine. Further, when the bypass cut valve is separated from the valve seat portion and the bypass side inlet is opened, the tip end portion of the guide portion projecting on the valve body causes the valve seat portion to By being configured to be located in the above-mentioned recess and an overlap portion is formed,
Since almost the entire amount of the cooling water flowing into the thermostat from the bypass passage during the warm-up operation can be guided to the temperature sensing unit, there is an advantage that the responsiveness of the temperature sensing unit can be improved as compared with the conventional similar device.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a preferred embodiment of the present invention.

FIG. 2 is a perspective view showing a structure of a thermostat housing near an opening end of a bypass side inflow port 28 in FIG.

FIG. 3 is a plan view of a bypass cut valve 42 in FIG.

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3 and viewed in the direction of the arrow.

FIG. 5 is a schematic configuration diagram showing an already proposed engine cooling device.

[Explanation of symbols]

10 ... Engine, 12 ... Radiator, 14 ... Entrance passage,
16 ... Thermostat, 18 ... Exit passage, 20 ... Water pump, 22 ... Bypass passage, 24 ... Radiator side inlet, 26 ... Cooling water outlet, 28 ... Bypass side inlet,
28 '... Valve seat part, 30 ... Thermostat housing, 36 ... Temperature sensing part, 38 ... Spindle, 40 ... Main valve, 42 ... Bypass cut valve, 56 ... Guide part, 58
… A recess.

Claims (4)

[Claims] 1. A thermostat housing has a radiator-side inlet into which cooling water from a radiator flows, a bypass-side inlet into which cooling water bypassing the radiator flows, and a cooling-water outlet from which cooling water flows out to an engine body. And a bypass cut valve that is arranged to face the bypass side inlet and opens and closes the bypass side inlet, and is operatively connected to the bypass cut valve to detect the cooling water temperature and automatically perform the same operation. The bypass cut valve is provided with a temperature sensing portion that drives the bypass cut valve to open and close, and a valve seat portion that is formed near the opening end of the bypass side inlet and on which the bypass cut valve is seated when the engine has finished warming up. On the valve body on the cooling water outlet side of the valve, extending toward the valve seat portion side, from the bypass side inlet when the bypass cut valve is opened. An engine cooling device characterized in that a guide part for guiding the inflowing cooling water to the temperature sensing part is provided in a protruding manner. 2. A guide portion projecting from the valve body of the bypass cut valve is housed in a recess formed in an outer portion of the valve seat portion facing the cooling water outlet when the engine is warmed up. The engine cooling device according to claim 1, wherein the engine cooling device is configured as follows. 3. A guide portion projectingly provided on the valve body of the bypass cut valve is provided in a recess formed on an inner peripheral surface of the cooling water flow outlet side of the bypass side inlet when the engine is warmed up. The engine cooling device according to claim 1, wherein the engine cooling device is configured to be housed. 4. When the bypass cut valve is separated from the valve seat portion and the bypass side inlet is opened, the tip end portion of the guide portion projecting on the valve body has the valve seat portion. 4. The engine cooling device according to claim 2, wherein the engine cooling device is configured to be located in the recess beyond the portion and form an overlap portion.