JP2019152130A - Cooling system of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress hunting of cooling water temperature. SOLUTION: A cooling system of an internal combustion engine has a housing having a first inflow port into which cooling water from a radiator flows in and a second inflow port into which cooling water bypassing the radiator flows in, and the temperature of the cooling water. A temperature-sensitive part that is displaced accordingly, a valve-opened state that allows the inflow of cooling water from the first inflow port due to the displacement of the temperature-sensitive part, and a closed valve that shuts off the inflow of cooling water from the first inflow port. It comprises a valve that is movable between states and a thermostat device that is housed in the housing, the second inlet being provided along an axis that intersects the axis of the temperature sensitive portion. The housing is located between the valve seat on which the valve is seated and the second inlet, and on the surface facing a part of the temperature-sensitive portion facing the second inlet, the first inlet. It is provided with a flow path throttle portion that reduces the flow rate of cooling water from. [Selection diagram] Fig. 2

Description

  The present invention relates to a cooling system for an internal combustion engine.

  An engine (internal combustion engine) cooling system includes a coolant circulation circuit having a water pump, a radiator, a thermostat device, and the like. When the engine is cold started, the valve of the thermostat device (the valve that opens and closes the return passage from the radiator) is closed to stop the flow of the cooling water from the radiator, so that the engine is warmed up early. On the other hand, after the warm-up of the engine is completed, the valve of the thermostat device is opened, the cooling water cooled in the radiator is circulated, the temperature of the cooling water is lowered, and the engine is prevented from overheating.

  Patent Document 1 discloses a thermostat device in which a valve is opened by a temperature sensing unit that incorporates a thermal expansion body that expands and contracts in accordance with the temperature of cooling water flowing into the thermostat device.

Japanese Patent Laid-Open No. 2003-328753

  When the cooling water from the engine flows in a part of the temperature sensing part (when the cooling water collides with part of the temperature sensing part), the thermal expansion body expands locally at the location where the cooling water collides. The valve may tilt and open. In this case, when the cooling water cooled by the radiator flows from a position opened by the inclination of the valve and flows in a concentrated manner to a location where the thermal expansion body is locally expanded, a temperature change of the temperature sensing portion is likely to occur. As a result, the movement of the valve is not stable and hunting of the coolant temperature may occur.

  Therefore, an object of the cooling system for an internal combustion engine disclosed in this specification is to suppress hunting of the coolant temperature.

  In order to solve this problem, a cooling system for an internal combustion engine disclosed in the present specification includes a first inlet into which cooling water from a radiator flows, and a second inlet into which cooling water that bypasses the radiator flows. , A temperature sensing portion that is displaced according to the temperature of the cooling water, a valve opening state that allows the cooling water to flow in from the first inlet due to the displacement of the temperature sensing portion, and the first inlet A thermostat device housed in the housing, wherein the second inflow port is provided in the temperature sensing portion. The housing is provided along an axis that intersects the axis, and the housing is between a valve seat on which the valve is seated and the second inlet, and is a part of the temperature sensing part that faces the second inlet Cooling water from the first inlet on the surface facing the Comprising a passage aperture portion to reduce the flow rate.

  According to the cooling system for an internal combustion engine disclosed in this specification, hunting of the coolant temperature can be suppressed.

FIG. 1 is a diagram illustrating a schematic configuration of a cooling system according to an embodiment. 2A is a cross-sectional view showing the internal structure of the thermostat device, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. FIG. 3A is a diagram for explaining a location where the cooling water collides with the temperature sensing portion, and FIG. 3B explains the flow rate of the cooling water when the housing has a flow passage restricting portion. FIG. 3C is a diagram for explaining the flow rate of the cooling water in the case where the housing does not have the flow passage restricting portion.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, and the like of each part may not be shown so as to completely match the actual ones. In some cases, details are omitted in some drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a cooling system 1 according to the present embodiment. The cooling system 1 includes a cooling water circulation circuit 10. The cooling water circulation circuit 10 includes an electric water pump 2 for circulating the cooling water, a radiator 3 for cooling the circulating cooling water, and a thermostat device 4 directly attached to the upper part of the electric water pump 2. I have. Cooling water is circulated in the cooling water circulation circuit 10 by the operation of the electric water pump 2, and the engine (internal combustion engine) 5 is cooled by this cooling water.

  The engine 5 is a gasoline engine or a diesel engine, and includes a cylinder head 51 and a cylinder block 52. A head-side water jacket 51 a is formed inside the cylinder head 51, and a block-side water jacket 52 a is formed inside the cylinder block 52. In the engine 5 in the present embodiment, a head-side water jacket 51a and a block-side water jacket 52a are communicated with each other.

  As a cooling water passage for connecting each device provided in the cooling water circulation circuit 10, a pump discharge passage 11, an engine outflow passage 12, a radiator return passage 13, and a warm-up return passage 14 are provided.

  The pump discharge passage 11 connects the discharge port 21 of the electric water pump 2 and the block-side water jacket 52 a of the engine 5. The engine outflow passage 12 connects the head-side water jacket 51 a of the engine 5 and the upper tank 31 of the radiator 3. The radiator return passage 13 connects the lower tank 32 of the radiator 3 and the radiator side inlet 41 of the thermostat device 4. The warm-up return passage 14 connects the engine outflow passage 12 and the engine side inlet 42 of the thermostat device 4. The radiator-side inlet 41 is an example of a first inlet (a first inlet into which cooling water from the radiator flows). The engine-side inlet 42 is an example of a second inlet (a second inlet into which cooling water that bypasses the radiator flows).

  The electric water pump 2 generates a water flow for circulating the cooling water in the cooling water circulation circuit 10.

  The radiator 3 is of a down flow type, for example, and a radiator core 33 is disposed between the upper tank 31 and the lower tank 32. The radiator 3 performs heat exchange between the cooling water and the outside air when the cooling water collected in the upper tank 31 flows down the radiator core 33 toward the lower tank 32, thereby generating heat of the cooling water. It is configured to be released into the atmosphere.

  As shown in FIG. 2A, the thermostat device 4 is accommodated in a housing 43 formed of synthetic resin or the like.

  A radiator-side inlet 41 is formed on a side surface in the vicinity of the upper end of the housing 43 (a side surface on the back side in FIG. 2A), and a radiator return that forms a radiator return passage 13 in the radiator-side inlet 41. A pipe (not shown) is connected.

  At the lower end portion of the housing 43, an outflow portion 45 is provided for allowing the cooling water that has flowed through the thermostat device 4 to flow out toward the electric water pump 2. An opening 45 a through which cooling water flows out is formed at the center of the outflow portion 45. The opening 45a and the suction port of the electric water pump 2 are in communication with each other, whereby the cooling water that has flowed through the thermostat device 4 flows into the electric water pump 2 through the opening 45a.

  For this reason, when cooling water flows into the thermostat device 4 from the radiator side inflow port 41 through the radiator return passage 13, the cooling water moves from the upper side to the lower side in FIG. 2 (A). It flows toward the electric water pump 2 from the opening 45a of the outflow portion 45.

  An engine side inlet 42 is formed on the side surface near the lower end of the housing 43 along an axis AX2 that intersects an axis AX1 of a temperature sensing portion 44 described later. A warm-up return pipe (not shown) that forms the mechanical return passage 14 is connected.

  For this reason, the cooling water that has flowed into the thermostat device 4 from the engine side inlet 42 through the warm-up return passage 14 flows through the lower portion inside the thermostat device 4, and the electric water pump 2 through the opening 45 a of the outflow portion 45. Will be leaked.

  The thermostat device 4 includes a temperature sensing part 44 that is displaced according to the cooling water temperature, and a valve opening state that allows the cooling water to flow from the radiator side inlet 41 and the radiator side inlet 41 due to the displacement of the temperature sensing part 44. A valve 44c that is movable between a closed state in which the inflow of cooling water from the valve is shut off.

  The temperature sensing part 44 includes a piston 44b supported by a piston support part 43a whose upper end protrudes from the upper inner surface of the housing 43, and a thermal expansion body (thermo wax) that expands and contracts in response to the temperature of the cooling water. And a case 44a having a built-in structure. A disc-shaped valve 44c is attached to the upper end side of the case 44a. The valve 44c is closed by seating on a valve seat 43b formed by a part of the inner surface of the housing 43 having a small diameter.

  The thermostat device 4 includes a coil spring 44d that urges the valve 44c in the valve closing direction. The upper end portion of the coil spring 44d is in contact with the lower surface of the valve 44c. The lower end portion of the coil spring 44d is supported by a metal spring receiving frame 6 provided at the outflow portion 45. The coil spring 44d is disposed in a compressed state between the valve 44c and the spring receiving frame 6, and thereby applies a biasing force in the valve closing direction (upward direction) to the valve 44c.

  The lower end portion of the coil spring 44d is supported by the spring receiving frame 6. Further, the lower end portion of the temperature sensing portion 44 is also supported by the spring receiving frame 6 (inserted into the opening 63 formed in the central portion of the spring receiving frame 6).

  In the thermostat device 4 having the above configuration, when the temperature of the cooling water flowing into the thermostat device 4 is low, the thermal expansion body built in the case 44a contracts and the piston 44b moves backward (with respect to the case 44a). Move relatively downward). Since the piston 44b is supported by the piston support portion 43a, the valve 44c on the upper end side of the case 44a moves relatively upward to come into contact with the valve seat 43b and receives the urging force of the coil spring 44d to close the valve. It operates to become. In this closed state, the inflow of cooling water from the radiator return passage 13 is blocked (the inflow of cooling water from the radiator side inlet 41 is blocked).

  On the other hand, when the temperature of the cooling water flowing into the thermostat device 4 rises, the thermal expansion body incorporated in the case 44a expands, and the piston 44b moves forward (moves upward relative to the case 44a). Since the piston 44b is supported by the piston support portion 43a, the valve 44c on the upper end side of the case 44a moves relatively downward against the urging force of the coil spring 44d and moves away from the valve seat 43b to open the valve. It operates to become. In this valve open state, the inflow of cooling water from the radiator return passage 13 is allowed (inflow of cooling water from the radiator side inlet 41 is allowed).

  By the way, since the engine side inlet 42 is provided at one place along the axis AX2 intersecting the axis AX1 of the temperature sensing portion 44, the cooling water W1 flowing from the engine side inlet 42 is shown in FIG. As shown in FIG. 4, the temperature-sensitive portion 44 collides with a portion P <b> 1 facing the engine side inlet 42. Then, the temperature of the location where the cooling water from the engine side inlet 42 collides locally increases, and the thermal expansion body at the location expands locally. As a result, as shown in FIG. 3B, the valve 44c may tilt and open.

  In this case, the cooling water cooled by the radiator 3 flows from the position where the valve 44c is inclined and opened, and is concentrated on the position where the thermal expansion body is locally expanded (part indicated by P1 in FIG. 3A). Flow into. Therefore, a temperature change is likely to occur at a portion of the temperature sensing unit 44 facing the engine side inlet 42. As a result, the movement of the valve 44c is not stable, and hunting of the coolant temperature may occur.

  Therefore, the housing 43 of the thermostat device 4 according to the present embodiment, as shown in FIGS. 2A and 2B, is between the valve seat 43 b and the engine side inlet 42 side, A flow path constricting portion 43 c that reduces the flow rate of the cooling water from the radiator side inflow port 41 is provided on a surface facing a part of the temperature sensing unit 44 facing the inflow port 42. FIG. 2B is a cross-sectional view taken along line AA in FIG. As shown in FIG. 2B, the flow passage restricting portion 43c protrudes toward the cooling water flow passage space inside the housing 43 and is provided so as to narrow the cooling water flow passage from the radiator-side inlet 41. It has been.

  When the housing 43 has the flow passage restricting portion 43c, as shown in FIG. 3B, even if the valve 44c is inclined and opened, the flow passage of the cooling water is narrowed by the flow restricting portion 43c. The flow rate of the cooling water W2 flowing from the radiator side inlet 41 to the engine side inlet 42 decreases. For this reason, in the temperature sensing part 44, the temperature change in the location where the cooling water which flowed in from the engine side inlet 42 collides becomes small. Thereby, since the operation of the valve 44c is stabilized, hunting of the coolant temperature can be suppressed.

  On the other hand, in the housing 43 ′ that does not have the flow passage restricting portion 43 c, as shown in FIG. 3C, a larger amount than the case where the flow restricting portion 43 c is provided from the opening portion where the valve 44 c is inclined. Since the cooling water W3 flows into the engine side inlet 42 side, the temperature change at the location where the cooling water flowing in from the engine side inlet 42 collides in the temperature sensing part 44 becomes large, and the operation of the valve 44c is not performed. May become stable. For this reason, hunting of the cooling water temperature may occur.

  As described above in detail, in the present embodiment, the cooling system 1 of the engine 5 includes the radiator side inlet 41 into which the cooling water from the radiator 3 flows, and the engine side into which the cooling water that bypasses the radiator 3 flows. A housing 43 having an inlet 42, a temperature sensing part 44 that is displaced according to the temperature of the cooling water, and a valve opening state that allows the cooling water to flow in from the radiator side inlet 41 due to the displacement of the temperature sensing part 44. And a thermostat device 4 accommodated in the housing 43, and a valve 44 c that is movable between a closed state in which the inflow of cooling water from the radiator side inlet 41 is shut off. The inlet 42 is provided along an axis AX2 intersecting the axis AX1 of the temperature sensing unit 44, and the housing 43 is formed between the valve seat 43b on which the valve 44c is seated and the engine side inlet 42. A is, in a part which faces the temperature-sensing portion 44 which faces the engine-side inlet 42, and a flow rate is to channel stop portion 43c reduce the cooling water from the radiator side inlet 41. As a result, as shown in FIG. 3B, even if the valve 44c is inclined and opened, the flow path of the cooling water is narrowed by the flow passage restricting portion 43c. The flow rate of the cooling water W2 flowing to the inlet 42 side decreases. For this reason, in the temperature sensing part 44, the temperature change in the location where the cooling water which flowed in from the engine side inlet 42 collides becomes small. Thereby, since the operation of the valve 44c is stabilized, hunting of the coolant temperature can be suppressed.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention, and It is apparent from the above description that various other embodiments are possible within the scope.

1 Cooling System 3 Radiator 5 Engine 41 Radiator Side Inlet (First Inlet)
42 Engine side inlet (second inlet)
43 Housing 43b Valve seat 43c Flow path restricting portion 44 Temperature sensing portion 44c Valve AX1 Temperature sensing portion axis AX2 Engine side inlet shaft

Claims (1)

A housing having a first inlet into which cooling water from the radiator flows, and a second inlet into which cooling water that bypasses the radiator flows;
A temperature sensing portion that is displaced according to the temperature of the cooling water, a valve opening state that allows the cooling water to flow in from the first inlet due to the displacement of the temperature sensing portion, and the cooling water inflow from the first inlet A valve that moves between a closed state and a thermostat device housed in the housing,
With
The second inflow port is provided along an axis that intersects the axis of the temperature sensing unit,
The housing is provided between the valve seat on which the valve is seated and the second inlet, and on a surface facing a part of the temperature sensing portion facing the second inlet. A flow passage restricting portion that reduces the flow rate of cooling water from
A cooling system for an internal combustion engine.

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