JP2018105185A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device for an internal combustion engine, capable of performing early warming-up at the time of cold start of the engine and effective overheat prevention after completing the warming-up.SOLUTION: At the downstream end of a warming-up return pipe 14A connected to a thermostat device 4 provided in a cooling water circulation circuit, a guide part is provided for guiding cooling water flowing through the warming-up return pipe 14A toward a thermoelement. A center position O1 of the end on the suction side of a motor water pump 2 mounted at the lower part of the thermostat device 4 is made to correspond to the center position of the thermostat device 4, while a center position O2 of the end on the discharge side of the motor water pump 2 is made eccentric with respect to the center position of the thermostat device 4. The winding end position of a coil spring for energizing a valve of the thermostat device 4 to the valve closing side is set to be a position on the side in the opposite direction to the direction of eccentricity.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a cooling device for an internal combustion engine. In particular, the present invention relates to an improvement in equipment provided in a cooling water circulation circuit of a cooling device.

  Conventionally, as disclosed in Patent Document 1, for example, a cooling device for an engine (internal combustion engine) includes a cooling water 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 in the radiator. That is, the engine is warmed up early by bypassing the radiator and circulating the coolant. After the engine is warmed up, the valve of the thermostat device is opened, and the cooling water that has flowed out of the water jacket of the engine is allowed to flow to the radiator, thereby releasing the heat recovered from the engine into the atmosphere and overheating the engine. To prevent.

  Moreover, the thermostat apparatus of the cooling device currently disclosed by patent document 1 is equipped with the thermo element unit for changing the opening degree of the said valve according to the temperature of the cooling water which flows in. The thermo element unit includes a coil spring that urges the valve in the valve closing direction, and a thermo element that incorporates a thermal expansion body (thermo wax) that expands and contracts according to the temperature of the cooling water flowing into the thermostat device. The thermo-element is actuated to open the valve by the expansion of the thermal expansion body accompanying the rise in the temperature of the cooling water flowing into the thermostat device.

JP 2011-179480 A

  By the way, in order to achieve both early warm-up after cold start of the engine and prevention of overheating after completion of warm-up, an electric water pump is used as the water pump and the engine is warming up (detected cooling). When the water temperature is lower than the predetermined value), the rotational speed of the electric water pump is set low to reduce the circulating flow rate of the cooling water, while the engine warm-up is completed (the detected cooling water temperature is equal to or higher than the predetermined value). In this case, it is conceivable to increase the circulating flow rate of the cooling water by setting the rotation speed of the electric water pump high. In other words, while warming up the engine, the amount of heat recovered by the cooling water per unit time is reduced to achieve early warm-up, while after the engine is warmed up, the amount of heat recovered by the cooling water per unit time is increased. Thus, overheating is prevented.

  When such an electric water pump is controlled, during the warm-up operation of the engine, the cooling water that bypasses the radiator (the cooling water that becomes hot as the warm-up operation proceeds) is in contact with the thermo element. In this case, the thermoelement is slightly warmed by the cooling water, the valve is slightly opened, and the cooling water (low temperature cooling water) from the radiator passes through the thermostat device toward the electric water pump. It becomes a flowing situation. In this case, if the cooling water from the radiator flows into the electric water pump without contacting the thermo element, the temperature of the cooling water around the thermo element cannot be lowered, that is, the valve is closed. Control during warm-up operation due to a decrease in the temperature of the cooling water flowing out of the thermostat device (electric water according to the detected cooling water temperature). The control of the rotational speed of the pump) cannot be performed with high accuracy. Such a situation is promoted as the rotational speed of the electric water pump is set lower for the purpose of early warm-up.

  In order to solve this problem, it is conceivable to improve the internal structure of the thermostat device so that the cooling water flowing into the thermostat device by bypassing the radiator is less likely to come into contact with the thermoelement. However, in this case, after the warm-up is completed, it is difficult for the high-temperature cooling water to come into contact with the thermo-element, so the thermo-element does not operate sufficiently, the valve opening is reduced, and the cooling-water circulation circuit is There is a possibility that the temperature of the circulating cooling water will rise more than necessary.

  As described above, the required temperature-sensitive state of the thermo-element differs between the warm-up operation (when the circulating flow rate of the cooling water is decreased) and after the warm-up is completed (when the circulating flow rate of the cooling water is increased). Yes. In other words, when reducing the circulating flow rate of the cooling water, it is desirable not to make the thermo-element temperature sensitive even if the temperature of the cooling water flowing into the thermostat device rises, and when increasing the circulating flow rate of the cooling water, It is desirable to make the thermo-element temperature sensitive with high temperature cooling water.

  The present invention has been made in view of such a point, and the object thereof is to effectively perform early warm-up after cold start of the engine and prevention of overheating after completion of warm-up. An object of the present invention is to provide a cooling device for an internal combustion engine capable of performing

  In order to achieve the above object, the solution means of the present invention comprises a thermostat device for switching the flow of cooling water in a cooling water circulation circuit through which the cooling water of the internal combustion engine circulates, and the thermostat device receives the cooling water from the radiator. A first inflow port that flows in, a second inflow port through which cooling water that bypasses the radiator flows in, a valve opening state that allows inflow of cooling water from the first inflow port, and cooling from the first inflow port A valve that is movable between a valve closing state that blocks inflow of water, a coil spring that applies an urging force in a direction toward the valve closing state to the valve, and a central portion inside the thermostat device And a thermoelement for opening the valve by changing the volume of the thermal expansion body corresponding to the rise in the temperature of the cooling water. The cooling device for the internal combustion engine includes a guide portion that guides the cooling water flowing in from the second inlet toward the thermo element, and includes a water pump attached to the outlet side of the thermostat device. The center position is decentered with respect to the center position of the thermostat device, and the winding end of the coil spring that contacts the valve at a position on the decentered direction side or a position opposite to the decentered direction side. The position is set.

  When the valve opens slightly against the urging force of the coil spring during the warm-up operation of the internal combustion engine (for example, when the circulating flow rate of the cooling water is set to be small), with respect to the winding end position of the coil spring It is opened at a position having a phase difference of 180 ° in the circumferential direction. Even if the cooling water from the radiator flows into the thermostat device from this position, the center position of the water pump is eccentric with respect to the center position of the thermostat device and the winding end position of the coil spring that contacts the valve Is set at a position on the eccentric direction side or a position on the opposite direction side to the eccentric direction, it is possible to suppress the situation where the high-temperature cooling water contacts the thermo element. That is, when the winding end position of the coil spring is set at a position opposite to the eccentric direction, the eccentric direction and the opening position of the valve are on the same phase side, and the second inlet port Cooling water (high temperature cooling water) flowing in from the valve becomes a flow toward the cooling water flowing from the opening position of the valve, and cooling water flowing from the first inflow port (opening of the valve) inside the thermostat device The low temperature cooling water flowing in from the position) and the cooling water flowing in from the second inlet (high temperature cooling water) are mixed to obtain a uniform temperature distribution. For this reason, the situation where the high temperature cooling water contacts the thermo element can be suppressed. Further, when the winding end position of the coil spring is set at a position on the side of the eccentric direction, the eccentric direction and the opening position of the valve are in opposite phases, but flowed in from the first inlet. Cooling water (low temperature cooling water flowing in from the opening position of the valve) drifts toward the center of the thermostat device, that is, the thermo element, and this low temperature cooling water comes into contact with the thermo element and opens the valve. The thermo-element can be actuated on the side that closes. In this way, it is possible to suppress the situation where the high-temperature cooling water contacts the thermo element during the warm-up operation, and the valve opening can be made small or fully closed, so that early warm-up can be achieved. Cooling water can be circulated. Moreover, in what controls the rotational speed of a water pump (electric water pump) according to the detected coolant temperature, control during warm-up operation can be performed with high accuracy.

  In addition, when the warm-up operation of the internal combustion engine is completed (for example, when the circulating flow rate of the cooling water is set to be large), the cooling water (high temperature cooling water) flowing in from the second inlet is the guide portion. Is guided towards the thermo element. For this reason, it is possible to continue the state in which the high-temperature cooling water is brought into contact with the thermoelement, the state of ensuring a large valve opening is continued, and the overheating of the internal combustion engine can be prevented.

  In the present invention, a guide portion for guiding the coolant bypassing the radiator toward the thermoelement is provided, and the center position of the water pump attached to the outlet side of the thermostat device is decentered with respect to the center position of the thermostat device. The winding end position of the coil spring that biases the valve in the valve closing direction is set at a position on the eccentric direction side or a position on the opposite direction side to the eccentric direction. As a result, during the warm-up operation of the internal combustion engine, it is possible to suppress the situation in which the high-temperature cooling water contacts the thermo element, and the valve opening can be reduced or fully closed for early warm-up. It becomes possible to circulate the cooling water. In addition, after completion of warming up of the internal combustion engine, the state in which the high temperature cooling water is brought into contact with the thermo-element and the opening degree of the valve is ensured is continued, and overheating of the internal combustion engine can be prevented.

It is a figure which shows schematic structure of the cooling device which concerns on embodiment. It is sectional drawing which shows the internal structure of a thermostat apparatus. It is a bottom view of a thermostat device. It is a top view of an electric water pump. FIG. 4 is a view corresponding to FIG. 3 for explaining the flow of cooling water inside the thermostat device. It is sectional drawing of the valve periphery which shows the state which the valve | bulb of the thermostat apparatus opened only the micro opening degree. It is a figure which shows the measurement result of the cooling water temperature by the side of a thermostat apparatus in the case of changing a cooling water flow rate. It is a figure which shows the measurement result of the cooling water temperature in each phase position inside a thermostat apparatus when changing the winding end position of a coil spring.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where this invention is applied as a cooling device of a motor vehicle engine.

-Schematic configuration of cooling device-
FIG. 1 is a diagram illustrating a schematic configuration of a cooling device 1 according to the present embodiment. As shown in FIG. 1, the cooling device 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. Then, the coolant is circulated in the coolant circulation circuit 10 by the operation of the electric water pump 2, and the engine (internal combustion engine) 5 is cooled by the coolant.

  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.

  The cooling water passages connecting the respective devices provided in the cooling water circulation circuit 10 include a pump discharge passage 11, an engine outflow passage 12, a radiator return passage 13, and a warm-up return passage 14.

  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 warm-up inlet 42 of the thermostat device 4. The radiator side inlet 41 corresponds to a first inlet (first inlet into which cooling water from the radiator flows) in the present invention. The warm-up inlet 42 corresponds to a second inlet (second inlet into which cooling water bypassing the radiator flows) referred to in the present invention.

  The electric water pump 2 generates a water flow for circulating the cooling water in the cooling water circulation circuit 10. The electric water pump 2 has a motor (not shown) that is operated by electric power from a battery (not shown), and controls the rotational speed of the motor to discharge the cooling water (flow rate per unit time). The flow rate is variable. That is, the electric water pump 2 is controlled in rotational speed by a pump rotational speed command signal from the ECU 100, and thereby the discharge flow rate is adjusted. The ECU 100 controls the rotation speed of the electric water pump 2 by outputting a pump rotation speed command signal corresponding to the temperature of the cooling water circulating in the cooling water circulation circuit 10. The control of the rotational speed of the electric water pump 2 will be described later.

  The radiator 3 is, for example, a down flow type, 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. 2 (a cross-sectional view showing the internal structure of the thermostat device 4), the thermostat device 4 has a configuration in which a thermo element unit 44 is incorporated in a central portion of the inside of a housing 43 formed of synthetic resin. Yes.

  The radiator side inflow port 41 is formed on the side surface near the upper end of the housing 43 (the back side surface in FIG. 2). The radiator return passage 13 forms the radiator return passage 13 in the radiator side inflow port 41. Pipe 13A is connected.

  As shown in FIG. 3 (a bottom view of the thermostat device 4), an outflow portion 45 is provided at the lower end portion of the housing 43 for allowing the cooling water flowing through the thermostat device 4 to flow out toward the electric water pump 2. Is provided. An opening 45 a through which cooling water flows out is formed at the center of the outflow portion 45. Flange 45b, 45b connected with the upper part of the electric water pump 2 is formed in the outer peripheral side of this opening 45a. Bolt insertion holes 45c and 45c are provided in the flanges 45b and 45b. That is, the upper part of the electric water pump 2 is superimposed on the lower side of the flanges 45b and 45b (see the phantom line in FIG. 2), and both of these are integrally assembled by bolt fastening, so that the outflow portion of the thermostat device 4 The opening 45a of 45 and the suction port of the electric water pump 2 are communicated. Thereby, the cooling water which 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 inlet 41 through the radiator return passage 13, the cooling water flows from the upper side to the lower side in the thermostat device 4 and flows out. It flows out toward the electric water pump 2 from the opening 45a of the part 45.

  Further, the warm-up inlet 42 is formed on a side surface (left side surface in FIG. 2) near the lower end of the housing 43, and the warm-up return passage 14 is formed in the warm-up inlet 42. Is connected to the warm-up return pipe 14A.

  For this reason, the cooling water that has flowed into the thermostat device 4 from the warm-up inlet 42 through the warm-up return passage 14 flows through the lower portion of the thermostat device 4, and the electric water from the opening 45 a of the outflow portion 45. It will flow out to the pump 2.

  The thermo element unit 44 is provided with a thermo element 44a containing a thermal expansion body (thermo wax) that expands and contracts in response to the temperature of the cooling water, and the piston 44b moves forward by expansion of the thermal expansion body. It is configured to move (moves upward relative to the thermo element 44a). The upper end portion of the piston 44b is supported by a piston support portion 43a formed by projecting the upper inner surface of the housing 43. For this reason, the thermo element 44a moves downward as the piston 44b moves forward.

  A disk-shaped valve 44c is attached to the thermo element 44a. The valve 44c is brought into a closed state by contacting a valve seat 43b formed by a part of the inner surface of the housing 43 having a small diameter.

  The thermo element unit 44 is provided with 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 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.

  As shown in FIG. 3, the spring receiving frame 6 is provided with locking pieces 61, 61 at two locations on the outer peripheral portion thereof and having a phase difference of approximately 180 ° in the circumferential direction. These locking pieces 61, 61 have a shape protruding toward the outer peripheral side, and are supported in a state in which they are prevented from rotating by the outflow portion 45 of the housing 43. As the formation positions of the engagement pieces 61, 61, the formation position of one engagement piece 61 is set on the arrangement position side (the left side in FIG. 3) of the warm-up return pipe 14A. The formation position is set on the side opposite to the position where the warm-up return pipe 14A is disposed (the right side in FIG. 3).

  As described above, the lower end portion of the coil spring 44d is supported by the spring receiving frame 6. Further, the lower end portion of the thermo element 44a 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). For this reason, the thermo element unit 44 is such that the upper end of the piston 44b is supported by the piston support 43a, and the lower ends of the coil spring 44d and the thermo element 44a are supported by the spring receiving frame 6. It is arranged at the center inside the housing 43.

  In the spring receiving frame 6, the outer diameter dimension other than the part where the locking pieces 61 are formed is set smaller than the inner diameter dimension of the opening 45a. Therefore, gaps S, S extending in the circumferential direction are formed between the inner edge of the opening 45a and the outer edge of the spring receiving frame 6. Further, slits 62, 62 penetrating along the plate thickness direction are formed in the locking pieces 61, 61 of the spring receiving frame 6. For this reason, the gaps S and S and the slits 62 and 62 are formed as a flow path of cooling water for communicating between the interior of the thermostat device 4 and the electric water pump 2. As described above, since the position where the one locking piece 61 is formed is set to the position where the warming return pipe 14A is disposed, the position where the slit 62 formed in this locking piece 61 is also warmed up. This is the arrangement position side of the return pipe 14A. That is, the slit 62 is disposed below the warm-up inlet 42.

  Since the thermostat device 4 is configured in this way, when the temperature of the cooling water flowing into the thermostat device 4 is low, the thermal expansion body built in the thermo element 44a contracts and the piston 44b moves backward. Move (moves downward relative to the thermo element 44a). As a result, the valve 44c attached to the thermo element 44a moves relatively upward and comes into contact with the valve seat 43b, and operates so as to be closed by receiving the urging force of the coil spring 44d. 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 thermo element 44a expands, and the piston 44b moves forward (moves upward relative to the thermo element 44a). ) As a result, the valve 44c attached to the thermo element 44a moves downward relative to the urging force of the coil spring 44d, moves away from the valve seat 43b, and operates to open the valve. 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).

  As described above, the ECU 100 controls the rotational speed of the electric water pump 2 by outputting a pump rotational speed command signal corresponding to the temperature of the cooling water.

  The ECU 100 is connected to a water temperature sensor 101 that detects the temperature of the cooling water, a pump rotation speed sensor 102 that detects the rotation speed of the electric water pump 2, and the like, and output signals from the sensors 101 and 102 are input. ing. The water temperature sensor 101 is disposed, for example, on the outlet side of the thermostat device 4. The arrangement position of the water temperature sensor 101 is not limited to this. The pump rotation speed sensor 102 is disposed in the electric water pump 2.

  As the rotational speed control of the electric water pump 2, during the warm-up operation of the engine 5, the rotational speed of the electric water pump 2 is set low to reduce the circulating flow rate of the cooling water in the cooling water circulation circuit 10. Further, the rotational speed of the electric water pump 2 calculated based on the output signal from the pump rotational speed sensor 102 becomes the target rotational speed during the warm-up operation (a fixed value or a value that varies according to the temperature of the cooling water). Thus, feedback control of the rotational speed is performed. On the other hand, after the warm-up of the engine 5 is completed, the rotational speed of the electric water pump 2 is set high to increase the circulating flow rate of the cooling water in the cooling water circulation circuit 10. Further, the rotational speed of the electric water pump 2 calculated based on the output signal from the pump rotational speed sensor 102 becomes the target rotational speed after completion of warming up (a fixed value or a value that varies depending on the temperature of the cooling water). Thus, feedback control of the rotational speed is performed. In this way, during the warm-up operation of the engine 5, the amount of heat recovered per unit time by the cooling water is reduced to achieve early warm-up, while the warm-up of the engine 5 is completed per unit time by the cooling water. The amount of heat recovery is increased to prevent overheating. Thereby, during the warm-up operation, it is possible to realize an early engine temperature that can minimize the friction between the cylinder inner wall surface of the engine 5 and the piston, and to improve the fuel consumption rate. Further, after the warm-up is completed, the engine temperature is maintained to improve the fuel consumption rate and prevent overheating.

  As described above, the cooling device 1 is configured by the cooling water circulation circuit 10 and the ECU 100.

  Hereinafter, a configuration that characterizes the present embodiment will be described. Configurations that characterize the present embodiment include a configuration around the warm-up inlet 42, an arrangement configuration of the electric water pump 2, and an arrangement configuration of the coil spring 44d. Each will be described below.

-Configuration around the warm-up inlet 42-
First, the configuration around the warm-up inlet 42 will be described. As shown in FIG. 2, the warm-up inlet 42 includes an opening that is open in the horizontal direction (left direction in FIG. 2). The warm-up return pipe 14 </ b> A extends in the vertical direction on the side of the thermostat device 4, and the lower end position thereof is set near the lower end position on the side surface of the thermostat device 4. In the housing 43, the warm-up inlet 42 is formed at a portion where the side surface of the warm-up return pipe 14A contacts. For this reason, the direction of the flow line of the cooling water flowing through the warming-up return passage 14 inside the warming-up return pipe 14A is from the downward direction in the drawing at the downstream end portion of the warming-up return passage 14. It changes in the right direction (direction toward the inside of the thermostat device 4) (see arrow W1 in FIG. 2).

  The warming-up return pipe 14A is provided with a guide function for guiding the cooling water flowing through the warming-up return passage 14 toward the thermo element 44a.

  Specifically, among the inner wall surfaces of the warm-up return pipe 14A, the inner wall surface farther from the thermostat device 4 at the lower end thereof (the inner wall surface located on the left side in FIG. 2) is directed downward. 4 is formed by an inclined surface 14a inclined in a direction toward 4. Thereby, while reducing the pressure loss with respect to the flow of the cooling water and suppressing the decrease in the flow velocity, the direction of the flow line of the cooling water described above is changed (changed from the downward direction toward the inside of the thermostat device 4). To be able to.

  As another guide function, the bottom plate 14c of the warm-up return pipe 14A having a horizontal surface 14b extending in the horizontal direction continuously to the lower end edge of the inclined surface 14a is directed toward the inside of the thermostat device 4. An extending guide portion 14d is provided. The horizontal dimension of this guide portion 14d (the dimension protruding toward the inside of the thermostat device 4; the dimension t1 in FIG. 2) is set so that the rotational speed of the electric water pump 2 is set high and the cooling in the cooling water circulation circuit 10 is performed. It is set by experiment or simulation as a dimension that can reliably bring the cooling water flowing through the warm-up return passage 14 into contact with the thermo element 44a when the water circulation flow rate is increased.

-Arrangement of electric water pump 2-
Next, the arrangement configuration of the electric water pump 2 will be described. FIG. 4 is a plan view of the electric water pump 2. FIG. 5 is a bottom view of the thermostat device 4 for explaining the flow of the cooling water inside the thermostat device 4, and shows the shape of the electric water pump 2 (the shape of the suction port 23 of the electric water pump 2 and the shape of the electric water pump 2). The shape of the discharge port 21) is indicated by imaginary lines.

  As shown in these drawings, the center position of the electric water pump 2 (the center position O2 of the discharge port 21 described later) is the center position of the thermostat device 4 (the center position O1 of the suction port 23 of the electric water pump 2 described later). Eccentric).

  Specifically, the center position (point O1 in FIG. 4) of the end portion on the suction side of the electric water pump 2 coincides with the center position of the thermostat device 4 (center position of the inner surface of the housing 43). That is, as shown in FIG. 4, an abutting flange 22 that abuts the flange 45 b of the outflow portion 45 of the thermostat device 4 is provided at the end of the electric water pump 2 on the suction side. Is formed with a circular suction port 23. That is, the center position O1 of the suction port 23 coincides with the center position of the thermostat device 4. The contact flange 22 of the electric water pump 2 is formed with bolt insertion holes 22a and 22a corresponding to the bolt insertion holes 45c and 45c formed in the flanges 45b and 45b of the thermostat device 4. Also, reference numeral 24 in FIG. 4 is an outer surface of the electric water pump 2.

  On the other hand, the center position (point O2 in FIG. 4) of the discharge-side end portion of the electric water pump 2 is the same as the center position of the thermostat device 4 (matches the center position O1 of the suction port 23 of the electric water pump 2). Eccentric. In the plan view shown in FIG. 4, the center position (end position of the discharge port 21) of the discharge side end of the electric water pump 2 with respect to the center position (center position of the suction port 23) O1 of the suction side of the electric water pump 2 is shown. (Center position) O2 is decentered obliquely downward to the left in the figure. Further, in the bottom view shown in FIG. 5, the center position O2 of the discharge side end of the electric water pump 2 is decentered obliquely upward to the left in the drawing with respect to the center position O1 of the end of the electric water pump 2 on the suction side. Yes.

  Thus, when the center position of the electric water pump 2 is decentered, the flow of the cooling water accompanying the operation of the electric water pump 2 is deflected in the decentered direction. That is, most of the flow of the cooling water is parallel to the flow of the stream line from the central position O1 toward the central position O2. This flow deflection also occurs in the cooling water flowing inside the thermostat device 4. An arrow W <b> 2 in FIG. 5 indicates the direction of the flow of the cooling water flowing inside the thermostat device 4. That is, the cooling water flowing through the warm-up return passage 14 inside the warm-up return pipe 14A flows into the thermostat device 4 and then the center position of the electric water pump 2 is decentered. In response, the thermostat device 4 is deflected in the eccentric direction (left direction in FIG. 5). As shown in FIG. 5, the arrangement position of the warm-up return pipe 14A is set to the position of “0 °” in the circumferential direction, the position of “90 °” in the clockwise direction, the position of “180 °”, “ When it is defined as the position of “270 °”, the cooling water flowing from the position of “0 °” is deflected toward the position of “270 °”. The radiator return pipe 13A is connected to the position of “270 °”.

-Arrangement configuration of coil spring 44d-
Next, the arrangement configuration of the coil spring 44d will be described. The coil spring 44d urging the valve 44c in the valve closing direction is such that the winding end position on the side contacting the lower surface of the valve 44c (the upper end side of the coil spring 44d) is the center position of the electric water pump 2 Is set in the direction opposite to the eccentric direction. That is, in the example shown in FIG. 5, the eccentric direction of the center position of the electric water pump 2 is the direction of about “270 °”, and therefore the winding end position of the coil spring 44d is about “90” in the figure. “°” position. Thus, when the winding end position of the coil spring 44d is set, when the valve 44c is in the closed state, the winding end portion of the coil spring 44d is in contact with the valve 44c at a substantially “90 °” position. The valve 44c is pressed against the valve seat 43b with a relatively high biasing force. On the other hand, the coil spring 44d is not in contact at a position of approximately “270 °”, which is a position having a phase difference of 180 ° in the circumferential direction with respect to the winding end position of the coil spring 44d. The biasing force from the coil spring 44d is relatively low.

  For this reason, when the cooling water flowing in from the warm-up return passage 14 is in contact with the thermo element 44a during the warm-up operation of the engine 5 or the like, the thermo element 44a is slightly heated by the cooling water and the valve 44c is slightly opened, and at this time, the coil spring 44d is opened at a position having a phase difference of 180 ° in the circumferential direction with respect to the winding end position of the coil spring 44d (position of “270 °”). FIG. 6 shows a state where the valve 44c is slightly opened on the left side (position of “270 °”) in the drawing. In this case, as indicated by an arrow W3 in the figure, the cooling water from the radiator return pipe 13A flows only in the open part of the valve 44c (the open part on the left side in the figure).

  In such a situation, as described above, the center position of the electric water pump 2 is eccentric with respect to the center position of the thermostat device 4, so that the eccentric direction and the opening position of the valve 44c are on the same phase side. Thus, the cooling water (high-temperature cooling water) flowing in from the warm-up inlet 42 through the warm-up return pipe 14A has a relatively low biasing force from the valve 44c (coil spring 44d). It becomes a flow toward the flow of cooling water flowing in from (position). For this reason, inside the thermostat device 4, cooling water that flows in from the radiator-side inlet 41 (low-temperature cooling water that flows in from the open position of the valve 44 c) and cooling water that flows in from the warm-up inlet 42 (high temperature) Of cooling water).

−Cooling water circulation operation−
Next, the cooling water circulation operation in the cooling water circulation circuit 10 will be described.

<Warm-up operation>
First, when the engine 5 is cold started, the temperature of the cooling water is low, so that the thermal expansion body of the thermo element 44a is contracted, and the valve 44c of the thermostat device 4 is closed.

  When the electric water pump 2 is actuated, the electric water pump 2, the pump discharge passage 11, the block-side water jacket 52a, the head-side water jacket 51a, and the engine outflow passage 12 as shown by solid arrows in FIG. Cooling water is circulated in the order of the warm-up return passage 14, the thermostat device 4, and the electric water pump 2.

  Thus, since the circulating cooling water bypasses the radiator 3, the cooling water is not cooled in the radiator 3, so that the warm-up of the engine 5 is completed early.

  For controlling the electric water pump 2 during such warm-up operation, as described above, the rotational speed of the electric water pump 2 is set low, thereby reducing the circulating flow rate of the cooling water in the cooling water circulation circuit 10. .

  During the warm-up operation, when the cooling water flowing into the thermostat device 4 from the warm-up return passage 14 (cooling water that becomes higher in temperature as the warm-up operation proceeds) is in contact with the thermo element 44a. The thermo-element 44a is slightly heated by this cooling water, and the valve 44c is slightly opened. At this time, as described above, the coil spring 44d is released at a position having a phase difference of 180 ° in the circumferential direction with respect to the winding end position of the coil spring 44d (see FIG. 6). In the case of the present embodiment, the valve 44c is slightly opened at the position “270 °” in FIG.

  Thus, even if the cooling water from the radiator 3 flows into the thermostat device 4, the central position of the electric water pump 2 (the central position O2 of the discharge port 21 of the electric water pump 2) is the same as that of the thermostat device 4. It is eccentric with respect to the center position (coincidence with the center position O1 of the suction port 23 of the electric water pump 2), and the winding end position of the coil spring 44d abutting on the valve 44c is at a position opposite to the eccentric direction. Therefore, the eccentric direction and the opening position of the valve 44c are on the same phase side, and the cooling water (high temperature cooling water) flowing in from the warming inlet 42 through the warming return pipe 14A. ) Is directed to the flow of cooling water flowing from the open position of the valve 44c (position where the biasing force from the coil spring 44d is relatively low). The cormorant flow. For this reason, in the thermostat device 4, the cooling water flowing from the radiator side inlet 41 (low temperature cooling water flowing from the opening position of the valve 44 c) and the cooling water flowing from the warming inlet 42 (high temperature) The cooling water is mixed with each other to obtain a uniform temperature distribution. As a result, it is possible to suppress the situation where the high-temperature cooling water contacts the thermo element 44a, and the opening degree of the valve 44c can be reduced or fully closed, and the cooling water is circulated for early warm-up. be able to. In addition, the cooling water temperature detected by the water temperature sensor 101 is less affected by the temperature (low temperature) of the cooling water flowing from the radiator-side inlet 41, so that the control of the rotational speed of the electric water pump 2 is high. Can be done with precision.

<After completion of warm-up>
When the warm-up operation is continued and the coolant temperature detected based on the output signal from the water temperature sensor 101 becomes high, and the coolant temperature reaches the warm-up completion temperature, the thermo element 44a is actuated greatly and the valve 44c opens.

  In this case, in addition to the cooling water circulation indicated by the solid arrow in FIG. 1, the cooling water circulation indicated by the one-dot chain arrow in FIG. 1 is also performed. That is, a part of the cooling water flowing through the engine outflow passage 12 flows toward the radiator 3, and after the heat is radiated by the radiator 3, the cooling water flows in the order of the radiator return passage 13, the thermostat device 4 and the electric water pump 2. It will be. For this reason, the cooling water that has flowed through the warm-up return passage 14 and the cooling water that has flowed through the radiator return passage 13 both flow into the thermostat device 4.

  As described above, the control of the electric water pump 2 after the completion of the warm-up is performed by setting the rotational speed of the electric water pump 2 high, thereby increasing the circulating flow rate of the cooling water in the cooling water circulation circuit 10. .

  After the warm-up is completed, the cooling water (high temperature cooling water) flowing in from the warm-up inlet 42 is guided toward the thermo element 44a by the guide portion 14d. For this reason, it is possible to continue the state in which the high-temperature cooling water is brought into contact with the thermo element 44a, the state of ensuring a large opening of the valve 44c is continued, and overheating of the engine 5 can be prevented.

  As described above, according to the present embodiment, when the circulating flow rate of the cooling water is reduced during the warm-up operation, even if the cooling water temperature rises, the high-temperature cooling water remains in the thermo element 44a. It is possible to suppress the situation where the thermoelement 44a comes into contact with the thermoelement 44a. Further, when the circulating flow rate of the cooling water is increased after completion of the warm-up operation, the situation where the high temperature cooling water is brought into contact with the thermo element 44a can be continued, and the thermo element is sensed by the high temperature cooling water. Can be warmed. For this reason, it is possible to effectively perform early warm-up after cold start of the engine 5 and prevention of overheating of the engine 5 after completion of warm-up. In addition, it is possible to control the rotational speed of the electric water pump 2 according to the temperature of the cooling water with high accuracy.

  FIG. 7 shows the measurement of the coolant temperature on the outlet side of the thermostat device 4 when the coolant flow rate (circulation flow rate) in the coolant circulation circuit 10 is changed by controlling the rotational speed of the electric water pump 2 during the warm-up operation. It is a figure which shows the result. The broken line in the figure is the result of measuring the cooling water temperature on the outlet side of the thermostat device when the flow rate of the cooling water is changed using a conventional thermostat device. The solid line in the figure is the result of measuring the cooling water temperature on the outlet side of the thermostat device 4 when the thermostat device 4 according to this embodiment is used and the cooling water flow rate is changed.

  When the conventional thermostat device is used, as described above, the valve is slightly opened, and the cooling water (low temperature cooling water) from the radiator flows through the thermostat device toward the electric water pump. In this case, the cooling water temperature around the thermo element cannot be lowered, and the cooling water temperature distribution on the outlet side of the thermostat device is uneven, so the cooling water flow rate is reduced. There is a range in which the coolant temperature on the outlet side of the thermostat device becomes lower (as the rotational speed of the electric water pump is set lower). For this reason, control of the coolant temperature during the warm-up operation cannot be realized with high accuracy.

  On the other hand, according to the present embodiment, even when the valve 44c is slightly opened and the cooling water (low temperature cooling water) from the radiator 3 flows into the thermostat device 4, As described above, since the low-temperature cooling water and the high-temperature cooling water are mixed inside the thermostat device 4 and the distribution of the cooling water temperature on the outlet side of the thermostat device 4 can be made uniform, the cooling water The smaller the flow rate (the lower the rotational speed of the electric water pump is set), the lower the cooling water temperature at the outlet side of the thermostat device 4 will not be, and the higher the accuracy of controlling the cooling water temperature during warm-up operation. Can be realized.

  FIG. 8 is a diagram illustrating a measurement result of the cooling water temperature at each phase position inside the thermostat device 4 when the winding end position of the coil spring 44d in contact with the valve 44c is changed. The horizontal axis is the winding end position of the coil spring 44d, and □ in the figure represents the cooling water temperature at the position of “0 °”, and x in the figure represents the cooling water temperature at the position of “90 °”. , In the figure represents the cooling water temperature at the position of “180 °”, and Δ in the figure represents the cooling water temperature at the position of “270 °”. In the present embodiment, as described above, the winding end position of the coil spring 44d is the “90 °” position, and at the “270 °” position, the low-temperature cooling water (cooling water flowing in from the radiator-side inlet 41). ) And high-temperature cooling water (cooling water flowing in from the warm-up inlet 42) are mixed, and the temperature of the cooling water temperature (cooling water temperature distribution) at each phase position becomes substantially uniform. Yes. For example, the distribution of the cooling water temperature is uniform as compared with the case where the winding end position of the coil spring 44d is set to a position of “180 °”. Thereby, it was confirmed that the control of the cooling water temperature during the warm-up operation can be realized with high accuracy.

(Modification)
Next, a modified example will be described. In the embodiment described above, the winding end position of the coil spring 44d on the side in contact with the valve 44c is set in a direction opposite to the eccentric direction of the central position of the electric water pump 2 (the eccentric direction with respect to the central position of the thermostat device 4). It was. In this modification, the winding end position of the coil spring 44d on the side in contact with the valve 44c is set in the eccentric direction of the center position of the electric water pump 2.

  If it demonstrates using FIG. 5, as mentioned above, the eccentric direction of the center position of the electric water pump 2 will be the direction of the position of "270 degrees". On the other hand, the winding end position of the coil spring 44d is also set at a position of “270 °” in the drawing. When the winding end position of the coil spring 44d is set in this manner, when the valve 44c is closed, the winding end portion of the coil spring 44d is in contact with the valve 44c at the "270 °" position. The valve 44c is pressed against the valve seat 43b with a relatively high biasing force. On the other hand, the winding end portion of the coil spring 44d is not in contact with the winding end position of the coil spring 44d at a position “90 °” that is a position having a phase difference of 180 ° in the circumferential direction. Thus, the urging force from the coil spring 44d is relatively low.

  According to such a configuration, even if the cooling water from the radiator 3 flows into the thermostat device 4 during the warm-up operation of the engine 5, the center position of the electric water pump 2 is the center position of the thermostat device 4. Since the winding end position of the coil spring 44d is set at a position on the eccentric direction side, the eccentric direction and the opening position of the valve 44c are in opposite phases, and the radiator side inlet The cooling water flowing in from 41 (low-temperature cooling water flowing in from the opening position of the valve 44c) drifts toward the center of the thermostat device 4, that is, the thermo-element 44a. The thermo element 44a can be operated on the side where the valve 44c is closed by contacting the thermo element 44a. For this reason, the situation where the high temperature cooling water contacts the thermo element 44a can be suppressed, the opening degree of the valve 44c can be made small or fully closed, and the cooling water circulation for early warm-up can be achieved. Can be performed. As a result, the control of the coolant temperature during the warm-up operation can be realized with high accuracy.

  Further, after the warm-up is completed, as in the case of the above-described embodiment, the cooling water (high-temperature cooling water) flowing in from the warm-up inlet 42 is guided toward the thermo element 44a by the guide portion 14d. Thus, the state of ensuring a large opening of the valve 44c is continued, and overheating of the engine 5 can be prevented.

  Even in this modification, as in the above-described embodiment, when the cooling water circulation flow rate is reduced during the warm-up operation, even if the cooling water temperature rises, the high-temperature cooling water is The situation in contact with the element 44a can be suppressed, and the thermo element 44a can be prevented from sensing temperature. Further, when the circulating flow rate of the cooling water is increased after completion of the warm-up operation, the situation where the high temperature cooling water is brought into contact with the thermo element 44a can be continued, and the thermo element is sensed by the high temperature cooling water. Can be warmed. For this reason, it is possible to effectively perform early warm-up after cold start of the engine 5 and prevention of overheating of the engine 5 after completion of warm-up.

-Other embodiments-
The present invention is not limited only to the embodiment and the modification examples, and all modifications and applications encompassed within the scope of the claims and the equivalent scope are possible.

  For example, in the embodiment and the modified example, the center position O1 of the end portion on the suction side of the electric water pump 2 is used as the thermostat device as a mode in which the center position of the electric water pump 2 is eccentric with respect to the center position of the thermostat device 4. 4, the center position O2 of the end portion on the discharge side of the electric water pump 2 is decentered. The present invention is not limited to this, and the center position O1 of the end portion on the suction side of the electric water pump 2 may be eccentric with respect to the center position of the thermostat device 4.

  In the embodiment and the modified example, during the warm-up operation of the engine 5, the rotational speed of the electric water pump 2 is set low to reduce the circulating flow rate of the cooling water in the cooling water circulation circuit 10, thereby After completion of the machine, the case where the present invention is applied to the control for setting the rotation speed of the electric water pump 2 to be high and increasing the circulating flow rate of the cooling water in the cooling water circulation circuit 10 has been described. The present invention can also be applied to those that perform other control as the rotational speed control of the electric water pump 2.

  Moreover, although the said embodiment and the said modification demonstrated the case where this invention was applied as a cooling device of a motor vehicle engine, this invention is applicable also as cooling devices other than a motor vehicle engine.

  The present invention can be applied to a cooling device that controls an electric water pump so that the cooling water circulation flow rate is decreased during the warm-up operation of the engine and the cooling water circulation flow rate is increased after the warm-up is completed.

DESCRIPTION OF SYMBOLS 1 Cooling device 10 Cooling water circulation circuit 14d Guide part 2 Electric water pump 3 Radiator 4 Thermostat device 41 Radiator side inlet (1st inlet)
42 Warm-up inlet (second inlet)
44a Thermo element 44c Valve 44d Coil spring 45 Outflow part 5 Engine (internal combustion engine)
O1 Center position on the suction side of the electric water pump (center position of the thermostat device)
O2 Electric water pump discharge center position (water pump center position)

Claims (1)

A thermostat device that switches a flow of cooling water in a cooling water circulation circuit through which cooling water of an internal combustion engine circulates, the thermostat device having a first inlet through which cooling water from a radiator flows, and cooling water that bypasses the radiator Is movable between a second inlet into which the refrigerant flows, a valve-opening state that allows inflow of cooling water from the first inlet, and a valve-closed state that blocks inflow of cooling water from the first inlet A valve, a coil spring that applies a biasing force in a direction toward the valve closing position with respect to the valve, and a thermal expansion body that is disposed in the center of the thermostat device and that responds to an increase in the temperature of the cooling water A cooling device for an internal combustion engine comprising a thermo element that opens the valve by a change in volume of
A guide portion for guiding the cooling water flowing in from the second inlet toward the thermo element;
The center position of the water pump attached to the outlet side of the thermostat device is decentered with respect to the center position of the thermostat device, and the position of the decentered direction side or the position opposite to the decentered direction side. Further, a winding end position of the coil spring that contacts the valve is set.

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