JP2017048682A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system for an engine 1 in which a rotary valve 5 is provided for adjusting the flow amount of cooling water and a radiator 2 is provided on the downstream side thereof, for suppressing a decline in the controllability of an engine water temperature resulting from a variation of individuals while sufficiently securing the opening area of a radiator side port 50b of the rotary valve 5 when fully opened.SOLUTION: In a predetermined turning angle range θ8-θ9 of a valve element 51 when starting opening the radiator side port 50b, the rate of an increase in the opening area of the port with a turning angle θ is lower than in another θ9-θ10 than the turning angle range.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an engine cooling device in which a radiator is disposed on the downstream side of a valve that adjusts the flow rate of cooling water.

  2. Description of the Related Art Conventionally, in an automobile engine, a cylinder head, a cylinder block, and the like that are heated by combustion in a cylinder are cooled by cooling water. In such an engine cooling system, a water jacket such as a cylinder head and a radiator outside the engine are connected by a water hose, and cooling water is circulated by a water pump.

  As an example, the engine cooling system described in Patent Document 1 includes a main flow path for circulating cooling water from the engine to the radiator, and a bypass flow path for bypassing the radiator. For example, a rotary valve is provided to adjust the flow rate of the gas. The temperature of the cooling water (hereinafter also referred to as engine water temperature) can be controlled by adjusting the opening degree of the valve according to the temperature of the cooling water and adjusting the flow rate of the cooling water cooled by the radiator. .

  That is, for example, by closing the valve for a while after the cold start of the engine and shutting off the flow of the cooling water through the main passage, the cooling water from the engine flows through the bypass passage and returns to the engine. Since it is not cooled by the radiator, warm-up of the engine can be promoted. Further, after the warming up, the engine water temperature can be controlled by adjusting the opening of the valve so that the combustion state in the cylinder becomes suitable.

JP 2013-068162 A

  By the way, the rotary valve of the conventional example changes the opening area of the port (the opening degree of the valve) with the rotation of the rotor (valve element) disposed in the casing, and rotates the rotor. An angle command is given to the stepping motor to rotate it to an angle corresponding to the target valve opening. In this case, the actual valve opening varies due to individual variation of the valve, and the controllability of the engine water temperature may be reduced.

  That is, for example, when the valve opening is increased in order to lower the engine water temperature, if the valve opening becomes larger than the target opening, the flow rate of the cooling water passing through the radiator will increase too much, so the engine water temperature will decrease. Too much. In particular, when cooling water is started to circulate between the radiator and the radiator in an environment where the outside air temperature is low, such as in winter, the low-temperature cooling water in the radiator flows into the water jacket, so that the problem is likely to become remarkable.

  On the other hand, it is conceivable to change the structure of the rotary valve so that the change (valve opening characteristic) of the valve opening due to the rotation of the rotor becomes gentle, but the rotation angle of the rotor is usually 300 at the maximum. Since it is about °, if the valve opening characteristics are made gentle, the opening area of the port when fully opened may not be secured.

  In consideration of such problems, an object of the present invention is to suppress a decrease in controllability of the engine water temperature due to individual variations while ensuring a sufficient opening area of the port when the rotary valve is fully opened. is there.

  In order to achieve the above object, the present invention is directed to an engine cooling system in which a valve for adjusting the flow rate of cooling water is disposed in an engine cooling system, and a radiator is disposed downstream thereof. Is a rotary valve in which the opening area of the port changes as the valve body rotates. And, in this rotary valve, in the predetermined rotation angle range of the valve body when the port for sending the cooling water to the radiator starts to open, the increasing ratio of the opening area with respect to the rotation angle is other than the rotation angle range. It is configured to be smaller than

  The engine cooling device configured as described above adjusts the flow rate of the cooling water circulating between the radiator and the radiator by controlling the opening of the rotary valve according to the operating state of the engine and the temperature of the cooling water. The temperature can be controlled. This makes it possible to control the temperature of the cooling water in the water jacket or the like of the cylinder head (that is, the engine water temperature) so that the combustion state in the cylinder becomes suitable.

  In the rotary valve described above, the increase ratio of the opening area of the port with respect to the rotation of the valve body is relatively small in a predetermined rotation angle range of the valve body in which the port for sending the cooling water to the radiator starts to open. Yes. In other words, when the cooling water circulation starts between the engine and the radiator, the increase in the opening area of the port becomes gradual, so the increase in the flow rate of the cooling water also becomes gradual, and individual variations of the rotary valve occur. The deterioration of the controllability of the engine water temperature due to this is suppressed.

  On the other hand, outside the predetermined rotation angle range, the increase ratio of the opening area with respect to the rotation angle of the valve body is relatively large. The flow rate of the gas also increases. Therefore, it is possible to secure a sufficient opening area of the port when the rotary valve is fully opened, thereby obtaining a sufficient flow rate of the cooling water. As described above, in order to relatively reduce the increase rate of the opening area of the port with respect to the rotation of the valve body of the rotary valve, the shape of the opening or groove of the valve body communicating with the port is devised. Thus, the change in the area of the portion communicating with the port may be reduced.

  According to the present invention, the opening characteristic of the rotary valve that adjusts the flow rate of the cooling water circulating between the engine and the radiator is devised to increase the opening area when the port for sending the cooling water to the radiator starts to open. Since it is relatively gradual, the change in the flow rate of the cooling water due to individual variation of the valve can be made gradual, and a decrease in controllability of the engine water temperature can be suppressed.

It is a figure showing typically composition of an engine cooling device concerning an embodiment of the invention. It is explanatory drawing which shows the structure of a rotary valve typically. FIG. 2 is a view corresponding to FIG. 1 and showing a flow of cooling water during warming up of the engine. FIG. 4 is a view corresponding to FIG. 3 after the engine is warmed up. It is a graph which shows the valve opening characteristic of each port of a rotary valve, and the total flow rate of a cooling water in correlation with each other. It is a graph which shows the valve opening characteristic of each port when there is no air-conditioning request | requirement as other embodiment.

  Hereinafter, an embodiment in which the present invention is applied to an engine mounted on an automobile will be described as an example. As schematically shown in FIG. 1, an engine cooling device according to an embodiment of the present invention is for cooling a cylinder head, a cylinder block, and the like of an engine 1 that is heated by combustion in a cylinder. 1 and the radiator 2 are connected by a water hose or the like to circulate cooling water. In addition, the radiator 2 is arrange | positioned at the front part of a motor vehicle, and heat-exchanges the cooling water which collect | recovered the heat | fever of the engine 1, and driving | running | working wind.

  In the present embodiment, a first cooling water passage 3 from the engine 1 to the radiator 2 and a second cooling water passage 4 from the radiator 2 to the engine 1 are provided, and the first cooling water passage 3 includes A rotary valve 5 for adjusting the flow rate of the cooling water is disposed. In other words, the radiator 2 is disposed downstream of the rotary valve 5 in the flow of the cooling water. On the other hand, a thermostat 6 and a water pump 7 are disposed in the second cooling water passage 4, and cooling water is sent out from the water pump 7.

  That is, the engine 1 is, for example, a gasoline engine or a diesel engine, and a water jacket is formed in each of the cylinder head and the cylinder block. As an example, the water pump 7 is disposed at the inlet of the water jacket of the cylinder block and is driven by a crankshaft via a belt or the like. The cooling water sent from the water pump 7 to the water jacket of the cylinder block flows to the water jacket of the cylinder head and then flows out from the outlet to the first cooling water passage 3.

  In the first cooling water passage 3, a bypass passage 8 is branched from a portion upstream of the rotary valve 5, and a downstream end portion thereof is connected to the second cooling water passage 4 via a thermostat 6. Yes. The thermostat 6 is a valve that operates by expansion and contraction of the thermowax, and closes the second cooling water passage 4 when the temperature of the cooling water is lower than 80 ° C., for example. On the other hand, if the temperature of the cooling water is, for example, about 80 ° C. or higher, the thermostat 6 is opened.

  Since the bypass passage 8 is connected to the downstream side of the valve of the thermostat 6 that is opened and closed in this way (the side close to the water pump 7), the cooling water flows regardless of the opening and closing of the valve. For example, when the temperature is low such as after a cold start of the engine 1, the cooling water bypasses the radiator 2 and flows through the bypass passage 8 and is not cooled by the radiator 2. Since the valve 6 is opened, a part of the cooling water passes through the radiator 2.

  Further, in the rotary valve 5 disposed in the first cooling water passage 3, a part of the cooling water discharged from the water jacket of the engine 1 as described above is supplied to, for example, the heater core 9 in addition to the radiator 2. A supply passage 10 and a passage 12 for supplying various devices 11 such as a throttle valve and a CVT warmer are connected to each other. The downstream ends of these passages 10 and 12 join the bypass passage 8.

  As shown in detail in FIG. 2, the rotary valve 5 includes a cylindrical casing 50 having four ports 50a to 50d, and a cylindrical valve body 51 rotatably accommodated therein. The valve body 51 is rotated around the axis X by a stepping motor 52 (indicated by a virtual line). The illustrated port 50a is connected to the upstream side 3a of the first cooling water passage 3 (referenced only in FIG. 2), and the engine into which the cooling water discharged from the water jacket of the engine 1 flows as described above. This is the side port 50a.

  Similarly, the illustrated port 50b is a radiator-side port 50b that is connected to the downstream side 3b of the first cooling water passage 3 (referenced only in FIG. 2) and sends the cooling water to the radiator 2 as described above. . The ports 50c and 50d are the heater-side port 50c and the device-side port 50d, which are connected to the upstream ends of the passages 10 and 12, respectively, and supply cooling water to the heater core 9 and the various devices 11 as described above. In other words, the ports 50b to 50d are cooling water outflow ports.

  As an example, the valve body 51 is closed at both ends in the axial center X direction, and the peripheral walls are formed with openings 51a to 51d extending in the circumferential direction at positions where they can communicate with the four ports 50a to 50d, respectively. ing. Moreover, the inside of the valve body 51 becomes a communicating path which connects the said opening parts 51a-51d. Then, as the valve body 51 rotates, the communication state between the openings 51a to 51d and the ports 50a to 50d changes, so that the ports 50a to 50d are opened and closed.

  That is, although not shown, a suitable rotation angle of the valve body 51 of the rotary valve 5 is calculated by the ECU according to the operating state of the engine 1, the temperature of the cooling water, the temperature of the outside air, etc., and is output as an angle command. The In response to this, the stepping motor 52 operates to rotate the valve body 51, whereby the ports 50a to 50d are opened and closed and the opening area thereof is adjusted.

  Specifically, for example, when the temperature of the cooling water is low after the engine 1 is cold started, the ports 50a to 50d of the rotary valve 5 are closed. When the water pump 7 is driven in this state, the cooling water flows out from the water jacket of the cylinder head to the first cooling water passage 3 and then flows through the bypass passage 8 so that the coolant of the cylinder block is not cooled by the radiator 2. Reflux to water jacket. Thereby, warm-up of the engine 1 is promoted.

  Further, if the engine water temperature becomes higher than a certain level even during warm-up, the stepping motor 52 is controlled by the ECU, whereby the valve body 51 is rotated and the engine-side port 50a of the rotary valve 5 and The heater side port 50c is opened. As a result, as shown in FIG. 3, a part of the cooling water that has flowed out into the first cooling water passage 3 flows out from the heater-side port 50 c to the passage 10 and is supplied to the heater core 9.

  Furthermore, when the temperature of the cooling water reaches, for example, about 80 degrees or more, the radiator side port 50b and the device side port 50d of the rotary valve 5 are also opened, and a part of the cooling water is discharged from the radiator side port 50b as shown in FIG. While flowing out to the downstream side of the first cooling water passage 3, it also flows out from the device side port 50 d to the passage 12 and is supplied to various devices 11. At this time, since the thermostat 6 is opened, a part of the cooling water passes through the radiator 2 and returns to the engine 1.

-Valve opening characteristics of each port-
By the way, as described above, the rotary valve 5 has its openings 51a to 51d communicating with the respective ports 50a to 50d as the valve body 51 rotates, and its communication area, that is, the ports 50a to 50d. The opening area changes. In response to an angle command from the ECU, the stepping motor 52 operates to rotate the valve body 51 to an angle corresponding to the target port opening area. However, the actual port opening area varies due to individual variations of the rotary valve 5, and the controllability of the engine water temperature may be reduced.

  That is, for example, when the radiator side port 50b is opened to lower the engine water temperature and the circulation of the cooling water between the engine 1 and the radiator 2 is started, the opening area of the radiator side port 50b is larger than the target. If it becomes, the flow volume of the cooling water which passes the radiator 2 will increase too much, and an engine water temperature will fall too much. In particular, when the low-temperature cooling water in the radiator 2 suddenly flows in an environment where the outside air temperature is low, such as in winter, the engine water temperature rapidly decreases.

  On the other hand, in the rotary valve 5 of the present embodiment, the increase rate of the port opening area relative to the rotation angle is relatively in a predetermined rotation angle range of the valve body 51 when the radiator side port 50b starts to open. The structure becomes smaller. For example, as shown in FIG. 2, by reducing the width of the opening 51 b of the valve body 51 that can communicate with the radiator side port 50 b at the end thereof, the area when starting to communicate with the radiator side port 50 b is reduced. The increase rate can be reduced.

  The opening characteristics (change characteristics of the opening area) of the radiator side port 50b, the heater side port 50c, and the device side port 50d of the rotary valve 5 configured as described above, and the total flow rate of the cooling water in the rotary valve 5 FIG. 5 shows the changes associated with each other. As shown in the figure, when the rotation angle of the valve body 51 is in an angle range of θ = θ3 to θ4, all the outflow ports 50b to 50d are closed. Here, the engine-side port 50a is also closed.

  Then, as the rotation angle θ increases in the angle range of θ4 to θ5, the heater-side port 50c opens, and as the opening area increases, the flow rate of the cooling water increases accordingly. After the heater side port 50c is fully opened at the angle θ5, the flow rate becomes constant until the rotation angle θ6. Further, when the device-side port 50d is opened in the angle range of θ6 to θ7, the flow rate of the cooling water increases again as the opening area increases. Note that the higher the engine speed, the higher the water pump 7 speed, and the greater the coolant flow rate.

  Then, after the device side port 50d is fully opened at the rotation angle θ7 of the valve body 51, the flow rate of the cooling water becomes constant until the rotation angle θ8, but the radiator side port 50b opens from the rotation angle θ8. When it starts, the flow rate increases again. In the rotation angle range θ8 to θ9 at which the radiator side port 50b starts to open, the increase rate of the port opening area with respect to the rotation of the valve body 51 is relatively small as described above. As shown, the increase in the flow rate of the cooling water is moderate.

  On the other hand, when the rotation angle of the valve body 51 exceeds θ9, the increasing ratio of the opening area of the radiator side port 50b with respect to the rotation angle θ becomes relatively large, and thereby the port opening area increases rapidly. The flow rate of the cooling water also increases rapidly. For this reason, if the radiator side port 50b is fully opened at the rotation angle θ10 of the valve body 51, the opening area of the port becomes sufficiently large, and the flow rate of the cooling water can be sufficiently secured.

  When the rotation angle θ of the valve body 51 is in the angle range of θ2 to θ3, the device-side port 50d opens as the rotation angle θ decreases as shown in the drawing, and the opening area thereof increases. Similarly, when the rotation angle θ is in the range of 0 to θ2, the radiator side port 50b is opened, and the opening area thereof is increased. Also in this case, in the rotation angle range θ1 to θ2 at which the radiator side port 50b starts to open, the increase rate of the port opening area with respect to the rotation of the valve body 51 is relatively small, and the increase in the flow rate of the cooling water is moderate. become. As described above, the rotation angles 0 to θ3 in which the port opening area increases as the rotation angle θ of the valve body 51 decreases are used when an air conditioning request for not supplying cooling water to the heater core 9 is performed.

  Therefore, according to the engine cooling apparatus according to the present embodiment, in the cooling system that circulates the cooling water between the engine 1 and the radiator 2, the valve opening characteristic of the rotary valve 5 that adjusts the flow rate of the cooling water is devised. In the predetermined rotation angle range θ8 to θ9 of the valve body 51 when the radiator-side port 50b starts to open, the increase in the port opening area is made relatively gentle. The change in the flow rate of the cooling water can be moderated, and the decrease in the controllability of the engine water temperature can be suppressed.

  On the other hand, when the rotation angle θ of the valve body 51 exceeds the rotation angle range θ8 to θ9 and further increases, the increase rate of the port opening area associated therewith becomes relatively large. And the flow rate of cooling water also increases. Thereby, the opening area of the port when the radiator side port 50b is fully opened can be sufficiently increased, and the flow rate of the cooling water can be sufficiently increased.

  In addition, in the present embodiment, the width of the opening 51b of the valve body 51 that can communicate with the radiator side port 50b is narrowed at the end thereof, thereby realizing the valve opening characteristics as described above, and the flow rate of the cooling water. Change can be moderated. Therefore, in controlling the flow rate, it is only necessary to output the angle command of the valve body 51, and troublesome feedback control and a sensor therefor are unnecessary, so there is no worry of cost increase.

-Other embodiments-
The above-described embodiments are merely examples, and are not intended to limit the configuration and use of the present invention. For example, in the above-described embodiment, the heater core 9 and the various devices 11 are disposed on the downstream side of the rotary valve 5 in the cooling system. However, the present invention is not limited thereto, and at least one of the heater core 9 and the various devices 11 is connected to the rotary valve 5. You may arrange | position upstream from this. At least one of the various devices 11 may be disposed upstream of the rotary valve 5 and at least one of the other devices 11 may be disposed downstream.

  In the above embodiment, the thermostat 6 is disposed in the second cooling water passage 4, but this may be disposed in the first cooling water passage 3, or the thermostat 6 may be provided by the rotary valve 5. Can be substituted.

  Furthermore, in the above embodiment, in consideration of the air conditioning requirement as described above with reference to FIG. 5, cooling water is supplied to the heater core 9 in the range of the rotation angle 0 to θ3 of the valve body 51 in the rotary valve 5. Although the radiator side port 50b and the device side port 50d are opened and the cooling water is sent out to the radiator 2 and the various devices 11 in a state where the supply is not performed, the present invention is not limited to this. For example, as shown in FIG. 6, the outflow side ports 50 b to 50 d may be closed in the range of the rotation angle 0 to θ3.

  Furthermore, in the above-described embodiment, the example in which the present invention is applied to an engine mounted on an automobile has been described. However, the present invention is not limited to this, and the present invention can also be applied to a cooling system of an engine other than an automobile. is there.

  The present invention can suppress a decrease in controllability of the engine water temperature when a rotary valve is used in an engine cooling system, and therefore can be applied to an automobile engine to obtain effects such as a reduction in fuel consumption.

1 Engine 2 Radiator 3 First Cooling Water Passage 5 Rotary Valve (Valve)
50 Casing 50b Radiator side port (Port for sending cooling water to the radiator)
51 Valve body θ8 to θ9 Predetermined rotation angle range of valve body

Claims (1)

An engine cooling device in which a valve for adjusting the flow rate of cooling water is disposed in the cooling system of the engine, and a radiator is disposed on the downstream side thereof,
The valve is a rotary valve in which the opening area of the port changes as the valve body rotates, and in a predetermined rotation angle range of the valve body when the port for sending cooling water to the radiator starts to open. An engine cooling device, characterized in that an increase rate of an opening area with respect to a rotation angle is configured to be smaller than outside the rotation angle range.

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