JP2016056760A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine cooling device which can improve a warm-up efficiency and sufficiently increase a circulation flow rate of cooling water, when cooling an engine in the combination of a mechanical water pump and an electrical water pump.SOLUTION: An engine cooling device 100 includes a mechanical water pump 10 which is driven by an engine 91 and is rotated synchronously with a rotation of the engine 91, an electrical water pump 20 which is provided in parallel with the mechanical water pump 10 and can change its revolution speed independently from the rotation of the engine 91, and a first switch valve 30 which is provided in a discharge side of the mechanical water pump 10, is opened when a temperature Tw of cooling water is higher than a first threshold value temperature T1, and blocks the flow from the mechanical water pump 10 when the temperature Tw of cooling water is equal to or less than the first threshold value temperature T1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine cooling device, and more particularly to an engine cooling device including a mechanical water pump and an electric water pump.

  Conventionally, an engine cooling device including a mechanical water pump and an electric water pump is known (see, for example, Patent Document 1).

  Patent Document 1 discloses an engine cooling device including a cooling water circulation path for circulating cooling water in an engine, and a mechanical water pump and an electric water pump provided in the cooling water circulation path. In the engine cooling device described in Patent Document 1, a mechanical water pump and an electric water pump are arranged in series in the coolant circulation path. In this engine cooling apparatus, the mechanical water pump is a main water pump, and operates so as to constantly circulate cooling water in conjunction with the rotation of the engine. The electric water pump is a sub-water pump, and operates with the mechanical water pump (both simultaneously) only when the temperature of the cooling water is equal to or higher than a predetermined threshold and the engine is rotating at a low speed. A flow path in which the electric water pump is installed is provided with a bypass that connects the discharge side and the suction side of the electric water pump, and the bypass is opened and closed by the control valve. When the electric water pump is in operation, the control valve closes the detour so that the mechanical water pump and the electric water pump are connected in series on the circulation path.

Japanese Patent Laid-Open No. 4-109028

  However, in the engine cooling device described in Patent Document 1, first, since a mechanical water pump that interlocks with the rotation of the engine constantly circulates the cooling water, the cooling water is generated immediately after the engine is started to be warmed up. It circulates and there is a problem that the warm-up efficiency is low. Secondly, when both the mechanical water pump and the electric water pump are operated, the pumps connected in series have water resistance. As a result, there is a problem that even if both the mechanical water pump and the electric water pump are operated, the effect of increasing the circulating flow rate of the cooling water is not sufficiently exhibited.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to warm up the engine when a mechanical water pump and an electric water pump are combined to cool the engine. It is an object of the present invention to provide an engine cooling device capable of improving efficiency and sufficiently increasing the circulating flow rate of cooling water.

  To achieve the above object, an engine cooling device according to one aspect of the present invention is driven by an engine and is rotated in synchronization with the rotation of the engine, and is arranged in parallel with the mechanical water pump. An electric water pump capable of changing the rotation speed independently of the engine rotation and a discharge side of the mechanical water pump, and is opened when the temperature of the cooling water is higher than the first threshold temperature. A first switching valve that shuts off the flow of the mechanical water pump when the temperature of the water is equal to or lower than the first threshold temperature.

  In the engine cooling device according to one aspect of the present invention, as described above, the mechanical water pump that rotates in synchronization with the rotation of the engine and the mechanical water pump are arranged in parallel with each other regardless of the rotation of the engine. An electric water pump capable of changing the rotation speed and disposed on the discharge side of the mechanical water pump, and is opened when the temperature of the cooling water is higher than the first threshold temperature. A first switching valve is provided that shuts off the flow of the mechanical water pump when the temperature is equal to or lower than one threshold temperature. As a result, at the time of cold immediately after engine startup when the temperature of the cooling water is equal to or lower than the first threshold temperature, the cooling water is circulated using only the electric water pump that can change the rotation speed regardless of the rotation of the engine. Since it can be suppressed, the circulation of the cooling water can be stopped regardless of the rotation of the engine, or the cooling water can be circulated at a very small flow rate. As a result, it is possible to improve the warming-up efficiency by reducing the circulating flow rate of the cooling water regardless of the engine rotation immediately after the engine is started to promote the warm-up.

  Further, when the mechanical water pump and the electric water pump are arranged in parallel, the temperature of the cooling water becomes higher than the first threshold temperature, and both the mechanical water pump and the electric water pump are operated. However, the pumps do not become resistance to water flow. As a result, even when both the mechanical water pump and the electric water pump are operated, the circulating flow rate of the cooling water can be increased.

  In the engine cooling device according to the above aspect, the radiator is preferably disposed between the radiator for cooling the cooling water and the radiator and the electric water pump, and is opened when the temperature of the cooling water is higher than the second threshold temperature. And a second switching valve that shuts off a flow from the radiator to the electric water pump when the temperature of the cooling water is equal to or lower than the second threshold temperature. With this configuration, when the temperature of the cooling water is warming up to the second threshold temperature or less, the cooling water can be prevented from circulating to the radiator side, so that the warming up efficiency is improved. Can be made. In addition, when the temperature of the cooling water is higher than both the first threshold temperature and the second threshold temperature, cooling is performed by operating both the electric water pump and the mechanical water pump in parallel to flow to the radiator. Sufficient water flow rate can be secured. Thereby, the heat dissipation performance when the temperature of the cooling water is high can also be improved.

  In this case, preferably, the first threshold temperature of the first switching valve is equal to or higher than the second threshold temperature of the second switching valve. With this configuration, when at least the first switching valve is opened and both the electric water pump and the mechanical water pump are operated in parallel, the second switching valve is also opened and the cooling water is allowed to flow to the radiator. Can do. As a result, when cooling water is allowed to flow through the radiator, the flow rate by the mechanical water pump can be added to the flow rate by the electric water pump, so that heat dissipation performance can be easily ensured when the temperature of the cooling water is high. it can.

  In the engine cooling apparatus according to the above aspect, the electric water pump is preferably configured to be operable even when the first switching valve is closed. If comprised in this way, only the electric water pump can be operated independently in the period when the temperature of cooling water becomes below 1st threshold temperature. Thereby, unlike the case where the mechanical water pump interlocked with the rotation of the engine is operated alone, the flow rate of the cooling water can be finely controlled regardless of the rotation of the engine. For this reason, even when the temperature of the cooling water is low, the pump can be controlled so that the flow rate of the cooling water becomes the optimum flow rate.

  In this case, preferably, the electric water pump is configured so that the temperature of the cooling water is equal to or lower than a third threshold temperature lower than the first threshold temperature, and whether the engine speed is higher than a predetermined speed. Alternatively, it is configured to operate when the engine load factor is higher than a predetermined load factor. If comprised in this way, even if the temperature of a cooling water is the cold time below a 3rd threshold temperature, when an engine becomes a high rotation or a high load, an electric water pump is operated. Can do. Thereby, the rapid temperature rise of cooling water can be suppressed.

  In the configuration including the second switching valve, preferably, both the first switching valve and the second switching valve are thermostat valves. If comprised in this way, the switching valve which can be opened and closed automatically when predetermined threshold temperature (1st threshold temperature, 2nd threshold temperature) is reached, without requiring electrical control Can be provided. Thereby, the control structure for opening and closing the first and second switching valves can be simplified.

  In the present application, the following configuration is also conceivable in the engine cooling device according to the above aspect.

(Additional item 1)
That is, in the engine cooling device in which the first threshold temperature of the first switching valve is equal to or higher than the second threshold temperature of the second switching valve, the first threshold temperature of the first switching valve is the second switching temperature. Even after the warm-up is completed, the temperature of the cooling water is set to be higher than the second threshold temperature of the valve, the temperature of the cooling water reaches the second threshold temperature, and the flow of the radiator is released. When the temperature is equal to or lower than the first threshold temperature, the flow of the mechanical water pump is blocked by the first switching valve.

(Appendix 2)
In the electric water pump, when the temperature of the cooling water is equal to or lower than the third threshold temperature and the engine speed is higher than the predetermined speed, or the engine load factor is higher than the predetermined load factor. In the engine cooling device configured to operate when the temperature is higher, the electric water pump is configured such that the temperature of the cooling water is equal to or lower than a third threshold temperature, and the engine speed is equal to or lower than a predetermined speed. When the engine load factor is equal to or lower than the predetermined load factor, the engine load factor is configured to stop.

(Additional Item 3)
In the electric water pump, when the temperature of the cooling water is equal to or lower than the third threshold temperature and the engine speed is higher than the predetermined speed, or the engine load factor is higher than the predetermined load factor. In the engine cooling device configured to operate when the temperature is higher, the electric water pump is configured to operate when the temperature of the cooling water is higher than the third threshold temperature.

(Appendix 4)
The engine cooling apparatus according to the above aspect further includes a check valve provided on the discharge side or suction side of the electric water pump.

  According to the present invention, as described above, when the engine is cooled by combining the mechanical water pump and the electric water pump, the warm-up efficiency is improved and the circulating flow rate of the cooling water is sufficiently increased. It is possible to provide an engine cooling device that can be used.

1 is a block diagram illustrating an overall configuration of an engine cooling device according to an embodiment of the present invention. It is a figure for demonstrating the operation state 1 of the engine cooling device by one Embodiment of this invention. It is a figure for demonstrating the operation state 2 of the engine cooling device by one Embodiment of this invention. It is a figure for demonstrating the operation state 3 of the engine cooling device by one Embodiment of this invention. It is a figure for demonstrating the operation state 4 of the engine cooling device by one Embodiment of this invention. It is a flowchart for demonstrating the operation control process of the electric water pump of the engine cooling device by one Embodiment of this invention. It is a figure for demonstrating the transition conditions of the operation state of the engine cooling device by one Embodiment of this invention. It is a flowchart for demonstrating the opening / closing control processing of the 1st switching valve and the 2nd switching valve in the modification of the engine cooling device by one Embodiment of this invention.

  First, with reference to FIGS. 1-7, the structure of the engine cooling device 100 by one Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the engine cooling device 100 according to the present embodiment is a device that cools an engine 91 mounted on a vehicle 90 such as an automobile, and is provided in the vehicle 90. The engine cooling device 100 includes a mechanical water pump 10, an electric water pump 20, and a first switching valve 30. The engine cooling device 100 includes a second switching valve 40 and a radiator 50. The engine cooling device 100 includes a pipe part 60 that connects these parts and distributes coolant (coolant). Circulating paths C <b> 1 and C <b> 2 are formed in the engine cooling device 100 by sequentially connecting the respective constituent elements by the piping unit 60. A radiator 50 is disposed in the circulation path C1. A heat utilization device 92 such as a heater core 92a provided in the vehicle 90 is disposed in the circulation path C2.

  In addition, the vehicle 90 is provided with a control unit (Engine Control Unit; ECU) 93 for controlling the engine 91. In the controller 93, the voltage applied to the ignition coil (not shown) is electrically counted to determine the rotational speed of the engine 91. Further, the load of the engine 91 is grasped based on the detection result of the throttle opening in the intake passage. The temperature of the cooling water (engine water temperature) Tw inside the engine 91 is controlled based on a detection signal of a temperature sensor 94 provided between the engine 91 and the heat utilization device 92 (cooling water outlet of the engine 91). It is grasped by the unit 93. In engine cooling device 100, electric water pump 20 is driven and controlled by control unit 93.

  The engine 91 is provided with a cooling water passage (not shown), and an inlet and an outlet of the cooling water passage are connected to the pipe portion 60, respectively. The inlet side of the engine 91 is connected to the first switching valve 30, and the outlet side of the engine 91 is connected to the radiator 50 and the heat utilization device 92, respectively. The temperature sensor 94 described above is provided on the outlet side of the cooling water flow path of the engine 91. The temperature sensor 94 may be provided in the cooling water flow path of the engine 91.

  The mechanical water pump 10 has a discharge side connected to the first switching valve 30 and a suction side connected to the radiator 50. The mechanical water pump 10 has a function of forcibly circulating cooling water in the engine 91. For the mechanical water pump 10, for example, a centrifugal centrifugal pump is used. The mechanical water pump 10 is driven by the engine 91 and rotates in synchronization with the rotation of the engine 91. For example, the mechanical water pump 10 is configured such that the shaft power of a crankshaft (not shown) is transmitted via a crank pulley (not shown) and an auxiliary machine driving belt (not shown). It is rotated in synchronization with the rotation. The discharge amount of the cooling water from the mechanical water pump 10 is proportional to the rotational speed of the engine 91.

  The electric water pump 20 has a discharge side connected to the first switching valve 30 and a suction side connected to the second switching valve 40. The electric water pump 20 is arranged in parallel with the mechanical water pump 10. That is, the discharge side of the mechanical water pump 10 and the discharge side of the electric water pump 20 are connected in parallel to the first switching valve 30 disposed between the engine 91 and the first switching valve 30. To the engine 91.

  Further, the electric water pump 20 is configured to be able to change the rotation speed regardless of the rotation of the engine 91. Electric water pump 20 includes an electric motor (not shown) and an impeller (not shown) that is rotationally driven by the electric motor. In the electric water pump 20, the rotation speed of the impeller can be changed by controlling the rotation speed of the electric motor regardless of the rotation of the engine 91. That is, the electric water pump 20 can arbitrarily increase or decrease the discharge amount. The electric water pump 20 is configured to change the rotation speed (discharge amount) according to the temperature Tw of the cooling water, the rotation speed Ne of the engine 91, and the load factor KL of the engine 91 under the control of the control unit 93. Has been. In the present embodiment, the electric water pump 20 is configured to be operable even when the first switching valve 30 is closed. Detailed operation of the electric water pump 20 will be described later.

  The first switching valve 30 is disposed on the discharge side of the mechanical water pump 10. The first switching valve 30 is a three-way valve, and a flow path 61 connected to the discharge side of the mechanical water pump 10, a flow path 62 connected to the discharge side of the electric water pump 20, and a flow path connected to the engine 91. 63 are connected to each other. The first switching valve 30 is configured to connect the flow path 62 and the flow path 63 in a constantly communicating state, and to be able to switch connection and blocking of the flow path 61 with respect to the flow path 62 and the flow path 63. In the open state (connected state), the first switching valve 30 connects the flow path 61 to the flow path 62 and the flow path 63 to open the flow of the mechanical water pump 10 to the engine 91 side. In the closed state (blocked state), the first switching valve 30 blocks the channel 61 with respect to the channel 62 and the channel 63 and blocks the flow of the mechanical water pump 10.

  In the present embodiment, the threshold temperature (opening temperature) of the switching operation of the first switching valve 30 is set to T1. That is, the first switching valve 30 is opened when the temperature Tw of the cooling water is higher than the first threshold temperature T1 (becomes open), and the temperature Tw of the cooling water is equal to or lower than the first threshold temperature T1. In such a case, the flow of the mechanical water pump 10 is cut off (closed).

  The second switching valve 40 is disposed between the radiator 50 and the electric water pump 20. The second switching valve 40 is a three-way valve, and includes a flow path 64 between the electric water pump 20, a flow path 65 connected to the outlet side of the radiator 50, and a flow path connected to the outlet side of the heat utilization device 92. 66 are connected to each other. The second switching valve 40 is configured to connect the flow path 64 and the flow path 66 in a constantly communicating state, and to switch between connection and blocking of the flow path 65 with respect to the flow path 64 and the flow path 66. In the open state (connected state), the second switching valve 40 connects the flow path 65 to the flow path 64 and the flow path 66 so that the coolant flows through the radiator 50 (connects the circulation path C1). . In the closed state (blocked state), the second switching valve 40 blocks the channel 65 with respect to the channel 64 and the channel 66 and blocks the flow of the radiator 50 (blocks the circulation path C1).

  In the present embodiment, the threshold temperature (opening temperature) of the switching operation of the second switching valve 40 is set to T2. That is, the second switching valve 40 is opened (becomes open) when the cooling water temperature Tw is higher than the second threshold temperature T2, and the cooling water temperature Tw is equal to or lower than the second threshold temperature T2. In this case, the flow of the radiator 50 is blocked (becomes closed).

  Here, the first threshold temperature T1 of the first switching valve 30 is preferably equal to or higher than the second threshold temperature T2 of the second switching valve 40. In the present embodiment, the first threshold temperature T1 of the first switching valve 30 is higher than the second threshold temperature T2 of the second switching valve 40 (T2 <T1). In the present embodiment, a third threshold temperature T3 lower than the first threshold temperature T1 is set as the threshold temperature of the cooling water related to the operation of the electric water pump 20.

  With the above configuration, the circulation path C <b> 2 is a circulation path that always communicates with the electric water pump 20, the first switching valve 30, the engine 91, the heat utilization device 92, and the second switching valve 40.

  The circulation path C1 is a circulation path that passes through the electric water pump 20, the first switching valve 30, the engine 91, the radiator 50, and the second switching valve 40 and communicates only when the second switching valve 40 is open. ing. When the second switching valve 40 is in the closed state, the cooling water from the radiator 50 is blocked by the second switching valve 40. Further, in the circulation path C1, when the first switching valve 30 is in the open state, the flow path 61 is opened (communication), and the electric water pump 20 and the mechanical water pump 10 are connected to the engine 91 in parallel. Is done. When the first switching valve 30 is closed, the flow of the mechanical water pump 10 is blocked (cooling water from the radiator 50 is blocked by the first switching valve 30).

  In terms of the configuration, the circulation path C1 can circulate cooling water between the engine 91 and the radiator 50 when one of the first switching valve 30 and the second switching valve 40 is opened. . However, in the present embodiment, since the first threshold temperature T1> the second threshold temperature T2, the first switching valve 30 alone is not opened. As a result, in this embodiment, the second switching valve 40 functions as a switching valve for connecting and shutting off the circulation path C1, and the first switching valve 30 switches between connecting and shutting off the mechanical water pump 10 to the circulation path C1. Acts as a valve.

  The flow path 63, the flow path 62, and the flow path 64 are common portions C3 of the circulation path C1 and the circulation path C2. Therefore, the circulation path C2 includes the flow path 63, the flow path 62, the flow path 64, and the flow path 66. Further, the circulation path C1 includes a flow path 63, a flow path 62, a flow path 64, and a flow path 65. When the first switching valve 30 is in an open state, the flow path 61 and the mechanical water pump 10 have a common portion C3 ( It is connected to the circulation path C1).

  In the present embodiment, the first switching valve 30 and the second switching valve 40 are both thermostat valves. The first switching valve 30 and the second switching valve 40 each have a cooling water temperature sensing portion, and when the temperature Tw of the cooling water in the temperature sensing portion exceeds each threshold temperature (T1, T2), the valve body Moves to the valve opening side, and the first switching valve 30 and the second switching valve 40 are switched to the open state. The threshold temperature is a temperature at which the thermostat valve starts to open. Above the threshold temperature, the valve opening increases with an increase in temperature.

  In addition, the 1st switching valve 30 and the 2nd switching valve 40 may be switching valves which open and close by the drive of an actuator, such as a solenoid valve (solenoid valve) and a motor-type rotary valve. In this case, the temperature Tw of the cooling water is acquired from the temperature sensor 94, and opening / closing control is performed by the control unit 93.

  The radiator 50 has an inlet side connected to the engine 91 and an outlet side connected to the second switching valve 40 and the mechanical water pump 10 via the flow path 65 in the circulation path C1. The radiator 50 is configured to cool the cooling water. That is, in the radiator 50, heat exchange is performed between the cooling water that has flowed through the engine 91 and has become high temperature, and the air (outside air) taken from outside the vehicle.

  In the circulation path C <b> 2, the heat utilization device 92 has an inlet side connected to the engine 91 and an outlet side connected to the second switching valve 40 via the flow path 66. In the heat utilization device 92, heat exchange between the heat utilization device 92 and the cooling water is performed in order to dissipate the heat of the device or to heat the device to prevent freezing. The heat utilization device 92 may be, for example, a heater core, an EGR (Exhaust Gas Recirculation) cooler, an oil warmer, a desiccant (dehumidification) device, a throttle valve, an ATF (Automatic Transmission Fluid) oil warmer (oil cooler), or the like. In this embodiment, the example which provided the heater core 92a in the circulation path C2 as the heat utilization device 92 is described.

  The heater core 92a is used when heating the interior of the vehicle. That is, when the cooling water heated by the engine 91 passes through the heat transfer pipe inside the heater core 92a, heat exchange between the air in the vehicle and the cooling water is performed.

  Next, each operation state of the engine cooling apparatus 100 will be described with reference to FIGS. As described above, the engine cooling device 100 includes the following four types of opening and closing of the first switching valve 30 and the second switching valve 40 according to the coolant temperature Tw and the operation of the electric water pump 20. It is possible to realize the operating state. 2 to 5, for convenience, the portions in the closed state or the stopped state are illustrated with hatching. A flow path through which the cooling water does not flow is indicated by a broken line.

(Operating state 1)
Operation state 1 shown in FIG. 2 is an operation state in which both first switching valve 30 and second switching valve 40 are closed and electric water pump 20 is stopped. In the operation state 1, the temperature Tw of the cooling water is Tw ≦ (T1, T2).

  In the operation state 1, since the flow path 61 and the flow path 65 are blocked, the flow of the cooling water to the mechanical water pump 10 and the radiator 50 (circulation path C1) side is blocked. Although the mechanical water pump 10 operates in synchronization with the rotation of the engine 91, the flow path 61 is blocked, so that the mechanical water pump 10 idles without sending the cooling water (only the cooling water in the pump is stirred). State). Further, since the electric water pump 20 is stopped, the cooling water is stopped without being circulated.

(Operating state 2)
The operation state 2 shown in FIG. 3 is an operation state in which the electric water pump 20 operates while both the first switching valve 30 and the second switching valve 40 are closed. In the operation state 2, the temperature Tw of the cooling water is Tw ≦ (T1, T2). In the operation state 2, since the electric water pump 20 operates in a state where the circulation path C1 and the flow path 61 of the mechanical water pump 10 are blocked, the cooling water circulates only through the circulation path C2.

(Operating state 3)
Operation state 3 shown in FIG. 4 is an operation state in which the second switching valve 40 is in an open state and the first switching valve 30 is in a closed state. In the operation state 3, the temperature Tw of the cooling water is T2 <Tw ≦ T1. In the operation state 3, the circulation path C1 is connected (communication) in addition to the circulation path C2, so that the cooling water circulates through both the heat utilization device 92 (circulation path C2) and the radiator 50 (circulation path C1). To do. Even in the operation state 3, the mechanical water pump 10 does not contribute to the circulation of the cooling water, and only the electric water pump 20 circulates the cooling water.

  As described above, in this embodiment, the engine cooling device 100 also provides the cooling water even when the temperature of the cooling water reaches the second threshold temperature T2 and the warming-up is completed after the flow of the radiator 50 is released. Is equal to or lower than the first threshold temperature T1 (when T2 <Tw ≦ T1), the flow of the mechanical water pump 10 is blocked by the first switching valve 30.

(Operating state 4)
The operation state 4 shown in FIG. 5 is an operation state in which both the first switching valve 30 and the second switching valve 40 are opened. In the operation state 4, the temperature Tw of the cooling water is Tw> (T1, T2). Even in the operation state 4, the cooling water circulates in both the circulation paths C1 and C2. By opening the first switching valve 30, the mechanical water pump 10 is connected to the circulation path C1 (common part C3). In the operation state 4, both the mechanical water pump 10 and the electric water pump 20 operate in parallel, and cooling water is supplied to both the radiator 50 and the heater core 92a (heat utilization device 92).

  In the operation state 4, the flow rate sent by the mechanical water pump 10 is added to the flow rate of the cooling water sent by the electric water pump 20. Therefore, the flow rate and flow velocity of the cooling water are increased as compared with the operation state 3, and the heat dissipation performance via the radiator 50 is improved. At this time, the discharge amount of the mechanical water pump 10 is a discharge amount that is proportional to the rotational speed of the engine 91. On the other hand, the electric water pump 20 can change the discharge amount regardless of the rotational speed of the engine 91. Therefore, in the operation state 4 of the engine cooling device 100, the discharge amount of the electric water pump 20 is controlled in response to the change in the discharge amount of the mechanical water pump 10 that increases or decreases depending on the engine speed, so that the operating state ( Cooling water is sent at an appropriate circulation flow rate according to the operation of the engine 91.

  In the operation state 4, when the mechanical water pump 10 and the electric water pump 20 operate in parallel, if there is a large difference in the discharge capacity of each pump, the discharge amount from the pump with the larger discharge amount is small. Cooling water may flow into the pump on the side. In this case, as shown in FIG. 1, it is preferable to provide a check valve 70 for preventing a backflow in the pump having the smaller discharge amount. FIG. 1 shows an example in which a check valve 70 is provided on the electric water pump 20 side when (discharge capacity of the mechanical water pump 10)> (discharge capacity of the electric water pump 20). In FIG. 1, the check valve 70 is provided on the discharge side (flow path 62) of the electric water pump 20, but the check valve 70 may be provided on the suction side (flow path 64) of the electric water pump 20. Good. If there is no significant difference between the discharge capacities of both pumps, the check valve 70 need not be provided.

  Next, the details of the operation control of the electric water pump 20 will be described with reference to FIG. The operation control of the electric water pump 20 is performed by the controller 93 (see FIG. 1).

  In step S <b> 1 of FIG. 6, the controller 93 reads the coolant temperature (engine water temperature) Tw obtained from the detection result of the temperature sensor 94.

  In step S2, the controller 93 determines whether or not the temperature Tw of the cooling water is higher than the third threshold temperature T3. When the temperature Tw of the cooling water is equal to or lower than the third threshold temperature T3, the control unit 93 advances the process to step S3.

  In step S <b> 3, the controller 93 reads the rotational speed Ne of the engine 91 and the load factor KL of the engine 91. In step S4, the controller 93 determines whether or not the engine speed Ne is larger than a predetermined speed Ne0 and whether or not the engine load factor KL is larger than a predetermined load factor KL0.

  When the engine speed Ne is equal to or lower than the predetermined speed Ne0 and the engine load factor KL is equal to or lower than the predetermined load factor KL0 (when the engine speed is low and the load is low), the controller 93 determines in step S5. The electric water pump 20 is stopped and the control is terminated.

  In step S4, when the engine speed Ne is larger than the predetermined speed Ne0 or when the engine load factor KL is larger than the predetermined load factor KL0, the control unit 93 performs the process in step S7. Proceed.

  On the other hand, when the temperature Tw of the cooling water is higher than the third threshold temperature T3 in step S2, the control unit 93 advances the process to step S6.

  In step S6, the controller 93 reads the rotational speed Ne of the engine 91 and the load factor KL of the engine 91, and proceeds to step S7.

  In step S <b> 7, the control unit 93 operates the electric water pump 20. At this time, the control unit 93 discharges the electric water pump 20 based on the read cooling water temperature Tw, the engine speed Ne, the engine load factor KL, the heating request of the heater core 92a (heat utilization device 92), and the like. Adjust the amount. And control is complete | finished.

  In the engine cooling device 100, the electric water pump 20 operates by repeatedly and continuously performing the above operation control at predetermined time intervals.

  In summary, the engine cooling device 100 according to the present embodiment is configured to transition the operation states 1 to 4 under the conditions shown in FIG. Below, the transition of the operation state accompanying the temperature rise of cooling water is demonstrated. As specific examples for reference, for example, the first threshold temperature T1 = 90 ° C., the second threshold temperature T2 = 80 ° C., and the third threshold temperature T3 = 70 ° C. Each threshold temperature has a relationship of T3 <T2 <T1.

  When the engine is cold immediately after the engine is started, the temperature Tw of the cooling water is Tw ≦ T3 (<T1, T2). For this reason, as shown in FIG. 7, both the 1st switching valve 30 and the 2nd switching valve 40 will be in a closed state. Since the opening and closing of the first switching valve 30 and the use state of the mechanical water pump 10 coincide with each other, the mechanical water pump 10 does not contribute to the circulation of the cooling water and is in an idle state (this state is shown in FIG. 7). (Indicated by a cross mark).

  The electric water pump 20 is configured such that the coolant temperature Tw is equal to or lower than the third threshold temperature T3, the engine speed Ne is equal to or lower than the predetermined speed Ne0, and the engine load factor KL is equal to the predetermined value. If the load factor is KL0 or less (see step S4 in FIG. 6), the operation stops. The state of low water temperature, low rotation, and low load immediately after engine startup is the operation state 1 shown in FIG. In the operation state 1, the cooling water does not circulate, the temperature of the cooling water in the engine 91 rises quickly, and warm-up is promoted.

  On the other hand, even in the low water temperature state of Tw ≦ T3, when the engine enters a high rotation or high load (or high rotation and high load) state, the electric water pump 20 operates (the operation state is shown in FIG. 7). (Indicated by a circle) That is, in the electric water pump 20, the cooling water temperature Tw is equal to or lower than the third threshold temperature T3, and the engine speed Ne is higher than the predetermined speed Ne0 or the engine load factor KL is It operates when it is higher than a predetermined load factor KL0. In this case, the operation state 2 shown in FIG. 3 is obtained.

  The electric water pump 20 operates regardless of the engine speed Ne and the load factor KL when the temperature Tw of the cooling water is higher than the third threshold temperature T3 (a state where the warm-up has progressed to some extent). . That is, even when the temperature Tw of the cooling water satisfies T3 <Tw ≦ T2, the operation state 2 shown in FIG. 3 is obtained. In the operation state 2, since the cooling water is circulated only by the electric water pump 20, it is possible to circulate the cooling water at a flow rate suitable for efficient warm-up regardless of the rotational speed of the engine 91. is there. As a result, the temperature Tw of the cooling water rises in the entire circulation path C2 while suppressing a rapid temperature rise inside the engine 91.

  When the temperature Tw of the cooling water rises to T2 <Tw ≦ T1, the second switching valve 40 is opened. The first switching valve 30 remains closed. With the opening of the second switching valve 40, the cooling water circulates on the circulation path C1 side in addition to the circulation path C2. That is, the engine cooling device 100 is in the operation state 3 shown in FIG. In the operation state 3, as a result of the temperature Tw of the cooling water being Tw> T2, the warm-up operation is completed and the cooling operation by the engine cooling device 100 is started. As a result of the electric water pump 20 circulating the cooling water in the circulation path C1, the radiator 50 cools the high-temperature cooling water.

  When the temperature Tw of the cooling water rises until T1 <Tw, the first switching valve 30 is opened. The second switching valve 40 has been opened. As the first switching valve 30 is opened, the mechanical water pump 10 enters an operating state (a state in which cooling water is discharged) indicated by a circle mark. As a result, the engine cooling device 100 enters the operation state 4 shown in FIG. 5, and the mechanical water pump 10 and the electric water pump 20 operate in parallel. In the operation state 4, the amount of heat radiation in the radiator 50 is increased by circulating cooling water having a larger flow rate than in the operation state 3 by parallel operation of the mechanical water pump 10 and the electric water pump 20. As described above, in the operation state 4, in the cooling operation after the warm-up of the engine 91 is completed, when the temperature of the cooling water reaches the higher first threshold temperature T <b> 1, the mechanical state is added to the electric water pump 20. This is an operation state in which the cooling capacity of the engine cooling device 100 is increased by operating the water pump 10 in parallel.

  In the present embodiment, the following effects can be obtained.

  In the present embodiment, as described above, the mechanical water pump 10 that rotates in synchronization with the rotation of the engine 91 and the mechanical water pump 10 are arranged in parallel, and the rotational speed is increased regardless of the rotation of the engine 91. A variable electric water pump 20 is provided. Moreover, it arrange | positions at the discharge side of the mechanical water pump 10, and is open | released when the temperature Tw of cooling water is higher than 1st threshold temperature T1, and the temperature Tw of cooling water is below 1st threshold temperature T1. In this case, a first switching valve 30 is provided to block the flow of the mechanical water pump 10. As a result, at the time of cold immediately after engine startup when the temperature Tw of the cooling water becomes equal to or lower than the first threshold temperature T1, cooling is performed using only the electric water pump 20 that can change the rotation speed regardless of the rotation of the engine 91. Since the circulation of water can be suppressed, the circulation of the cooling water can be stopped regardless of the rotation of the engine 91 (operation state 1), or the cooling water can be circulated at a very small flow rate (operation state 2). it can. As a result, it is possible to improve the warm-up efficiency by reducing the circulating flow rate of the cooling water regardless of the rotation of the engine 91 immediately after the engine is started to promote the warm-up.

  Further, by arranging the mechanical water pump 10 and the electric water pump 20 in parallel, the temperature Tw of the cooling water becomes higher than the first threshold temperature T1, and the mechanical water pump 10 and the electric water pump 20 are provided. Even when both of these are operated (operation state 4), the pumps do not become resistance to water flow. As a result, even when both the mechanical water pump 10 and the electric water pump 20 are operated, the circulating flow rate of the cooling water can be increased.

  Moreover, in this embodiment, as mentioned above, it arrange | positions between the radiator 50 and the electric water pump 20, and is opened when the temperature Tw of the cooling water is higher than the second threshold temperature T2, and the cooling water A second switching valve 40 is provided that shuts off the flow from the radiator 50 to the electric water pump 20 when the temperature Tw is equal to or lower than the second threshold temperature T2. With this configuration, when warming up so that Tw ≦ T2 (operation states 1 and 2), it is possible to prevent the cooling water from being circulated to the radiator 50 side, thereby improving the warming up efficiency. be able to. In addition, when Tw> (T1, T2), it is possible to sufficiently secure the flow rate of the cooling water that flows to the radiator 50 by operating both the electric water pump 20 and the mechanical water pump 10 in parallel. Thereby, the heat dissipation performance when the temperature Tw of the cooling water is high can also be improved.

  In the present embodiment, as described above, the first threshold temperature T1 of the first switching valve 30 is set to be equal to or higher than the second threshold temperature T2 of the second switching valve 40. Accordingly, when at least the first switching valve 30 is opened and both the electric water pump 20 and the mechanical water pump 10 are operated in parallel (operation state 4), the second switching valve 40 is also opened and the cooling water is supplied. Can flow to the radiator 50. As a result, when cooling water is allowed to flow through the radiator 50, the flow rate by the mechanical water pump 10 can be added to the flow rate by the electric water pump 20, so that the heat radiation performance when the temperature Tw of the cooling water is high can be easily achieved. Can be secured.

  In the present embodiment, as described above, the electric water pump 20 is configured to be operable even when the first switching valve 30 is closed. Thereby, only the electric water pump 20 can be operated independently during the period of Tw ≦ T1 (operation states 2 and 3). As a result, even when the temperature Tw of the cooling water is low, the pump can be controlled so that the flow rate of the cooling water becomes the optimum flow rate regardless of the engine speed.

  In the present embodiment, as described above, the electric water pump 20 is configured to operate when Tw ≦ T3 and the engine speed Ne> Ne0 or the engine load factor KL> KL0. Thereby, even at the cold time when Tw ≦ T3, the electric water pump 20 can be operated when the engine 91 is at a high speed or a high load. Thereby, the rapid temperature rise of cooling water can be suppressed.

  In the present embodiment, as described above, both the first switching valve 30 and the second switching valve 40 are composed of thermostat valves. Accordingly, a switching valve that can be automatically opened and closed when a predetermined threshold temperature (first threshold temperature T1, second threshold temperature T2) is reached without requiring electrical control is provided. be able to. As a result, the controllable configuration for opening and closing the first switching valve 30 and the second switching valve 40 can be simplified.

(Modification)
Next, a modification of the engine cooling device 100 according to the present embodiment will be described. In the above embodiment, by configuring the first switching valve 30 and the second switching valve 40 with thermostat valves, the controller 93 is not involved in opening and closing the first switching valve 30 and the second switching valve 40, and the cooling water The example which comprised so that the opening / closing state of the 1st switching valve 30 and the 2nd switching valve 40 might switch automatically according to a temperature change was shown. In this modification, unlike the above-described embodiment, the first switching valve 30 and the second switching valve 40 are configured by electromagnetic valves or the like, and the control unit 93 performs opening / closing control of the first switching valve 30 and the second switching valve 40. An example of the case will be described.

  With reference to FIG. 8, the opening / closing control of the switching valve in the modification will be described. In this operation flow, the control unit 93 performs opening / closing control of the first switching valve 30 and the second switching valve 40 including electromagnetic valves and rotary valves. The operation control of the electric water pump 20 is the same as the control shown in FIG.

  In step S <b> 11 of FIG. 8, the control unit 93 reads the cooling water temperature (engine water temperature) Tw obtained from the detection result of the temperature sensor 94.

  In step S12, the controller 93 determines whether or not the temperature Tw of the cooling water is higher than the second threshold temperature T2. When the temperature Tw is equal to or lower than the second threshold temperature T2, the control unit 93 advances the process to step S13.

  In step S13, the controller 93 closes the second switching valve 40. As a result, the flow path 65 (see FIG. 2) is blocked and the cooling water circulation to the circulation flow path C1 (the radiator 50) is blocked.

  On the other hand, when the temperature Tw of the cooling water is higher than the second threshold temperature T2 in step S12, the controller 93 opens the second switching valve 40 in step S14. As a result, the circulation of the cooling water to the circulation path C1 in which the flow path 65 (see FIG. 4) communicates and the radiator 50 is disposed is started.

  Next, in step S15, the controller 93 determines whether or not the cooling water temperature Tw is higher than the first threshold temperature T1. When the temperature Tw becomes equal to or lower than the first threshold temperature T1, the control unit 93 ends the control.

  When the temperature Tw of the cooling water is higher than the first threshold temperature T1, the control unit 93 opens the first switching valve 30 in step S16. Thereby, the flow path 61 (refer FIG. 5) communicates and the circulation of the cooling water by the mechanical water pump 10 is started. As described above, the discharge amount of the mechanical water pump 10 is proportional to the engine speed Ne, and the discharge amount of the mechanical water pump 10 is added to the discharge amount of the electric water pump 20 that operates in parallel. In this way, the opening / closing control of the first switching valve 30 and the second switching valve 40 is performed by the control unit 93.

  In the case of this modification, the opening / closing control of the first switching valve 30 and the second switching valve 40 by the control unit 93 and the operation control of the electric water pump 20 by the control unit 93 shown in FIG. 6 are performed at predetermined time intervals. The operation states 1 to 4 shown in FIGS. 2 to 5 are realized by being repeatedly and continuously performed. As a result, also in this modified example, the operation states 1 to 4 transition under the transition condition shown in FIG.

  In addition, it should be thought that embodiment disclosed this time and a modification are illustrations in all the points, and are not restrictive. The scope of the present invention is shown not by the description of the above-described embodiment and modification, but by the scope of claims, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

  For example, in the above-described embodiment, an example in which the engine cooling device 100 is mounted on a vehicle 90 such as an automobile provided with the engine 91 has been described, but the present invention is not limited to this. For example, you may apply this invention with respect to the engine cooling device mounted in equipment other than the vehicle provided with the internal combustion engine. Further, as the engine (internal combustion engine) 91, a gasoline engine, a diesel engine, a gas engine, or the like can be applied.

  In the above embodiment, an example in which the first threshold temperature T1 is higher than the second threshold temperature T2 has been described, but the present invention is not limited to this. In the present invention, for example, the first threshold temperature T1 and the second threshold temperature T2 may be set to the same temperature. In this case, since the first switching valve 30 and the second switching valve 40 are switched at the same temperature, there is no transition to the operation state 3 in FIG.

  In the above embodiment, the operation is performed when the temperature Tw of the cooling water is Tw ≦ T3 and the engine speed Ne is Ne> Ne0 or the engine load factor KL is KL> KL0. Thus, although the example which comprised the electric water pump 20 was shown, this invention is not limited to this. In the present invention, the electric water pump 20 does not operate when the temperature Tw of the cooling water is equal to or lower than the third threshold temperature T3, and operates when the temperature Tw of the cooling water is higher than the third threshold temperature T3. You may comprise.

  Further, in the above embodiment, when the temperature Tw of the cooling water satisfies Tw ≦ T3, the engine speed Ne is Ne ≦ Ne0, and the engine load factor KL is KL ≦ KL0, the operation is stopped. Thus, although the example which comprised the electric water pump 20 was shown, this invention is not limited to this. In the present invention, the electric water pump 20 may be configured to operate even when the temperature Tw of the cooling water is equal to or lower than the third threshold temperature T3. That is, the electric water pump 20 may be configured to always operate. In this case, there is no transition to the operation state 1 in FIG.

  In the above-described embodiment, an example in which the first threshold temperature T1 is 90 ° C., the second threshold temperature T2 is 80 ° C., and the third threshold temperature is 70 ° C. has been described. Not limited to. The temperatures described in the above embodiment are merely examples, and the first threshold temperature T1, the second threshold temperature T2, and the third threshold temperature T3 are temperatures other than 80 ° C., 90 ° C., and 70 ° C., respectively. It may be.

  Further, in the above-described embodiment and modification, for convenience of explanation, the control processing by the control unit 93 has been described using the “flow drive type” flowchart in which processing is performed in order along the processing flow. Not limited to. In the present invention, the process of the control unit 93 may be performed by an “event driven type (event driven type)” process in which the process is executed in units of events. In this case, it may be performed by a complete event drive type or a combination of event drive and flow drive.

DESCRIPTION OF SYMBOLS 10 Mechanical water pump 20 Electric water pump 30 1st switching valve 40 2nd switching valve 50 Radiator 91 Engine T1 1st threshold temperature T2 2nd threshold temperature T3 3rd threshold temperature Tw Cooling water temperature Ne Engine speed KL Engine load factor

Claims (6)

A mechanical water pump driven by an engine and rotating in synchronization with the rotation of the engine;
An electric water pump arranged in parallel with the mechanical water pump and capable of changing a rotation speed independently of the rotation of the engine;
It is arranged on the discharge side of the mechanical water pump and is opened when the temperature of the cooling water is higher than the first threshold temperature, and the mechanical type when the temperature of the cooling water is equal to or lower than the first threshold temperature. An engine cooling device comprising: a first switching valve that shuts off a flow of the water pump. A radiator for cooling the cooling water;
It is arranged between the radiator and the electric water pump, and is opened when the temperature of the cooling water is higher than the second threshold temperature, and when the temperature of the cooling water is equal to or lower than the second threshold temperature, the The engine cooling device according to claim 1, further comprising a second switching valve that blocks a flow from a radiator to the electric water pump.   The engine cooling device according to claim 2, wherein the first threshold temperature of the first switching valve is equal to or higher than the second threshold temperature of the second switching valve.   The engine cooling device according to any one of claims 1 to 3, wherein the electric water pump is configured to be operable even when the first switching valve is closed.   In the electric water pump, the temperature of the cooling water is equal to or lower than a third threshold temperature lower than the first threshold temperature, and the engine speed is higher than a predetermined speed, or the engine The engine cooling device according to claim 4, wherein the engine cooling device is configured to operate when the load factor is higher than a predetermined load factor.   The engine cooling device according to claim 2, wherein both the first switching valve and the second switching valve are thermostat valves.

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