JP6375709B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling system, and more particularly to a technique for controlling a plurality of electric pumps for circulating a refrigerant in a refrigerant flow path between a heat source and a radiator.

  As a cooling system configured as described above, Patent Document 1 discloses a cooling jacket to which a liquid refrigerant for cooling a semiconductor is supplied, a radiator for radiating the heat of the liquid refrigerant, and an electric type for circulating the liquid refrigerant. A liquid cooling system with two circulation pumps is shown.

  In this Patent Document 1, two circulation pumps are connected in series by piping, and a bypass tube is provided at a position parallel to the two circulation pumps. When one circulation pump stops due to a failure or the like, The liquid refrigerant can be circulated by sending the liquid refrigerant to the tube.

  Moreover, in this patent document 1, the sensor which detects rotation of two circulation pumps is provided, and when it is determined by the sensor that one circulation pump has stopped, the rotation speed is increased by a rise in voltage with respect to the circulation pump having no failure. It is comprised so that control which raises may be performed.

  Patent Document 2 discloses a cooling device including two electric water pumps having different ratings in parallel with respect to a cooling water passage between an internal combustion engine and a radiator, and an electronic control unit that controls the driving of these water pumps. Has been.

  In this patent document 2, when the electronic control unit can not cope with the state in which one electric water pump that is optimized is driven based on the required circulation amount according to the operation state of the internal combustion engine, and one drive cannot cope with the two It is comprised so that it may switch to the state which drives an electric water pump simultaneously.

JP 2005-228237 A JP 2006-37883 A

  In a cooling device that circulates engine coolant as a refrigerant with an electric pump between an internal combustion engine as a heat source and a radiator as a radiator so as to cool an internal combustion engine of an automobile, Patent Document 1 and Patent Document 2 As described above, efficient cooling is realized by adjusting the driving speed of the water pump.

  Considering the characteristics of a water pump driven by an electric motor, the power supplied when cooling water is circulated most efficiently is a fixed value, and the amount of refrigerant that can be circulated in this efficient driving state is also determined. Value.

  On the other hand, in the case of using two water pumps having different ratings as described in Patent Document 2, the circulation amount can be adjusted by adjusting the power supplied, and the efficiency can be improved by switching the water pump. It can also be increased. However, since the power supplied by selecting two water pumps is adjusted in the configuration of Patent Document 2, the water pump is not necessarily used with good efficiency, and power consumption is reduced. There was room for improvement.

  An object of the present invention is to configure a cooling system capable of suppressing power consumption when circulating a required amount of cooling water by controlling a plurality of electric pumps.

A feature of the present invention includes a plurality of electric pumps that circulate refrigerant in a refrigerant flow path between a heat source and a radiator, and a pump control device that individually controls the plurality of electric pumps. Are all capable of adjusting the circulation amount of the refrigerant, and when the set target circulation amount is 0, the pump control device maintains all the electric pumps in a stopped state, and the target circulation amount Is larger than 0 and smaller than the efficiency circulation amount of one of the plurality of electric pumps, power for obtaining the target circulation amount is supplied to the one electric pump, and among the plurality of electric pumps, The other electric pumps other than the one electric pump are stopped, the target circulation amount exceeds the efficiency circulation amount of the one electric pump, and all the efficiency circulation amounts of the plurality of electric pumps are integrated. does not exceed the Expediently, to drive the one of the electric pump at maximum efficiency, that drives the other of the electric pump to circulate the retentate obtained by subtracting the efficiency circulation amount of the one of the electric pump from the target circulation amount It is in.

According to this configuration, the set target circulation amount exceeds the integrated value of the efficiency circulation amount of one electric pump among the plurality of electric pumps, and the total efficiency circulation amount of other electric pumps excluding this electric pump is reduced. When the total amount is not exceeded, driving one electric pump with the highest efficiency results in no waste of electric power and driving of other electric pumps, but waste of electric power required for this driving can be reduced.
This reduces the power consumed by the electric pump compared to, for example, a configuration in which only a single electric pump is driven or a configuration in which an electric pump with a different rating is selected and supplied power is adjusted. be able to.

  In the present invention, when the set target circulation amount is larger than a value obtained by integrating all the efficient circulation amounts of the plurality of electric pumps, the pump control device, for all of the plurality of electric pumps, You may drive by supplying electric power larger than the electric power which obtains an efficient circulation amount.

  According to this, for example, when the temperature of the heat source becomes higher than the target temperature and the set target circulation amount is large, all the electric pumps are driven with electric power larger than the electric power for obtaining the efficient driving amount. Thereby, the temperature fall of a heat source is accelerated | stimulated and a target circulation amount reduces. As a result, the power consumption can be reduced by returning to the state in which at least one electric pump is driven at the highest efficiency.

  In the present invention, when the set target circulation amount is larger than a value obtained by integrating all the efficient circulation amounts of the plurality of electric pumps, the pump control device is configured for at least one of the plurality of electric pumps. Thus, the electric power to be driven at the highest efficiency of the electric pump may be supplied, and the electric pump may be driven by supplying electric power larger than the electric power for obtaining the efficiency circulation amount.

  According to this, by driving at least one of the plurality of electric pumps with the highest efficiency, power consumption can be suppressed even when other electric pumps are driven in an inefficient region.

  In the present invention, as the plurality of electric pumps, two electric pumps having the same power consumption and efficiency circulation amount when driven at the highest efficiency may be used.

  By using two electric pumps having the same performance, control is simplified and maintenance is facilitated.

  In the present invention, as the plurality of electric pumps, two electric pumps having different power consumption and efficiency circulation amount when driven at the highest efficiency may be used.

According to this, by using an electric pump with different performance, for example, when the target circulation amount increases from 0, the power consumption when the pump controller is driven at the highest efficiency of the two electric pumps, and By driving the electric pump with a small amount of efficient circulation first, fine control is possible even when the amount of refrigerant circulation is small.
According to the present invention, when the target circulation amount increases from 0, an electric pump having a small power consumption and an efficient circulation amount when the pump control device is driven at the highest efficiency among the two electric pumps. It may be driven first.

It is a figure which shows the cooling system of an engine. It is a block circuit diagram which shows the structure of a motor control unit. It is a flowchart of a pump control routine. It is a graph showing the flow volume and efficiency of two electric pumps. It is a graph which shows the relationship between the output and flow volume of two electric pumps. It is a timing chart which shows the electric power supplied to two electric pumps. It is a timing chart which shows vibration and phase difference of two electric pumps. It is a timing chart which shows the relation of vibration of two electric pumps.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Cooling system configuration]
As shown in FIG. 1, cooling water (an example of a refrigerant) of a water jacket 1 (an example of a heat source) of an engine E provided in a vehicle such as a passenger car is sent to a radiator 2 (an example of a radiator), and after the heat dissipation, the water jacket A circulation type refrigerant flow path R returning to 1 is configured. The first electric pump P1 and the second electric pump P2 that circulate the cooling water in the refrigerant flow path R are provided, and the pump control device 10 that individually controls them, and the electric pumps P (the first electric pump P1 and the first electric pump P1). And a motor control unit 11 that supplies electric power to the electric pump P2), and constitutes an engine cooling system.

  The engine E is a general internal combustion engine such as a 4-cycle type, and the refrigerant flow path R has a supply pipe 3 for sending cooling water from the water jacket 1 and cooling water radiated by the radiator 2 to the water jacket 1 of the engine E. And a return pipe 4 to be returned. The supply pipe 3 is provided with a temperature sensor TS for measuring the temperature of the cooling water.

  A radiator cap 2A is provided at the upper part of the radiator 2, and a reservoir tank 5 is provided in the vicinity thereof, and supply / discharge of cooling water to / from the reservoir tank 5 through a pressure valve formed integrally with the radiator cap. A tube 6 is provided.

  Two electric pumps P (superior concepts of the first electric pump P1 and the second electric pump P2) are connected in series along the circulation direction of the cooling water in the refrigerant flow path R (the direction indicated by the arrow in FIG. 1) in the reduction pipe 4. Is arranged. Each electric pump P is configured as a centrifugal pump type having a motor M composed of a three-phase brushless DC motor and an impeller W. As the motor M, a synchronous motor or an induction motor may be used.

  The electric pump P has a gap formed between the impeller W and the housing that accommodates them, and drives one of the two electric pumps P even when one of the two electric pumps P is stopped. Circulation is possible. Further, when the two electric pumps P are driven simultaneously, the flow rate increases as the pressure in the supply pipe 3 increases.

  The motor M includes a rotor composed of permanent magnets and a field coil arranged at a position surrounding the rotor. The motor M is configured as a 6-pole 3-phase 9-slot type that rotates when supplied with 3-phase AC.

[Control configuration]
In this engine cooling system, the same performance as that of the first electric pump P1 and the second electric pump P2 is used. Specifically, the power consumption when each electric pump P is driven at the highest efficiency and the efficiency circulation amount Qe are equal.

  The motor control unit 11 generates three-phase alternating current from the electric power from the power source 12 under the control of the pump control device 10 and supplies it to the motor M of at least one of the electric pumps P, thereby rotating the rotational speed of the electric pump P. It functions as an inverter that sets (the number of revolutions per unit time).

  That is, as shown in FIG. 2, the motor control unit 11 includes a pair of power control units 11A corresponding to each motor M, a pair of PWM control units 11C, and a pair of phase detection units 11B. A single relative phase control unit 11D that outputs a signal for adjusting the rotational phase of the motor M to the power control unit 11A.

  The power control unit 11 </ b> A has a plurality of power control elements for generating a three-phase alternating current from the power of the direct-current power supply 12 and supplying the three-phase alternating current to the field coil of the motor M. The PWM control unit 11C has a power control element for controlling the power (voltage) supplied from the power control unit 11A to the field coil by setting the duty ratio. The phase detection unit 11B has an A / D conversion element, a shunt resistor, and the like so as to acquire an induced voltage of each phase of the three-phase alternating current and acquire a rotational phase of the rotor from the zero cross timing. The relative phase control unit 11D sets the output timing of the three-phase power in each power control unit 11A.

  The pump control device 10 receives a measurement signal from the temperature sensor TS, receives a control signal from the motor control unit 11, and outputs a control signal to the motor control unit 11. The pump control device 10 is configured as an ECU by using a microprocessor or a DSP, and includes a circulation amount setting unit 10A, a drive mode setting unit 10B, a phase control unit 10C, and a storage unit 10D. I have.

  The circulation amount setting unit 10A sets a target circulation amount Qd (water amount per unit time) of the cooling water in the refrigerant flow path R based on the measurement signal of the temperature sensor TS. The drive mode setting unit 10B sets the drive mode of the electric pump P. The phase control unit 10 </ b> C suppresses vibration caused by the rotation of each motor M when the two electric pumps P are driven simultaneously.

  The storage unit 10D is configured by a nonvolatile memory such as an EEPROM, and a table for setting the target circulation amount Qd corresponding to the cooling water temperature measured by the temperature sensor TS, or a function for setting the target circulation amount Qd by calculation, Information such as coefficients is stored. This table or information corresponds to the target power signal output to the motor control unit 11. For example, by outputting the target power signal read from the table to the motor control unit 11, the motor control unit 11 Electric power corresponding to the target power signal is supplied to the motor M of the electric pump P to obtain the target circulation amount Qd.

  Furthermore, the storage unit 10D stores the efficiency circulation amount Qe when the electric pump P is driven at the highest efficiency and the supply power value required when driving the electric pump P at the highest efficiency. The circulation amount setting unit 10A, the drive mode setting unit 10B, and the phase control unit 10C are configured by software, but may be configured by hardware such as logic.

  In this engine cooling system, for example, when a plurality of electric pumps P having different maximum efficiencies are provided, a plurality of tables representing the circulation amount of the cooling water with respect to the supply power value corresponding to each motor M, and the supply power A plurality of functions indicating the relationship between the value and the circulation amount, a plurality of data as a basis of calculation such as coefficients, and the like are stored in the storage unit 10D. In addition to this, the storage unit 10D has an efficiency circulation amount Qe when each electric pump P is driven at the highest efficiency and a plurality of supply power values for each electric pump as required when driving at the highest efficiency. Is remembered.

  In this engine cooling system, the supply power is changed by changing the voltage applied to the motor M of the electric pump P under the control of the PWM control unit 11C of the motor control unit 11, so that the rotation speed (rotation per unit time) is changed. Number).

  The efficiency circulation amount Qe is a value measured in advance. When measuring the efficiency circulation amount Qe, the supply power for driving the motor M of the electric pump P is continuously changed (the applied voltage), and the supply power and the circulation amount of the cooling water are sampled. Measurement is performed, and supply power values and circulation amounts at a plurality of sampling timings are acquired. Of the values obtained by dividing the circulation amount by the supply power value acquired in this way, the largest value is the highest efficiency. Therefore, when the electric pump P is driven with the highest efficiency, the supply power value required to circulate the cooling water with the unit flow rate is the smallest. In order to realize power saving using this phenomenon, the circulation amount at the maximum efficiency is set to the efficiency circulation amount Qe, and the supply power value corresponding to this is stored in the storage unit 10D.

[Control form]
The outline of the control mode of the pump control device 10 is shown in the flowchart of FIG. 3 as a pump control routine. In this control, the circulation amount setting unit 10A sets a target circulation amount Qd to be circulated through the refrigerant flow path R based on the coolant temperature measured by the temperature sensor TS (step # 1).

  In this step, the target circulation amount Qd is obtained based on the data stored in the storage unit 10D and the coolant temperature.

  Next, the target circulation amount Qd and the efficiency circulation amount Qe are compared (step # 2). When the target circulation amount Qd is “0”, the drive mode setting unit 10B The electric pump P is maintained in a stopped state (steps # 3 and # 4). In this pump control routine, the electric pump P is stopped by controlling the motor control unit 11 so as to stop the power supply to the motor M.

  Further, when the target circulation amount Qd is smaller than the efficiency circulation amount Qe (including the case where they are equal) by comparison in the # 2 step, the electric power for obtaining the target circulation amount Qd is supplied to one electric pump P, and the other The electric pump P stops (steps # 5 and # 6). When the target circulation amount Qd matches the efficiency circulation amount Qe, electric power for obtaining the efficiency circulation amount Qe is supplied to one electric pump P.

  As described above, the storage unit 10D includes either table data indicating the relationship between the supply power value supplied to the electric pump P and the circulation amount of the cooling water corresponding to the supply power value, or data that is the basis of the calculation. Is remembered. Therefore, the pump control device 10 determines the power to be supplied from the target circulation amount Qd based on the data.

  As described above, in steps # 5 and # 6, the required circulation amount is obtained by supplying the electric power obtained based on the target circulation amount Qd to one of the electric pumps P.

  Further, when the target circulation amount Qd is larger than the efficiency circulation amount Qe and smaller than twice the efficiency circulation amount Qe (including the case where they are equal) as a result of the comparison in the step # 2, the drive mode setting unit 10B has one electric pump. The electric power for obtaining the efficiency circulation amount Qe is supplied to P, and the other electric pump P supplies the electric power for obtaining the remaining circulation amount (Qd-Qe) (steps # 7 and # 8). When the circulation amount of the remaining (Qd−Qe) coincides with the efficiency circulation amount Qe, electric power for obtaining the efficiency circulation amount Qe is supplied to the other electric pump P.

  In steps # 7 and # 8, both electric pumps P are driven, and at this time, electric power for obtaining an efficient circulation amount Qe is supplied to at least one electric pump P. The electric pump P is driven to realize power saving.

  In particular, when two electric pumps P are used as in this embodiment, in step # 7, the set target circulation amount Qd exceeds the efficiency circulation amount of one electric pump P, and one electric pump is It is determined that the total efficiency circulation amount of the other electric pumps P is not exceeded. In this determination, since there is only one other electric pump P, the total efficiency circulation amount matches the efficiency circulation amount Qe of one electric pump P. In step # 8, one electric pump P is driven at the highest efficiency, and another electric pump is circulated so that the remainder obtained by subtracting the efficiency circulation amount Qe of the one electric pump P from the target circulation amount Qd is circulated. P will be driven.

  In this embodiment, the control mode in the cooling system using two electric pumps P has been described. For example, when N electric pumps P of three or more are used, the target circulation amount Qd is 1 The efficiency circulation amount Qe of one electric pump P is exceeded, and (N-1) times the efficiency circulation amount Qe of other electric pumps P (N-1) is not exceeded ((N-1) electric Also in the case of the total efficiency circulation amount of the pump [(N-1) × Qe] is not exceeded), the same control as the steps # 7 and # 8 is performed. Specifically, power for obtaining an efficient circulation amount Qe is supplied to at least one electric pump P, and the remaining circulation amount is circulated by the remaining (N-1) electric pumps P. Electric power is supplied to the electric pump P.

  The relationship between the flow rate Q and the efficiency of the electric pump P can be shown as in the graph of FIG. 4, and when the power supplied to the first electric pump P1 is increased, the flow rate Q reaches the efficient circulation amount Qe. The maximum efficiency is achieved. In the figure, in the situation where the first electric pump P1 is driven so as to obtain the efficiency circulation amount Qe, when the second electric pump P2 is started to drive, the first electric pump P1 and the second electric pump P2 are combined. It also shows that the efficiency rises from a low state, and the flow rate Q of the cooling water flowing through the refrigerant flow path R is equal to the flow rate Q that combines the flow rates of the first electric pump P1 and the second electric pump P2. It can be understood that the cooling water is circulated at the highest efficiency when the amount reaches twice the amount Qe.

  The graph of “pressure” shown in the figure is the pressure acting on the cooling water provided with the pressure sensor in the refrigerant flow path R, and indicates that the pressure decreases as the flow rate of the cooling water increases.

  The graph of FIG. 5 shows the relationship between the output and flow rate of the first electric pump P1 and the second electric pump P2. From this graph, when the flow rate Q by the first electric pump P1 reaches the efficiency circulation amount Qe, the driving state of the first electric pump P1 is maintained and the driving of the second electric pump P2 is started to obtain the required flow rate. I can understand.

  Further, when the target circulation amount Qd is larger than twice the efficiency circulation amount Qe, the drive mode setting unit 10B both circulates the flow rate that is 1/2 of the efficiency circulation amount Qe by both the electric pumps P. Electric power equal to the electric pump P is supplied (step # 9). The electric power supplied in this way is larger than the electric power supplied to obtain an efficient circulation amount by the two electric pumps P.

  In step # 9, when the target circulation amount Qd is slightly larger than twice the efficiency circulation amount Qe, electric power for obtaining the efficiency circulation amount Qe is supplied to one electric pump P, and the other electric motor is supplied. The control mode may be set so as to supply the pump P with electric power for obtaining the circulation amount of the remaining (Qd−2Qe).

  Furthermore, in the situation where the two electric pumps P are driven, the vibration suppression control for suppressing the vibration is performed by the phase control unit 10C setting the phase difference α between the two motors M (step # 10).

  In this vibration suppression control (# 10 step), the PWM control unit is configured so that the drive phase setting unit 10B of the pump control device 10 acquires the rotation phase from the two phase detection units 11B and rotates at a constant speed (equal rotation speed). A control signal is output to 11C. Furthermore, when the two motors M rotate at a constant speed in this way, the relative phase control unit 11D controls the power control unit 11A to set the phase difference α between the two motors M and suppress vibration. Is done.

  The motor M is a 6-pole, 3-phase, 9-slot type as described above, and the stator includes field coils for each of the U phase, V phase, and W phase, and includes a rotor made of permanent magnets. As shown in FIG. 6, the motor M of the first electric pump P1 is applied to the U phase, V phase, and W phase in this order with a phase difference of 120 degrees in electrical angle. Since current flows through the three-phase stator coils of U phase, V phase, and W phase in this way, in this motor M, the rotor can be rotated by the attractive force and repulsive force acting between the rotor and the field coil. It becomes.

  Further, when the motor M is driven, vibration is mainly generated by the action of cogging torque. When the two motors M are driven in the same phase, the vibration is superimposed and the engine cooling system is vibrated as a result. There was also.

  In this type of motor M, six phase switching timings are generated in one rotation, and the phase switching is performed at a period T corresponding to the phase switching timing of 60 degrees as shown in the timing chart of FIG. Since the motor M is a pole 3-phase 9-slot type, phase switching is performed 18 times when the motor M rotates once.

  Since the phase is switched in this way, the vibration caused by the cogging torque is also synchronized with the period T. For this reason, vibration is suppressed by supplying current to each phase of the other motor M at a timing (phase difference of 30 degrees) that is out of phase by 1/2 of the period T.

  The timing chart shown in FIG. 6 shows the current supply timing in each of the U-phase, V-phase, and W-phase in the half-wave (unipolar) driving method, and the first electric pump P1 shown in the upper part of FIG. Compared with the current supply timing to the motor M, the current supply timing to the motor M of the second electric pump P2 shown in the lower part of the figure is shifted by a phase difference α that is ½ of the period T, Two vibrations having opposite phases are canceled out by mutual vibrations to realize vibration suppression.

  That is, as shown in FIG. 7, when the vibration generated in the first electric pump P1 is continuously generated in the period T, the vibration generated in the second electric pump P2 is shifted by a timing corresponding to the phase difference α. Thus, the superposition of vibration is suppressed. In particular, when the vibration generated by driving the motor M of the first electric pump P1 is shown by a solid line as shown in FIG. 8, the vibration generated by driving the motor M of the second electric pump P2 is shown by a wavy line. The vibration is reduced by creating and canceling each vibration.

  When the two motors M are driven with such a phase difference α, the relative phase control unit 11D controls each power control unit 11A. That is, the relative phase control unit 11D creates the phase difference α by advancing or delaying the phase by temporarily increasing or temporarily reducing the power to the one motor M. Control is performed so as to maintain the phase difference α.

[Modification of Step # 10]
In the above-described embodiment, the phase difference α is set to ½ of the period T. However, when the electric pump P is driven, vibration may be generated by rotation of the rotating system including the rotor and the impeller W. In many cases, it depends on the vibration characteristics of the rotating system, the positional relationship between the two motors M, the rotational speed of the motors M, the pulsation of cooling water sent by the impeller W, interference between cooling waters, and the like. It is difficult to uniquely determine the phase difference α.

  For this reason, when the two motors M are simultaneously driven at a constant speed (equal rotational speed), the phase difference α that is best suppressed in vibration is determined in advance by an FFT analyzer or the like corresponding to the rotational speed of the motor M. The vibration is measured by the above, and the phase difference α at which the vibration is minimized is obtained and stored as table data in the storage unit 10D. When the two motors M are simultaneously driven at a constant speed, the phase difference α stored in the storage unit 10D is read based on the rotation speed, and the two motors M are controlled to be driven with the phase difference α. May be performed.

  In this way, by setting the phase difference α based on actual measurement, vibration can be suppressed satisfactorily while reflecting the rotational speed, the relative positional relationship between the two motors M, or the pulsation of the cooling water. It becomes.

[Effect of the embodiment]
In this way, not only is power saving achieved by driving at least one of the two electric pumps P with the highest efficiency, but a plurality of electric pumps P are provided, so that it is compared with one having a single electric pump P. Thus, the cooling water can be circulated even when the electric pump P fails, and overheating of the engine E can be suppressed.

  Further, by using two electric pumps P having the same performance, for example, compared to a configuration using electric pumps P having different performances, maintenance of the electric pump P is easy, and a plurality of types of electric pumps P are used for replacement. There is no need to prepare.

  Further, by using two electric pumps P having different power consumption and efficiency circulation amount when driven at the maximum efficiency, for example, when the target circulation amount increases from 0, of the two electric pumps P By driving the electric pump P (electric pump P on the small capacity side) that has low power consumption and efficient circulation amount when driven at maximum efficiency, fine control is possible even when the circulation amount of refrigerant is small. It becomes possible.

  In addition, when two electric pumps P having different performances are used and the target circulation amount increases from 0, control is performed so that the electric pump P on the large capacity side of the two electric pumps P is driven first. The order may be set. By setting the order in this manner, the frequency of use of the electric pump P on the small capacity side is reduced to suppress the occurrence of a failure. For example, when the electric pump P on the large capacity side fails, It is also possible to suppress overheating of the engine E by the operation of the pump P.

  When the target circulation amount Qd does not exceed the efficiency circulation amount Qe, only one electric pump P is driven. For example, waste of electric power is suppressed as compared with a case where one large-capacity electric pump P is driven. To do. Further, when driving a plurality of electric pumps P, driving one electric pump P with the highest efficiency realizes efficient circulation of cooling water without wasting power.

  When the two electric pumps P are simultaneously driven with an equal number, by setting the phase difference α of the rotational phase, the vibration is suppressed and the vibration sound felt by the driver is reduced to obtain a comfortable driving environment. Further, when suppressing the vibration, if the phase difference α is set based on the actual measurement, the vibration can be further suppressed.

[Another embodiment]
The present invention may be configured as follows in addition to the embodiment described above.

(A) Three or more electric pumps P are provided in the refrigerant flow path R as the plurality of electric pumps P. Further, when a plurality of electric pumps P are provided, these may be arranged in parallel. As described above, when three or more electric pumps P are provided, two or more electric pumps P can be simultaneously driven at maximum efficiency, and power consumption can be suppressed.

(B) When the target circulation amount Qd is set by the circulation amount setting unit 10A, the control mode is set so that the electric pump P that is driven first among the two electric pumps P is switched every time the engine E is started. . By setting the control mode in this way, the integrated drive time of both electric pumps P is made substantially equal, the time until falling into a failure state is lengthened, and simultaneous replacement is possible during maintenance.

(C) For example, in a system including three or more N electric pumps P, when the target circulation amount Qd exceeds the value obtained by integrating the efficient circulation amounts Qe of the N electric pumps P, (N−1 ) Electric power is supplied to each of the electric pumps P so as to obtain an efficient circulation amount Qe, and the remaining one electric pump P is driven to circulate the remaining [Qd− (N−1) × Qe] refrigerant. . When controlled in this way, one electric pump P is driven in a state exceeding the efficiency circulation amount Qe, but (N−1) pieces of electric pumps P are driven so as to obtain the efficiency circulation amount Qe. It is possible to reduce waste of power.

(D) By using a configuration capable of detecting the rotational phase of the electric pump P, it is configured so that a failure can be detected and notified based on the number of rotations of the electric pump P with respect to the supplied power. Thereby, the replacement time of the electric pump P can be easily grasped.

  The present invention can be used in a cooling system including a plurality of electric pumps for circulating a refrigerant in a refrigerant flow path between a heat source and a radiator.

1 Heat source (water jacket)
2 radiator (radiator)
10 Pump control device P Electric pump R Refrigerant flow path Qd Target circulation amount Qe Efficiency circulation amount

Claims (6)

A plurality of electric pumps that circulate refrigerant in a refrigerant flow path between a heat source and a radiator, and a pump control device that individually controls the plurality of electric pumps,
The plurality of electric pumps can all adjust the circulation amount of the refrigerant,
The pump control device stores the circulation amount of the refrigerant per unit time when the plurality of electric pumps are individually driven at the highest efficiency as an efficient circulation amount for each electric pump,
The pump controller is
When the set target circulation amount is 0, all the electric pumps are maintained in a stopped state,
When the target circulation amount is larger than 0 and smaller than the efficiency circulation amount of one of the plurality of electric pumps, the electric power for obtaining the target circulation amount is supplied to the one electric pump, The other electric pumps except the one electric pump are stopped,
The target circulation amount is greater than the efficiency circulation amount of the one of the electric pump, and, if not exceed the value obtained by integrating all the efficiency circulation amount of the plurality of the electric pump, maximum efficiency the single electric pump in addition to driving, the cooling system for driving the other of the electric pump to circulate the retentate obtained by subtracting the efficiency circulation amount of the one of the electric pump from the target circulation amount.   When the set target circulation amount is larger than a value obtained by integrating all the efficiency circulation amounts of the plurality of electric pumps, the pump control device sets the efficiency circulation amount for all of the plurality of electric pumps. The cooling system according to claim 1, wherein the cooling system is driven by supplying electric power larger than the electric power obtained.   When the set target circulation amount is larger than a value obtained by integrating all the efficient circulation amounts of the plurality of electric pumps, the pump control device applies the electric drive to at least one of the plurality of electric pumps. The cooling system according to claim 1, wherein electric power that is driven at the highest efficiency of the pump is supplied, and electric power that is larger than electric power that obtains an efficient circulation amount is supplied to and driven by another electric pump.   The cooling system according to any one of claims 1 to 3, wherein as the plurality of electric pumps, two electric pumps having the same power consumption when driven at maximum efficiency and an efficient circulation amount are used.   The cooling system according to any one of claims 1 to 3, wherein as the plurality of electric pumps, two electric pumps having different power consumption and efficiency circulation amount when driven at maximum efficiency are used. When the target circulation amount increases from 0, the pump control device first drives the electric pump having the small power consumption and the efficient circulation amount when driven at the highest efficiency among the two electric pumps. The cooling system according to claim 5.

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