Radiator cooling system

Abstract

To provide a radiator cooling system that can reduce a power consumption of an electric pump that generates a driving force for moving cooling water and a driving force for rotating a fan that cools a radiator.SOLUTION: A radiator cooling system includes: a fan located behind a radiator and rotating around a rotary axis to generate negative pressure; a cooling water channel connected to the radiator; an electric pump that moves the cooling water along the channel; a water wheel that is rotated around its axis by the cooling water flowing through the channel; a water temperature sensor that detects an inlet water temperature of an inverter that is cooled by the cooling water; and a control part that performs PWM control of the electric pump based on a map 40 that defines a relationship between the inlet water temperature, a vehicle speed value that indicates a vehicle speed, and a duty ratio of an electric power supplied to the electric pump. The map specifies that when the vehicle speed value is equal to or greater than a first predetermined value and equal to or less than a second predetermined value and the inlet water temperature is equal to or greater than a third predetermined value, the duty ratio is decreased as the vehicle speed value increases.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a radiator cooling system. [Background technology]

[0002] Patent Document 1 below discloses a radiator cooling system installed in a vehicle. This cooling system includes a fan that generates negative pressure immediately behind the radiator by rotating around a rotation axis, a flow path through which cooling water supplied to the radiator flows, and an electric pump that moves the cooling water along the flow path. The cooling system further includes a water wheel that is rotated by the cooling water flowing through the flow path. The water wheel and the fan share a common rotation axis. This cooling system rotates the fan using the force generated by the cooling water, so no dedicated drive source for the fan is required. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-92531 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned Patent Document 1 leaves room for improvement in terms of reducing the power consumption of the electric pump.

[0005] In consideration of the above, the present invention has an object to provide a radiator cooling system that can reduce the power consumption of an electric pump that generates the driving force for moving the cooling water and the driving force for rotating a fan that cools the radiator. [Means for solving the problem]

[0006] The radiator cooling system of claim 1 comprises a fan located behind a radiator mounted on a vehicle and generating negative pressure by rotating around a rotation axis, a flow path connected to the radiator through which cooling water flows and is supplied to the radiator, an electric pump moving the cooling water along the flow path, a water wheel rotated about the rotation axis by the cooling water flowing through the flow path, a water temperature sensor detecting an inlet water temperature of an inverter cooled by the cooling water flowing through the flow path, and a control unit that PWM controls the electric pump based on a map that defines the relationship between the inlet water temperature, a vehicle speed value that represents the speed of the vehicle, and a duty ratio of power supplied to the electric pump, and the map specifies that when the vehicle speed value is greater than or equal to a first predetermined value and less than a second predetermined value, and the inlet water temperature is greater than or equal to a third predetermined value, the duty ratio is reduced as the vehicle speed value increases.

[0007] In the radiator cooling system of claim 1, the control unit PWM controls the electric pump based on a map that defines the relationship between the inlet water temperature of the inverter, a vehicle speed value that indicates the vehicle speed of the vehicle, and a duty ratio of the power supplied to the electric pump. The map further defines that, when the vehicle speed value is equal to or greater than a first predetermined value and equal to or less than a second predetermined value, and the inlet water temperature of the inverter is equal to or greater than a third predetermined value, the duty ratio is lowered as the vehicle speed value increases. As the vehicle speed value increases, the cooling effect of the radiator due to the wind while traveling increases. Therefore, when the vehicle speed value increases, the radiator is sufficiently cooled even if the duty ratio of the power supplied to the electric pump that generates the driving force for rotating the fan is lowered. Therefore, the radiator cooling system of claim 1 can reduce the power consumption of the electric pump that generates the driving force for moving the coolant and the driving force for rotating the fan that cools the radiator.

[0008] The radiator cooling system of claim 2 is based on claim 1, wherein the map defines the relationship between the inlet water temperature and the duty ratio for each of a plurality of vehicle speed values ​​included in a range equal to or greater than the first predetermined value and equal to or less than the second predetermined value.

[0009] The control unit of the radiator cooling system of claim 2 PWM controls the electric pump based on the relationship between the inlet water temperature and the duty ratio for each vehicle speed value. Therefore, the radiator cooling system of claim 2 can further reduce the power consumption of the electric pump.

[0010] The radiator cooling system of claim 3 is the same as claim 2, further comprising a vehicle speed sensor that detects the vehicle speed of the vehicle, and the vehicle speed value is an average value of the vehicle speed over a predetermined time period or an exponentially smoothed average value obtained based on a plurality of the vehicle speeds.

[0011] The operation of the electric pump PWM-controlled by the radiator cooling system of claim 3 is likely to be smoother than when the vehicle speed detected by the vehicle speed sensor is used as an argument to apply to the map. Effect of the Invention

[0012] As described above, the radiator cooling system according to the present invention has the excellent effect of reducing the power consumption of the electric pump that generates the driving force for moving the coolant and the driving force for rotating the fan that cools the radiator. [Brief description of the drawings]

[0013] [Figure 1] 1 is an overall view of a radiator cooling system according to an embodiment; [Diagram 2] FIG. 2 is a control block diagram of an ECU of a vehicle. [Diagram 3] FIG. 2 is a functional block diagram of the ECU. [Figure 4] 6 is a graph showing the relationship between a pump share rate, which is the ratio of the driving force to be generated by the electric pump to the required driving force of the fan, and the vehicle speed value. [Diagram 5] 4 is a diagram showing a map that defines the relationship between the inlet water temperature of the inverter, the vehicle speed value, and the duty ratio of the electric power supplied to the electric pump. FIG. [Figure 6] 4 is a flowchart showing a process executed by a CPU of the ECU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a radiator cooling system 50 (hereinafter, referred to as cooling system 50) according to the present invention will be described with reference to the accompanying drawings.

[0015] As shown in FIG. 1, a vehicle 10 equipped with a cooling system 50 is a hybrid vehicle. The vehicle 10 includes a radiator 12, an inverter 14 electrically connected to an AC electric motor and a drive battery (both not shown) that are drive sources of the vehicle 10, a flow path configuration unit 16 for supplying cooling water to the radiator 12 and the inverter 14, an electric pump 18 provided in the flow path configuration unit 16, a water wheel 20 provided in a flow path 17 (see FIG. 1) that is an internal space of the flow path configuration unit 16, and a fan 22 provided immediately after the radiator 12. The water wheel 20 and the fan 22 share a rotating shaft 24. The rotating shaft 24 is fixed to the water wheel 20 and the fan 22, and is rotatably supported by the flow path configuration unit 16. The water wheel 20 and the rotating shaft 24 can rotate only in a specific direction that is one direction. The flow path 17 of the flow path configuration unit 16, the internal flow path of the radiator 12, and the internal flow path of the inverter 14 are filled with cooling water (not shown). Furthermore, a bumper (grill) opening (not shown) is provided at the front end of the vehicle 10, located immediately in front of the radiator 12. The inverter 14 converts the power of the drive battery from DC to AC and supplies it to the electric motor, and also converts the AC power generated by the electric motor into DC and supplies it to the drive battery.

[0016] The vehicle 10 further includes a water temperature sensor 28 that detects the temperature of the coolant at a coolant inlet (not shown) of the inverter 14, a vehicle speed sensor 30 that detects the vehicle speed of the vehicle 10, and an ECU (Electronic Control Unit) 35.

[0017] 2, the ECU 35 includes a CPU (Central Processing Unit) (control unit) 35A, a ROM (Read Only Memory) 35B, a RAM (Random Access Memory) 35C, a storage 35D, a communication I / F 35E, and an input / output I / F 35F. The CPU 35A, the ROM 35B, the RAM 35C, the storage 35D, the communication I / F 35E, and the input / output I / F 35F are connected to each other so as to be able to communicate with each other via an internal bus 35Z.

[0018] The CPU 35A is a central processing unit that executes various programs and controls each part. The CPU 35A reads a program from the ROM 35B or the storage 35D, and executes the program using the RAM 35C as a working area. The CPU 35A controls each component and performs various calculation processes according to the program recorded in the ROM 35B or the storage 35D.

[0019] The ROM 35B stores various programs and various data. The RAM 35C temporarily stores programs or data as a working area. The storage 35D is configured by a storage device such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various programs and various data.

[0020] The communication I / F 35E is an interface for connecting via an external bus (not shown) to an ECU (not shown) other than the ECU 35. For example, the communication standard of the CAN protocol is used for this interface.

[0021] The input / output I / F 35F is an interface for communicating with various devices, including the electric pump 18, the water temperature sensor 28, and the vehicle speed sensor 30.

[0022] 3 is a block diagram showing an example of the functional configuration of the ECU 35. The ECU 35 has, as its functional configuration, a pump control unit 351, a vehicle speed calculation unit 352, and a duty ratio acquisition unit 353. The pump control unit 351, the vehicle speed calculation unit 352, and the duty ratio acquisition unit 353 are realized by the CPU 35A reading and executing a program stored in the ROM 35B.

[0023] The pump control unit 351 supplies power from a battery (not shown) provided in the vehicle 10 to the electric pump 18 to operate the electric pump 18. More specifically, the pump control unit 351 executes PWM (Pulse Width Modulation) control based on the duty ratio acquired by the duty ratio acquisition unit 353. When an ignition switch (not shown) provided in the vehicle 10 is in an on state, the electric pump 18 is operated by the pump control unit 351. Note that this "ignition switch" includes an ignition switch operated by a key and other switches. The other switches include, for example, a push-type start button. When the electric pump 18 operates, the coolant circulates through the flow path 17, the internal flow path of the radiator 12, and the internal flow path of the inverter 14 in the direction of the arrow in FIG. 1 by the power generated by the electric pump 18. This cools the radiator 12 and the inverter 14.

[0024] 1, the cooling water causes the water wheel 20 to rotate in a specific direction together with the rotary shaft 24. This causes the fan 22 to rotate in a specific direction, and the fan 22 generates negative pressure immediately behind the radiator 12. This causes the airflow that has passed through the bumper opening at the front end of the vehicle 10 to pass rearward through the radiator 12. This airflow therefore cools the radiator 12.

[0025] The vehicle speed calculation unit 352 calculates an input vehicle speed, which is a vehicle speed value to be applied to a map 40 described later, based on the vehicle speed detected by the vehicle speed sensor 30 every time a predetermined time elapses. That is, the vehicle speed calculation unit 352 obtains, as the input vehicle speed, the average value of all vehicle speeds detected by the vehicle speed sensor 30 between the current time and the time one minute before the current time.

[0026] The duty ratio acquisition unit 353 acquires the duty ratio based on the map 40 shown in FIG. 5, which is created based on the technical concept represented by the graph 37 shown in FIG.

[0027] The horizontal axis of graph 37 represents the vehicle speed of vehicle 10, and the vertical axis represents the pump share rate. The pump share rate is a value obtained by dividing the magnitude of the driving force that electric pump 18 should generate by the required driving force, which is the driving force required to rotate fan 22. When the vehicle speed value of vehicle 10 is less than 20 km / h, there is almost no airflow (traveling wind) passing through the bumper opening toward radiator 12. Therefore, as is clear from FIG. 4, when the vehicle speed value is less than 20 km / h, the pump share rate is 100%. In other words, electric pump 18 is controlled to generate a driving force equivalent to the required driving force.

[0028] When the vehicle speed value is 20km / h or more, it is considered that an air flow (driving wind) is generated passing through the bumper opening toward the radiator 12. Therefore, when the vehicle speed value is 20km / h or more, the radiator 12 can be sufficiently cooled by the air flow even if the negative pressure generated by the fan 22 is smaller than when the vehicle speed value is less than 20km / h. Therefore, the pump share rate when the vehicle speed value is 20km / h or more may be smaller than when the vehicle speed value is less than 20km / h. Therefore, the graph 37 specifies the pump share rate when the vehicle speed value is 40km / h as 80% and the pump share rate when the vehicle speed value is 60km / h as 60%. Furthermore, the graph 37 specifies the pump share rate when the vehicle speed value is 100km / h or more as 50%.

[0029] The map 40 shown in FIG. 5 and recorded in the ROM 35B defines the relationship between the temperature of the cooling water at the inlet of the inverter 14 detected by the water temperature sensor 28 (hereinafter, inlet water temperature) and the duty ratio for each of a plurality of vehicle speed values. The map 40 includes a first map 41, a second map 42, and a third map 43. The first map 41 is a map when the input vehicle speed acquired by the vehicle speed calculation unit 352 is less than 20 km / h. The second map 42 is a map when the input vehicle speed is 40 km / h. The third map 43 is a map when the input vehicle speed is 100 km / h. When the inlet water temperature is less than 0° C., the duty ratios indicated by the first map 41, the second map 42, and the third map 43 are the same. In other words, for the region where the inlet water temperature is less than 0° C., the first map 41, the second map 42, and the third map 43 are created regardless of the technical idea represented by the graph 37. When the inlet water temperature is below 0° C., there is a risk that the cooling water will freeze in the flow passage 17, and therefore the electric pump 18 needs to generate a relatively large driving force. That is, the viscosity of the cooling water when the inlet water temperature is below 0° C. is higher than the viscosity of the cooling water when the inlet water temperature is 0° C. or higher. Therefore, regardless of the magnitude of the input vehicle speed, the duty ratio when the inlet water temperature is below 0° C. is higher than the duty ratio when the inlet water temperature is 0° C. or higher and 40° C. or lower.

[0030] 5, when the inlet water temperature is 0° C. or higher, the duty ratio indicated by the second map 42 is greater than the duty ratio indicated by the third map 43, and the duty ratio indicated by the first map 41 is greater than the duty ratio indicated by the second map 42. This is because the lower the vehicle speed value (input vehicle speed), the less the airflow (traveling wind) passing through the bumper opening toward the radiator 12. That is, for the region where the inlet water temperature is 0° C. or higher, the first map 41, the second map 42, and the third map 43 are created based on the technical concept represented by the graph 37.

[0031] Furthermore, an upper limit duty ratio 45 and a lower limit duty ratio 46 are set in the map 40. That is, regardless of the input vehicle speed and the inlet water temperature, the magnitudes of the duty ratios in the first map 41, the second map 42, and the third map 43 are included in a range that is equal to or less than the upper limit duty ratio 45 and equal to or more than the lower limit duty ratio 46. In this embodiment, the upper limit duty ratio 45 is 95%, and the lower limit duty ratio 46 is 45%. However, the upper limit duty ratio 45 and the lower limit duty ratio 46 may be different magnitudes.

[0032] The vertical axis on the right side of Fig. 5 represents the required flow rate (liters / minute), which is the flow rate of cooling water that needs to flow through the flow paths 17 in the flow path configuration portion 16 per minute. As is clear from Fig. 5, when the inlet water temperature is higher than 35°C, the required flow rate gradually increases as the inlet water temperature increases. Furthermore, when the inlet water temperature is higher than 50°C, the required flow rate becomes substantially constant. When the inlet water temperature is higher than 35°C and equal to or lower than 50°C, the duty ratios represented by the first map 41 and the second map 42 are higher than the lower limit duty ratio 46 and gradually increase as the inlet water temperature increases.

[0033] The numbers written along the first map 41, the second map 42, and the third map 43 indicate the duty ratio at the inlet water temperature of each of the first map 41, the second map 42, and the third map 43. For example, when the inlet water temperature is 20° C., the duty ratio of the first map 41 is 60%, and the duty ratio of the second map 42 is 48 percent (=60%×0.8). Furthermore, when the inlet water temperature is 50° C., the duty ratio of the first map 41 is 95%, and the duty ratio of the third map 43 is 47.5 percent (=95%×0.5).

[0034] The duty ratio acquisition unit 353 acquires the duty ratio at the current time by applying the inlet water temperature detected by the water temperature sensor 28 and the input vehicle speed as arguments to the map 40. Furthermore, the pump control unit 351 executes PWM control of the electric pump 18 based on this duty ratio.

[0035] Among the components described above, the flow passage configuration unit 16, the electric pump 18, the water wheel 20, the fan 22, the rotating shaft 24, the water temperature sensor 28, the vehicle speed sensor 30, the CPU 35A, and the map 40 are components of the cooling system 50.

[0036] (Action and Effects) Next, the operation and effects of this embodiment will be described.

[0037] The following describes the processing executed by the CPU 35A of the ECU 35. The CPU 35A repeatedly executes the processing of the flowchart shown in Fig. 6 every time a predetermined time has elapsed. For example, the predetermined time in this embodiment is one minute.

[0038] In step S10 (hereinafter, the word "step" will be omitted), the CPU 35A acquires, from the water temperature sensor 28, information relating to the inlet water temperature detected by the water temperature sensor 28 at the current time.

[0039] After completing the process of S10, the CPU 35A proceeds to S11 and obtains, as an input vehicle speed, the average value of all vehicle speeds detected by the vehicle speed sensor 30 between the current time and a predetermined time (one minute) before the current time.

[0040] After completing the process of S11, the CPU 35A proceeds to S12, where it obtains the duty ratio at the current time by applying the obtained inlet water temperature and the input vehicle speed as arguments to the map 40. Furthermore, the CPU 35A executes PWM control of the electric pump 18 based on this duty ratio.

[0041] Here, it is assumed that the inlet water temperature is 0°C or higher at the time when the process of S12 is executed. In this case, the duty ratio when the input vehicle speed is 40km / h is smaller than when the input vehicle speed is less than 20km / h. Also, in this case, the duty ratio when the input vehicle speed is 100km / h is smaller than when the input vehicle speed is 40km / h.

[0042] After completing the process of S12, the CPU 35A temporarily ends the process of this flowchart.

[0043] As described above, in the cooling system 50 of the present embodiment, the CPU 35A PWM controls the electric pump 18 based on the map 40 that defines the relationship between the inlet water temperature of the coolant, the input vehicle speed of the vehicle 10, and the duty ratio of the power supplied to the electric pump 18. Furthermore, the map 40 specifies that, when the vehicle speed value is 20 km / h (first predetermined value) or more and 100 km / h (second predetermined value) or less, and the inlet water temperature is 0° C. (third predetermined value) or more, the duty ratio is lowered as the input vehicle speed increases. When the vehicle speed value (input vehicle speed) increases, the cooling effect of the radiator 12 by the running wind increases. Therefore, when the vehicle speed value (input vehicle speed) increases, the radiator 12 is sufficiently cooled even if the duty ratio of the power supplied to the electric pump 18 that generates the driving force for rotating the fan 22 is lowered. Furthermore, when the flow velocity of the running wind increases with an increase in the vehicle speed value, the running wind rotates the fan 22 and the water wheel 20 in a specific direction. When the water turbine 20 rotates in a specific direction, the cooling water reliably circulates through the flow path 17 even if the driving force of the electric pump 18 is reduced. In other words, when the vehicle speed value (input vehicle speed) is high, the traveling wind can be used as the driving force for rotating the water turbine 20. Therefore, the cooling system 50 of this embodiment can reduce the power consumption of the electric pump 18 that generates the driving force for moving the cooling water and the driving force for rotating the fan 22.

[0044] Furthermore, the map 40 includes a plurality of second maps 42 and a third map 43 corresponding to a plurality of vehicle speed values ​​included in a range (specific range) of 20 km / h or more (first predetermined value) and 100 km / h or less (second predetermined value). Therefore, the cooling system 50 can reduce the power consumption of the electric pump 18, as compared with a case in which the map 40 includes only one map corresponding to one specific vehicle speed value included in the specific range.

[0045] The magnitude of the vehicle speed detected by the vehicle speed sensor 30 tends to increase and decrease in a short period of time. Therefore, when the vehicle speed detected by the vehicle speed sensor 30 is applied as an argument to the map 40 to obtain the duty ratio, the operation of the PWM-controlled electric pump 18 tends to become unsmooth. However, in this embodiment, the input vehicle speed, which is the average value of all vehicle speeds detected by the vehicle speed sensor 30 in one minute, is applied as the vehicle speed value to the map 40 to obtain the duty ratio. Therefore, in this embodiment, the operation of the PWM-controlled electric pump 18 tends to become smoother than when the vehicle speed detected by the vehicle speed sensor 30 is applied as an argument to the map 40.

[0046] Although the cooling system 50 according to the embodiment has been described above, appropriate design changes are possible without departing from the gist of the present invention.

[0047] For example, the vehicle speed calculation unit 352 may acquire the vehicle speed value by performing a process (smoothing process) of finding an exponentially smoothed average value of a plurality of vehicle speeds detected by the vehicle speed sensor 30, and the duty ratio acquisition unit 353 may acquire the duty ratio by applying this vehicle speed value as an argument to the map 40. Even in this modified example, the operation of the PWM-controlled electric pump 18 is likely to be smoother than when the vehicle speed detected by the vehicle speed sensor 30 is applied to the map 40 as an argument.

[0048] The map 40 may define the relationship between the inlet water temperature and the duty ratio for a vehicle speed value different from the above.

[0049] The graph showing the relationship between the vehicle speed value and the pump share ratio may be a graph different from graph 37. For example, the pump share ratio when the vehicle speed value is 40 km (km / h) may be a value different from 0.8.

[0050] Further, the duty ratio acquisition unit 353 may use the vehicle speed detected by the vehicle speed sensor 30 as the vehicle speed value. That is, the duty ratio may be acquired by applying the vehicle speed detected by the vehicle speed sensor 30 as an argument to the map 40. [Explanation of symbols]

[0051] 10 Vehicles 12 Radiator 14 Inverter 16 Flow path configuration section 17 Flow Path 18 Electric Pump 20 Waterwheel 22 Fan 24 Rotational Axis 28 Water temperature sensor 30 Vehicle speed sensor 35A CPU (control unit) 40 Maps 50 Radiator cooling system (cooling system)

Claims

1. A fan that is located behind a radiator mounted on a vehicle and rotates around a rotation axis to generate negative pressure; a flow path connected to the radiator through which coolant supplied to the radiator flows; an electric pump that moves the cooling water along the flow path; a water turbine that is rotated about the rotation shaft by the cooling water flowing through the flow path; a water temperature sensor that detects an inlet water temperature of an inverter that is cooled by the cooling water flowing through the flow path; a control unit that performs PWM control of the electric pump based on a map that defines a relationship between the inlet water temperature, a vehicle speed value that indicates a vehicle speed of the vehicle, and a duty ratio of electric power supplied to the electric pump; Equipped with A radiator cooling system, wherein the map specifies that when the vehicle speed value is greater than or equal to a first predetermined value and less than or equal to a second predetermined value, and the inlet water temperature is greater than or equal to a third predetermined value, the duty ratio is reduced as the vehicle speed value increases.

2. 2. The radiator cooling system according to claim 1, wherein the map defines a relationship between the inlet water temperature and the duty ratio for each of a plurality of vehicle speed values ​​included in a range equal to or greater than the first predetermined value and equal to or less than the second predetermined value.

3. A vehicle speed sensor is provided to detect the speed of the vehicle.

3. The radiator cooling system according to claim 1, wherein the vehicle speed value is an average value of the vehicle speed in a predetermined time period or an exponentially smoothed average value obtained based on a plurality of the vehicle speeds.

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