JP7180106B2 - In-vehicle cooling system - Google Patents

Description

The present invention relates to a vehicle-mounted cooling device.

2. Description of the Related Art As a cooling device provided in a vehicle, a two-fan radiator system is sometimes provided for the purpose of ensuring cooling performance. In this case, the two fans may comprise one brushless motor and one brushed motor.

With this configuration, when the motor drive device receives a cooling command signal from the engine ECU, the fan of the brushless motor with a long life is operated when the cooling command is low, and when the cooling command is high, an inexpensive brushless fan is operated. The fan of the motor is also operated to supplement the cooling capacity. As a result, cost reduction and life extension can be achieved without providing two brushless motor fans.

However, brushless motors require detection of the rotational position in rotation control, so if a low-cost method such as sensorless control is adopted, the brushless motor can be easily controlled by relay control. There is a problem of weakening.

For example, when the vehicle is running, the fan may be rotated by wind generated from the front to the rear of the vehicle. or the position detection signal cannot be generated due to motor lock.

If the fan of the brushless motor that operates mainly stops, the original cooling performance of the cooling device cannot be ensured, which leads to overheating.

JP-A-2005-30363

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and its object is to prevent insufficient cooling due to disturbances even when brushless motors and brushed motors are used as the motors of the two fans. It is an object of the present invention to provide an in-vehicle cooling device capable of

A vehicle-mounted cooling device according to claim 1 comprises: a first fan using a brushless motor driven by a battery; a second fan using a brushed motor driven by a battery; An energization relay provided in an energization path to the second fan , and driving the first fan according to a cooling command given from a command unit, and the energization relay when the cooling command is at a high load level. is turned on to drive the second fan to blow air, wherein the drive circuit drives the first fan but does not drive the second fan, the first fan detects that an abnormality has occurred in the rotating state of the brushless motor under the influence of disturbance, the first fan is stopped and the energization relay is turned on to drive the second fan.

By adopting the above configuration, the drive circuit first drives the first fan according to the cooling command given from the command unit, and turns on the energization relay when the cooling command cannot be satisfied by blowing air from the first fan. It drives and the 2nd fan also drives and blows air. As a result, a long-life brushless motor is used for the first fan, which is used frequently, and an inexpensive brushed motor is used for the second fan, which is used infrequently. .

In addition, in the above configuration, in addition to the case where the cooling capacity of the first fan is insufficient in response to the cooling command given from the command unit, the cooling capacity of the first fan is insufficient when the first fan is driven by the drive circuit. Therefore, there is a case where an abnormality occurs in the operation of the first fan and the cooling capacity becomes insufficient.

For example, there is a case where the rotation state of the first fan is disturbed due to the influence of disturbance such as wind, and the operation becomes impossible. In this case, the drive circuit stops the first fan and instead drives the second fan for cooling. As a result, the second fan is driven only when the first fan is abnormal, so the service life of the brushed motor of the second fan is not significantly shortened.

Electrical configuration diagram showing the first embodiment Block diagram of in-vehicle cooling system Flowchart of fan control processing Diagram showing the relationship between motor speed and cooling command Action diagram Action diagram Time chart (Part 1) Time chart (Part 2) Time chart (Part 3) FIG. 10 is a graph showing the relationship between drive frequency and life of the brushed motor according to the second embodiment; The figure which shows the relationship of the operation rate of the 2nd fan with respect to a cooling command. FIG. 11 is a diagram showing the relationship between the temperature of circuit elements and fan driving, showing the third embodiment; Diagram showing relationship between circuit element temperature and fan drive (comparative example)

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 9. FIG.
The vehicle is provided with a condenser 1 and a radiator 2 in the front bonnet, which require cooling during running. The condenser 1 is for cooling the refrigerant of the air conditioner, and the radiator 2 is for cooling the cooling water of the engine. The condenser 1 and the radiator 2 are arranged side by side in the front-rear direction so as to cool the internal refrigerant or cooling water when the wind taken in from the front of the vehicle passes through the inner heat radiating part.

The vehicle-mounted cooling device 3 blows air for cooling the capacitor 1 and the radiator 2 in response to a cooling command signal Sd from the engine ECU 5 using a vehicle-mounted battery (hereinafter simply referred to as battery) 4 as a power source. The first fan 6 and the second fan 7 are arranged behind the radiator 2, and are provided so as to draw air from the front of the vehicle and force it to flow backward.

The first fan 6 is rotationally driven by a brushless motor 6a, and the second fan 7 is rotationally driven by a brushed motor 7a. The first fan 6 is driven and controlled by a motor drive circuit 8 . Also, the second fan 7 is energized from the battery 4 via the energization relay 9 . The energization relay 9 is on/off controlled by the motor drive circuit 8 .

FIG. 2 shows the block configuration of the signal system of the motor drive circuit 8. As shown in FIG. 2, the motor drive circuit 8 includes a communication circuit 11, a brushless motor rotation command circuit 12, a three-phase inverter circuit 13, a brushless motor position detection circuit 14, a brushed motor rotation command circuit 15, and a relay signal output circuit 16. The communication circuit 11 has a function of receiving a cooling command signal from the engine ECU 5 and transmitting an abnormality detection signal from the brushless motor rotation command circuit 12 to the engine ECU 5 .

The brushless motor rotation command circuit 12 supplies a rotation command signal to the three-phase inverter circuit 13 to control the rotational drive of the brushless motor 6a, thereby controlling the air volume of the first fan 6. FIG. The three-phase inverter circuit 13 converts the DC voltage of the battery 4 into a three-phase AC voltage of a predetermined frequency by on/off-controlling six switching elements, and supplies power to the brushless motor 6a. The rotational position of the brushless motor 6a is detected by a brushless motor position detection circuit 14, which outputs a detection signal to the brushless motor rotation command circuit 12. FIG.

The brushed motor rotation command circuit 15 outputs a rotation command signal to the relay signal output circuit 16 based on the ON/OFF drive signal from the brushless motor rotation command circuit 12 . The relay signal output circuit 16 outputs an ON signal Sa to the energization relay 9 in response to the rotation command signal to turn it on, thereby energizing the brushed motor 7a.

Next, the operation of the above configuration will be described with reference to FIGS. 3 to 8 as well.
In this embodiment, in the vehicle-mounted cooling device 3, the first fan 6 and the second fan 7 are controlled according to the flow of fan control processing shown in FIG. First, in step S1, the engine ECU 5 determines a necessary cooling command according to the operating conditions of the engine, etc. In the next step S2, the engine ECU 5 sends a cooling command signal Sd corresponding to the determined cooling command to the in-vehicle cooling device 3. Send.

On the other hand, in the in-vehicle cooling device 3, the motor drive circuit 8 receives the cooling command signal Sd in step S3. Subsequently, in step S4, the motor drive circuit 8 drives the first fan 6, which is the main at first, according to the cooling command level of the received cooling command signal Sd.

Specifically, the brushless motor rotation command circuit 12 of the motor drive circuit 8 receives the cooling command signal Sd from the engine ECU 5 via the communication circuit 11 . Thereafter, the brushless motor rotation command circuit 12 of the motor drive circuit 8 generates a rotation command signal of a cooling command corresponding to the received cooling command signal and outputs it to the three-phase inverter circuit 13 . The three-phase inverter circuit 13 converts the DC voltage of the battery 4 into a three-phase AC voltage and feeds the brushless motor 6a.

In the motor drive circuit 8, the brushless motor rotation command circuit 12 detects the rotation position of the brushless motor 6a based on the detection signal from the brushless motor position detection circuit 14. FIG. As a result, the first fan 6 is driven to rotate at a predetermined number of revolutions, and the cooling air generated cools the condenser 1 and the radiator 2 . In driving the first fan 6, by energizing the three-phase inverter circuit 13, the control circuit, and the like, the energized electronic components generate a certain amount of self-heating.

Next, in step S5, the motor drive circuit 8 uses the brushless motor rotation command circuit 12 to determine whether or not the cooling command given from the engine ECU 5 is at a high load level. Here, the brushless motor rotation command circuit 12 determines whether or not the duty indicated by the cooling command signal is equal to or higher than the threshold level set for determining the high load level. This corresponds to a case where the cooling command becomes higher due to a rise in the water temperature due to the start of the engine, a rise in the temperature of the engine room, or the like. If the cooling command is not for a high load, the motor drive circuit 8 determines NO in step S5 and proceeds to the next step S6.

Next, in the brushless motor rotation command circuit 12, the motor drive circuit 8 determines in step S6 whether the first fan 6 is abnormal. repeat the process. In this case, the brushless motor rotation command circuit 12 means that the abnormal state of the first fan 6 is, for example, a state in which the rotational position of the brushless motor 6a cannot be detected normally. For example, as a disturbance, the rotating state of the first fan 6 may be disturbed by being forced to rotate by the wind from the front while the vehicle is running, and such an abnormal state occurs.

When the motor drive circuit 8 repeatedly executes steps S5 and S6 as described above, if the cooling command from the engine ECU 5 changes to a high load level, the motor drive circuit 8 determines YES in step S5 and proceeds to step S7. . In step S7, the motor drive circuit 8 outputs a control signal from the brushless motor rotation command circuit 12 to the brushed motor rotation command circuit 15 so as to output an ON drive signal to the energization relay 9. FIG.

The motor drive circuit 8 outputs a control signal to the energization relay 9 through the relay signal output circuit 16 in the brushed motor rotation command circuit 15 so that the energization relay 9 is turned on. As a result, the motor 7a with brush is supplied with power from the battery 4, and the second fan 7 rotates at a predetermined number of revolutions. At this time, the motor drive circuit 8 causes the brushless motor rotation command circuit 12 to reduce the rotational speed of the first fan 6 in consideration of the airflow rate caused by the drive of the second fan 7. Secondly, the blowing volume converted to the number of revolutions is controlled so as to continuously increase.

After that, the motor drive circuit 8 determines whether or not the first fan 6 is abnormal in the brushless motor rotation command circuit 12 in step S8, and if there is no abnormality, the process proceeds to step S9. The motor drive circuit 8 uses the brushless motor rotation command circuit 12 to determine whether or not the cooling command given from the engine ECU 5 has changed to a low load level. If NO here as well, the motor drive circuit 8 repeats steps S8 and S9 described above.

In this case, when the cooling command given from the engine ECU 5 has changed to the low load level, the motor drive circuit 8 determines YES in step S9 and proceeds to step S10. In order to stop the second fan 7, the motor drive circuit 8 outputs a signal to stop the energization relay 9 from the brushless motor rotation command circuit 12 to the brushed motor rotation command circuit 15 in step S10. As a result, the energization relay 9 is turned off, and the rotation of the second fan 7 is stopped. After that, the motor drive circuit 8 returns to step S5 and shifts to a state in which steps S5 and S6 described above are repeatedly executed.

At this time, the motor drive circuit 8 causes the brushless motor rotation command circuit 12 to increase the rotational speed of the first fan 6 in consideration of the decrease in airflow due to the stoppage of the second fan 7, thereby increasing the speed shown in FIG. , the air blow volume converted to the number of revolutions is controlled to continuously increase.

In this manner, in a state where no abnormality occurs in the rotating state of the first fan 6, the motor drive circuit 8 operates the first fan 6 independently when the cooling command given from the engine ECU 5 indicates a low load. When the load changes to high, the second fan 7 is also driven to perform the cooling operation. As a result, by supplementing the cooling capacity of the first fan 6 with the second fan 7, it is possible to respond to the cooling command.

In this case, the first fan 6 is mainly used, and the second fan 7 is driven when the cooling command indicates a high load. As a result, the service life of the brushed motor 7a that drives the second fan 7 can be extended.

Next, a case where an abnormality occurs in the rotational state of the first fan 6 while the cooling control is being performed by the motor drive circuit 8 as described above will be described. As shown in FIG. 6, this state corresponds to the case where the rotational position of the brushless motor 6a is disturbed due to a disturbance or the like while the first fan 6 is being driven, and control becomes impossible.

First, in a state where the first fan 6 is driven alone, if an abnormality of the first fan 6 is detected in step S6, YES is determined and the process proceeds to step S11. The motor drive circuit 8 stops the first fan 6 in step S11, and gives a drive signal Sa to the energization relay 9 to drive the second fan 7 in the subsequent step S12.

As a result, when the rotation of the first fan 6 becomes uncontrollable, the first fan 6 is stopped and instead the cooling operation is continued by the second fan 7 . In this case, the motor drive circuit 8 determines whether the cooling capacity of the second fan 7 is sufficient for the cooling command given from the engine ECU 5 in the next step S13.

In step S13, the motor drive circuit 8 determines YES when the cooling command is equal to or greater than the capacity, and proceeds to step S14. In step S14, the motor drive circuit 8 notifies the engine ECU 5 of the abnormal state from the brushless motor rotation command circuit 12 via the communication circuit 11. FIG. As a result, it is possible to warn the driver that the vehicle will overheat due to insufficient cooling capacity if the vehicle is driven as it is. In addition, this also makes it possible to quickly evacuate and stop the engine.

It should be noted that in step S13, the motor drive circuit 8 determines NO when the cooling command is not equal to or greater than the capacity, and terminates the process. Although not shown, if the abnormal state of the first fan 6 is recovered after this, the normal control shown in FIG. 3 can be resumed. It is possible to take countermeasures such as displaying the abnormality on the display unit and prompting the driver.

On the other hand, when both the first fan 6 and the second fan 7 are being driven while the cooling control is being performed by the motor drive circuit 8 as described above, an abnormality of the first fan 6 is detected in step S8. If so, YES is determined and the process proceeds to step S15. In step S15, the motor drive circuit 8 stops the first fan 6, then proceeds to step S13, where the cooling capacity of the second fan 7 is sufficient for the cooling command given from the engine ECU 5 in the same manner as described above. determine whether or not

Next, the relationship between the cooling command and the cooling capacity will be described with reference to FIGS. 4 and 5 when the motor drive circuit 8 controls the driving of the first fan 6 and the second fan 7 as described above. As shown in FIG. 4, in a low load region where the duty indicated by the cooling command is Da or less, the first fan 6 is driven alone to blow air. The characteristics of the air blown by the first fan 6 are indicated by broken lines in FIG.

On the other hand, in a high load region where the duty indicated by the cooling command exceeds Da, the second fan 7 is also driven to blow air. Since the second fan 7 is driven by on/off control, the rotational speed is fixed at Ra [rpm] as indicated by the dotted line in FIG. When both the first fan 6 and the second fan 7 are driven, as indicated by the solid line in FIG. there is The characteristic indicated by the solid line in FIG. 4 indicates the cooling capacity when the first fan 6 and the second fan 7 are combined, converted into the number of motor revolutions.

Next, the characteristics shown in FIG. 5 describe the state in which the first fan 6 is stopped and the cooling operation is performed only by the second fan 7 when YES in step S6 or S8 of FIG. It is something to do. Since the second fan 7 drives the motor 7a with a brush by an ON/OFF operation by means of the energization relay 9, the motor rotation speed is constant at Ra. Therefore, when the cooling command is the duty Db, it matches the cooling capacity, so cooling can be performed just enough. Further, when the cooling command is equal to or less than the duty Db, the cooling capacity is sufficient, so the situation is NO in step S13 of FIG.

In this case, when cooling is performed only by the second fan 7, the motor drive circuit 8 controls the energization relay 9 appropriately in order to prevent excessive cooling because the cooling capacity is large in response to the cooling request from the engine ECU 5. It can be turned on and off in time. As a result, it is possible to improve the fuel efficiency and suppress the reduction in the service life of the brushed motor of the second fan 7 while preventing excessive cooling.

On the other hand, when the cooling command exceeds the duty Db, the cooling capacity is insufficient, so the situation is YES in step S13 of FIG. In this case, the cooling is insufficient, so it is difficult to continue running the vehicle as it is. The operating time can be extended to perform evacuation operation.

Next, with respect to the above control, changes in the signals of the respective parts by the motor drive circuit 8 will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 shows the case where the first fan 6 does not become abnormal, and FIG. 8 corresponds to the case where the first fan 7 becomes abnormal.

As shown in FIG. 7(a), the engine ECU 5 determines the duty of the cooling command and outputs a low-load cooling command signal Sd at time t0 (steps S1 and S2 in FIG. 3). Then, in the motor drive circuit 3, as shown in FIG. 7(b), the signal is received at time t1 after a slight delay in the communication circuit 11 (step S3 in FIG. 3). As shown in FIG. 7(c), the motor drive circuit 3 outputs a drive signal for driving the first fan 6 at time t2 when two cycles of the cooling command signal are detected (step S4 in FIG. 3). In this case, the motor drive circuit 3 sets the rotation speed of the brushless motor 6a of the first fan 6 in accordance with the duty of the cooling command.

Next, as shown in FIG. 7A, when the engine ECU 5 changes the duty of the cooling command and outputs a high-load cooling command signal Sd at time t3 (step S5 in FIG. 3), the motor drive circuit 3 , it is received at time t4 as shown in FIG. 7(b). As shown in FIG. 7(d), the motor drive circuit 3 outputs a drive signal for driving the second fan 7 at time t5 when two cycles of the cooling command signal are detected (step S7 in FIG. 3). In this case, the motor drive circuit 3 changes and sets the rotational speed of the brushless motor 6a of the first fan 6 in accordance with the duty of the cooling command.

Thereafter, as shown in FIG. 7(a), the engine ECU 5 changes the duty of the cooling command and outputs a low-load cooling command signal Sd at time t6 (step S9 in FIG. 3). , it is received at time t4 as shown in FIG. 7(b). As shown in FIG. 7(d), the motor drive circuit 3 outputs an off signal to the energization relay 9 to stop the second fan 7 at time t5 when two cycles of the cooling command signal are detected (see FIG. 3). step S10). In this case, the motor drive circuit 3 changes and sets the rotational speed of the brushless motor 6a of the first fan 6 in accordance with the duty of the cooling command.

Next, FIGS. 8 and 9 are time charts when the first fan 6 is in an abnormal state due to disturbance. 8 and 9 show the case where the first fan 6 is in an abnormal state while the cooling command is lower in load than the cooling capacity of the second fan 7 (duty Da or less).

FIG. 8 shows an example in which the cooling command from the engine ECU 5 is low load, and the first fan 6 is in an abnormal state when the load is lower than the cooling capacity of the second fan 7 (duty Db or less). ing. The motor drive circuit 8 receives a low-load cooling command signal from the engine ECU 5, drives the first fan 6 by executing step S4 in FIG. 3, and repeats the following steps S5 and S6.

In this state, when the motor drive circuit 8 detects an abnormality in the first fan 6 at time ta in FIG. 8 (YES in step S6), it stops the first fan 6 as shown in FIG. 8(c). (Step S11 in FIG. 3). Also, as shown in FIG. 8(d), the motor drive circuit 8 simultaneously drives the second fan 7 at time ta (step S12 in FIG. 3). At this time, the cooling command is a low load equal to or less than the duty Db, and cooling by the second fan 7 does not cause a shortage of cooling capacity, so the cooling operation is continued as it is.

As a result, when the first fan 6 is in an abnormal state and stops driving, the second fan 7 driven by the motor 7a with a brush operates independently as a fail-safe function for avoiding overheating of the vehicle. performance can be compensated for.

FIG. 9 shows an example in which the cooling command from the engine ECU 5 is on the higher load side than the cooling capacity of the second fan 7 (duty Da or less and greater than Db) and the first fan 6 is in an abnormal state. is shown.

The cooling command signal received from the engine ECU 5 has a low load but is set to be greater than the duty Db, and the motor drive circuit 8 drives the first fan 6 at a rotation speed corresponding to the cooling command, and the following steps S5 and S6 are performed. is being executed repeatedly. In this state, when the motor drive circuit 8 detects an abnormality in the first fan 6 at time ta in FIG. 9 (YES in step S6 in FIG. 3), the first fan 6 is stopped (step S11 in FIG. 3). In addition, the motor drive circuit 8 simultaneously drives the second fan 7 at time ta, as shown in FIG. 9(d) (step S12 in FIG. 3).

At this time, the cooling command from the engine ECU 5 is for a low load, but the load is higher than the duty Db, so the cooling capacity of the second fan 7 is insufficient. Therefore, when the motor drive circuit 8 receives the cooling command signal Sd over two cycles, it notifies the engine ECU 5 of the abnormality notification signal at the time tb as shown in FIG. , step S14).

As a result, in addition to supplementing the cooling performance in the same manner as described above, it is possible to notify the engine ECU 5 that the cooling performance is insufficient due to the driving of the second fan 7 due to the abnormal state of the first fan 6 .

Also, although not shown, when the cooling command from the engine ECU 5 indicates a high load, both the first fan 6 and the second fan 7 are driven. Then, the motor drive circuit 8 stops the first fan 6 and drives the second fan 7 alone.

In this case, the cooling capacity is greatly reduced in response to the cooling command, but the continuous driving of the second fan 7 can earn time until the vehicle overheats. You can extend the escape distance.

According to the first embodiment as described above, when an abnormality occurs in the rotational state of the first fan 6 used as the main fan, the motor drive circuit 8 stops the first fan 6 and drives the second fan 7. By doing so, the cooling operation was continued. Thereby, the cooling capacity can be supplemented by using the second fan 7 when the first fan 6 cannot be used.

When the cooling operation is performed by the second fan 7 with the first fan 6 stopped, if the cooling capacity for the cooling instruction is insufficient, the motor drive circuit 8 is turned off so that the vehicle will continue to run without overheating. Since an abnormality notification signal is output to the engine ECU 5, measures can be taken to issue a warning to the driver only when evacuation running is required.

(Second embodiment)
FIGS. 10 and 11 show the second embodiment, and the differences from the first embodiment will be explained below. In this embodiment, when the first fan 6 is in an abnormal state, the control method of the second fan 7 is improved so as to optimize the cooling capacity by driving the second fan 7. It is.

The second fan 7 is driven by a motor 7a with brushes, but since it has contacts of the brushes, its service life depends on the time of use. Therefore, shortening the usage time leads to a longer life. On the other hand, the service life of the energization relay 9 that controls the energization/disconnection of the second fan 7 depends on the number of times it is used.

For this reason, it is preferable that the service life of the brushed motor 7a and the energization relay 9 can be extended while maintaining the cooling ability of the second fan 7. FIG. In this embodiment, drive control of the second fan 7 is performed in consideration of this point.

FIG. 10 shows the relationship between the life of the energization relay 9 and the ON/OFF drive cycle. The longer the ON/OFF driving cycle of the energization relay 9 is, the less frequently it is used, and thus the longer the life of the energization relay 9 is. However, since the second fan 7 requires a motor starting period of, for example, about one second, it is necessary to set the period longer than this period. On the other hand, lengthening the driving cycle of the second fan 7 results in an increase in the ON period and the OFF period, which causes unevenness in the cooling capacity. It is preferable to set

Therefore, the drive cycle of the energization relay 9 must be set to a period longer than the motor starting period of the second fan 7, longer than the guaranteed service life of the vehicle, and set so as to suppress uneven cooling. The drive cycle can be set so that the cooling capacity can be secured at .

FIG. 11 shows the drive cycle set so as to satisfy such conditions. For example, when the cooling command from the engine ECU 5 is 30%, the energization relay 9 is turned on for 2 minutes and turned off for 2 minutes. The operating rate of the second fan 7 is 50%. Also, when the cooling command has a duty of 50%, the energization relay 9 is turned on for 2 minutes and turned off for 1 minute. The operating rate of the second fan 7 is 66%. Furthermore, when the cooling command has a duty of 70%, the energization relay 9 is always turned on. The operating rate of the second fan 7 is 100%.

According to the second embodiment, when cooling is performed by driving the second fan 7 alone, the second fan 7 is operated by changing the ON/OFF time interval of the energization relay 9 according to the cooling command. By adjusting the rate, drive control can be performed so that the cooling capacity is not excessive. As a result, the service life of the second fan 7 and the energization relay 9 can be extended.

(Third embodiment)
12 and 13 show a third embodiment, and the differences from the first embodiment will be explained below. In this embodiment, the driving of the first fan 6 and the second fan 7 is controlled in consideration of the temperature of the environment in which the vehicle is used.

If the vehicle is in a high-temperature environment, self-heating due to energization of the electronic parts located in the engine compartment when the engine is started may cause the temperature to rise further and exceed the maximum operating temperature, which may lead to failure. there is a possibility. For example, in an electrolytic capacitor provided as an electronic component, there is concern about a decrease in capacity due to transpiration of the electrolytic solution filled in the element, and because the specification temperature is lower than that of other electronic components, it is a bottleneck in life. . Therefore, if other devices are operated at the same time as the engine is started, the upper temperature limit for use will be exceeded due to self-heating and radiant heat from peripheral devices.

In the first embodiment, when the engine is started, a method of driving the main first fan 6 is adopted at first. Excessive temperature may be expected.

FIG. 13 shows a state in which the temperature Ta of the electronic component indicated by the thick solid line does not reach the use upper limit temperature Tup, but reaches a temperature close to it. Further, it is assumed that due to the self-heating of the electronic parts due to the driving of the first fan 6, the temperature rises by Thg as indicated by the dashed line in FIG. Then, when the first fan 6 is driven at time t0 immediately after the engine is started, the temperature of electronic components such as the motor drive circuit 8 rises by a constant temperature Thg due to self-heating due to energization. Then, the temperature may temporarily exceed the upper limit temperature Tup.

Therefore, in this embodiment, as shown in FIG. 12, when the temperature Ta of the electronic components is higher than the threshold temperature Tmo at the engine start time t0, the first fan 6 is not driven and the second fan 7 is driven. to drive. It should be noted that the threshold temperature Tmo is set to a temperature lower than the use upper limit temperature Tup by a certain temperature Thg. Since the second fan 7 uses a motor 7a with a brush and is driven only by turning on and off the energization relay 9, there is no energization to the electronic components in the engine room, so temperature rise can be suppressed. . After that, when the temperature Ta of the electronic component reaches the threshold temperature Tmo due to cooling by the second fan 7 at time t1, the second fan 7 is stopped and the first fan 6 is driven.

As a result, even if the temperature of the electronic components rises due to the driving of the first fan 6, and even if the constant temperature Thg rises at the time t2, the first fan 6 can be driven within a range not exceeding the upper limit temperature Tup for use. will be able to

(Other embodiments)
The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the scope of the invention. For example, the following modifications or extensions can be made.

Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to such examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

In the drawings, 1 is a condenser, 2 is a radiator, 3 is a vehicle cooling device, 4 is a vehicle battery, 5 is an engine ECU, 6 is a first fan, 6a is a brushless motor, 7 is a second fan, and 7a is a brushed motor. 11 is a communication circuit; 12 is a brushless motor rotation command circuit; 13 is a three-phase inverter circuit; 14 is a brushless motor position detection circuit; is the relay signal output circuit.

Claims (5)

a first fan (6) using a brushless motor (6a) driven by a battery (4);
a second fan (7) using a brushed motor (7a) driven by the battery as a power source;
an energization relay (9) provided in an energization path from the battery to the second fan ;
The first fan is driven according to the cooling command given from the command unit , and when the cooling command is at a high load level, the energization relay is turned on to drive the second fan to blow air. A drive circuit (8),
The drive circuit detects that the first fan is affected by a disturbance and an abnormality has occurred in the rotation state of the brushless motor while the first fan is being driven and the second fan is not being driven. A vehicle-mounted cooling device that stops the first fan and turns on the energization relay to drive the second fan. 2. The vehicle-mounted cooling device according to claim 1, wherein the drive circuit includes a communication circuit (11) capable of transmitting an abnormality notification signal to the command unit. The drive circuit stops the first fan after detecting that an abnormality has occurred in the rotational state of the brushless motor, and then drives the second fan. 3. The in-vehicle cooling device according to claim 2, wherein the abnormality notification signal is transmitted to the command section when the cooling capacity of the second fan is exceeded. The drive circuit detects that an abnormality has occurred in the rotational state of the brushless motor, stops the first fan, and then drives the second fan. 4. The vehicle-mounted cooling device according to claim 2, wherein the operation rate of the second fan is changed by on/off control of the energization relay. Even if the cooling command given from the command unit starts the first fan at a predetermined level or less, the drive circuit is configured to operate when the heat generated by driving the first fan is expected to exceed the upper limit temperature of the circuit components. 5. The second fan is driven independently until the temperature of the circuit component rises to the upper limit temperature or less even if the temperature of the circuit component rises due to heat generated by driving the first fan. A vehicle cooling system as described.

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