JPH04365923A - Controller for electric fan for vehicle - Google Patents

Abstract

PURPOSE:To provide a controller for an electric fan for a vehicle capable of coping with a situation such as an increase in water temperature and a lock without inducing a large size of a device. CONSTITUTION:Operation of an electric fan 2 for cooling a heat exchanger for a vehicle, rotation speed of which fan 2 is changed depending on an applied voltage, is controlled. A controller (special operating condition detector) 4 detects a special operating condition such as an increase in water temperature and a lock. The controller (fan operation controller) 4 applies a voltage higher than a normal applied voltage to the electric fan 2 for a vehicle for a predetermined short period upon detection of the special operating condition. Accordingly, if the electric fan 2 for a vehicle is operated under the specific operating condition, electric power larger than that in a normal operation is input into a motor 20 for the electric fan 2 for a vehicle for a short period. During this short period, the fan is driven at torque higher than a rated value by the motor 20. The application of a high voltage for a short period does not require a large size of the motor 20.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric fan for a vehicle.

0002

[Prior Art] JP-A-61-15096 discloses that an air-cooled heat exchanger is provided with a plurality of electric fans, and when one electric fan locks, the remaining electric fans are operated at high speed to ensure the required air volume. This patent discloses an operation control system for an air-cooled heat exchanger, and in its embodiment, an electric fan is frequency-controlled to change its rotation speed.

0003

[Problem to be Solved by the Invention] However, as in the above-mentioned conventional technology, it is uneconomical to always have multiple electric fans on hand in case one electric fan becomes locked (in a state where it cannot rotate due to dirt etc. being caught). and the device weight,
The space required also increases. Furthermore, as the speed of the electric fan increases, the power consumption of the motor increases, so in order to operate the electric fan at high speed, all motors must be designed for high output and high speed.

On the other hand, when the water temperature in a vehicle heat exchanger such as a radiator rises due to some change in conditions, the vehicle electric fan is operated at high speed in response to the rise in water temperature to increase the air volume, as in the prior art described above. It is possible that however,
In order to operate a vehicle electric fan at high speed, it is necessary to design a large motor to match the power consumption of the motor corresponding to the expected maximum rotation speed, and furthermore, it is necessary to design the alternator output. The problem arose that it also had an impact.

The present invention has been made in view of the above-mentioned problems, and provides a vehicle that does not need to increase the size of devices such as fan drive motors and can cope with emergencies such as rising water temperature and locking. To provide an electric fan control device for
That is the purpose.

[0006]

[Means for Solving the Problems] The present invention provides a control device for a vehicle electric fan that controls the operation of an electric fan for cooling a vehicle heat exchanger whose rotation speed changes depending on an applied voltage. special operating condition detection means for detecting;
The fan operation control means applies a high voltage higher than the normally applied voltage to the electric fan for a predetermined short time when the special operating condition is detected.

In a preferred embodiment, the fan operation control means reverses the rotational direction of the electric fan and applies a high voltage higher than a normal applied voltage to the electric fan when the lock is detected.

[0008]

[Operation and Effects of the Invention] The control device for a vehicle electric fan of the present invention controls the operation of an electric fan for cooling a vehicle heat exchanger whose rotation speed changes depending on the applied voltage. The special operating condition detection means detects special operating conditions such as water temperature rise and locking. The fan operation control means applies a high voltage higher than the normally applied voltage to the electric fan for a predetermined short time when the special operating condition is detected.

[0009] Therefore, when special operating conditions occur in the vehicle electric fan, a larger electric power is input to the vehicle electric fan motor for a short time than during normal operation, and during this short time, The motor drives the fan with high torque. As a result, for example, when the water temperature rises for a short time or when the water is locked, the motor can be operated at high power for a short period of time to lower the water temperature or release the lock.
There is no need to increase the number of units, and there is no need to review the power supply system, such as increasing the size of the alternator.

0010

As explained above, the control device for a vehicle electric fan of the present invention includes fan operation control means that applies a high voltage higher than the normally applied voltage to the electric fan for a predetermined short period of time under special operating conditions. Therefore, there is no need to unnecessarily increase the size of the electric fan motor, which is an excellent advantage in vehicle applications where mounting space and weight are strongly restricted.

[0011]

【Example】

(Embodiment 1) An embodiment of a control device for a vehicle electric fan according to the present invention is shown in FIGS. 1 to 5. FIG. 1 shows a vehicle cooling system equipped with this control device. Pump 6 is engine 5
Cooling water is circulated between the radiator 1 and the radiator 1. fan 2
An electric fan 2 consisting of a radiator 1 and a motor 20 for rotating it supplies a predetermined amount of air to the radiator 1 to cool it. The control device 4 receives a water temperature signal output from the water temperature sensor 40, and controls the electric fan 20 based on this water temperature signal.

The configuration of the control device 4 is shown in FIG. The control device 4 includes a main battery 41, a sub-battery 42, a transistor 43, a switch 44, a changeover switch 45, and a microcomputer device 46. The positive end of the main battery 41 is supplied with power from an alternator 71 and is supplied to a vehicle load 72. In addition, the positive terminal of the main battery 41 is connected to the switch 4
4 is connected to one end of the motor of electric fan 2 and the positive end of sub-battery 42, and the other end of this motor is grounded through transistor 43. main battery 4
1 and the negative terminals of the sub-battery 42 are grounded.

Further, the transistor 43, the switch 44, and the selector switch 45 are connected to an output port of a microcomputer device 46, and an input port of the microcomputer device 46 receives a water temperature signal from the water temperature sensor 40. The operation of this device will be explained below with reference to FIGS. 2 to 5. 3 is a flowchart of the microcomputer device 46, and FIG. 4 is a characteristic diagram showing the relationship between the water temperature detected by the water temperature sensor 40 and the rotation speed of the electric fan 2.
FIG. 5 is a water temperature state change diagram showing the relationship between water temperature and elapsed time.

First, when the engine 5 is started, the routine shown in FIG. 3 is started, and the water temperature Tw is input (102).
, check whether the water temperature Tw is greater than or equal to T1 (see Figure 4) (1
04), if Tw is smaller than T1, the electric fan 2 is stopped (106) and the process returns to 102. If it is T1 or more, search the duty ratio of the energizing current (108
), the electric fan 2 is PWM controlled based on the searched duty ratio.

[0015] That is, this PWM control
The duty ratio of the voltage applied to the motor 20 of the water temperature Tw
The relationship between the water temperature Tw and the rotation speed and the relationship between the rotation speed and the duty ratio of the applied voltage are determined in advance from water temperature T1 to T2 in FIG. The duty ratio corresponding to the water temperature Tw input in step 102 is searched from these tables, and the pulse voltage of the searched duty ratio is applied to the motor 20. This is a subroutine that applies to Incidentally, in FIG. 4, the duty ratio is approximately 0 at water temperature T1 and rotational speed N1, and approximately 1 at water temperature T3 and rotational speed N2.

Next, it is checked whether the water temperature Tw is higher than the water temperature T5 (112), and if it is, the battery series connection subroutine is executed (118), and if it is not, it is checked whether the water temperature Tw is higher than the water temperature T2. (114), if it is not high, return to 102, and if it is high, check whether the water temperature increase rate ΔTw is greater than a predetermined increase rate ΔT1 (11
6) If it is not larger, return to 102. and,
If the water temperature increase rate ΔTw is larger than the predetermined increase rate ΔT1, the battery series connection subroutine is executed (11
8).

This battery series connection subroutine in FIG. 2 opens the switch 44 and sets the selector switch 45 to a.
This is a routine for switching from end to end b. Furthermore, at the start of this battery series connection subroutine, a built-in timer is started (120), and then it is checked whether or not this timer has expired (122).
Proceeding to step 30, a battery parallel connection subroutine is executed. On the other hand, if the timer has not expired, it is checked whether the water temperature Tw is lower than the water temperature T3 (124), and if it is, the battery parallel connection subroutine is executed (130), and if it is not, the water temperature Tw is lower than the water temperature T4. Check whether (1
26) If it is not low, the process returns to 122, and if it is low, it is checked whether the water temperature decreasing rate ΔTw is greater than a predetermined decreasing rate ΔT2 (128), and if it is not, the process returns to 122. If the water temperature decreasing rate ΔTw is greater than the predetermined increasing rate ΔT2, a battery parallel connection subroutine is executed (130).

The battery series connection subroutine is a routine for closing the switch 44 in FIG. 2 and switching the selector switch 45 from the b end to the a end. That is, according to this embodiment, even when operating at a duty ratio of 1, if the water temperature Tw exceeds the highest threshold water temperature T5, or if the water temperature exceeds the high water temperature T4 and the water temperature rise rate is high,
Since a series voltage approximately twice as high as the normal (rated) voltage is applied to the motor 20 for a predetermined short time, the radiator 1 can be cooled with a larger air volume than during rated operation. In addition,
Since this high-voltage operation is limited to a predetermined short time, it is possible to use a motor designed for regular operation at the rated voltage. There is no need to increase the capacity.

In general, as the water temperature (or refrigerant temperature) rises in the radiator 1 (or the condenser of a refrigeration cycle device), a larger air volume (peak air volume) than the rated air volume is required. As shown in Fig. 5, it is a short period of time, and at the peak air volume for such a short time, by temporarily applying a voltage higher than the rated voltage to the motor 20 to obtain a large air volume, the motor can be The size of the fan 20 and the fan 21 can be reduced.

Furthermore, in this embodiment, a voltage higher than the rated voltage is generated by switching the main battery 41 and sub-battery 42 from parallel connection to series connection, so the DC voltage is boosted. There is no up circuit means and therefore no power loss. Furthermore, a large capacity capacitor may be used instead of the sub-battery 42. (Embodiment 2) Another embodiment of the control device for a vehicle electric fan of the present invention is shown in FIGS. 6 and 7.

This embodiment is an embodiment in which the electric fan 2 is unlocked, and the control device 4 controls the main battery 4.
1. It is equipped with a sub-battery 42, switches S5, S6, S7, changeover switches S3, S4, and a microcomputer device 46, and further includes a current detection resistor 8 provided between the low voltage end of the motor 20 and the ground wire. are doing. Each switch S3 to S7 is
It is used to change the rotation direction of the motor and to switch both batteries in series and parallel.

The operation of this apparatus will be explained below with reference to the flowchart of FIG. However, initially, both batteries 41 and 42 are connected in parallel so that the electric fan 2 rotates in the normal direction. Each switch S3 to S7 is controlled. First, the voltage Vr from one end of the current detection resistor 8 is read to detect the current value (200), and it is checked whether the motor 20 is being driven (202). If so, check whether the motor is locked by checking whether the current value is greater than a predetermined value (204).
), if the current value is smaller than the predetermined value, it returns to 200; if it is larger, it is assumed that the current value is locked, and the switch S5 is turned off (200
6) Turn on S2 and S4 (208, 210) to reverse the motor 20, and after a predetermined time has elapsed (212), turn off switches S2 and S4 (214, 216), and turn on S5 (218). ), detect motor lock again (220
).

Then, if the motor 20 is unlocked (if the voltage Vr is below a predetermined value), the value returns to 200, and if the motor 20 is still locked, the motor 20 is reversed (222, 224, 226), switch S3 is turned off (228), and S1 is turned on (230).
), both batteries 41 and 42 are connected in series to supply high voltage to the motor.
20 to drive the electric fan 2 with high torque. Next, turn off switches S1, S2, and S4, and turn off switches S3 and S5.
(236), connect both batteries 41 and 42 in parallel again, rotate them in the normal direction, and check the motor lock (238).
If the lock is released, the process returns to 200, and if the lock is still locked, the controller is notified that the lock cannot be released, and the switch S5 is opened (240) to protect the motor 20.

In the present embodiment described above, when the motor 20 is locked, it is first attempted to release the lock by reverse rotation at the rated torque, and if the motor 20 is still locked, a high voltage is applied to the motor 20 to release the lock at high torque. Since the motor is unlocked by reversing the rotation, the probability of unlocking increases, and it becomes more likely that situations such as overheating or stopping of driving due to locking of the electric fan can be avoided.

In this embodiment, the lock is released by rotating the motor in the reverse direction with high torque, but it is also possible to release the lock by rotating the motor in the forward direction with high torque. Also in this example,
Since high voltage is achieved by connecting both batteries in series, there is an advantage that the circuit configuration is simple. Further, in this embodiment as well, since a high voltage higher than the rated (common use) voltage is applied only for a predetermined allowable time, seizure of the motor 20 manufactured for the rated voltage can be prevented. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of a vehicle water cooling system equipped with a vehicle electric fan control device of the present invention;

[Fig. 2] Block diagram of the control device of Example 1

[Fig. 3] Flowchart of the microcomputer device of Example 1

[Figure 4] Water temperature Tw
Characteristic diagram showing the relationship between and the rotation speed of the electric fan,

[Figure 5] Water temperature change diagram showing the occurrence of short-term high water temperature states in vehicle water cooling systems

[Fig. 6] Block diagram of the control device of Example 2

[Fig. 7] Flowchart of the microcomputer device of Example 2

[Figure 8] Complaint correspondence diagram

[Explanation of symbols]

1 Radiator (vehicle heat exchanger) 2 Electric fan 4 Control device 46 Microcomputer device (special operating condition detection means, fan operation control means)

Claims (2)

[Claims] 1. A control device for a vehicle electric fan that controls the operation of an electric fan for cooling a vehicle heat exchanger whose rotation speed changes depending on an applied voltage, comprising: a special operating condition detection means for detecting a special operating condition; , a fan operation control means for applying a high voltage higher than a normal applied voltage to the electric fan for a predetermined short time when the special operating condition is detected. . 2. The fan operation control means for a vehicle according to claim 1, wherein the fan operation control means reverses the rotational direction of the electric fan when locking is detected and applies a high voltage higher than a normal applied voltage to the electric fan. Electric fan control device.