JP4078896B2 - Control device for motor fan for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle motor fan control device for cooling an engine cooling radiator and an air conditioner condenser.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 2001-317353 discloses a control technique for a motor fan for a vehicle.
In this control technique, a motor fan control command value includes a motor fan first duty command value that satisfies the air conditioner performance requirement and a motor fan second duty command value that satisfies the engine coolant temperature requirement. A large command value is set as the first duty target value, and then the second duty target value of the motor fan is calculated such that the total torque of the generator torque and the compressor torque of the air conditioner is minimized. The motor fan is controlled by a large duty target value of the first and second duty target values to maintain the required performance of the engine coolant and the air conditioner and improve the fuel consumption of the vehicle. .
[0003]
[Problems to be solved by the invention]
In the above conventional technique, the calculation of the compressor torque at the second duty target value is performed based on the refrigerant pressure of the air conditioner and the outside air temperature. For this reason, the second duty target value corresponding to the refrigerant pressure and the outside air temperature can be calculated, and the fuel consumption can be improved without being influenced by the change in the refrigerant pressure or the outside air temperature.
[0004]
However, the actual compressor torque changes according to the cooling requirement in the passenger compartment. As described above, the compressor torque calculated only from the outside air temperature and the refrigerant pressure changes the cooling requirement in the passenger compartment. In some cases, a deviation occurs from the actual torque.
For this reason, the calculated second duty target value may not necessarily correspond to the minimum torque, and the engine does not necessarily drive the motor fan and the compressor with the minimum load, which improves the fuel consumption of the vehicle. Will be constrained.
An object of the present invention is to provide a control device for a motor fan for a vehicle that can improve the fuel efficiency of the vehicle without being restricted by the cooling requirement in the passenger compartment.
[0005]
[Means for Solving the Problems]
The present invention calculates the first command value and the second command value of the duty ratio of the motor fan according to the engine coolant temperature and the refrigerant pressure of the air conditioner, respectively, and compares the magnitudes to determine the larger one. Is set as the first target value of the duty ratio. Also, the total torque of the generator torque and the compressor torque is calculated, and a duty ratio that minimizes the total torque is set as the second target value. The total torque depends on the rotational speed of the blower fan motor. Correct based on. And the greater the first target value and the second target value as a final duty ratio, so as to approach the target refrigerant pressure refrigerant pressure of the air conditioner is calculated on the basis of the ambient temperature and the final duty ratio, Control the final duty ratio .
[0006]
【The invention's effect】
According to the present invention, the required performance of the air conditioner is maintained because the motor fan duty ratio is controlled so as to satisfy the control requirements of the cooling water temperature and the refrigerant pressure and to minimize the generator torque and the compressor torque. In addition, the load on the engine is reduced, and the fuel efficiency of the vehicle can be improved.
In particular, since the total torque of the generator torque and the compressor torque is corrected by the rotational speed of the blower fan, the second torque that minimizes the total torque even when the cooling requirement in the passenger compartment changes. The target value can be calculated, and the fuel efficiency of the vehicle can be improved without being restricted by the cooling requirement in the passenger compartment.
When the target refrigerant pressure of the compressor is calculated based on the outside air temperature and the final duty ratio and the motor fan is controlled, if there is a deviation between the actual refrigerant pressure and the target refrigerant pressure, the refrigerant pressure Since the duty ratio is corrected so as to approach the target refrigerant pressure, the compressor can operate in an ideal state.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described by way of examples.
FIG. 1 is a diagram showing a vehicle cooling system to which the present invention is applied as an embodiment.
The control unit 100 includes a rotation speed sensor 25 that detects the rotation speed of the engine 20, a cooling water temperature sensor 85 that detects the cooling water temperature of the engine 20, and the pressure of the refrigerant flowing in the condenser 90 of the air conditioner (A / C). A discharge pressure sensor 95 and an outside air temperature sensor 110 are connected.
[0008]
The cooling water of the engine 20 is cooled by a radiator 80 arranged in the engine room.
The condenser 90 and the radiator 80 are disposed so as to overlap in the vehicle front-rear direction, and the motor fan 70 is disposed on the rear side thereof. The condenser 90 and the radiator 80 are cooled by the outside air and the motor fan 70 as the vehicle travels. It has become. The outside air temperature sensor 110 is installed on a passage of outside air entering the condenser 90 and the like.
[0009]
The engine 20 is connected to a generator (ALT) 10 and a compressor (COMP) 30 of an air conditioner, and the refrigerant compressed by the compressor 30 absorbs heat by an evaporator 53 of a cooling unit 50 provided in the passenger compartment. The capacitor 90 dissipates.
The generator 10 is connected to the battery (BAT) 40 and the control unit 100 and supplies power to them. The battery 40 supplies power to the control unit 100 when the engine 20 is stopped.
[0010]
The cooling water of the engine circulates in the heater core 54 of the cooling unit 50 during heating.
The evaporator 53 and the heater core 54 are provided with a blower fan 51 so as to send the temperature-adjusted air into the vehicle interior.
A rotation speed sensor 55 that detects the rotation speed of the blower fan 51, an air conditioner switch (air conditioner SW) 115, and a vehicle speed sensor 120 are connected to the control unit 100.
[0011]
Next, the control flow of the motor fan in the control unit 100 will be described.
2 and 3 are flowcharts showing the flow of control of the motor fan.
If it is detected in step 100 that an ignition switch (not shown) is turned on and the engine is started, the process proceeds to step 101.
In step 101, the engine speed is read from the rotation speed sensor 25, and the detected value of the outside air temperature is read from the outside air temperature sensor 110.
[0012]
In step 102, it is checked whether the air conditioner SW 115 is on or off. If it is on, the process proceeds to step 103, and if it is off, the process proceeds to step 125.
In step 103, the detected value of the refrigerant pressure of the air conditioner is read from the discharge pressure sensor 21.
In step 104, the detected value of the engine coolant temperature is read from the coolant temperature sensor 85.
[0013]
In step 105, the refrigerant pressure read in step 103 is used to satisfy the requirements for the performance of the air conditioner using the map showing the relationship between the refrigerant pressure and the motor fan duty ratio shown in FIG. The first command value X of the duty ratio of the motor fan is calculated. In the map of FIG. 4A, the duty ratio is constant at about 30% when the refrigerant pressure is P1 or less, and the duty ratio increases in proportion to the refrigerant pressure until it exceeds P1 and reaches P2. The characteristic that becomes constant at a duty ratio of 100% is set.
[0014]
In step 106, the motor fan for satisfying the requirement for the cooling water temperature using the map showing the relationship between the cooling water temperature and the duty ratio of the motor fan shown in FIG. 4B from the cooling water temperature read in step 104. The second command value Y of the duty ratio is calculated. The map in FIG. 4B shows that when the cooling water temperature is equal to or lower than T1, the motor fan is not driven with a duty ratio of 0%, and the duty ratio increases in proportion to the cooling water temperature until it exceeds T1 and reaches T2. , T2 is set so as to be constant at a duty ratio of 100%.
[0015]
In step 107, the magnitudes of the first command value X and the second command value Y are compared. If the first command value X is equal to or greater than the second command value Y, the process proceeds to step 108. If the first command value X is smaller than the second command value Y, the process proceeds to step 109.
In step 108, the first command value X is set to the first target value D1 of the duty ratio of the motor fan.
In step 109, the second command value Y is set to the first target value D1 of the motor fan duty ratio.
Thus, the larger one of the first command value X and the second command value Y is adopted as the first target value, and the requirements for both the cooling water temperature and the performance of the air conditioner can be satisfied.
[0016]
In step 110, based on the duty ratio of the first target value D1 and the outside air temperature read in step 101, an ideal target refrigerant pressure of the compressor is calculated using the refrigerant pressure map shown in FIG.
The map of FIG. 5 defines the relationship between the duty ratio, the refrigerant pressure, and the outside air temperature, and is set so that the refrigerant pressure is low when the duty ratio is high and the refrigerant pressure is high when the outside air temperature is high. This means that as the duty ratio of the motor fan increases, the amount of air blown by the motor fan increases and the cooling capacity of the condenser is relatively improved, so that the refrigerant pressure sent out by the compressor may be lowered. Further, as the outside air temperature rises, the cooling capacity decreases accordingly, so that the correction is taken into consideration.
[0017]
In step 111, the power generation current I1 of the generator is calculated from the first target value D1 using the map representing the relationship between the duty ratio of the motor fan and the power generation current of the power generator shown in FIG. The map of FIG. 6 represents the characteristic that the generated current required to drive the motor fan with the duty ratio increases in proportion to the duty ratio.
[0018]
In step 112 of FIG. 3, the generator torque Ti1 is calculated from the generated current I1 and the rotational speed of the engine using a map showing the relationship between the generated current and torque of the generator shown in FIG. The map of FIG. 7 represents a characteristic that, at a predetermined engine speed (that is, the speed of the generator), the torque required to generate the current is increased in proportion to the magnitude of the generated current of the generator. Such a map is prepared for each engine speed.
[0019]
In step 113, the torque Tc1 of the compressor is calculated from the first target value D1 using a map representing the relationship between the motor fan duty ratio and the compressor torque shown in FIG. The map in FIG. 8 shows the compressor when the condenser is cooled by the motor fan duty ratio and the motor fan driven at the duty ratio under a predetermined engine speed (that is, the compressor speed) and outside air temperature. This represents a characteristic that the required torque decreases as the duty ratio increases. Such a map is prepared for each combination of engine speed and outside air temperature.
In step 114, the total torque T1 of the generator torque Ti1 and the compressor torque Tc1 is calculated.
[0020]
In step 115, the detected value of the outside air temperature is read from the outside air temperature sensor 110.
The detected value of the outside air temperature has already been read in step 101, but is read again here to improve the accuracy.
In step 116, the rotational speed of the blower fan is read from the rotational speed sensor 55.
[0021]
In step 117, the total torque T1 of the generator and the compressor calculated in step 114 is corrected using the total torque correction value from the correction map shown in FIG. 9 based on the outside air temperature and the rotation speed of the blower fan. The correction total torque T1 ′ is calculated.
In the correction map of FIG. 9, the correction value is set so that the total torque T1 increases as the outside air temperature increases, and the total torque T1 increases as the rotation speed of the blower fan increases. This is because, when the outside air temperature or the rotation speed of the blower fan becomes higher than the condition at the time when the target refrigerant pressure is set in step 110, the torque must be increased by that amount.
[0022]
In step 118, the second target value D2 of the duty ratio of the motor fan is determined so that the corrected total torque T1 ′ of the generator torque and the compressor torque is minimized in consideration of the operating states of the generator and the compressor. . Specifically, the motor fan duty ratio is changed little by little from the first target value D1, and after the generator current I2 is calculated in the same manner as in step 111, the generator torque Ti2 is set in the same manner as in step 112. The compressor torque Tc2 is calculated in the same manner as in step 113.
[0023]
Finally, corrected by the correction map of FIG. 9 calculates the sum T2 of Ti2 and Tc2, obtains the duty ratio of the motor fan when the corrected T2 'is T1' becomes smaller than the corrected total torque is repeated this The duty ratio when becomes the minimum is the second target value D2.
Then, after calculating the second target value D2, an ideal target refrigerant pressure of the compressor is obtained using the map shown in FIG.
[0024]
In step 119, the magnitudes of the first target value D1 and the second target value D2 are compared. If the second target value D2 is greater than or equal to the first target value D1, the process proceeds to step 120, and if the second target value D2 is smaller than the first target value D1, the process proceeds to step 121.
In step 120, the motor fan is controlled using the duty ratio of the second target value D2 as the duty ratio of the motor fan. In this case, since the load torque of the engine is minimized and the duty ratio (that is, D2) of the motor fan that does not affect the performance of the air conditioner is used, the operating state of the generator and the compressor is optimized. .
In step 121, the duty ratio of the first target value D1 is controlled as the duty ratio of the motor fan.
[0025]
In step 122, the detected value of the refrigerant pressure of the compressor is read from the discharge pressure sensor 95.
In step 123, a deviation between the target refrigerant pressure obtained in step 110 or 118 and the detected refrigerant pressure is detected.
In step 124, the motor fan duty ratio D is corrected so as to eliminate the deviation.
[0026]
On the other hand, if the air conditioner SW is off in the check in step 102, the detected value of the cooling water temperature is read in step 125 as in step 104.
In step 126, similarly to step 106, the second command value Y is calculated from the coolant temperature read in step 125.
[0027]
In step 127, the second command value Y is set as the first target value D1. Here, since the air conditioner SW is off, the second target value D2 in consideration of the operating state of the compressor is not calculated.
In step 128, the target refrigerant pressure of the compressor corresponding to the first target value D1 is calculated from the map of FIG. Then, after the motor fan control based on the duty ratio of the first target value D1 and the correction for the subsequent duty ratio are performed in step 121, the process is returned and the above control is repeated.
[0028]
In the present embodiment, the above steps 103 and 105 constitute the first command value calculating means, the above steps 104 and 106 constitute the second command value calculating means, and the steps 107 to 109 are the first target value setting means. Steps 111 to 114 and Step 118 constitute second target value setting means, and Step 119 and Steps 120 and 121 constitute duty ratio determining means. Steps 115 to 117 constitute correction means, and steps 122 to 124 constitute duty control means.
[0029]
The present embodiment is configured as described above, and the total torque of the generator and the compressor is minimized while satisfying the requirements for the cooling water temperature and the performance of the air conditioner. Can be improved. In particular, when calculating the second target value, the total torque of the generator and the compressor is corrected based on the outside air temperature and the rotation speed of the blower fan, so the outside air temperature and the cooling requirement in the cooling unit change. Even in this case, the engine can drive the generator and the compressor with the minimum torque, and the fuel efficiency of the vehicle can be improved without being affected by the cooling request in the passenger compartment.
[0030]
Further, when calculating the target refrigerant pressure of the compressor corresponding to the calculated duty ratio of the first and second target values and controlling the motor fan, there is a difference between the actual refrigerant pressure and the target refrigerant pressure. In such a case, since the duty ratio is corrected so that the refrigerant pressure approaches the target refrigerant pressure, the compressor can operate in an ideal state.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cooling system for a vehicle to which the present invention is applied.
FIG. 2 is a flowchart showing a control flow of a motor fan.
FIG. 3 is a flowchart showing a control flow of a motor fan.
FIG. 4 is a map showing the relationship between the refrigerant pressure and the motor fan duty ratio, and the relationship between the coolant temperature and the motor fan duty ratio.
FIG. 5 is a map showing the relationship between the duty ratio, the refrigerant pressure, and the outside air temperature.
FIG. 6 is a map showing a relationship between a duty ratio of a motor fan and a generated current of a generator.
FIG. 7 is a map showing the relationship between the generated current and torque of the generator.
FIG. 8 is a map showing a relationship between a duty ratio of a motor fan and a torque of a compressor.
FIG. 9 is a map for correcting the total torque.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Generator 20 Engine 25 Generator 30 Compressor 40 Battery 50 Cooling unit 51 Blower fan 53 Evaporator 54 Heater condenser 55 Speed sensor 70 Motor fan 80 Radiator 90 Condenser 100 Control unit 110 Outside temperature sensor 115 Air conditioner SW
120 Vehicle speed sensor

Claims (2)

In a vehicle motor fan control device for controlling a motor fan that cools a radiator of engine cooling water and a condenser of an air conditioner refrigerant with a duty ratio,
First command value calculating means for calculating a first command value of a duty ratio for satisfying the performance requirement of the air conditioner indicated by the refrigerant pressure;
Second command value calculating means for calculating a second command value of the duty ratio according to the coolant temperature;
First target value setting means for setting a larger one of the first command value and the second command value as a first target value of the duty ratio;
A second target value setting means for calculating a total torque of the generator torque and the compressor torque, and setting a duty ratio that minimizes the total torque as a second target value;
A duty ratio determining means having a larger one of the first target value and the second target value as a final duty ratio ;
Duty ratio control means for controlling the determined final duty ratio so that the refrigerant pressure of the air conditioner approaches the target refrigerant pressure calculated based on the outside air temperature and the final duty ratio ,
Correcting means for correcting the total torque of the calculated generator torque and compressor torque with respect to the second target value setting means based on the rotational speed of the blower fan motor;
The second target value setting means sets a duty ratio that minimizes the corrected total torque as the second target value.   2. The vehicle motor fan control device according to claim 1, wherein the correction means corrects the total torque based on a rotational speed and an outside air temperature of the blower fan motor.

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