JPH10138749A - Air-conditioning device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of fan motors driving a plurality of compressor fans, respectively. SOLUTION: An air-conditioning device for an automobile is composed of first and second condenser fans 35, 36 for cooling first and second condensers 24, 29, first and second fan motors 41, 42 fir driving condenser fans, respectively, a control means 52 for changing the rotational speeds of the condenser fan motors 41, 42 in accordance with a thermal load in the evaporators 27, 32. In particular, the control means 52 changes the operation of the condenser fan motors 41, 42 so as to stop and start the motors or to change the rotational speed thereof in order to set the operating times of these two condenser fan motors 41, 42 to be equal to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for an automobile having a condenser fan for individually cooling a plurality of condensers, and to extend the life of a motor for driving each condenser fan.

[0002]

2. Description of the Related Art As an air conditioner for a vehicle having a plurality of condensers, an air conditioner mounted on a roof mounted on a large vehicle such as a bus is known (Japanese Patent Application Laid-Open No. 61-25731).
No. 7). Since the air conditioner for automobiles is installed on the roof of the vehicle, it is not possible to obtain sufficient wind for cooling the capacitors even when the vehicle is running, so a condenser fan that individually cools the capacitors is incorporated. Have been. Each of these condenser fans is rotationally driven by a condenser fan motor.

[0003] Generally, in an air conditioner for a vehicle, the amount of refrigerant circulating in a cooling cycle is adjusted to increase or decrease according to the heat load on an evaporator. Since it is necessary to dehumidify the cabin even during low loads such as in winter or rainy weather,
The air conditioner for a vehicle is always operated within a range where the evaporator does not freeze, even at a low load. Since the proper condenser cooling air volume varies depending on the heat load in the evaporator, all of the condenser fan motors rotate at high speed when the heat load is high, and all of the condenser fan motors when the heat load is low. Is rotated at a low speed to reduce power waste.

[0004]

As described above, as long as the air conditioner for a vehicle is operating, the fan motor is driven to rotate, the heat load is smaller than the low load, and a plurality of capacitors are used. Even in the case of an extremely low load where only one capacitor is required to function, all of the fan motors are driven to rotate at a low speed.

For this reason, there is a problem that the cumulative operation time of each fan motor becomes longer, the brush is worn, and the life of the fan motor is shortened. Along with this, maintenance of the fan motor must be performed in a short cycle.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems associated with the above-mentioned prior art, and provides an air conditioner for an automobile which can extend the life of a fan motor for driving each of a plurality of condenser fans. The purpose is to:

[0007]

According to the first aspect of the present invention, at least two condensers for condensing refrigerant from a compressor, an evaporator for cooling air blown into a vehicle interior, At least two condenser fans for cooling each of the condensers, at least two condenser fan motors for driving each of the condenser fans, and all of the condenser fan motors when the thermal load in the evaporator is high. At a high speed, and in the case of a low load, control means for rotating all of the condenser fan motors at a low speed.In an automotive air conditioner, the control means further comprises a heat load lower than the low load. In the case of even smaller, very low loads, said at least two condenser fan motors , And wherein the actuating switch to alternately stop and low-speed rotation.

[0008] In the air conditioner for a vehicle having such a configuration,
When the heat load is a very low load which is smaller than the low load, the control means alternately switches the stop or low-speed rotation of at least two condenser fan motors. The cumulative operation time of the individual condenser fan motors is shorter than in the configuration in which all are rotated at a low speed. For this reason, wear of sliding parts such as brushes is suppressed, the life of the capacitor fan motor is extended, and the period in which the maintenance of the capacitor fan motor should be performed becomes longer.

Further, in the air conditioner for a vehicle according to the present invention, the control means may stop and rotate the at least two condenser fan motors at a low speed so that the operation time of each condenser fan motor is substantially equal. Is switched.

According to such a configuration, the operation time of each condenser fan motor becomes substantially equal, and the life of each capacitor fan motor is made uniform.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an on-vehicle state of an automotive air conditioner according to an embodiment of the present invention.
FIG. 3 is a configuration diagram showing a main part of the vehicle air conditioner together with a cooling cycle.

As shown in FIG. 1, the vehicle air conditioner according to the present embodiment is a roof mounted type installed on a large vehicle such as a bus, and has a unit case 11 fixed on a roof 10. Is housed inside.

As shown in FIG. 2, the automotive air conditioner has first and second cooling systems 21 and 22 of two systems. As is well known, the first cooling cycle 21 includes a first compressor 23 for compressing the refrigerant, a first condenser 24 for liquefying the gas refrigerant discharged from the first compressor 23, a temporary storage of the refrigerant, and gas-liquid separation. A first liquid tank 25 that performs the following operations: a first expansion valve 26 that adiabatically expands the liquid refrigerant from the first liquid tank 25; and a first evaporator 27 that cools outside air or vehicle interior air that blows into the vehicle interior, These are connected by a refrigerant conduit. Similarly, the second cooling cycle 22 is configured by connecting a second compressor 28, a second condenser 29, a second liquid tank 30, a second expansion valve 31, and a second evaporator 32 by a refrigerant conduit. I have. Also, the first and second condensers 24,
First and second condenser fans 35 and 36 for blowing outside air to cool the condensers 24 and 29, and first and second ventilation fans 3 for blowing air blown into the vehicle interior.
7, 38 are provided. The first and second condenser fans 35 and 36 are driven to rotate by first and second condenser fan motors 41 and 42, respectively, and the first and second blower fans 37 and 38 are respectively driven by the first and second condenser fan motors 41 and 42. The two blower fan motors 43 and 44 are driven to rotate.

The unit case 11 is formed of glass fiber reinforced plastic (FRP),
As shown in FIG. 2,
A case body 46 in which a storage chamber 45 is formed;
And a cover 47 that covers the The case body 46 and the cover 47 include an outside air inlet 48 for taking in outside air for cooling the condensers 24 and 29 into the storage chamber 45, and an outside air outlet 49 for blowing out the outside air heat exchanged by the condensers 24 and 29 to the outside. Are formed.

The first capacitor 24 includes two capacitors 24a and 24b, and each of the capacitors 24a and 24b
Is mounted so as to be substantially perpendicular to the bottom plate of the case body 46. Between the condensers 24a and 24b, the first condenser fan 35 for sucking the outside air heat exchanged by the condensers 24a and 24b is provided. Similarly, the second capacitor 29 is connected to the case body 4
6, two capacitors 29a, 29 attached to the bottom plate portion
9b, the second condenser fan 36 is provided between the condensers 29a and 29b. And
When each of the condenser fans 35 and 36 is driven, the outside air flows as shown by the arrows in the figure, and the first and second condensers 2 and 3 are driven.
At 4 and 29, the gaseous refrigerant compressed by the compressors 23 and 28 and having a relatively high temperature and high pressure exchanges heat with the outside air, and the refrigerant becomes a relatively high pressure liquid refrigerant.

The amount of refrigerant circulating in the cooling cycles 21 and 22 is adjusted by changing the discharge amount from the compressors 23 and 28 in accordance with the heat load. The amount of circulating refrigerant is increased when the heat load is small, such as in winter. Temperature sensors 50 and 51 for detecting a refrigerant temperature are provided on outlet-side conduits of the evaporators 27 and 32, respectively.
The degree of heat load is detected based on the evaporator outlet temperature. The control means 52 controls ON / OFF of the compressors 23 and 28, the first and second condenser fan motors 41 and 42, and the first and second blower fan motors 43 and 44 according to the detected degree of heat load.

FIG. 3 is a schematic block diagram showing a control system of the first and second condenser fan motors.

The evaporator outlet temperature signal detected by the temperature sensors 50 and 51 is input to the CPU 52 as control means. Further, the CPU 50 or 51 outputs a control signal to the first condenser fan motor 41 to rotate the first condenser fan 35 at high speed, to rotate at low speed, or to stop the first condenser fan 35 in accordance with the detected heat load. Is done. Similarly, the CPU 52 outputs a control signal to the second condenser fan motor 42 to rotate the second condenser fan 36 at high speed, to rotate at low speed, or to stop the second condenser fan 36 according to the detected heat load. You. Further, a timer 53 is connected to the CPU 52.

Next, the operation of the present embodiment will be described.

FIG. 4 is a flowchart showing a control procedure of the first and second condenser fan motors.

First, in step S10, the degree of heat load on the evaporators 27 and 32 is detected based on the evaporator outlet temperatures detected by the temperature sensors 50 and 51. The subsequent control is performed when the detected heat load is a high load, when the detected heat load is a low load, and when an extremely low load that is smaller than the low load and only one of the cooling cycles 21 (or 22) is required to function. The case is made separately.

If it is detected that the heat load on the evaporators 27 and 32 is high, the cooling cycles 2
By operating the first and second condenser fan motors 41 and 42 at high speed (S11). Thereby, air conditioning according to the high heat load is performed.

If it is detected that the heat load is low, both cooling cycles 21 and 22 are activated, and both the first and second condenser fan motors 41 and 42 are rotated at a low speed (S12). ). Thereby, air conditioning according to the low heat load is performed.

On the other hand, if it is detected that the heat load is extremely low, the first cooling cycle 21 and the second cooling cycle 2
2 and alternately operates, and correspondingly, the first
The condenser fan motor 41 and the second condenser fan motor 42 are alternately switched and operated (S13 to S1).
6).

More specifically, first, the first cooling cycle 21
By operating only the first condenser fan motor 41 at a low speed, the second condenser fan motor 42 is stopped (S13). At the same time, the timer 53 is activated, and the operation of rotating and driving only the first condenser fan motor 41 is continued for a predetermined time (for example, 30 minutes to 1 hour) (S13, S14). By operating only the first cooling cycle 21, air conditioning according to the extremely low heat load is performed.

After the lapse of the predetermined time, the second cooling cycle 22 which has been stopped is operated to start rotating the second condenser fan motor 42 at a low speed. The cooling cycle 21 is stopped, and the first condenser fan motor 41 is stopped (S15).
At the same time, the timer 53 operates, and only for the predetermined time,
The operation of rotating only the second condenser fan motor 42 is continued (S15, S16). By operating only the second cooling cycle 22, air conditioning according to the extremely low heat load is performed.

As described above, when the heat load is a very low load that is smaller than the low load, the CPU 52 alternately switches the two condenser fan motors 41 and 42 between stop and low-speed rotation. Even in the case of the above, compared to the conventional example in which both of the two condenser fan motors are rotated at low speed, each condenser fan motor 4
The cumulative operation time of 1,42 is shortened. Therefore, abrasion of sliding parts such as brushes is suppressed, the life of the condenser fan motors 41 and 42 can be extended, and the period for performing maintenance management of the condenser fan motors 41 and 42 can be lengthened.

Further, two condenser fan motors 4
Since the stop or low-speed rotation of the first and second condenser fan motors 41 and 42 is switched at predetermined time intervals, the operation times of the respective condenser fan motors 41 and 42 become substantially equal, and
Only the life of 1 (42) is not shortened.

The embodiment in which the present invention is applied to an air conditioner for a vehicle mounted on a roof has been described.
The present invention is not limited to this case. Although the case where two condenser fan motors 41 and 42 are provided is shown, the operation of three or more condenser fan motors can be switched according to the number of capacitors. Further, although the stop or low-speed rotation of the condenser fan motor is directly switched by the CPU 52, a configuration in which an operating state is switched by providing a relay or the like may be adopted. Furthermore, although the case where two cooling cycles 21 and 22 are provided is shown, a cooling valve provided in a cooling cycle having one compressor may be provided with a switching valve or the like to distribute refrigerant to a plurality of condensers.

[0030]

As described above, according to the first aspect of the present invention, when the heat load is a very low load that is smaller than the low load, the control means includes at least two condenser fan motors. In this case, the total operation time of the individual condenser fan motors is shorter than in the case where all the condenser fan motors are rotated at a low speed in the case of an extremely low heat load. Therefore, wear of sliding parts such as brushes is suppressed, the life of the condenser fan motor can be extended, and the period in which maintenance of the condenser fan motor should be performed can be lengthened.

Further, in the air conditioner for a vehicle according to the second aspect, the operation time of each condenser fan motor is substantially equal, and the life of only one condenser fan motor is not shortened. The life is made uniform.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a vehicle air conditioner according to an embodiment of the present invention is mounted on a vehicle.

FIG. 2 is a configuration diagram showing a main part of the air conditioner for a vehicle together with a cooling cycle.

FIG. 3 is a schematic block diagram showing a control system of first and second condenser fan motors.

FIG. 4 is a flowchart showing a control procedure of first and second condenser fan motors.

[Explanation of symbols]

 21 first cooling cycle 22 second cooling cycle 23, 28 compressor 27, 32 evaporator 24 (24a, 24b) first capacitor 29 (29a, 29b) second capacitor 35 first Condenser fan 36 ... second condenser fan 41 ... first condenser fan motor 42 ... second condenser fan motor 52 ... CPU (control means)

Claims (2)

[Claims] 1. At least two condensers (24, 29) for condensing refrigerant from a compressor (23, 28).
And an evaporator (27,
32), at least two condenser fans (35, 36) for cooling each of the condensers (24, 29), and at least two condenser fan motors for driving each of the condenser fans (35, 36) 41,
42), and when the thermal load on the evaporator (27, 32) is high, the condenser fan motor (41, 4)
Control means (52) for rotating all of 2) at high speed and for low load to rotate all of the condenser fan motors (41, 42) at low speed. The means (52) further activates the at least two condenser fan motors (41, 42) by alternately switching between stop and low-speed rotation when the heat load is a very low load smaller than the low load. An air conditioner for an automobile, characterized in that the air conditioner is used. 2. The control means (52) stops and rotates the at least two condenser fan motors (41, 42) at a low speed so that the operation times of the condenser fan motors (41, 42) are substantially equal. The vehicle air conditioner according to claim 1, wherein the air conditioner is switched.