JP2005306051A - Air conditioner for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle for improving acceleration performance. <P>SOLUTION: This air conditioner is provided with a control means 100 for performing a control in a direction for reducing discharge capacity of a variable displacement compressor 2 during a refrigerating cycle 1 and a control in a direction for reducing the number of rotation of a condenser fan 7 at the time of acceleration of the vehicle by an engine E. Only when an actually measured temperature of an evaporator 5 is judged to be substantially equal to a target temperature, the controls are executed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle air conditioner including a variable capacity compressor in a cooling cycle (refrigeration cycle).

  The vehicle air conditioner includes a compressor for compressing the refrigerant gas, and the compressor is driven by power supply from an engine mounted on the vehicle. For the engine as the drive source, the compressor is a heavy load. For example, even if the driver steps on the accelerator to accelerate the vehicle, it is difficult to obtain agile acceleration when the compressor is driven. In particular, in the case of an engine having no output, the ratio of the compressor load to the engine load is considerably large, and the acceleration stagnation becomes remarkable.

  In this regard, when a fixed displacement compressor is used, the compressor and the engine are connected via an electromagnetic clutch, and the clutch is disengaged during vehicle acceleration to reduce the load on the engine.

  However, when the compressor is stopped, the cooling operation is completely stopped during that time, so that there is a problem that the cold air does not come into the passenger compartment.

Therefore, to improve this, a variable displacement compressor is used as the compressor, and when the vehicle is accelerated, the discharge capacity of the variable displacement compressor is forcibly reduced, thereby reducing the engine power load and improving the acceleration performance. Some have been designed to improve the performance (for example, see Patent Document 1).
JP 2000-158939 A

  Conventionally, as shown in FIG. 4, for a variable displacement compressor that is directly driven by an engine, acceleration control (acceleration engine load reduction control) is performed to forcibly limit the discharge capacity to a smaller value during acceleration. However, condenser fans that generate other loads are not driven directly by the engine, so they are excluded from the control during acceleration, and are driven normally regardless of whether or not they are accelerated.

  However, the condenser fan is not directly driven by the engine, but is supplied with driving power via a generator driven by the engine, which has a negative effect on the acceleration control by the engine. There was a possibility of effect.

  In view of the above circumstances, an object of the present invention is to provide a vehicle air conditioner that can further improve acceleration performance.

  The invention of claim 1 has a refrigeration cycle in which a compressor, a condenser, an expansion means, and an evaporator are connected by piping, the evaporator is arranged in an air conditioning duct, and the condenser is arranged in an outside air circulation location outside the air conditioning duct, As the compressor in the refrigeration cycle, a variable capacity compressor that is driven by a vehicle engine as a drive source and whose discharge capacity can be changed by external control is used, and the power of the engine is used as means for forcibly air-cooling the condenser. In a vehicle air conditioner equipped with a condenser fan that is driven by electric power generated using an electric motor and that can change the rotational speed by external control, the discharge capacity of the variable-capacity compressor when the vehicle is accelerated by the engine In the direction of decreasing the Characterized by comprising control means for controlling the direction of reducing the rotation number.

  The invention according to claim 2 is the vehicle air conditioner according to claim 1, wherein acceleration of the vehicle by the engine is performed only when the control means determines that the measured temperature of the evaporator is substantially equal to the target temperature. In some cases, the discharge capacity of the variable capacity compressor is controlled to be decreased and the rotational speed of the condenser fan is decreased.

  According to the first aspect of the present invention, when the vehicle is accelerated, the variable capacity compressor is controlled to the discharge capacity decreasing side, and at the same time, the condenser fan is controlled to the rotation speed decreasing (rotation stop or rotation speed decreasing) side. The load on a certain engine can be reduced, and accordingly, the power distribution to the drive wheels can be increased, and the acceleration of the vehicle can be improved. However, since the discharge capacity of the compressor does not necessarily become zero even during this vehicle acceleration, it is possible to achieve both vehicle acceleration and air conditioning capacity maintenance. By the way, with the accelerator fully opened from the idle state, the time required to reach a vehicle speed of 100 km / h was shortened by about 0.3 seconds (about 5%).

  According to the invention of claim 2, the above control is performed at the time of vehicle acceleration only when it is determined that the actually measured temperature of the evaporator is substantially equal to the target temperature, so that the acceleration performance can be improved without impairing the cooling power. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a vehicle 10 equipped with a vehicle air conditioner. In the figure, 1 is a refrigeration cycle of an air conditioner, 11 is an engine room, and 12 is a passenger compartment. The refrigeration cycle 1 is configured by connecting a compressor 2, a condenser 3, an expansion means 4, and an evaporator 5 with piping.

  The evaporator 5 is disposed in the air conditioning duct 21 of the air conditioning unit 20, and the condenser 3 is disposed alongside a radiator (not shown) at a location where the outside air in the engine room 11 circulates well. In the engine room 11, an engine E for driving the vehicle, a generator 30 driven by the engine E, a battery 40, a condenser fan 7 for forcibly air-cooling the condenser 3 and the like are mounted. The condenser fan 7 is driven by the electric power generated by the generator 30.

  As the compressor 2 in this case, a variable capacity compressor whose discharge capacity can be changed by external control is used. Moreover, the rotation speed of the condenser fan 7 can be changed by external control. In addition, this vehicle is provided with a control unit 100 for controlling the engine E and other devices.

  As shown in FIG. 2, the control unit 100 controls the discharge capacity of the variable capacity compressor 2 to decrease in the acceleration of the vehicle by the engine E, and reduces the rotation speed of the condenser fan 7 (illustrated example). Is provided with a control function for controlling to OFF. This function is set to be executed only when it is determined that the actually measured temperature of the evaporator 5 is substantially equal to the target temperature.

  Further, the air conditioning unit 20 includes a blower fan 22 for circulating the conditioned air in the air conditioning duct 21, a heater core 23 for heating the conditioned air in the downstream of the evaporator 5, and an air mix door 24 for adjusting the ratio of the cold air and the hot air. Etc.

  FIG. 3 is a flowchart showing the contents of the acceleration control.

  In step 101, the engine computer (included in the control unit 100) makes a primary determination of acceleration control establishment. In this acceleration control establishment primary determination step, when all of the following conditions are satisfied, it is determined that the control is satisfied, and otherwise, it is determined that the control is not established.

(1) The engine speed is greater than a predetermined value X.
(2) The throttle opening is larger than the predetermined angle Y.
(3) The compressor discharge pressure is smaller than the predetermined value Z.
(4) The engine water temperature is lower than the predetermined value W.

  When the control is established, in step 102, the air conditioning amplifier (included in the control unit 100) makes a secondary determination of the acceleration control establishment. In this step of secondary determination of acceleration control establishment, when all of the following conditions are established, it is determined that the control is established, and otherwise, it is determined that the control is not established.

(1) A value (T−T ′) obtained by subtracting the control cooling power T ′ (° C.) from the target cooling power T (° C.) is smaller than the predetermined value A.
(2) The compressor control duty ratio is smaller than B (%).

  If the control is established, an acceleration control command is issued in the next step 103, and step 104 condenser fan control (capacitor fan OFF) is performed as part of the command. At the same time, in step 105, control is performed to reduce the discharge capacity of the compressor.

  As described above, during the acceleration of the vehicle, the variable capacity compressor 2 is controlled to the discharge capacity decreasing side, and at the same time, the condenser fan 7 is controlled to the rotation speed decreasing (rotation stop or rotation speed decreasing) side. The load of E can be reduced, and accordingly, the power distribution to the drive wheels can be increased, and the acceleration of the vehicle can be improved.

  Further, since the discharge capacity of the compressor 2 is not necessarily zero even during the acceleration of the vehicle, it is possible to achieve both the acceleration of the vehicle and the maintenance of the air conditioning capacity.

  Further, only when it is determined that the actually measured temperature (T ′) of the evaporator 5 is substantially equal to the target temperature (T), if the above control is performed during vehicle acceleration, the acceleration performance can be improved without impairing the cooling power. Can be achieved.

It is a block diagram of the vehicle air conditioner of embodiment of this invention. It is a time chart which shows the contents of control in the embodiment. It is a flowchart which shows the control content in the same embodiment. It is a time chart which shows the control content in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Variable capacity compressor 3 Condenser 4 Expansion means 5 Evaporator 7 Condenser fan 21 Air conditioning duck 100 Control unit (control means)

Claims (2)

Having a refrigeration cycle (1) in which a compressor (2), a condenser (3), an expansion means (4), and an evaporator (5) are connected by piping, and the evaporator (5) is disposed in an air conditioning duct (21); The condenser (3) is disposed at an outside air circulation location outside the air conditioning duct (21), and the compressor (2) in the refrigeration cycle (1) is driven using a vehicle engine (E) as a drive source and external control. As a means for forcibly air-cooling the condenser (3), the variable capacity compressor (2) whose discharge capacity can be changed by the above is used and driven by the electric power generated using the power of the engine (E). In addition, in the vehicle air conditioner provided with the condenser fan (7) whose rotational speed can be changed by external control,
When the vehicle is accelerated by the engine (E), the control means (100) controls the discharge capacity of the variable capacity compressor (2) in a direction to decrease and also controls the speed of the condenser fan (7) to decrease. A vehicle air conditioner characterized by comprising: The vehicle air conditioner according to claim 1,
Only when the control means (100) determines that the measured temperature of the evaporator (5) is substantially equal to the target temperature, the discharge capacity of the variable capacity compressor (2) during acceleration of the vehicle by the engine (E) The vehicle air conditioner is controlled so as to reduce the rotational speed of the condenser fan (7).

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