JP2007216818A - Freezing cycle device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly start an electric compressor in a cooling system for a vehicle. <P>SOLUTION: While an air conditioner switch 10a is turned on, when blowoff air temperature of an evaporator 5 is higher than fixed temperature (namely, freezing point temperature) and vehicle speed is less than fixed speed, ventilation is started by a cooling fan 8. Then, after the expiration of fixed period t, the electric compressor 1 is started. Thus, after a number of rotations of the cooling fan 8 reaches a target number of rotation and the cooling performance of the cooling fan 8 reaches a fixed level, the electric compressor 1 is started, so that high pressure coolant is sufficiently cooled by a capacitor 8. Coolant pressure is made a proper value thereby, so that the electric compressor is smoothly started. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicular refrigeration cycle apparatus including an electric blower for compressing a refrigerant.

  Conventionally, in a refrigeration cycle apparatus mounted on an electric vehicle or a hybrid vehicle, an electric compressor that compresses the refrigerant, a condenser that cools the high-pressure refrigerant discharged from the electric compressor, and an expansion that depressurizes the refrigerant discharged from the condenser Some include a valve and an evaporator that cools the air by evaporating the refrigerant decompressed by the expansion valve (see, for example, Patent Document 1).

Moreover, although this Patent Document 1 does not describe a condenser cooling device, a general vehicle refrigeration cycle apparatus is provided with an electric blower that blows air toward the condenser to cool the condenser. .
JP-A-8-20231

  When this inventor earnestly examined about the operation | movement immediately after starting of an electric compressor in the above-mentioned refrigeration cycle apparatus, the following problems were found.

  In order to obtain a high cooling capacity from the evaporator in a short period of time immediately after the start of the electric compressor, it is necessary to rotate the electric compressor to a high rotational speed in a short period of time. In this case, even if the electric blower is started simultaneously with the start of the electric compressor, it takes time to increase the rotational speed of the electric blower to the target rotational speed, and the condenser is sufficiently cooled by the electric blower. I can't.

  For this reason, the condenser cannot sufficiently cool the high-pressure refrigerant, and the refrigerant pressure causes an overshoot, which places a high load on the electric compressor and consumes extra power.

  An object of this invention is to provide the refrigerating-cycle apparatus which started the electric compressor favorably in view of the said point.

  In order to achieve the above object, in the present invention, the electric compressor (1) for compressing the refrigerant, the cooler (2) for cooling the high-pressure refrigerant discharged from the electric compressor, and the refrigerant discharged from the cooler are decompressed. A pressure reducer (4), a cooling heat exchanger (5) that evaporates the refrigerant decompressed by the pressure reducer and cools the air, and an electric blower (8) that blows air to the cooler to cool the cooler And a control means (10) for controlling the electric compressor so as to start the operation of the electric compressor after a certain period of time has elapsed since the start of starting the electric blower.

  Therefore, since the electric compressor is started after a certain period of time has elapsed since the start of starting the electric blower, the electric compressor is started in a state where sufficient cooling capacity of the electric blower with respect to the cooler is ensured. For this reason, since the cooler can be sufficiently cooled, an overshoot of the refrigerant pressure does not occur. For this reason, a high load is not applied to the electric compressor, and the electric compressor can be started well.

  In addition, the code | symbol in the bracket | parenthesis of each means described in a claim and this column shows the correspondence with the specific means as described in embodiment mentioned later.

  FIG. 1 shows an embodiment of a vehicular cooling system for a hybrid vehicle to which the vehicular refrigeration cycle apparatus of the present invention is applied.

  As shown in FIG. 1, the vehicle cooling system of the present embodiment includes an electric compressor 1, a condenser 2, a pressure sensor 3, an expansion valve 4, an evaporator 5, a radiator 7, and cooling fans 8 and 9. The electric compressor 1 is driven by an electric motor to compress the refrigerant. The condenser 2 cools the high-pressure refrigerant discharged from the electric compressor 1 with the air blown from the cooling fan 8. The expansion valve 4 depressurizes the refrigerant discharged from the capacitor 2.

  The evaporator 5 is a cooling heat exchanger disposed in the indoor air conditioning unit of the air conditioner, and evaporates the refrigerant to cool the air. The radiator 7 cools the engine coolant with the blown air from the cooling fan 9. The cooling fan 8 blows air to the capacitor 2 in order to cool the capacitor 2. The cooling fan 9 blows air to the radiator 7 in order to cool the radiator 7.

  Next, an electric circuit configuration of the vehicle cooling system of the present embodiment will be described with reference to FIG. FIG. 2 is a schematic diagram showing an electric circuit configuration of the vehicle cooling system of the present embodiment.

  The vehicle cooling system includes an inverter 2a, a pressure sensor 3, a temperature sensor 6, an air conditioner ECU 10, an engine ECU 11, a fan drive circuit 11a, an air conditioner switch 10a, a vehicle speed sensor 13, and a water temperature sensor 14. The air conditioner ECU 10 is a well-known electronic control device including a microcomputer, a memory, a timer circuit, and the like. The air conditioner ECU 10 acquires the detection values of the sensors 13, 14, and 15 through communication with the engine ECU 11, and detects them. The electric compressor 1 is controlled based on the value. The inverter 2a drives the electric motor of the electric compressor 1 based on a control signal from the air conditioner ECU10. The temperature sensor 6 detects the temperature of air blown from the evaporator 5.

  The engine ECU 11 controls the cooling fans 8 and 9 via the fan drive circuit 11a based on the detection signals of the sensors 13, 14, and 15. The fan drive circuit 11 a drives the cooling fans 8 and 9 based on a control signal from the engine ECU 11. The pressure sensor 15 detects the pressure of the refrigerant discharged from the capacitor 2. The vehicle speed sensor 13 detects the vehicle speed based on the rotation speed of the vehicle driving wheel. The water temperature sensor 14 detects the temperature of engine cooling water. The air conditioner switch 10 a is a switch that is operated by a passenger to start the electric compressor 1.

  Next, the operation of the vehicle cooling system of the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing the control process of the air conditioner ECU 10. FIG. 4 shows (a) the operating state of the air conditioner switch 10a, (b) the temperature of the air blown from the evaporator 5 (denoted as the post-evaporation temperature in the figure), 4 is a timing chart showing detection output of the vehicle speed sensor 13, (d) an operating state of the cooling fan 8, and (e) an operating state of the electric compressor 1.

  When the ignition switch IG is turned on, the air conditioner ECU 10 starts executing the computer program according to the flowchart of FIG. The computer program is repeatedly executed at regular intervals.

  First, if the occupant has turned on the air conditioner switch 10a, it is determined YES in step 100. Next, in step 101, based on the temperature detected by the temperature sensor 6 acquired from the engine ECU 11, it is determined whether the temperature of the air blown from the evaporator 5 is higher than a certain temperature. If the temperature of the air blown out from the evaporator 5 is higher than a certain temperature, it is determined as YES.

  Thereafter, in step 102, it is determined whether or not the refrigerant has sufficiently returned to the inlet side of the electric compressor 1 based on the detected value of the pressure sensor 15 acquired via the engine ECU 11.

  For example, when the detection value of the pressure sensor 15 is equal to or higher than a certain level, it is determined that the refrigerant has sufficiently returned to the inlet side of the electric compressor 1. Accordingly, YES is determined in step 102, the process proceeds to step 103, and a command signal for starting the cooling fan 8 is output to the engine ECU 11. As a result, the engine ECU 11 starts controlling the cooling fan 8 via the inverter 2 a, so that the cooling fan 8 starts blowing air toward the capacitor 2.

  Thereafter, in step 104, the air conditioner ECU 10 determines whether or not the vehicle speed is less than a certain speed based on the detection output of the vehicle speed sensor 13 acquired via the engine ECU 11. When the vehicle speed is less than a certain speed, it is determined as YES, and the process proceeds to step 105 to start the timer.

  Thereafter, in step 106, it is determined whether or not a predetermined time (t) has elapsed based on the time count of the timer. The determination of NO is repeated at step 106 until the predetermined time (t) elapses. After that, when the predetermined time (t) elapses, YES is determined at step 106 and the electric compressor 1 is started at step 107. As a result, the electric compressor 1 starts to compress the refrigerant, and the refrigerant circulates through the path of the electric compressor 1 → the condenser 2 → the expansion valve 4 → the evaporator 5 → the electric compressor 1.

  Further, when the vehicle speed is equal to or higher than a certain speed based on the detection output of the vehicle speed sensor 13 acquired from the engine ECU 11 in step 104, the processing of steps 104 and 105 is skipped and the electric compressor 1 is started (step 107). .

  In step 101, if the temperature of the air blown from the evaporator 5 is lower than a certain temperature, it is determined as NO and the process returns to step 100. In step 102, when the detected value of the pressure sensor 15 is less than a certain level, it is determined as NO because the refrigerant is insufficient, and the process returns to step 100.

  Since the control process by the air conditioner ECU 10 is performed as described above, the temperature of the air blown from the evaporator 5 is constant (that is, the freezing point temperature) with the air conditioner switch 10a turned on (see (a) in FIG. 4). ) (See (b) in FIG. 4), and when the vehicle speed is less than a certain speed (specifically, 0 km / sec or low speed) (see (c) in FIG. 4), the cooling fan 8 starts air blowing. (See (d) in FIG. 4). Thereafter, when a predetermined period t has elapsed, the electric compressor 1 is started (see (e) in FIG. 4).

  In addition, when the air conditioner switch 10a is turned on (see (a) in the figure), the temperature of the air blown from the evaporator 5 is higher than a certain temperature (that is, the freezing point temperature) (see (b) in FIG. 4). When the vehicle speed is equal to or higher than a certain speed (see (c) in FIG. 4), the cooling fan 8 starts air blowing (see (d) in FIG. 4) and starts the electric compressor 1 ((e) in FIG. 4). reference).

  As described above, according to the present embodiment, when the vehicle speed is less than a certain speed, the electric compressor 1 is started when a certain period of time t has elapsed after the cooling fan 8 starts blowing air. For this reason, even if the electric compressor 1 is started in order to start the electric compressor 1 after the rotation speed of the cooling fan 8 reaches the target rotation speed and the cooling capacity of the cooling fan 8 reaches a certain level, The condenser 8 can sufficiently cool the high-pressure refrigerant.

  Here, as described above, when the electric compressor 1 is started at the same time as the cooling fan 8 is started, the high pressure refrigerant is not sufficiently cooled by the condenser as shown in the graph a in FIG. Wake up.

  On the other hand, according to this embodiment, the expansion valve 4 is in a state where the high-pressure refrigerant is sufficiently cooled by the condenser 8 in order to start the electric compressor 1 after the cooling capacity of the cooling fan 8 reaches a certain level. And it returns to the electric compressor 1 through the evaporator 5. Accordingly, the high-pressure refrigerant is sufficiently cooled by the capacitor 8 and the refrigerant pressure can be set to an appropriate value as shown in the graph b in FIG. 5, so that a high load is not applied to the electric compressor 1. The electric compressor 1 can be activated satisfactorily.

  Here, the high-frequency noise generated from the electric compressor 1 is generally unfamiliar. Further, when the traveling engine of the hybrid vehicle is stopped (or at a low speed), the traveling engine noise is low. For this reason, when the electric compressor 1 is started simultaneously with the start of the cooling fan 8 when the traveling engine is stopped, the noise generated from the cooling fan 8 (graph d in FIG. 6) as shown in the graph c in FIG. Since the rise of the reference) is slow, the passenger can hear extremely high-frequency noise (metal sound) generated from the electric compressor 1.

  That is, when the electric compressor 1 is activated simultaneously with the activation of the cooling fan 8 when the traveling engine of the hybrid vehicle is stopped, the high-frequency noise generated from the electric compressor 1 is distorted by the noise of the traveling engine. There is no (masking).

  On the other hand, according to the present embodiment, the noise generated from the electric compressor 1 (graph f in FIG. 7) is started to start the electric compressor 1 after a certain period t has elapsed after the cooling fan 8 starts blowing air. Is referred to by the noise generated from the cooling fan 8 (see graph e in FIG. 7). For this reason, the uncomfortable feeling by the noise given to a passenger | crew can be reduced.

It is a block diagram showing a schematic structure of one embodiment of a cooling system for vehicles concerning the present invention. It is a block diagram which shows the electrical schematic structure of the cooling system for vehicles of the above-mentioned embodiment. It is a flowchart which shows the control processing of the air-conditioner ECU of FIG. It is a timing chart for demonstrating schematic operation | movement of the cooling system for vehicles of the above-mentioned embodiment. It is a graph for demonstrating the change of the refrigerant | coolant pressure of the above-mentioned embodiment. It is a graph for demonstrating noise. It is a graph for demonstrating the noise of the above-mentioned embodiment.

Explanation of symbols

2a ... inverter, 3 ... pressure sensor, 10 ... air conditioner ECU,
11 ... Engine ECU, 11a ... Fan drive circuit,
10a ... air conditioner switch, 6 ... temperature sensor,
13 ... Vehicle speed sensor, 14 ... Water temperature sensor.

Claims (1)

An electric compressor (1) for compressing the refrigerant;
A cooler (2) for cooling the high-pressure refrigerant discharged from the electric compressor;
A decompressor (4) for decompressing the refrigerant discharged from the cooler;
A cooling heat exchanger (5) for cooling the air by evaporating the refrigerant decompressed by the decompressor; and
An electric blower (8) for blowing air to the cooler to cool the cooler, and a vehicle refrigeration cycle apparatus comprising:
A refrigeration cycle apparatus for vehicles, comprising control means (10) for controlling the electric compressor so as to start operation of the electric compressor after a certain period of time has elapsed after starting the electric blower.

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