JP2003034135A - Vehicle air conditioner - Google Patents

Abstract

(57) [Summary] [Problem] To make a heat exchanger inside a vehicle exhibit sufficient cooling capacity even immediately after driving a compressor. SOLUTION: After a compressor 1 is started, a driving speed of an engine is maintained at a set speed or more by a control means 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, as a vehicle air conditioner, the temperature of a refrigerant flowing through a condenser outlet side high pressure passage from a condenser outlet side of a refrigeration cycle to an inlet side of an expansion valve is detected,
There is a method in which the optimum pressure of the refrigerant flowing through the high-pressure passage is calculated from this refrigerant temperature to determine whether the actual high-pressure pressure in the high-pressure passage is higher than the optimum high pressure (Japanese Patent Laid-Open No. 7-294033). ).

[0003]

However, in the above-mentioned conventional vehicle air conditioner, when the compressor is started, it takes time to increase the refrigerant pressure on the high pressure side of the outlet, which is sufficient for the heat exchanger inside the vehicle. The cooling capacity cannot be obtained.
In particular, this problem becomes significant when the engine speed is low.

Therefore, it is an object of the present invention to provide an air conditioning system for a vehicle, which allows the heat exchanger inside the vehicle to exhibit a sufficient cooling capacity even immediately after driving the compressor.

[0005]

As a means for solving the above problems, the present invention radiates a refrigerant discharged from a compressor driven by an engine by a heat exchanger outside the vehicle and reduces the pressure by an expansion valve, In a vehicle air conditioner equipped with a refrigeration cycle in which the heat is vaporized by the heat exchanger inside the vehicle and then returned to the compressor for circulation, a control means for maintaining the drive speed of the engine at a set speed or more after the compressor is started is provided. It is provided.

Further, as a means for solving the above problems, the present invention radiates the refrigerant discharged from a compressor driven by an engine by a heat exchanger outside the vehicle, decompresses it by an expansion valve, and exchanges heat inside the vehicle. In a vehicle air conditioner having a refrigerating cycle in which the gas is vaporized by a device and then returned to the compressor for circulation, the compressor has a configuration capable of changing the discharge capacity, and is based on the drive speed of the engine after the compressor is activated. A control means for controlling the discharge capacity of the refrigerant by the compressor is provided.

With these configurations, the drive of the compressor is maintained in an appropriate state, and the pressure of the refrigerant on the outlet side of the compressor can be set to a desired high pressure so that the interior heat exchanger can exhibit a desired cooling capacity.

Pressure detecting means for detecting the pressure of the refrigerant on the high pressure side of the outlet of the compressor is provided, and the control means controls the drive speed of the engine or the pressure so that the pressure detected by the pressure detecting means becomes a set pressure. By controlling the discharge capacity of the refrigerant by the compressor, it is possible to cause the in-vehicle heat exchanger to exhibit a desired cooling capacity, as described above.

An outside blower for adjusting the amount of air blown to the outside heat exchanger is provided, and the amount of air blown by the outside blower is controlled by the control means based on the drive speed of the engine after the compressor is started. Is preferable because it is possible to adjust the amount of heat released from the refrigerant in the vehicle exterior heat exchanger and increase the amount of heat absorbed when the refrigerant passes through the vehicle interior heat exchanger.

An oil separator for separating oil contained in the refrigerant discharged from the compressor, and an oil return pipe provided with a throttle valve for returning the oil separated by the oil separator to the inlet side pipe of the compressor are provided. When the compressor is stopped by the control means,
The throttle valve may be fully closed.

CO ₂ can be used as the refrigerant.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a refrigeration cycle C of the vehicle air conditioner according to this embodiment. In the refrigeration cycle C, the refrigerant (CO ₂ is used here) discharged from the compressor 1 is passed through the oil separator 2, the vehicle exterior heat exchanger 3, the expansion valve 4, and the vehicle interior heat exchanger 5. It returns to the compressor 1 and circulates. The control device 6 drives and controls the compressor 1, the expansion valve 4, and the vehicle exterior blower 11, which will be described later.

The compressor 1 can be driven by the power of an engine (not shown). A pressure sensor 7 is provided in the outlet side pipe of the compressor 1.

The oil separator 2 separates the oil contained in the refrigerant discharged from the compressor 1 and returns it to the compressor 1 via the oil return pipe 8. The oil return pipe 8 is an inlet side pipe 9 of the exterior heat exchanger 3.
By mixing the oil, which is connected in the middle of the process and which has become high temperature and high pressure in the compressor 1, with the refrigerant flowing into the compressor 1, the liquid is completely vaporized and further brought into a superheat state. Further, a throttle valve 10 is provided in the middle of the oil return pipe 8 so that the amount of recirculated oil can be adjusted.

The exterior heat exchanger 3 is arranged in the front part of the vehicle and has a conventionally known structure suitable for condensing the refrigerant. The exterior heat exchanger 3 includes an exterior blower 11. The blower 11 for the vehicle exterior can change the air flow rate freely, and the amount of heat radiated from the refrigerant in the vehicle exterior heat exchanger 3 can be adjusted by changing the air flow rate.

The expansion valve 4 is changed by changing the opening degree.
The refrigerant pressure on the upstream side is adjusted and the refrigerant passing therethrough is depressurized.

The heat exchanger 5 inside the vehicle is arranged in the air conditioning unit 12 at the front of the vehicle and has a conventionally well-known structure for cooling and dehumidifying the air passing through the air conditioning unit 12. A blower 14 that is rotated by the drive of a blower motor 13 is disposed on the upstream side of the vehicle interior heat exchanger 5 of the air conditioning unit 12, and blows inside air or outside air into the vehicle with a predetermined air volume. Also,
An air mix door 15 is rotatably provided on the downstream side of the vehicle interior heat exchanger 5 of the air conditioning unit 12 to divert the cool air and direct one of them to the heater core 16. The heater core 1 depends on the rotational position (opening) of the air mix door 15.
The amount of air heated in 6, that is, the ratio of mixed cold air and warm air is changed, and the air is blown into the vehicle at a desired temperature.

The control device 6 operates on the basis of the value detected by the pressure sensor 7 and the like, as will be described later, the driving rotational speed of the compressor 1, the opening degree of the expansion valve 4, the amount of air blown by the exterior blower 11, or the throttle valve 10. Adjust the opening of.

Next, the operation of the vehicle air conditioner having the above-mentioned structure will be described.

First, the compressor 1 is started (step S1), and it is determined whether or not a predetermined time has passed since the start of the start (step S2). If a predetermined time has passed from the start of the compressor 1, air conditioning control is performed as usual, and if not, the engine speed is read (step S3). Then, it is determined whether or not the engine speed exceeds a preset speed (for example, 800 rpm) (step S4). If the engine speed is equal to or lower than the set speed, the refrigerant pressure rises slowly, and the cooling capacity of the in-vehicle heat exchanger 5 becomes insufficient. Therefore, the engine speed is corrected to the set speed (corrected upward) (step S5). As a result, even immediately after the compressor 1 is started, it is possible to increase the discharge capacity of the refrigerant, that is, the refrigerant pressure on the outlet side, and enhance the cooling capacity of the in-vehicle heat exchanger 5.

Further, the pressure detected by the pressure sensor 7 is read (step S6), and it is judged whether or not the detected pressure exceeds the target pressure (step S7). If the detected pressure has not reached the target pressure, the engine speed is corrected upward (step S8). However, this upward revision of the engine speed does not affect the running of the vehicle (for example, 15
00 rpm or less). This makes it possible to increase the discharge capacity of the refrigerant from the compressor 1, especially even when the vehicle is stopped or is moving at a low speed.

Further, based on the pressure detected by the pressure sensor 7 (which may be the rotational speed of the engine), the amount of air blown by the exterior blower 11 is gradually increased as the detected pressure increases ( Step S
9). This makes it possible to change the amount of heat radiated from the refrigerant in the vehicle exterior heat exchanger and increase or decrease the refrigerant pressure on the outlet side of the compressor 1.

When the compressor 1 is stopped (step S10), the throttle valve 10 provided in the middle of the oil return pipe 8 is fully closed to prevent oil from flowing back (step S11). As a result, it is possible to prevent a pressure drop due to the circulation of the refrigerant on the high pressure side (the outlet side of the compressor 1).

As described above, according to the vehicle air conditioner according to the above-described embodiment, the refrigerant pressure on the outlet side of the compressor 1 and the heat radiation amount in the vehicle exterior heat exchanger 3 are increased even in the initial stage of starting the compressor 1. By making the inside heat exchanger 5
The cooling capacity of can be improved.

In the above embodiment, the engine speed is adjusted to compensate for the lack of capacity immediately after the compressor 1 is started. However, if the compressor 1 has a configuration in which the discharge capacity can be changed, This can be dealt with by changing only the discharge capacity. That is, instead of changing the driving speed of the engine in steps S4 and S7, by changing the discharge capacity of the compressor 1, the refrigerant pressure on the outlet side of the compressor is directly increased, and the cooling capacity by the in-vehicle heat exchanger 5 is increased. May be improved.

[0027]

As is apparent from the above description, according to the present invention, after the compressor is started, the drive speed of the engine is maintained at the set speed or more, so that the desired output side of the compressor is obtained. The refrigerant pressure can be obtained,
Even after the start of operation of the compressor, the heat exchanger inside the vehicle can exhibit the desired cooling capacity.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a refrigeration cycle of a vehicle air conditioner according to the present embodiment.

FIG. 2 is a flowchart showing air conditioning control according to the present embodiment.

[Explanation of symbols]

1 ... Compressor 2 ... Oil separator 3 ... Exterior heat exchanger 4 ... Expansion valve 5 ... Inside heat exchanger 6 ... Control device 7 ... Pressure sensor 8 ... Oil return pipe 9 ... Suction side piping 10 ... throttle valve 11 ... Exterior blower

Continued front page    (72) Inventor Shinji Watanabe             3-11 Yoshikawa Industrial Park, Higashihiroshima City, Hiroshima Prefecture             In ceremony company Japan Climate Systems

Claims (6)

[Claims] 1. A refrigeration system in which refrigerant discharged from a compressor driven by an engine is radiated by a heat exchanger outside the vehicle, decompressed by an expansion valve, vaporized by a heat exchanger inside the vehicle, and then returned to the compressor for circulation. In a vehicle air conditioner having a cycle, a vehicle air conditioner is provided with a control means for maintaining a drive speed of the engine at a set speed or more after the compressor is activated. 2. A refrigeration system in which refrigerant discharged from a compressor driven by an engine is radiated by a heat exchanger outside the vehicle, decompressed by an expansion valve, vaporized by a heat exchanger inside the vehicle, and then returned to the compressor for circulation. In a vehicle air conditioner provided with a cycle, the compressor is configured to be capable of changing a discharge capacity, and after starting the compressor, a control means for controlling a discharge capacity of a refrigerant by the compressor based on a drive speed of the engine. A vehicle air conditioner characterized by being provided. 3. A pressure detecting means for detecting the refrigerant pressure on the high pressure side of the outlet of the compressor is provided, and the control means drives the engine so that the pressure detected by the pressure detecting means becomes a set pressure. Alternatively, the discharge capacity of the refrigerant by the compressor is controlled, and the vehicle air conditioner according to claim 1 or 2. 4. An exterior blower capable of adjusting the amount of air blown to the heat exchanger outside the vehicle is provided, wherein the control means drives the engine to rotate after the compressor is started or discharge capacity of refrigerant by the compressor. The air conditioner for a vehicle according to claim 1 or 2, wherein the amount of air blown by the outside blower is controlled on the basis of the above. 5. An oil separator for separating the oil contained in the refrigerant discharged from the compressor, and an oil return pipe provided with a throttle valve for returning the oil separated by the oil separator to the compressor, The vehicle air conditioner according to any one of claims 1 to 4, wherein the means is configured to fully close the throttle valve when the compressor is stopped. 6. The vehicle air conditioner according to claim 1, wherein the refrigerant is CO ₂ .