JPH09295510A - Vehicle air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a car air conditioner that is able to secure a sufficiently high cooling capacity even in time of low engine speed and low output power, and also to obtain the specified cooling capacity on the whole driving area of an engine as well. SOLUTION: In a car air conditioner being composed of constituting a refrigerant circuit by connecting a compressor, a condenser, an expansion means and an evaporator to be driven by a traveling engine in this order, at least more than one unit of auxiliary compressors 7 are connected together in parallel with the said compressor via an on-off valve opening or closing a pipeline leading to these compressors, while a controller 14 operating these auxiliary compressors to be turned on or off according to request cooling capacity of rotational frequency of the traveling engine is installed there, through which a shortage of refrigerant circulation value in time of low output of the engine is prevented from occurring. In addition, the auxiliary compressors 7 are driven by a battery power source 9, thereby reducing the extent of engine load.

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 having a plurality of compressors.

[0002]

2. Description of the Related Art FIG. 2 shows a system diagram of a general automobile air conditioner (hereinafter referred to as a car air conditioner). In FIG. 2, 1 is a compressor for compressing a gas refrigerant, 2 is a condenser for cooling and liquefying the refrigerant with air, 3 is a throttle for decompressing, 4 is an evaporator for evaporating and vaporizing the refrigerant, and the compressor 1 is an engine. Directly driven by a crankshaft 5 through a belt 51 and a clutch 6.

During operation of the conventional car air conditioner described above, the gas refrigerant compressed by the compressor 1 which is directly driven by the engine 5 is cooled by the cooling air in the condenser 2 and radiates heat to be condensed and liquefied. This liquid refrigerant is decompressed by the throttle 3, then evaporated and vaporized by the evaporator 4, and in this process heat is taken from the air in the vehicle interior to cool it. This cools the vehicle interior. The refrigerant vaporized in the evaporator 4 is sucked into the compressor 1.

[0004]

In the above car air conditioner, the rotational force of the compressor 1 is obtained from the engine 5 via the clutch 6. Therefore, when the engine speed is lower than usual, such as in the idling state of the engine 5, the refrigerant circulation amount is also smaller than usual, so that the refrigerant circuit system is extremely low in maximum cooling capacity. It becomes the cooling capacity. When the vehicle is parked outdoors for a long time in the hot sun of summer, the temperature inside the vehicle compartment becomes extremely high. To cope with this, rapid cooling operation is required.

However, when the passenger compartment temperature is high, there is a case where a person cannot enter the passenger compartment, and even if the engine is operated in such a case, the cooling capacity is insufficient due to the low rotation speed, and the passenger compartment temperature is lowered. Is hard to fall.

An object of the present invention is to provide a car air conditioner capable of obtaining a sufficiently high cooling capacity even when the engine speed is low and at a low rotation speed and a low output, and a required cooling capacity is obtained in the entire operating range of the engine. To do.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the gist of the means is to provide a compressor driven by an engine for traveling, a condenser, an expansion means, and an evaporator. In a vehicle air conditioner configured by connecting in this order to form a refrigerant circuit, at least one or more auxiliary compressors are connected in parallel with the compressor via an on-off valve that opens and closes a pipe line to the auxiliary compressor, An air conditioner for a vehicle, comprising: a controller for operating the auxiliary compressor on / off according to a required cooling capacity or a rotational speed of the engine for traveling.

According to the above means, when the rotational speed of the main compressor driven by the engine is low and the amount of refrigerant circulation is insufficient to obtain the required cooling state, such as immediately after the engine is started or when idling. In response to a command from the controller, the auxiliary compressor is operated and the on-off valve that opens and closes the pipeline of the auxiliary compressor is opened.

As a result, the shortage of the refrigerant circulation amount of the main compressor is replenished, and the required cooling temperature is maintained.

When the engine speed and output increase and the main compressor reaches the required speed, the controller stops the auxiliary compressor and closes the on-off valve. As a result, the normal cooling operation using only the main compressor is performed.

By operating or stopping the auxiliary compressor as described above, the vehicle interior temperature can be always maintained at the required cooling temperature in the entire operating range of the engine.

In the above means, preferably, the auxiliary compressor is driven by a motor having a battery as a power source. With this configuration,
The drive of the auxiliary compressor can be separated from the engine output system when the engine output is low, and the engine load can be reduced when the output is low.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIG. FIG. 1 is a system diagram of an automobile air conditioner (abbreviated as car air conditioner) according to an embodiment of the present invention.

In FIG. 1, reference numeral 5 is a running engine, 1 is a main compressor which is directly driven by the engine 5 via a clutch 6 and a belt 51, 2 is a condenser for cooling and liquefying a refrigerant by air, and 3 is a decompressor. A throttle 4 for use is an evaporator for evaporating and evaporating the refrigerant.

Reference numeral 7 is an auxiliary compressor for compressing the gas refrigerant, 10 is a motor for driving the auxiliary compressor 7, and 9 is a battery as a power source for the motor 9.
The auxiliary compressor 7 is provided in parallel with the main refrigerant line 21 to the main compressor 1, that is, is provided in the sub-refrigerant line 22 that is connected from the suction side of the main compressor 1 to the discharge side by bypassing the suction side. ing. Reference numeral 8a is an opening / closing valve A provided on the discharge side of the auxiliary compressor 7 of the auxiliary refrigerant line 22, and 8b is an opening / closing valve B provided on the suction side of the auxiliary compressor 7.

Reference numeral 14 is a controller, which is a room temperature setting device 1.
1 from the vehicle interior temperature setting signal, the room temperature sensor 12 from the vehicle interior temperature detection signal, the engine speed sensor 13
The detection signals of the number of revolutions of the engine 5 are input from respectively.
Based on the input signals, the controller 14 sends an opening control signal to the opening / closing valve A8a and the opening / closing valve B8b provided in the sub-refrigerant pipeline 22, and an operation control signal to the motor 10 for driving the auxiliary compressor 7, respectively. Output. Further, the room temperature setting device 11 is set with a vehicle interior temperature required to obtain comfortable cooling.

In the car air conditioner configured as described above, the controller 14 compares the vehicle interior temperature T detected by the room temperature sensor 12 with the set temperature To set in the room temperature setting device 11, and Temperature deviation ΔT = T−T
o is within a certain allowable value, that is, the temperature inside the vehicle is in a comfortable cooling state, and the detected value N of the engine speed is the required speed No of the main compressor 1 (main compressor 1
When the vehicle interior temperature is equal to or higher than the rotational speed at which the vehicle interior temperature can reach the set temperature To, that is, when the main compressor 1 alone is operating to sufficiently cool the vehicle interior, the opening / closing operation is performed. Both the valve A8a and the on-off valve B8b are closed and the motor 10 is stopped.

As a result, the auxiliary compressor 7 is not operated, and the cooling operation similar to the conventional one shown in FIG. 2 is performed. That is, the gas refrigerant compressed by the main compressor 1 directly driven by the engine 5 is cooled by the cooling air in the condenser 2 and radiates heat to be condensed and liquefied.

This liquid refrigerant is decompressed by the throttle 3, then evaporated and vaporized by the evaporator 4, and in this process heat is taken from the air in the passenger compartment to cool it. This cools the vehicle interior. The refrigerant vaporized in the evaporator 4 is the main compressor 1
Inhaled.

The temperature deviation ΔT becomes larger than the allowable value, that is, the vehicle compartment temperature T becomes higher than the comfortable cooling temperature range, and the engine rotational speed N is higher than the required rotational speed No of the main compressor 1. When it becomes smaller, that is, when the main compressor 1 alone cannot provide the required vehicle interior air conditioning, such as when the engine is running at low speed and at low output,
The controller 14 determines from the comparison result of the temperature deviation ΔT and the rotation speed that the above state is present, and the on-off valve A8
Both a and the on-off valve B8b are opened, the motor 10 is started, and the auxiliary compressor 7 is started and operated.

As a result, the circulation amount of the refrigerant is increased when the engine is operating at a low speed or at a low output, and the shortage of the circulation amount of the refrigerant due to only the operation of the main compressor 1 is replenished.

Since the operation of the auxiliary compressor 7 compensates for the temporary shortage of the circulating amount of the refrigerant, it is sufficient to operate the auxiliary compressor 7 by the motor 10 using the battery 9 as a power source as in this embodiment. Is. As a result, an increase in engine load for driving the auxiliary compressor 7 is avoided.

[0023]

The present invention is configured as described above.
According to the present invention, even when the engine speed or output is low, such as during idling, it is possible to obtain a greater refrigerant circulation amount and cooling capacity than conventional ones. Therefore, by operating or stopping the auxiliary compressor, the vehicle interior temperature can be maintained at the required cooling temperature in the entire operating range of the engine.

According to the second aspect of the invention, since the driving power for the auxiliary compressor can be obtained from the battery power source when the engine output is low, a temporary shortage of the refrigerant amount can be achieved without increasing the engine load. Can be supplemented.

[Brief description of drawings]

FIG. 1 is a system diagram of a vehicle air conditioner according to an embodiment of the present invention.

FIG. 2 is a system diagram showing a conventional air conditioner.

[Explanation of symbols]

 1 Main Compressor 2 Condenser 4 Evaporator 5 Engine 7 Auxiliary Compressor 8a Open / close valve A 8b Open / close valve B 9 Battery 10 Motor 14 Controller 21 Main Refrigerant Pipeline 22 Sub Refrigerant Pipeline

Claims (2)

[Claims] 1. A vehicle air conditioner in which a compressor driven by a running engine, a condenser, an expansion means, and an evaporator are connected in this order to form a refrigerant circuit, and at least one compressor is arranged in parallel with the compressor. Connect more than one auxiliary compressor through an on-off valve that opens and closes a pipe to this auxiliary compressor, and install a controller that turns the auxiliary compressor on and off according to the required cooling capacity or the engine speed for running. A vehicle air conditioner characterized by being provided. 2. The auxiliary compressor is driven by a battery-powered motor.
The air conditioner for vehicles according to any one of the preceding claims.