CN113834237B - Vehicle heat pump air conditioning system, control method and vehicle - Google Patents

Abstract

The invention provides a heat pump air-conditioning system for a vehicle, a control method and a vehicle, relating to the field of automobiles, capable of avoiding vibration and noise caused by wide-range adjustment of an electronic expansion valve under specific working conditions. The system includes: a main circuit, on which a second solenoid valve and an electronic expansion valve are arranged, the inlet port of the electronic expansion valve communicates with the main circuit, and the outlet port of the electronic expansion valve communicates with the second solenoid valve The inlet port is connected; the first branch is provided with a first electromagnetic valve; the controller is configured to control the opening and closing of the first electromagnetic valve according to the cooling and heating conditions and the ambient temperature, and according to the heat pump The rotation speed of the compressor of the system controls the opening and closing of the second electromagnetic valve, so that the electronic expansion valve works under the target working condition that the flow of coolant flowing through it is stable.

Description

Heat pump air conditioning system for vehicle, control method and vehicle

technical field

The invention relates to the field of automobiles, in particular to a heat pump air-conditioning system for a vehicle, a control method and a vehicle.

Background technique

The electronic expansion valve is a common component of the heat pump system of the vehicle, and the electronic expansion valve may vibrate under certain working conditions and generate noise. In order to solve this problem, the vibration isolation of the electronic expansion valve is usually carried out at present, so as to reduce the abnormal sound and noise, or avoid some specific working conditions through post-calibration.

Due to the frequent update of car models, in the existing car production and debugging process, each car must go through the production and debugging process, which takes a lot of time and manpower; especially when it comes to the adjustment of the car heat pump system, due to the heat pump system The electronic expansion valve needs vibration isolation or post-calibration to reduce noise. Therefore, in the process of debugging it, it is necessary to simulate a variety of environments that are prone to vibration and noise, which is extremely inconvenient.

In the prior art, there is a device that uses a capillary tube combined with an electronic expansion valve to widen the adjustment range of the cooling capacity of the throttling device through the adjustment and switching of different circuits. However, it cannot adjust the electronic expansion valve according to specific working conditions. It is also impossible to accurately control the abnormal sound and noise of the electronic expansion valve even if targeted adjustments are made.

Contents of the invention

An object of the first aspect of the present invention is to provide a vehicle heat pump air-conditioning system to avoid vibration and noise caused by wide-range adjustment of the electronic expansion valve under specific working conditions.

A further object of the present invention is to increase the adaptability of the electronic expansion valve in the automobile heat pump.

An object of the second aspect of the present invention is to provide a control method for a vehicle heat pump air-conditioning system, which simplifies the vibration and noise debugging steps of the heat pump system during vehicle testing.

It is an object of the third aspect of the present invention to provide a vehicle capable of avoiding vibration and noise of the heat pump system.

In particular, the present invention provides a heat pump regulation system for vehicles with stage regulation, including:

The main circuit is provided with a second solenoid valve and an electronic expansion valve, the inlet port of the electronic expansion valve communicates with the main circuit, and the outlet port of the electronic expansion valve communicates with the inlet port of the second solenoid valve ;

The first branch is provided with a first solenoid valve;

a controller, configured to control the opening and closing of the first electromagnetic valve according to the cooling and heating conditions and the ambient temperature, and control the opening and closing of the second electromagnetic valve according to the compressor speed of the heat pump system, so as to The electronic expansion valve is made to work under the target working condition that the flow of coolant flowing through it is stable.

Further, the controller is configured to control the second solenoid valve to open when the compressor speed is within a preset speed range, and to control the second solenoid valve to open when the compressor speed reaches or exceeds the upper limit of the preset speed range. value closes the second solenoid valve.

Further, the controller is configured to control the first solenoid valve to close when the ambient temperature is within a first preset temperature range under cooling conditions, and to control the first electromagnetic valve to close when the ambient temperature is greater than the first preset temperature range. Open the first solenoid valve when the upper limit of the temperature range;

The controller is configured to control the opening of the first solenoid valve when the ambient temperature is within a second preset temperature range under heating conditions, and to control the first electromagnetic valve to open when the ambient temperature is greater than the second preset temperature range The upper limit value closes the first solenoid valve.

Any temperature value within the first preset temperature range is greater than any temperature value within the second preset temperature range.

Further, the controller is configured to close the first solenoid valve when the ambient temperature is lower than the lower limit of the first preset temperature range under the cooling condition;

The controller is configured to open the first electromagnetic valve when the ambient temperature is lower than the lower limit of the second preset temperature range under the heating condition.

Further, a first capillary is also provided on the first branch, the inlet of the first capillary communicates with the inlet of the electronic expansion valve, and the outlet of the first capillary communicates with the second solenoid valve. The outlet port of the second solenoid valve is connected in parallel; the two ends of the second solenoid valve are also connected in parallel with a second branch, and the second branch includes a second capillary.

In particular, the present invention also provides a control method for a vehicle heat pump air conditioning system, using the vehicle heat pump conditioning system to obtain the vehicle's cooling and heating conditions, ambient temperature and compressor speed;

Control the opening and closing of the first solenoid valve of the heat pump system according to the cooling and heating conditions and the ambient temperature, and control the opening and closing of the second solenoid valve of the heat pump system according to the compressor speed, so as to The electronic expansion valve of the heat pump system is made to work under the target working condition that the flow of cooling liquid flowing through it is stable.

Further, when the speed of the compressor is within a preset speed range, the second solenoid valve is opened, and when the speed of the compressor reaches or exceeds the upper limit of the preset speed range, the second electromagnetic valve The solenoid valve is closed.

Further, when the ambient temperature is within a first preset temperature range under cooling conditions, the first solenoid valve is closed, and when the ambient temperature is greater than the upper limit of the first preset temperature range value, the first solenoid valve is opened;

Under the heating condition, and the ambient temperature is within the second preset temperature range, the first solenoid valve is opened, and when the ambient temperature is greater than the upper limit value of the second preset temperature range , the first solenoid valve is closed;

Any temperature value within the first preset temperature range is greater than any temperature value within the second preset temperature range.

Further, under the cooling condition, and the ambient temperature is lower than the lower limit of the first preset temperature range, the first solenoid valve is closed;

Under the heating condition and the ambient temperature is lower than the lower limit of the second preset temperature range, the first electromagnetic valve is opened.

In particular, the present invention also provides a car, including the heat pump air-conditioning system for a car.

The first solenoid valve and the second solenoid valve in the vehicle heat pump air-conditioning system provided by the present invention can make the electronic expansion valve work under the target working condition that the flow of coolant flowing through it is stable under the control of the controller , so that the electronic expansion valve is always maintained in a safe adjustment range, reducing the noise generated by the electronic expansion valve.

Further, the present invention uses a capillary tube as the first branch and the second branch of the auxiliary regulating electronic expansion valve, and the starting ends of the first branch and the second branch are connected to the first end and the second end of the electronic expansion valve respectively. , the ends of the first branch and the second branch are connected to the end of the second solenoid valve, so the present invention can use the first branch and the main circuit to adjust the overall coolant flow, and also use the second The branch circuit provides the minimum flow, thereby avoiding the noise of the electronic expansion valve on the basis of maintaining the flow rate of the electronic expansion valve, and at the same time prolonging the service life of the electronic expansion valve.

Furthermore, the controller in the present invention can adjust the solenoid valve according to the ambient temperature, thereby adjusting the refrigerant flow rate, and expanding the adjustment range of the heat pump system.

Those skilled in the art will be more aware of the above and other objects, advantages and features of the present invention according to the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the attached picture:

Fig. 1 is a schematic diagram of the system composition of a heat pump regulating system for an automobile in which refrigerant moves in a first direction according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of the system composition of a heat pump regulating system for an automobile in which the refrigerant moves in the second direction according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of a control method for a first solenoid valve according to one or more embodiments of the present invention;

Fig. 4 is a schematic diagram of a method for controlling a second solenoid valve according to one or more embodiments of the present invention.

Reference signs:

1- Electronic expansion valve;

21 - the first solenoid valve;

22 - the second solenoid valve;

31 - the first branch;

32 - the second branch;

41 - the first capillary;

42 - Second capillary.

Detailed ways

Fig. 1 is a system configuration diagram of an automotive heat pump regulating system according to an embodiment of the present invention. The heat pump regulation system for vehicles with segment regulation may generally include a refrigerant circuit, an electronic expansion valve 1, a first solenoid valve 21, a second solenoid valve 22, a first branch circuit 31 and a second branch circuit 32, and the refrigerant circuit The circuit is used in a heat pump air-conditioning system, and a coolant circulates inside. The electronic expansion valve is arranged on the refrigerant circuit for throttling the refrigerant circuit; the second solenoid valve 22 is arranged on the refrigerant at the outlet end of the electronic expansion valve 1 On the circuit, it is used to regulate the refrigerant flow in the refrigerant circuit; the refrigerant circuit is also connected in parallel with a first branch 31 and a second branch 32, wherein the inlet of the first branch 31 is connected to the inlet of the electronic expansion valve 1 In the refrigerant circuit, the outlet of the first branch 31 is connected to the second solenoid valve 22 ; the second branch 32 is connected in parallel with the second solenoid valve, and the first solenoid valve 21 is also arranged on the first branch 31 .

More specifically, in this embodiment, the flow direction of the refrigerant is used as the naming basis of the inlet port and the outlet port, the port where the refrigerant flows in is named as the inlet port, and the port where the refrigerant flows out is named as the outlet port. According to the structural diagram shown in FIG. 1 , it can be seen that the flow direction of the refrigerant in the present invention is from right to left in the figure.

Both the first branch 31 and the second branch 32 in this embodiment use capillary tubes, which can assist the electronic expansion valve 1 to throttle in the refrigerant circuit, increase the adaptability of the electronic expansion valve 1, and avoid specific working conditions. Vibration and noise caused by wide range adjustment of electronic expansion valve 1 under normal conditions.

More specifically, the capillary used in the first branch 31 is the first capillary 41 , and the capillary used in the second branch 32 is the second capillary 42 .

In this embodiment, in order to control the first solenoid valve 21 and the second solenoid valve 22, a controller is also included, and the controller is coupled to the electronic expansion valve 1, the first solenoid valve 21 and the second solenoid valve 22 to adjust the opening and closing of the valve body The controller is also coupled to the compressor to obtain the compressor speed, and the temperature sensor to obtain the ambient temperature; the controller can adjust the flow rate of the electronic expansion valve 1 in the entire system by controlling the first solenoid valve 21 and the second solenoid valve 22 operating conditions.

Specifically, the controller is configured to control the opening and closing of the first electromagnetic valve according to the cooling and heating working conditions and the ambient temperature, and control the opening and closing of the second electromagnetic valve according to the compressor speed of the heat pump system. , so that the electronic expansion valve works under the target operating condition of a stable flow of coolant flowing through it.

The aforementioned target operating conditions are operating conditions that can maintain the electronic expansion valve 1 in a quiet state.

More specifically, for the above controller, the controller is configured to control the second electromagnetic valve to open when the compressor speed is within a preset speed range, and to control the second electromagnetic valve to open when the compressor speed reaches or exceeds the preset speed range. When the upper limit of the speed range is set, the second electromagnetic valve is closed.

More specifically, the controller is configured to control the first solenoid valve 21 to close when the ambient temperature is within a first preset temperature range under cooling conditions, and when the ambient temperature is greater than the first opening the first solenoid valve 21 at the upper limit of the preset temperature range;

The controller is configured to control the opening of the first solenoid valve when the ambient temperature is within a second preset temperature range under heating conditions, and to control the first electromagnetic valve to open when the ambient temperature is greater than the second preset temperature range The upper limit value closes the first solenoid valve.

Any temperature value within the first preset temperature range is greater than any temperature value within the second preset temperature range.

More specifically, the controller is configured to close the first solenoid valve 21 when the ambient temperature is lower than the lower limit of the first preset temperature range under the cooling condition;

The controller is configured to open the first electromagnetic valve when the ambient temperature is lower than the lower limit of the second preset temperature range under the heating condition.

The above-mentioned first preset temperature range and the second preset temperature range are both artificially set numerical ranges. In a specific implementation scenario, the above-mentioned first preset temperature range is below 35°C, and the above-mentioned second preset temperature range The range is below 10°C.

In this embodiment, the refrigerant circuit refers to the circuit through which the refrigerant runs in a heat pump system, and generally includes a condenser, an evaporator, and a compressor, which are connected in series through copper pipes to form a circuit. The electronic expansion valve 1 in this embodiment plays the role of throttling in this circuit, reducing the saturated liquid under the condensing pressure in the condenser to the evaporation pressure and evaporation temperature after throttling treatment, and at the same time adjusts the flow rate according to the change of the load. The flow rate of refrigerant in the evaporator.

Regarding the electronic expansion valve 1 in this embodiment, when the refrigerant flows through the electronic expansion valve 1, the flow section suddenly shrinks, the fluid flow speed increases, and the pressure drops, thereby achieving the functions of regulating the flow rate, controlling the degree of superheat and the evaporation liquid level. Specifically, when the refrigerant enters the valve core from the bottom of the electronic expansion valve 1, the pressure is transmitted upwards through the balance hole of the valve core. Since the upper and lower sections of the valve core are equal, the additional operating force generated by the pressure difference is offset. In the same way, when the refrigerant enters from the side port, the refrigerant passes through the balance hole of the spool to finally achieve pressure balance. The electronic expansion valve 1 in the general sense is composed of three parts: the controller, the actuator and the sensor. The electronic expansion valve 1 shown in Figure 1 only refers to the actuator. In fact, only this part cannot complete the control function. The electronic expansion valve 1 The core hardware of the controller is a single-chip microcomputer. The sensor of the electronic expansion valve 1 usually adopts a thermocouple or a thermal resistance, or adopts a pressure sensor. The electronic expansion valve 1 in this embodiment adjusts the flow rate of the refrigerant entering the evaporator, and then controls the target degree of superheat, so as to ensure the economical and stable operation of the system.

In this embodiment, the first branch 31 and the second branch 32 are actually used as regulating branches of the loop. As we all know, the capillary itself has a certain throttling function, so the system in this embodiment can expand the electronic expansion valve 1 on the basis of the original electronic expansion valve 1 and maintain the adjustment range of the electronic expansion valve 1. scope of application. In this embodiment, no valve is provided on the second branch 32 , the purpose of which is to maintain the minimum flow rate when the first solenoid valve 21 and the second solenoid valve 22 are adjusted.

In one embodiment, the electronic expansion valve 1 does not have a regulating area where the flow rate is less than 15%. According to the above description of the principle of the electronic expansion valve 1, it can be deduced that the electronic expansion valve 1 is prone to friction of internal moving elements when the refrigerant flow rate is insufficient, which reduces the service life of the electronic expansion valve 1, so this embodiment The second branch 32 can provide minimum flow support for the electronic expansion valve 1, thereby avoiding its noise on the basis of maintaining the flow rate of the electronic expansion valve, and at the same time can improve the electronic expansion by avoiding the friction of the components in the electronic expansion valve 1 Service life of valve 1.

In yet another embodiment, the electronic expansion valve 1 does not have an adjustment region where the flow rate is less than 20%.

In yet another embodiment, the electronic expansion valve 1 does not have an adjustment region where the flow rate is less than 30%.

In this embodiment, since the first port of the controller is connected to the temperature sensor to obtain the ambient temperature, the second port of the controller is also connected to the compressor to obtain the compressor speed. The first port and the second port mentioned above are not specific, and may be physical ports or software ports.

Fig. 2 shows that in another embodiment, the flow direction of the refrigerant is from left to right in the figure, a schematic diagram of the system composition of the heat pump regulating system for automobiles, the connection of each component in this embodiment is the same as that shown in Fig. 1 The system is the same.

In this embodiment, the controller is a single-chip microcomputer or PLC provided separately.

In yet another embodiment, the controller can also be the controller of the above-mentioned electronic expansion valve 1. Correspondingly, the controller of the electronic expansion valve 1 is not only connected to the sensor that it should be connected to, but also connected to the above-mentioned temperature sensor to obtain the environment temperature, and also connect the compressor above to get the compressor speed.

It can be understood that the ambient temperature in the above embodiments refers to the temperature of the air around the circuit, which is determined by the specific installation location of the temperature sensor. Generally speaking, the temperature sensor is installed far away from the condenser, evaporator and compressor. to avoid being directly affected by the operation of the condenser, evaporator and compressor.

In one embodiment, the third port in the controller corresponding to the first port is connected to the first solenoid valve 21 , and the fourth port in the controller corresponding to the second port is connected to the second solenoid valve 22 . The "correspondence" in this embodiment refers to the establishment of a connection relationship between ports. This connection relationship can be a hardware connection, or a software module in the controller to perform a logical connection between ports. This logical connection is realized by establishing a corresponding relationship between data, which belongs to the content well known to those skilled in the art.

Fig. 3 and Fig. 4 have shown a kind of heat pump adjustment method of segmental adjustment for automobiles, using the heat pump adjustment system of segmental adjustment in the above embodiment, the controller obtains the ambient temperature and then adjusts the output according to the ambient temperature The first signal of the first solenoid valve 21; the controller outputs the second signal for adjusting the second solenoid valve 22 according to the compressor speed after obtaining the speed of the compressor.

In one embodiment, after the controller acquires the ambient temperature, the numerical value of the ambient temperature is judged, and then the first signal for adjusting the first solenoid valve 21 is output; after the controller acquires the rotational speed of the compressor, the The rotational speed is numerically judged, and then the second signal for adjusting the second electromagnetic valve 22 is output.

When the controller obtains the ambient temperature, it obtains the working state of the heat pump in advance, and then adjusts the first solenoid valve 21 according to the working state of the heat pump. The reason why the first electromagnetic valve 21 is connected with the working state of the heat pump and the ambient temperature is to adjust the flow rate of the coolant in the first branch 31 in the above embodiment. The coolant in the first branch 31 has not undergone electronic expansion in fact. The throttling treatment of the valve 1, but only through the throttling effect of the capillary in the first branch 31, is an auxiliary means to expand the working range of the electronic expansion valve 1, so the adjustment of the first solenoid valve 21 means Regulates the coolant flow, which in turn regulates the power of the heat pump.

Therefore, if the heat pump is in the heating working state, after the controller acquires the ambient temperature, if the ambient temperature is less than or equal to the first set temperature, the first solenoid valve 21 will remain open; A solenoid valve 21 is closed; if the heat pump is in the cooling working state, after the controller acquires the ambient temperature, if the ambient temperature is lower than the second set temperature, the first solenoid valve 21 is closed; if the ambient temperature is greater than or equal to the second set temperature and less than is equal to the third set temperature, the first electromagnetic valve 21 remains closed; if the ambient temperature is greater than the third set temperature, the first electromagnetic valve 21 is opened.

In the above adjustment strategy for the first solenoid valve 21, on the one hand, when heating, the ambient temperature increases, which means that the power of the circuit gradually increases. When the ambient temperature is below the first set temperature, the flow rate needs to be increased to quickly For heating, when the temperature is above the first set temperature, the power of the circuit has reached the requirement, the refrigerant is sufficient, and there is no need to continue to increase the flow of refrigerant; on the other hand, when cooling, the ambient temperature increases, which means that the circuit The power gradually increases. When the surrounding environment is above the third set temperature, additional refrigerant flow is required to further increase the cooling power. When the ambient environment is between the second set temperature and the third set temperature and below the second set temperature, There is no need to increase the cooling power.

In one embodiment, the above-mentioned first set temperature, second set temperature and third set temperature are 10°C, 25°C, and 35°C, respectively.

As shown in Table 1, it shows a specific control strategy for the first electromagnetic valve 21:

Table 1

When the speed of the compressor is less than or equal to the first set speed, the second solenoid valve 22 remains open; when the speed of the compressor is greater than the first set speed, the second solenoid valve 22 is closed.

In one embodiment, the first set rotation speed is 5000r/min.

In the above control strategy for the second solenoid valve 22, the rotation speed of the compressor is positively correlated with its power. The higher the rotation speed of the compressor, the higher its power, and it also means that it needs more refrigerant. Therefore, the first The second electromagnetic valve 22 is in an open state, and the electronic expansion valve 1 plays a major throttling role, and since the electronic expansion valve 1 is adjustable, it can adapt to more and more refrigerant demands; and when the compressor speed is greater than the first setting At constant speed, in order to maintain smooth circulation of the refrigerant, the second solenoid valve 22 is no longer open, but closed. At this time, the throttling of the entire circuit is realized through the electronic expansion valve 1 and capillary in series, throttling The capacity is stronger than the case of only the electronic expansion valve 1.

As shown in Table 2, it shows the specific control strategy for the second solenoid valve 22:

Table 2

In a specific application scenario, the heat pump is set to be in the heating working state, the ambient temperature range is 0°C to 15°C, and the specific temperature change nodes are 0°C, 10°C, 15°C, 10°C, and 5°C. The change range of the compressor speed is 0~6000r/min, the specific speed change nodes are 0r/min, 3000r/min, 6000r/min, 3000r/min, 1000r/min, and the change of the ambient temperature and the change of the compressor speed is linear synchronization, the first solenoid valve 21 starts at 0°C in this application scenario, and then the first solenoid valve 21 remains open at 0°C to 10°C, and at 10°C to 15°C and 15°C to The first solenoid valve 21 is closed at 10°C, and resumes its open state at 10°C to 5°C; the second solenoid valve 22 remains open at 0r/min to 3000r/min in this application scenario, and remains open at 3000r/min to It remains open at 5000r/min, closes at 5000r/min～6000r/min and 6000r/min～5000r/min, and resumes open at 5000r/min～3000r/min and 3000r/min～1000r/min.

The present invention also provides an automobile using the heat pump regulating system for the automobile.

So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (9)

1. A heat pump air conditioning system for a vehicle, comprising:

the electronic expansion valve is arranged in the main loop, and the inlet end of the electronic expansion valve is communicated with the main loop;

the first branch is communicated with the inlet end of the electronic expansion valve and is provided with a first electromagnetic valve;

the controller is arranged to control the first electromagnetic valve to be opened and closed according to the refrigeration and heating conditions and the ambient temperature, and control the second electromagnetic valve to be opened and closed according to the rotating speed of the compressor of the heat pump system, so that the electronic expansion valve works under the target working condition that the flow of the cooling liquid flowing through the electronic expansion valve is stable;

the first branch is also provided with a first capillary tube, the inlet end of the first capillary tube is communicated with the inlet end of the electronic expansion valve, and the outlet end of the first capillary tube is communicated with the outlet end of the second electromagnetic valve; and two ends of the second electromagnetic valve are also connected with a second branch in parallel, and the second branch comprises a second capillary tube.

2. The heat pump air conditioning system for vehicles of claim 1, wherein the controller is configured to control the second solenoid valve to be opened when the compressor rotation speed is within a preset rotation speed range, and to close the second solenoid valve when the compressor rotation speed reaches or is greater than an upper limit value of the preset rotation speed range.

3. The vehicle heat pump air conditioning system according to claim 1, wherein the controller is configured to control the first solenoid valve to close under a cooling condition and when the ambient temperature is within a first preset temperature range, and to open the first solenoid valve when the ambient temperature is greater than an upper limit value of the first preset temperature range;

the controller is configured to control the first electromagnetic valve to be opened when the ambient temperature is within a second preset temperature range and close the first electromagnetic valve when the ambient temperature is greater than an upper limit value of the second preset temperature range under the heating condition;

any temperature value in the first preset temperature range is larger than any temperature value in the second preset temperature range.

4. The vehicle heat pump air conditioning system of claim 1, wherein the controller is configured to close the first solenoid valve when the ambient temperature is less than a lower limit of the first preset temperature range in the cooling condition;

the controller is configured to open the first electromagnetic valve under the heating working condition and when the ambient temperature is smaller than the lower limit value of the second preset temperature range.

5. A control method of a heat pump air conditioning system for a vehicle based on any one of claims 1 to 4, characterized by comprising the steps of:

obtaining the refrigeration and heating conditions, the ambient temperature and the rotating speed of a compressor of the vehicle;

and controlling the opening and closing of a first electromagnetic valve of the heat pump system according to the refrigerating and heating conditions and the ambient temperature, and controlling the opening and closing of a second electromagnetic valve of the heat pump system according to the rotating speed of the compressor, so that an electronic expansion valve of the heat pump system works under the target working condition that the flow of the cooling liquid flowing through the electronic expansion valve is stable.

6. The control method of a heat pump air conditioning system for vehicles according to claim 5, wherein the second electromagnetic valve is opened when the compressor rotation speed is within a preset rotation speed range, and the second electromagnetic valve is closed when the compressor rotation speed reaches or is greater than an upper limit value of the preset rotation speed range.

7. The control method of a heat pump air conditioning system for vehicles according to claim 5, wherein, in a cooling condition, when the ambient temperature is within a first preset temperature range, the first electromagnetic valve is closed, and when the ambient temperature is greater than an upper limit value of the first preset temperature range, the first electromagnetic valve is opened;

under the heating condition, when the environment temperature is within a second preset temperature range, the first electromagnetic valve is opened, and when the environment temperature is greater than the upper limit value of the second preset temperature range, the first electromagnetic valve is closed;

any temperature value in the first preset temperature range is larger than any temperature value in the second preset temperature range.

8. The control method of a vehicle heat pump air conditioning system according to claim 5, wherein in the cooling condition, and when the ambient temperature is less than the lower limit value of the first preset temperature range, the first electromagnetic valve is closed;

and under the heating working condition, when the ambient temperature is less than the lower limit value of the second preset temperature range, the first electromagnetic valve is opened.

9. An automobile comprising a heat pump air conditioning system for a vehicle as claimed in claims 1-4.

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