An air source heat pump system for a pure electric bus and a control method thereof

Abstract

The application provides a pure electric bus air source heat pump system and relates to the technical field of air conditioners. The system comprises one common circulation pipeline and multiple heat circulation pipelines, a four-way valve and a condenser are arranged on the common circulation pipeline, a floor heat dissipation unit is arranged on each heat circulation pipeline, the condenser is connected with each floor heat dissipation unit through the four-way valve, the floor heat dissipation unit comprises a heat exchanger and a floor electronic expansion valve which are connected through a pipeline, a temperature sensor is arranged at the return air inlet of each floor heat dissipation unit, and the opening degree of the corresponding floor electronic expansion valve is adjusted based on the return air temperature data collected by each temperature sensor. The application increases the multiple floor heat dissipation units distributed on the bus floor, controls the electronic expansion valve of each floor heat dissipation unit through the sub-controller of the floor heat dissipation unit, selectively controls the opening and closing of the floor electronic expansion valve, simultaneously adjusts the opening degree, and improves the heating comfort of passengers.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioning, and in particular relates to an air source heat pump system for a pure electric bus and a control method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Compared to traditional internal combustion engine and hybrid buses, existing pure electric buses generally utilize a cooling system plus a PTC heating system because they lack the ability to utilize waste heat from the engine. PTC electric heating can be used for heating in winter. Heating with PTC electric heating equipment can be divided into two methods: direct heating of the interior air by the PTC, and heating of a liquid by the PTC before heating the interior air. However, due to the very low efficiency of PTC electric heating, heating in winter requires a high amount of electricity, significantly reducing the range of pure electric buses. Using a heat pump air conditioning system in pure electric buses can effectively improve efficiency in heating mode, thereby increasing range.

[0004] However, the inventors found that the heat pump air-conditioning system used in pure electric buses in the existing technology is composed of only a heat dissipation unit placed on the top of the vehicle. Its hot air first enters the air duct through the top air-conditioning outlet, and then blows toward the passengers from the air duct outlet. The air supply distance is long and the heat loss is large. In addition, the hot air is sent from top to bottom toward the passenger's head, and the air supply resistance is also large. At the same time, the passenger's head is hot and the feet are cold, and the human body's heating comfort is not very strong. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides an air source heat pump system for a pure electric bus and a control method thereof. On the basis of the original pure electric bus roof heat dissipation unit, a plurality of floor heat dissipation units distributed on the bus floor are added. The plurality of floor heat dissipation units constitute a heat circulation pipeline. The electronic expansion valve of each floor heat dissipation unit is controlled by a sub-controller of the floor heat dissipation unit, and the opening and closing of the floor electronic expansion valve are selectively controlled and the opening degree is adjusted at the same time, breaking the discomfort caused by the warm air blowing towards the passenger's head during traditional car heating, achieving energy-saving effects, and improving the heating comfort of the passengers.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides an air source heat pump system for a pure electric bus.

[0008] A pure electric bus air source heat pump system includes a common circulation pipeline and multiple heat circulation pipelines, the common circulation pipeline is provided with a four-way valve and a condenser, each of the heat circulation pipelines is provided with a floor cooling unit, the condenser is connected to each floor cooling unit through a four-way valve; the floor cooling units are dispersedly arranged on the bus floor, each of the floor cooling units includes an air outlet, a return air outlet, a heat exchanger and a floor electronic expansion valve arranged on the floor, the heat exchanger and the floor electronic expansion valve are connected by a pipeline, the heat exchanger is connected to a heat dissipation fan, the heat dissipation fan is used to blow warm air out from the air outlet; a temperature sensor is provided at the return air outlet of each floor cooling unit, and the opening of the corresponding floor electronic expansion valve is adjusted based on the return air temperature data collected by each temperature sensor.

[0009] Preferably, the four-way valve is provided with a C connection end, a D connection end, an S connection end and an E connection end, the condenser is connected to the C connection end of the four-way valve, and each of the heat exchangers is connected to the E connection end of the four-way valve; a compressor is connected between the D connection end and the S connection end of the four-way valve.

[0010] Preferably, each of the floor cooling units further comprises a sub-controller, which is electrically connected to the floor electronic expansion valve and the cooling fan respectively, and is used to control the opening and closing, the opening degree of the floor electronic expansion valve and the opening and closing of the cooling fan.

[0011] Preferably, the common circulation pipeline also includes a main controller, which is electrically connected to the condensing fan, four-way valve and compressor respectively, and is used to control the compressor, four-way valve and condenser; the main controller and sub-controllers are connected via CAN communication.

[0012] Preferably, the temperature sensor is used to feed back the return air temperature data to the sub-controller, and the sub-controller transmits the return air temperature data to the main controller.

[0013] Preferably, it also includes a cold circulation pipeline, which includes a top electronic expansion valve and an evaporator located on the top of the vehicle and connected by pipelines, the top electronic expansion valve is connected to the condenser, the evaporator is connected to the E connection end of the four-way valve, and the evaporator is connected to the evaporator. The evaporator is connected to an evaporator fan, and the evaporator fan is used to blow cold air out from the top of the bus; the main controller is electrically connected to the top electronic expansion valve and the evaporator fan, respectively, and is used to control the opening and closing, the opening degree of the top electronic expansion valve, and to control the opening and closing of the evaporator fan.

[0014] Preferably, a condensing fan is connected to the condenser, and the condensing fan is used to dissipate heat from the condenser.

[0015] A second aspect of the present invention provides a control method for an air source heat pump system of a pure electric bus.

[0016] A method for controlling an air source heat pump system of a pure electric bus includes a heating control method, wherein the heating control method includes the following steps:

[0017] The main controller sends instructions to the sub-controllers of the floor cooling units that need to start the heating function;

[0018] The sub-controller controls the opening and closing of the corresponding floor electronic expansion valve according to the instructions sent by the main controller;

[0019] The main controller turns on the compressor, four-way valve, and condenser. The high-temperature refrigerant is input from the exhaust port of the compressor to the S connection of the four-way valve, and then output to the floor cooling unit with the heating function turned on through the E connection of the four-way valve.

[0020] The cooling fan of the floor cooling unit blows warm air out from the bus floor. At the same time, the temperature sensor detects the return air temperature data of the floor cooling unit and feeds the return air temperature data back to the sub-controller. The sub-controller transmits the return air temperature data to the main controller via CAN communication.

[0021] The high-temperature refrigerant after heat dissipation is input into the condenser from the floor electronic expansion valve of the floor cooling unit, condensed by the condenser, and then returns to the C connection end of the four-way valve, and is input into the suction end of the compressor through the D connection end of the four-way valve;

[0022] The main controller compares the return air temperature data fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller based on the comparison result;

[0023] The sub-controller controls the floor electronic expansion valve accordingly according to the opening instruction and opening and closing instruction of the floor electronic expansion valve sent by the main controller.

[0024] Preferably, the main controller compares the return air temperature data fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller according to the comparison result, specifically:

[0025] If the return air temperature data is the same as the set heating temperature, the opening of the floor electronic expansion valve is reduced, and the main controller sends the instruction of reducing the opening of the floor electronic expansion valve to the corresponding sub-controller;

[0026] If the return air temperature is lower than the set heating temperature, the floor electronic expansion valve will be opened wider, and the master controller will send the command to increase the floor electronic expansion valve opening to the corresponding sub-controller;

[0027] Among them, the increase in the opening degree of the floor electronic expansion valve is proportional to the temperature difference between the return air temperature and the set heating temperature.

[0028] Preferably, the refrigeration control method further comprises the following steps:

[0029] The total controller sends a command to close all floor electronic expansion valves and a command to open the top electronic expansion valve to the top electronic expansion valve;

[0030] The sub-controller controls all floor electronic expansion valves to be closed according to the command sent by the total controller;

[0031] The top electronic expansion valve is in an open state according to the command sent by the total controller;

[0032] The total controller controls the compressor, the four-way valve and the condenser to be opened, low-temperature refrigerant is input from the exhaust end of the compressor to the S connection end of the four-way valve, output to the condenser through the C connection end of the four-way valve, and reaches the top electronic expansion valve and the evaporator inlet through the condenser, and cold air is blown out from the top of the vehicle through the evaporator fan;

[0033] Low-temperature refrigerant output from the evaporator inlet is input to the E connection end of the four-way valve, and reaches the suction end of the compressor from the D connection end of the four-way valve.

[0034] The above one or more technical solutions have the following beneficial effects:

[0035] 1. The present application provides a pure electric bus air source heat pump system and its control method, which breaks the original bus heating mode and avoids the discomfort caused by the direct blowing of warm air to the head of passengers during the heating of traditional pure electric buses. Based on the original pure electric bus roof heat dissipating unit, multiple floor heat dissipating units distributed on the bus floor are added, and the heating of the bus is carried out through the multiple floor heat dissipating units, so that the warm air is blown to the soles of the passengers, the heating comfort of the passengers is enhanced, and the experience of the passengers that the head is hot and the feet are cold during the heating in the prior art is avoided.

[0036] 2. Compared with the traditional roof heat pump air conditioning heating, the warm air enters the air duct through the roof air outlet, and then is blown to the passengers from the air outlet. This traditional air supply method has a long air supply distance, large heat loss, and large resistance of hot air from top to bottom to the passengers. In the present application, the heat obtained by the heat pump unit is directly sent to the soles of the passengers through each floor heat dissipating unit, and the thermal efficiency is high.

[0037] 3. The multiple floor heat dissipating units constitute a heat circulation pipeline, the heat circulation pipeline and the public circulation pipeline jointly constitute a heat circulation system, the electronic expansion valve of each floor heat dissipating unit is controlled by the sub-controller of the floor heat dissipating unit, the floor electronic expansion valve is selectively controlled to be opened and closed, and the opening degree is adjusted at the same time, so that the energy-saving effect is realized.

[0038] 4. Each floor cooling unit of the present invention includes a temperature sensor, which collects the return air temperature. The sub-controller feeds the return air temperature back to the main controller, which compares the return air temperature with the set heating temperature. The main controller controls the opening of each floor electronic expansion valve based on the comparison result, thus realizing the air outlet control of each floor cooling unit. This is very user-friendly, energy-saving and provides passengers with a better riding experience.

[0039] 5. Compared with the PTC heating water or coolant heating method, the heat obtained in the present invention is directly used to heat the air in the vehicle, without the need for heat exchange through a plate heat exchanger or other form of heat exchanger, thus avoiding energy loss in the intermediate heat exchanger. The system is simpler and more reliable, with low cost and high heat exchange efficiency.

[0040] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0042] Figure 1 This is the overall system structure diagram of the first embodiment.

[0043] Figure 2 This is a structural diagram of the refrigeration control system of the first embodiment.

[0044] Figure 3 This is a structural diagram of the control system of the floor cooling unit of the first embodiment. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0046] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0047] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0048] Example 1

[0049] This embodiment discloses an air source heat pump system for a pure electric bus.

[0050] like Figure 1As shown, an air source heat pump system for a pure electric bus includes a common circulation pipeline and multiple heat circulation pipelines, the common circulation pipeline is provided with a four-way valve and a condenser, each of the heat circulation pipelines is provided with a floor cooling unit, the condenser is connected to each floor cooling unit through a four-way valve; the floor cooling units are dispersedly arranged on the bus floor, each of the floor cooling units includes an air outlet, a return air outlet, a heat exchanger and a floor electronic expansion valve arranged on the floor, the heat exchanger and the floor electronic expansion valve are connected through a pipeline, the heat exchanger is connected to a heat dissipation fan, the heat dissipation fan is used to blow warm air out from the air outlet; a temperature sensor is provided at the return air outlet of each floor cooling unit, and the opening of the corresponding floor electronic expansion valve is adjusted based on the return air temperature data collected by each temperature sensor.

[0051] Unlike the heat pump air-conditioning system used in traditional pure electric buses, which consists of only a heat dissipation unit placed on the roof of the vehicle, this embodiment provides an air source heat pump system for pure electric buses. On the basis of the original heat dissipation unit on the roof of the pure electric bus, multiple floor heat dissipation units distributed on the floor of the bus are added. The multiple floor heat dissipation units respectively constitute multiple heat circulation pipelines. The electronic expansion valve of each floor heat dissipation unit is controlled by the sub-controller of the floor heat dissipation unit, and the opening and closing of the floor electronic expansion valve are selectively controlled and the opening degree is adjusted at the same time. This breaks the traditional heating in the car, where warm air blows towards the passenger's head, causing the passenger's head to be hot and the feet to be cold, thereby achieving energy saving effects and improving the heating comfort of the passengers.

[0052] At the same time, compared with the prior art in which hot air is sent from top to bottom toward the passenger's head and there is a problem of large air supply resistance, this embodiment uses the floor cooling unit to deliver warm air, and the warm air is supplied from bottom to top, with small air supply resistance.

[0053] In this embodiment, the heat exchanger may be a tube-fin type or fish-scale type heat exchanger, or a microchannel heat exchanger core may be used to achieve heat exchange.

[0054] Furthermore, the four-way valve is provided with a C connection end, a D connection end, an S connection end and an E connection end. The condenser is connected to the C connection end of the four-way valve, and each heat exchanger is connected to the E connection end of the four-way valve; a compressor is connected between the D connection end and the S connection end of the four-way valve.

[0055] The four-way valve switches the system between cooling and heating modes. In cooling mode, the high-temperature, high-pressure refrigerant discharged from the compressor enters the S connection of the four-way valve and then enters the condenser through the C connection. Simultaneously, the low-temperature, low-pressure refrigerant returned from the evaporator enters the E connection of the four-way valve and then enters the compressor through the D connection. In heating mode, the high-temperature, high-pressure refrigerant discharged from the compressor enters the S connection of the four-way valve and then enters the floor cooling units through the E connection. The floor cooling units then converge and reach the condenser. The low-temperature, low-pressure refrigerant returned from the condenser enters the C connection of the four-way valve and then enters the compressor through the D connection.

[0056] like Figure 1 and Figure 3 As shown, in order to realize the control of multiple floor cooling units, each floor cooling unit in this embodiment further includes a sub-controller, which is electrically connected to the floor electronic expansion valve and the cooling fan, respectively, and is used to control the opening and closing, the opening degree of the floor electronic expansion valve, and the opening and closing of the cooling fan.

[0057] In order to control the condenser, four-way valve and compressor on the common circulation pipeline, and to control multiple sub-controllers at the same time, the common circulation pipeline also includes a master controller, which is electrically connected to the condensing fan, four-way valve and compressor respectively, and is used to control the compressor, four-way valve and condenser; the master controller and sub-controllers are connected via CAN communication.

[0058] In order to collect the real-time temperature of the floor cooling unit, the floor cooling unit also includes a temperature sensor. The floor cooling unit includes a return air vent and an air outlet arranged on the floor. The temperature sensor is installed at the return air vent of the floor cooling unit to collect return air temperature data.

[0059] The temperature controller feeds back the collected return air temperature data to the sub-controller, and the sub-controller then transmits the return air temperature data to the main controller.

[0060] like Figure 1 and Figure 2 As shown, in order to realize the refrigeration cycle, the pure electric bus air source heat pump system of this embodiment also includes a cold circulation pipeline, which includes a top electronic expansion valve and an evaporator located on the top of the vehicle and connected by pipelines. The top electronic expansion valve is connected to the condenser, and the evaporator is connected to the E connection end of the four-way valve. The evaporator is connected to an evaporating fan, which is used to blow cold air out from the top of the bus; the main controller is electrically connected to the top electronic expansion valve and the evaporating fan respectively, and is used to control the opening and closing, the opening degree of the top electronic expansion valve and the opening and closing of the evaporating fan.

[0061] Furthermore, a condensing fan is connected to the condenser, and the condensing fan is used to dissipate heat from the condenser.

[0062] Example 2

[0063] This embodiment discloses a control method for an air source heat pump system of a pure electric bus.

[0064] A method for controlling an air source heat pump system of a pure electric bus includes a heating control method, which includes the following steps:

[0065] The main controller sends instructions to the sub-controllers of the floor cooling units that need to start the heating function;

[0066] The sub-controller controls the opening and closing of the corresponding floor electronic expansion valve according to the instructions sent by the main controller;

[0067] The main controller turns on the compressor, four-way valve, and condenser. The high-temperature refrigerant is input from the exhaust port of the compressor to the S connection of the four-way valve, and then output to the floor cooling unit with the heating function turned on through the E connection of the four-way valve.

[0068] The cooling fan of the floor cooling unit blows warm air out from the bus floor. At the same time, the temperature sensor detects the return air temperature data of the floor cooling unit and feeds the return air temperature data back to the sub-controller. The sub-controller transmits the return air temperature data to the main controller via CAN communication.

[0069] The high-temperature refrigerant after heat dissipation is input into the condenser from the floor electronic expansion valve of the floor cooling unit, condensed by the condenser, and then returns to the C connection end of the four-way valve, and is input into the suction end of the compressor through the D connection end of the four-way valve;

[0070] The main controller compares the return air temperature data fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller based on the comparison result;

[0071] The sub-controller controls the floor electronic expansion valve accordingly according to the opening instruction and opening and closing instruction of the floor electronic expansion valve sent by the main controller.

[0072] Specifically, according to needs, the pure electric bus air source heat pump system of the present invention can operate in full heating mode and local heating mode.

[0073] In full heating mode, all floor electronic expansion valves are open, the top electronic expansion valve is closed, all heat exchangers are open, the high-temperature and high-pressure refrigerant discharged by the compressor enters each floor cooling unit, and the hot air blows towards the passengers' feet.

[0074] In local heating mode, only the electronic expansion valves and heat exchangers corresponding to the floor cooling units in the heating demand area are opened, achieving precise control of the floor cooling units, minimizing heating energy consumption and improving human comfort.

[0075] Furthermore, the main controller compares the return air temperature fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller based on the comparison result, specifically:

[0076] If the return air temperature data is the same as the set heating temperature, the opening of the floor electronic expansion valve is reduced, and the main controller sends the instruction of reducing the opening of the floor electronic expansion valve to the corresponding sub-controller;

[0077] If the return air temperature is lower than the set heating temperature, the floor electronic expansion valve will be opened wider, and the master controller will send the command to increase the floor electronic expansion valve opening to the corresponding sub-controller;

[0078] Among them, the increase in the opening degree of the floor electronic expansion valve is proportional to the temperature difference between the return air temperature and the set heating temperature.

[0079] Furthermore, a refrigeration control method is also included, and the refrigeration control method includes the following steps:

[0080] The main controller sends a command to close the floor electronic expansion valve to all sub-controllers, and sends a command to open the top electronic expansion valve to the top electronic expansion valve;

[0081] The sub-controller controls all floor electronic expansion valves to close according to the instructions sent by the main controller;

[0082] The top electronic expansion valve operates according to the instruction sent by the main control and is in the open state;

[0083] The main controller controls the start-up of the compressor, four-way valve, and condenser. The low-temperature refrigerant is input from the exhaust port of the compressor into the S connection of the four-way valve, output to the condenser through the C connection of the four-way valve, passes through the condenser to the top electronic expansion valve and the evaporator inlet, and is blown out from the top of the vehicle through the evaporator fan.

[0084] The low-temperature refrigerant from the evaporator outlet is input into the E connection end of the four-way valve, and reaches the suction end of the compressor from the D connection end of the four-way valve.

[0085] Those skilled in the art should understand that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software. Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not a limitation on the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. An air source heat pump system for a pure electric bus, characterized in that: The system comprises a common circulation pipeline and multiple heat circulation pipelines, each of which is connected to the common circulation pipeline; a four-way valve and a condenser are provided on the common circulation pipeline, and each of the heat circulation pipelines is provided with a floor cooling unit, which is dispersedly arranged on the bus floor. The floor cooling unit includes a heat exchanger and a floor electronic expansion valve connected by pipelines, and a heat dissipation fan is connected to the heat exchanger, which is used to blow warm air out of the bus floor; each floor electronic expansion valve is connected to the condenser by a pipeline, and each heat exchanger is connected to the four-way valve by a pipeline; The control method of the air source heat pump system of the pure electric bus includes a heating control method, which includes the following steps: The main controller sends instructions to the sub-controllers of the floor cooling units that need to start the heating function; The sub-controller controls the opening and closing of the corresponding floor electronic expansion valve according to the instructions sent by the main controller; The main controller turns on the compressor, four-way valve, and condenser. The high-temperature refrigerant is input from the exhaust port of the compressor to the S connection of the four-way valve, and then output to the floor cooling unit with the heating function turned on through the E connection of the four-way valve. The cooling fan of the floor cooling unit blows warm air out from the bus floor. At the same time, the temperature sensor detects the return air temperature of the floor cooling unit and feeds the return air temperature back to the sub-controller. The sub-controller transmits the return air temperature to the main controller via CAN communication. The high-temperature refrigerant after heat dissipation is input into the condenser from the floor electronic expansion valve of the floor cooling unit, condensed by the condenser, and then returns to the C connection end of the four-way valve, and is input into the suction end of the compressor through the D connection end of the four-way valve; The main controller compares the return air temperature fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller based on the comparison result; The sub-controller controls the floor electronic expansion valve accordingly according to the opening instruction and opening and closing instruction of the floor electronic expansion valve sent by the main controller.

2. The pure electric bus air source heat pump system according to claim 1, characterized in that: The four-way valve is provided with a C connection end, a D connection end, an S connection end and an E connection end. The condenser is connected to the C connection end of the four-way valve, and each of the heat exchangers is connected to the E connection end of the four-way valve; a compressor is connected between the D connection end and the S connection end of the four-way valve.

3. The pure electric bus air source heat pump system according to claim 2, characterized in that: Each of the floor cooling units further comprises a sub-controller, which is electrically connected to the floor electronic expansion valve and the cooling fan respectively, and is used to control the opening and closing, the opening degree of the floor electronic expansion valve and the opening and closing of the cooling fan.

4. The pure electric bus air source heat pump system according to claim 3, characterized in that: The common circulation pipeline also includes a main controller, which is electrically connected to the condensing fan, four-way valve and compressor respectively, and is used to control the compressor, four-way valve and condenser; the main controller and sub-controllers are connected via CAN communication.

5. The pure electric bus air source heat pump system according to claim 4, characterized in that: The floor heat dissipation unit further includes a temperature sensor, which is used to detect the return air temperature of the floor heat dissipation unit and feed back the return air temperature to the sub-controller, and the sub-controller transmits the return air temperature to the main controller.

6. The pure electric bus air source heat pump system according to claim 4, characterized in that: It also includes a cold circulation pipeline, which includes a top electronic expansion valve and an evaporator located on the top of the vehicle and connected by pipelines. The top electronic expansion valve is connected to the condenser, and the evaporator is connected to the E connection end of the four-way valve. The evaporator is connected to an evaporator fan, and the evaporator fan is used to blow cold air out from the top of the bus; the main controller is electrically connected to the top electronic expansion valve and the evaporator fan respectively, and is used to control the opening and closing, the opening degree of the top electronic expansion valve, and the opening and closing of the evaporator fan.

7. The pure electric bus air source heat pump system according to claim 6, characterized in that: The condenser is connected to a condensing fan, which is used for heat dissipation of the condenser.

8. The air source heat pump system for a pure electric bus according to claim 1, characterized in that: The main controller compares the return air temperature fed back by the sub-controller with the set heating temperature, and sends the opening and closing instructions of the floor electronic expansion valve to the sub-controller based on the comparison results. Specifically: If the return air temperature is the same as the set heating temperature, the opening of the floor electronic expansion valve is reduced, and the main controller sends the instruction of reducing the opening of the floor electronic expansion valve to the corresponding sub-controller; If the return air temperature is lower than the set heating temperature, the floor electronic expansion valve will be opened wider, and the master controller will send the command to increase the floor electronic expansion valve opening to the corresponding sub-controller; Among them, the increase in the opening degree of the floor electronic expansion valve is proportional to the temperature difference between the return air temperature and the set heating temperature.

9. The pure electric bus air source heat pump system according to claim 1, characterized in that: The invention also includes a refrigeration control method, the refrigeration control method comprising the following steps: The main controller sends a command to close the floor electronic expansion valve to all sub-controllers, and sends a command to open the top electronic expansion valve to the top electronic expansion valve; The sub-controller controls all floor electronic expansion valves to close according to the instructions sent by the main controller; The top electronic expansion valve operates according to the instruction sent by the main control and is in the open state; The main controller controls the start-up of the compressor, four-way valve, and condenser. The low-temperature refrigerant is input from the exhaust port of the compressor into the S connection of the four-way valve, output to the condenser through the C connection of the four-way valve, passes through the condenser to the top electronic expansion valve and the evaporator inlet, and is blown out from the top of the vehicle through the evaporator fan. The low-temperature refrigerant from the evaporator outlet is input into the E connection end of the four-way valve, and reaches the suction end of the compressor from the D connection end of the four-way valve.

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