A roof-mounted thermal control system for new energy buses

Abstract

The present invention relates to a roof-mounted thermal control system for new energy buses. The thermal control system includes a roof-mounted air-conditioning thermal control subsystem, a battery thermal control subsystem, and a motor electric control subsystem that are interconnected. The roof-mounted air-conditioning thermal control subsystem includes a compressor, an air-conditioning evaporator, a plate heat exchanger, and an air-conditioning condenser. The compressor is connected to the a interface of the four-way valve successively through a pressure relief valve and a high-pressure switch. The c interface of the four-way valve is connected to the compressor through a low-pressure switch and a gas-liquid separator in another loop. The b interface of the four-way valve is connected to the sight glass after passing through the air-conditioning evaporator and the plate heat exchanger respectively. The sight glass is connected to the d interface of the four-way valve after passing through a dryer and the air-conditioning condenser successively. The air-conditioning condenser is also connected to the battery thermal control subsystem and the motor electric control subsystem respectively through cooling hoses. Compared with the prior art, the present invention has the advantages of not occupying space and having a low failure rate, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive thermal control, and particularly to a roof-mounted thermal control system for new energy buses. Background Art

[0002] Currently, the battery thermal management technology adopted by new energy buses mainly uses the technical solution of an independent air-conditioning unit. This technical solution separately equips a set of air-conditioning units for the batteries of new energy buses, cools the batteries in summer and heats the batteries in winter, so as to ensure the stability of the battery temperature. However, this technical solution requires the whole vehicle to reserve additional installation space for the air-conditioning. Therefore, not only does the occupied space increase, but also the weight of the whole vehicle increases, which is not conducive to the overall streamlined design, energy conservation and consumption reduction of new energy buses.

[0003] The air-conditioning is an important energy-consuming accessory of new energy buses, which will seriously affect the endurance and riding comfort of the whole vehicle. Currently, a set of heat pump air-conditioning is adopted for the refrigeration and heating of new energy buses, which results in that the air-conditioning cannot reach the highest energy efficiency when refrigerating or heating, especially the energy efficiency is lower during heating operation: because the hot air of the air-conditioning is blown out from the air duct at the top of the vehicle, the density of the hot air is low and it converges to the upper part of the carriage, which causes the temperature of the lower part of the carriage to be low, not only affecting the comfort of passengers, but also increasing the energy consumption of the air-conditioning, and further affecting the endurance of the whole vehicle. Therefore, the deficiencies of the existing new energy buses in the carriage and battery thermal management technologies are as follows: (1) The cost of independently setting up the battery thermal management unit is high, and additional installation space is required, which will increase the weight of the whole vehicle and is not conducive to the energy conservation and consumption reduction of new energy buses. (2) The heat pump type electric air-conditioning is adopted for the refrigeration and heating of the carriage. Since it needs to take into account both refrigeration and heating, the air-conditioning cannot reach the highest energy efficiency, and the hot air of the air-conditioning is blown out from the roof air duct, which is not conducive to vehicle energy conservation and riding comfort. (3) The thermal management of the whole vehicle carriage and batteries are separate independent devices, and the centralized thermal management of the whole vehicle is not realized, which is easy to cause energy waste. Summary of the Invention

[0004] The purpose of the present invention is to provide a roof-mounted thermal control system for new energy buses to overcome the defects existing in the above-mentioned prior art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A roof-mounted thermal control system for a new energy bus, the thermal control system comprising an interconnected roof-mounted air-conditioning thermal control subsystem, a battery thermal control subsystem and a motor electronic control subsystem, the roof-mounted air-conditioning thermal control subsystem comprising a compressor, an air-conditioning evaporator, a plate heat exchanger and an air-conditioning condenser, the compressor sequentially passes through a pressure relief valve and a high-pressure switch and is connected to an a interface of a four-way valve, the c interface of the four-way valve sequentially passes through a low-pressure switch and a gas-liquid separator in another loop and is connected to the compressor, the b interface of the four-way valve passes through the air-conditioning evaporator and the plate heat exchanger respectively and is connected to a sight glass, the sight glass sequentially passes through a dryer and the air-conditioning condenser and is connected to the d interface of the four-way valve, and the air-conditioning condenser is further connected to the battery thermal control subsystem and the motor electronic control subsystem through a cooling hose.

[0007] Furthermore, a first solenoid valve is connected to the connection position between the air-conditioning evaporator and the b interface of the four-way valve, and a first electronic expansion valve is connected to the connection position between the air-conditioning evaporator and the sight glass.

[0008] Furthermore, a second solenoid valve is connected to the connection position between the plate heat exchanger and the b interface of the four-way valve, and a second electronic expansion valve is connected to the connection position between the plate heat exchanger and the sight glass.

[0009] Furthermore, the motor electronic control subsystem includes an ATS, a first water pump, a motor electronic control all-in-one controller and a first water tank which are connected in series in a closed loop. The air-conditioning condenser is connected to the vehicle thermal control return water port and the vehicle thermal control water outlet of the motor electronic control subsystem through the cooling hose and through the third solenoid valve respectively.

[0010] Furthermore, the battery thermal control subsystem includes a power battery pack, a fourth solenoid valve, a second water pump, a second water tank and the plate heat exchanger which are connected in series in a closed loop, and the air-conditioning condenser is directly connected to the air-conditioning water outlet and the air-conditioning water inlet of the battery thermal control subsystem through the cooling hose.

[0011] Furthermore, the compressor is a positive displacement compressor, a rotary compressor or a scroll compressor.

[0012] Furthermore, the connecting pipes in the ceiling-mounted air-conditioning thermal control subsystem are refrigerant pipelines.

[0013] Furthermore, the air-conditioning evaporator adopts a parallel-flow air-conditioning evaporator, and the air-conditioning condenser adopts a tube-belt air-conditioning condenser.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) Since the system of the present invention integrates the three parts of the thermal control system and shares some components, it does not occupy additional installation space and is beneficial to the design of the entire vehicle.

[0016] (2) The system of the present invention shares components such as a compressor and a condenser, which are inexpensive, and is easy to maintain because it is installed in the roof-mounted air conditioner of a bus.

[0017] (3) The system of the present invention adopts an independently developed control program for the electronic expansion valve, which can accurately adjust the cooling capacity according to the changes in the battery load from time to time, achieve constant control of the water temperature, and keep the battery at the optimal operating temperature.

[0018] (4) The system of the present invention has a wide range of applications because it integrates the three-part thermal control system: different types of batteries have different cooling requirements, and can achieve a cooling capacity adjustment range of 2 to 10 kW.

[0019] (5) Rapid cooling of the system of the present invention: for the first startup, especially under high temperature, the vehicle compartment and the battery can be cooled quickly, and the cooling capacity is reasonably allocated: the cooling capacity demand of the battery is prioritized, and the cooling capacity provided to the vehicle compartment and the battery is reasonably allocated during vehicle operation.

[0020] (6) The system of the present invention has high reliability: it solves the problems of oil return difficulty and low pressure protection under harsh working conditions, and ensures the reliability of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0022] In the figure, 1 is a compressor, 2 is an air-conditioning evaporator, 3 is a plate heat exchanger, 4 is an air-conditioning condenser, 5 is a pressure relief valve, 6 is a high-pressure switch, 7 is a four-way valve, 8 is a low-pressure switch, 9 is a gas-liquid separator, 10 is a sight glass, 11 is a dryer, 12 is a cooling hose, 13 is a first solenoid valve, 14 is a first electronic expansion valve, 15 is a second solenoid valve, 16 is a second electronic expansion valve, 17 is an ATS, 18 is a first water pump, 19 is a motor electronic control all-in-one controller, 20 is a first water tank, 21 is a third solenoid valve, 22 is a power battery pack, 23 is a fourth solenoid valve, 24 is a second water pump, 25 is a second water tank, and 26 is a refrigerant pipeline. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0024] Example

[0025] like Figure 1 The figure shows the overall system structure diagram of the present invention. The thermal control system includes interconnected overhead air-conditioning thermal control subsystems. The connecting pipelines in the overhead air-conditioning thermal control subsystems use refrigerant pipelines 26, battery thermal control subsystems and motor electronic control subsystems. The overhead air-conditioning thermal control subsystem includes a compressor 1, an air-conditioning evaporator 2, a plate heat exchanger 3 and an air-conditioning condenser 4. The compressor 1 passes through a pressure relief valve 5 and a high-pressure switch 6 in sequence and is connected to an a interface of a four-way valve 7. The c interface of the four-way valve 7 passes through a low-pressure switch 8 and a gas-liquid separator 9 in sequence through another loop and is connected to the compressor 1. The b interface of the four-way valve 7 passes through the air-conditioning evaporator 2 and the plate heat exchanger 3 respectively and is connected to a sight glass 10. The sight glass 10 passes through a dryer 11 and The air conditioning condenser 4 is connected to the d interface of the four-way valve 7, and the air conditioning condenser 4 is also connected to the battery thermal control subsystem and the motor electronic control subsystem through the cooling hose 12. Among them, the connection position between the air conditioning evaporator 2 and the b interface of the four-way valve 7 is also connected with a first solenoid valve 13, the connection position between the air conditioning evaporator 2 and the sight glass 10 is also connected with a first electronic expansion valve 14, the connection position between the plate heat exchanger 3 and the b interface of the four-way valve 7 is also connected with a second solenoid valve 15, and the connection position between the plate heat exchanger 3 and the sight glass 10 is also connected with a second electronic expansion valve 16. The motor electronic control subsystem includes an ATS (Automatic The air conditioning condenser 4 is connected to the vehicle thermal control water return port and the vehicle thermal control water outlet of the motor and electronic control subsystem through the cooling hose 12 and the third solenoid valve 21 respectively, corresponding to the upper and lower circles of the motor and electronic control subsystem in the figure. The battery thermal control subsystem includes a power battery pack 22, a fourth solenoid valve 23, a second water pump 24, a second water tank 25 and a plate heat exchanger 3 connected in series in a closed loop. The air conditioning condenser 4 is directly connected to the air conditioning water outlet and the air conditioning water inlet of the battery thermal control subsystem through the cooling hose 12, corresponding to the upper and lower circles of the battery thermal control subsystem in the figure.

[0026] In this embodiment, the compressor 1 is a positive displacement, rotary, scroll compressor; through the four processes of compression, exhaust, expansion, and intake, it realizes the function of compressing and driving the refrigerant; the air conditioner condenser 4 is of a tube-and-fin structure; it can realize the transformation of gas or steam into liquid, and transfer the heat in the tubes to the nearby air in a very fast manner; the air conditioner evaporator 2 is of a parallel flow type. The low-temperature condensed liquid passes through the evaporator, and can exchange heat with the outside air, vaporize and absorb heat to achieve the refrigeration effect; the plate heat exchanger 3 is of a tube-and-fin structure and is a highly efficient heat exchanger formed by stacking corrugated metal sheets; all electronic expansion valves are electronic temperature and pressure sensing solenoid valves, which use the electrical signals generated by the regulated parameters to control the voltage or current applied to the expansion valve, and thus achieve the purpose of regulating the liquid supply volume.

[0027] The pressure relief valve 5 can automatically open and close according to the working pressure of the system, and is generally installed on the equipment or pipeline of a closed system to protect the safety of the system. When the pressure in the equipment or pipeline exceeds the set pressure of the safety valve, it will automatically open to relieve pressure, ensuring that the pressure of the medium in the equipment and pipeline is below the set pressure, protecting the equipment and pipeline, and preventing accidents. The high and low pressure switch is a pressure switch that detects the refrigerant pressure in the system. Its main function is to detect whether the system pressure is normal. When the pressure exceeds the allowable range, the pressure switch acts and transmits the abnormal signal to the air conditioner controller. After processing, the air conditioner controller will stop the operation of the refrigeration system and display the fault. The low-pressure protection detects that the suction pressure in the system is lower than 0.05 MPA and the switch acts. Its function is to prevent the compressor from being damaged due to the operation of the system without refrigerant. The high-pressure protection detects that the discharge pressure is higher than 3.5 MPA and the switch acts. Its function is to prevent the compressor from being damaged or the pipeline from bursting due to excessive refrigerant in the system and poor heat dissipation of the condenser. The gas-liquid separator 9 is installed at the inlet of the compressor; its function is to prevent the compressor inlet from sucking in liquid refrigerant and causing liquid hammer damage to the compressor, and at the same time has a liquid storage function. The dryer 11 functions to absorb the moisture in the refrigeration system, block the impurities in the system so that they cannot pass through, and prevent ice blockage and dirt blockage in the refrigeration system pipeline. Since the most easily blocked part of the system is the capillary tube (or expansion valve), the dryer filter is usually installed between the condenser and the capillary tube (or expansion valve). The sight glass 10 is installed on the outlet pipeline of the dryer 11. Since the dryer 11 can absorb moisture, the color of the indicating paper inside the sight glass 10 is normally green. Once the dryer 11 fails to absorb moisture, the indicating paper turns yellow. At this time, the dryer 11 needs to be replaced. After replacing the dryer 11 and evacuating, the color of the indicating paper returns to the normal color - green.

[0028] The four-way valve 7 is a control valve with four oil ports. The four-way valve is an essential component in refrigeration equipment. Its working principle is as follows: when the solenoid valve coil is de-energized, the pilot spool moves leftward under the drive of the compression spring on the right side. High-pressure gas enters the capillary tube and then enters the right-end piston chamber. On the other hand, the gas in the left-end piston chamber is discharged. Due to the pressure difference between the two ends of the piston, the piston and the main spool move leftward, making the exhaust pipe communicate with the outdoor unit connection pipe, and the other two connection pipes communicate, forming a refrigeration cycle. All control solenoid valves are solenoid valves with the ability to control the on-off of the refrigerant and coolant pipelines.

[0029] In addition, in this embodiment, the material of the water tank is aluminum, the refrigerant pipeline 26 is an aluminum copper pipe, and its burst pressure meets more than 5 times the operating pressure. All electronic expansion valves adopt the external balance view mode. The maximum working temperature of the sight glass 10 is 80 °C, and the maximum working pressure is 35 bar. The pressure relief valve 5 relieves pressure > 31 bar. The refrigerant used is R134a - tetrafluoroethane (CH2FCF3), boiling point: -26.5 °C, freezing temperature -101.1 °C.

[0030] In this embodiment, as Figure 1 shown, it can be divided into different working conditions. The following is a description of various working conditions:

[0031] When the ambient temperature is high in summer and the vehicle's power battery has a demand for refrigeration capacity, in the form of being connected in parallel with the air conditioner evaporator, the refrigerant coming out of the air conditioner condenser is divided into two paths. One path enters the evaporator through the electronic expansion valve to cool the air inside the vehicle; the other path enters the plate heat exchanger through the electronic expansion valve to cool the heat-conducting fluid. Finally, they converge and return to the compressor to form a refrigerant cycle. After the heat-conducting fluid is cooled in the plate heat exchanger under the action of the water pump, it returns to the inside of the battery pack to release cold energy, forming a heat-conducting fluid cycle. This solution can allow the air conditioner to distribute the refrigeration capacity to the power battery by itself, provided that the refrigeration capacity demand of the passenger compartment is met;

[0032] At this time, the inlet and outlet solenoid valves and the air conditioner condenser control solenoid valve of the vehicle's thermal management control are closed throughout the process. The battery thermal management control solenoid valve, the air conditioner condensation control solenoid valve, and the plate heat exchanger solenoid valve are open throughout the process;

[0033] When the vehicle's power battery has no demand for refrigeration capacity, the compressor can work alone to refrigerate the passenger compartment. When the battery needs refrigeration, the air conditioner can flexibly control the opening and closing of the plate heat exchanger control solenoid valve.

[0034] When the ambient temperature is low in winter, the vehicle's thermal management control solenoid valve, the air conditioner condenser control solenoid valve, and the battery thermal management control solenoid valve are opened, and the plate heat exchanger control solenoid valve is closed. At this time, the motor and electronic control thermal management and the battery thermal management can jointly provide heat for defrosting the air conditioner condenser, and at the same time can assist in providing warm air for the carriage.

[0035] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A roof-mounted thermal control system for new energy buses, characterized in that, The thermal control system comprises an overhead air conditioning thermal control subsystem, a battery thermal control subsystem and a motor electronic control subsystem which are interconnected. The overhead air conditioning thermal control subsystem comprises a compressor (1), an air conditioning evaporator (2), a plate heat exchanger (3) and an air conditioning condenser (4). The compressor (1) passes through a pressure relief valve (5) and a high-pressure switch (6) in sequence and is connected to an a interface of a four-way valve (7). The c interface of the four-way valve (7) passes through a low-pressure switch (8) and a gas-liquid separator (9) in sequence through another loop and is connected to the compressor (1). The b interface of the four-way valve (7) passes through the air conditioning evaporator (2) and the plate heat exchanger (3) respectively and is connected to a sight glass (10). The sight glass (10) passes through a dryer (11) and the air conditioning condenser (4) in sequence and is connected to the d interface of the four-way valve (7). The air conditioning condenser (4) is also connected to the battery thermal control subsystem and the motor electronic control subsystem respectively through a cooling hose (12). The motor electronic control subsystem comprises an ATS (17), a first water pump (18), a motor electronic control all-in-one controller (19) and a first water tank (20) which are connected in series in a closed loop; the air conditioning condenser (4) is connected to a vehicle thermal control water return port and a vehicle thermal control water outlet of the motor electronic control subsystem through the cooling hose (12) and respectively through a third solenoid valve (21); The battery thermal control subsystem comprises a power battery pack (22), a fourth solenoid valve (23), a second water pump (24), a second water tank (25) and the plate heat exchanger (3) which are connected in series in a closed loop, and the air conditioning condenser (4) is directly connected to the air conditioning water outlet and the air conditioning water inlet of the battery thermal control subsystem through the cooling hose (12).

2. The overhead thermal control system for a new energy bus according to claim 1, wherein A first solenoid valve (13) is also connected to the connection position between the air-conditioning evaporator (2) and the b interface of the four-way valve (7), and a first electronic expansion valve (14) is also connected to the connection position between the air-conditioning evaporator (2) and the sight glass (10).

3. The overhead thermal control system for a new energy bus according to claim 1, wherein A second solenoid valve (15) is also connected to the connection position between the plate heat exchanger (3) and the b interface of the four-way valve (7), and a second electronic expansion valve (16) is also connected to the connection position between the plate heat exchanger (3) and the sight glass (10).

4. The overhead thermal control system for a new energy bus according to claim 1, wherein, The compressor (1) is a positive displacement compressor, a rotary compressor or a scroll compressor.

5. The overhead thermal control system for a new energy bus according to claim 1, wherein, The connecting pipeline in the ceiling-mounted air-conditioning thermal control subsystem adopts a refrigerant pipeline (26).

6. The overhead thermal control system for a new energy bus according to claim 1, wherein, The air-conditioning evaporator (2) is a parallel-flow air-conditioning evaporator, and the air-conditioning condenser (4) is a tube-belt air-conditioning condenser.

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