When it comes to driving in the hot summer or the cold winter, having a functioning air conditioning system in your electric vehicle (EV) is crucial for comfort and safety. But how does the air conditioning system in EVs actually work? Unlike traditional fuel-powered vehicles, EVs lack a heat source for heating and the engine’s driving force to power the compressor. In this short article, we will explore the components of the air conditioning cooling system in EVs, as well as the heating system and the control mechanisms. So, buckle up and let’s dive into the world of EV air conditioning!
Components of the Air Conditioning Cooling System in EVs
The electric compressor plays a crucial role in the air conditioning cooling system of electric vehicles (EVs). It takes in low-temperature and low-pressure gaseous refrigerant and compresses it into high-temperature and high-pressure liquid refrigerant gas. This compression process increases the temperature and pressure of the refrigerant, forming superheated gas. The compressor is controlled electronically to drive the motor, which operates the compressor through the crankshaft.
The condenser in the air conditioning system of EVs is responsible for dissipating the heat from the high-temperature and high-pressure refrigerant to the surrounding air. It uses a dedicated cooling fan to cool down the refrigerant, causing it to change from a gaseous state to a liquid state. The condenser plays a crucial role in the cooling process of the refrigerant.
The pressure sensor is an essential component in the EV air conditioning system. It helps monitor the pressure of the refrigerant and provides feedback to the control circuit. The pressure sensor ensures that the refrigerant flows at the optimal pressure, allowing for efficient cooling and operation of the system.
Electronic Expansion Valve
The electronic expansion valve is responsible for regulating the flow of refrigerant in the air conditioning system. It helps throttle and reduce the pressure of the high-temperature and high-pressure liquid refrigerant before it enters the evaporator. This process enables the cooling and depressurization of the refrigerant and controls the cooling capacity of the system.
The evaporator is where the actual cooling takes place in the air conditioning system of EVs. The low-temperature and low-pressure liquid refrigerant coming from the expansion valve absorbs a significant amount of heat from the surrounding air in the evaporator. This absorption of heat causes the refrigerant to change from a liquid to a low-temperature and low-pressure gas. The compressor then suctions this gas for compression.
Air Conditioning Hard Pipes
The air conditioning hard pipes in EVs are the tubes or pipes that transport the refrigerant throughout the cooling system. They provide a pathway for the refrigerant to flow from one component to another, ensuring the efficient operation of the system. These hard pipes are designed to withstand the high temperatures and pressures of the refrigerant.
Hoses in the EV air conditioning system are flexible tubes that connect various components together. They allow for the transfer of refrigerant, ensuring proper flow and operation of the system. Hoses need to be resistant to high temperatures and pressures to handle the refrigerant effectively.
The control circuit in the air conditioning system of EVs is responsible for managing and controlling the operation of the different components. It receives signals from various sensors, such as the pressure sensor, and generates control signals to regulate the compressor and other parts of the system. The control circuit ensures that the air conditioning system operates efficiently and optimally.
Role of the Compressor
Compression of Low-pressure Refrigerant
The compressor’s primary role is to compress low-temperature and low-pressure gaseous refrigerant. It takes in the refrigerant and increases its pressure, which also increases its temperature. This compression process remains unchanged in the state of the refrigerant.
Formation of High-temperature, High-pressure Liquid Refrigerant Gas
As the compressor compresses the refrigerant, it transforms it into high-temperature and high-pressure liquid refrigerant gas. This high-pressure state is necessary for efficient heat transfer and cooling in the air conditioning system.
During the compression process, the refrigerant undergoes a superheating process. The temperature and pressure continuously increase, resulting in superheated gas. This superheating is crucial for effective cooling and air conditioning in EVs.
Function of the Condenser
Dissipation of Heat from Refrigerant
The condenser’s main function is to dissipate the heat from the high-temperature and high-pressure refrigerant. It uses a dedicated cooling fan to transfer the heat to the surrounding air. This heat dissipation process is vital for cooling down the refrigerant and ensuring proper functioning of the air conditioning system.
Cooling down the Refrigerant
As the condenser dissipates heat, it cools down the refrigerant. The high-temperature and high-pressure refrigerant changes from a gaseous state to a liquid state, reducing its temperature and pressure. This cooling process prepares the refrigerant for further cooling in the evaporator.
Change of Refrigerant State
The condenser also facilitates the change of state of the refrigerant. It transforms the refrigerant from a gaseous state to a liquid state. This change in state is important for the refrigerant’s ability to absorb heat during the cooling process.
Understanding the Expansion Valve
Pressure Reduction of Refrigerant
The expansion valve in the air conditioning system reduces the pressure of the refrigerant. It allows the high-temperature and high-pressure liquid refrigerant to pass through and throttle, reducing its pressure before it enters the evaporator. This pressure reduction is essential for controlling the flow and cooling capacity of the refrigerant.
Regulation of Refrigerant Flow
The expansion valve regulates the flow of the refrigerant in the air conditioning system. It controls the amount of refrigerant that enters the evaporator, ensuring optimal cooling performance. By regulating the flow, the expansion valve helps maintain efficient operation of the system.
Cooling and Depressurization of the Refrigerant
As the refrigerant passes through the expansion valve, it undergoes a cooling and depressurization process. The high-temperature and high-pressure liquid refrigerant changes to a low-temperature and low-pressure liquid state. This cooling and depressurization are necessary for the refrigerant to absorb heat effectively in the evaporator.
Working of the Evaporator
Absorption of Heat from the Surrounding Air
The evaporator’s primary function is to absorb heat from the surrounding air. The low-temperature and low-pressure liquid refrigerant from the expansion valve enters the evaporator, where it comes into contact with the air. As the refrigerant absorbs heat from the air, it undergoes a change of state.
Change of Refrigerant State
As the refrigerant absorbs heat, it changes from a liquid state to a low-temperature and low-pressure gas. This change in state is crucial for the refrigerant’s ability to absorb heat effectively and facilitate the cooling process in the air conditioning system.
Suction of Gas by the Compressor
Once the refrigerant has absorbed heat and changed into a low-temperature and low-pressure gas, it is suctioned by the compressor. The compressor then compresses the gas, increasing its temperature and pressure, to continue the cooling process.
Distinctness of the EV Air Conditioning System
Similarity to Traditional Fuel-powered Vehicles
From a cooling principle standpoint, the air conditioning system of EVs is similar to that of traditional fuel-powered vehicles. The components and their functions remain largely the same, such as the compressor, condenser, expansion valve, and evaporator. The main difference lies in the driving method of the air conditioning compressor.
Difference in Driving Method of the Air Conditioning Compressor
In traditional fuel-powered vehicles, the air conditioning compressor is driven by the engine’s belt pulley. However, in EVs, the compressor is controlled electronically and driven by a motor. The motor operates the compressor through the crankshaft, ensuring the cooling functions of the air conditioning system.
Electronic Control of the Compressor
Another distinctive aspect of the EV air conditioning system is the electronic control of the compressor. EVs use electronic control systems to manage the operation of the compressor and other components. This electronic control allows for precise regulation and optimal efficiency of the air conditioning system.
Air Conditioning Heating System
PTC (Positive Temperature Coefficient) Heating
The heating source in the air conditioning system of EVs is mainly obtained through PTC heating. PTC is a type of semiconductor thermistor with a characteristic of increasing resistance as the temperature rises. The PTC heating system operates under constant voltage and maintains a relatively constant temperature by adjusting the resistance.
Air Heating PTC Module
The air heating PTC module is a component in the air conditioning heating system that directly installs the PTC at the core of the cabin’s warm air system. The cabin air is circulated by the blower and heated directly by the PTC heater. It provides effective heating for the cabin, ensuring comfort in cold weather.
Water Heating PTC Module
Apart from the air heating PTC module, EVs may also have a water heating PTC module. This module uses PTC technology to heat the water circulating through the vehicle’s heating system. It helps provide warm water for cabin heating and ensures a comfortable driving experience in cold climates.
Characteristic of the PTC Material
The PTC material used in the heating system has a characteristic resistance that increases as the temperature rises. This characteristic allows for quick heating at low temperatures and maintains a relatively constant temperature as the temperature rises further. It ensures efficient and controlled heating in the air conditioning system.
Internal Structure of Air Heating PTC Module
Controller (including low voltage/high voltage drive module)
The air heating PTC module consists of a controller that includes a low voltage/high voltage drive module. The controller manages the operation of the PTC module and controls the heating functions. It ensures safe and efficient heating in the air conditioning system.
High/low-pressure Wire Harness Connectors
The high/low-pressure wire harness connectors are essential components that provide the electrical connection between the PTC module and the rest of the heating system. They ensure the proper transmission of electrical signals and the efficient functioning of the PTC module.
PTC Heating Resistive Film
The PTC heating resistive film is the main element responsible for generating heat in the air heating PTC module. It is powered by high voltage and controlled by the vehicle’s control unit. The resistive film heats up quickly at low temperatures and maintains a relatively constant temperature as the resistance increases.
Thermally conductive Insulating Silicone Pad
The thermally conductive insulating silicone pad ensures proper heat transfer and insulation within the air heating PTC module. It allows for efficient heat conduction from the resistive film to the surrounding air, ensuring effective heating of the cabin.
The outer shell of the air heating PTC module provides protection for the internal components and ensures the durability and safety of the module. It is designed to withstand the high temperatures and pressures within the air conditioning system.
Control of the Electric Vehicle Air Conditioning System
Signal Collection by the VCU
The vehicle control unit (VCU) is responsible for collecting signals from various components in the air conditioning system. It collects signals from the A/C switch, A/C pressure switch, evaporator temperature, fan speed, and ambient temperature. These signals provide important input for controlling the operation of the system.
Generation of Control Signals
Once the VCU collects the signals, it processes and calculates the data to generate control signals. These control signals determine the operation and settings of the air conditioning system. The VCU ensures optimal functioning and efficiency of the system based on the collected data.
Transmission to the Air Conditioning Controller
The control signals generated by the VCU are then transmitted to the air conditioning controller. The air conditioning controller receives the signals and interprets them to control the operation of the compressor and other components in the system. It ensures that the air conditioning system operates according to the desired settings and requirements.
Controls the On/Off of the High-voltage Circuit of the Air Conditioning Compressor
The air conditioning controller is responsible for controlling the on/off of the high-voltage circuit of the air conditioning compressor. It ensures that the compressor operates only when necessary and according to the desired settings. This control helps optimize the energy usage and efficiency of the air conditioning system in EVs.
Driving Comfort and Safety provided by the EV Air Conditioning System
Defogging and Defrosting Capabilities
The air conditioning system in EVs plays a crucial role in defogging and defrosting the windows. These functions are essential for driving safety, especially in cold weather conditions. The efficient operation of the air conditioning system ensures clear visibility and prevents fogging or frosting of the windows.
Heating and Cooling Functions
The EV air conditioning system provides both heating and cooling functions, ensuring comfort in various weather conditions. Whether it’s hot summer temperatures or cold winter weather, the system can regulate the cabin’s temperature and create a comfortable driving environment.
Importance for Driving Safety
The air conditioning system’s ability to quickly defog and defrost the windows is vital for driving safety. Clear visibility is essential for safe driving, and the air conditioning system ensures that the windows remain clear and free from condensation or frost. Additionally, the system’s heating and cooling functions contribute to the comfort and focus of the driver, enhancing overall driving safety.
In conclusion, the air conditioning system in EVs consists of various components like the electric compressor, condenser, expansion valve, evaporator, and control circuit. These components work together to provide cooling and heating functions. The compressor compresses the refrigerant, the condenser dissipates heat, the expansion valve regulates flow, and the evaporator absorbs heat. The system operates similarly to traditional fuel-powered vehicles but with electronic control. In addition to cooling, EV air conditioning systems also have heating functions, mainly through PTC heating technology. The control circuit collects signals, generates control signals, and manages the system’s operation. The EV air conditioning system provides driving comfort and safety by enabling defogging and defrosting capabilities, offering heating and cooling functions, and contributing to overall driving safety.