Automotive Thermal Management System
This time we talk about some thermal management topics in automobiles, look at some differences between traditional automobiles and new energy vehicles, and understand some system control methods for thermal management.
When it comes to car thermal management, some people may be a little unfamiliar with this concept. It is not as intuitive as the car's torque control. Evaluators will tell you a lot about the car's power and economical performance. Most consumers understand it more and focus more on the experience of using air conditioners in the passenger cabin. In fact, vehicle thermal management is not only used for the air conditioning of the passenger compartment.
It also takes into account the heating and insulation or heat dissipation and cooling of vehicle parts, and the thermal energy management of the vehicle system. It is like a warm-hearted protector of the car, silently managing the temperature status of the car parts, protecting the cold and warm well, allowing the car to handle a comfortable temperature environment, maintaining the best performance of the parts, and indirectly ensuring the safety of the car. Excellent vehicle performance and economy.
With the development of the automobile industry, new energy vehicles have rapidly emerged and become a new force. The driving experience and safety have attracted more attention from consumers. New energy pure electric vehicles have undergone tremendous changes in structure from traditional gasoline vehicles, and the control of thermal management functions is also very different. Let's first look at the differences in thermal management between traditional gasoline vehicles and pure electric vehicles
There are obvious differences in the structure and control methods of the two types of cars. For traditional cars, vehicle thermal management mainly focuses on the engine cooling system and passenger cabin air conditioning. The main heat source of gasoline vehicles is the engine, which needs to be cooled down by a cooling medium. The use of air conditioning in the passenger compartment also relies on the power of the engine. The cold air output of the passenger cabin air conditioner relies on the engine to drive the air conditioner compressor through a belt to start refrigeration; the warm air output relies on the heat generated by the engine to heat the air inside the car's passenger cabin through heat exchange.
When it comes to new energy pure electric vehicles, big changes have taken place. Pure electric vehicles use motors to replace engines, without gearboxes, and the entire power system is updated to a three-electric architecture platform: motor, battery, and electronic control. The vehicle has newly added DCDC converter, charger (OBC), and electric heater (PTC). Then, pure electric vehicles do not have the power source of the engine, and the thermal management has changed accordingly. For example, the air conditioning compressor uses the power supply of the battery pack, and the warm air is realized by PTC heating. Let's use this topic to have some discussions and understand how the car's hot and cold protection system divides labor and cooperates.
Through the above, after knowing some structural differences between gasoline vehicles and electric vehicles, let's look at the differences in control. The cooling method of the engine is commonly used water cooling + air cooling. This cooling system mainly consists of a water pump, electronic fan, radiator, thermostat, water jacket, etc. By using the water pump to control the water circulation, the electronic fan is used for air cooling and the radiator is used for cooling. As shown in Figure 2, a thermostat is used to divide the cooling system into "large and small circulation" loops. When the water temperature is high, the radiator is used, and when the water temperature is low, the radiator is not used for thermal management. This thermal management system controls the operating temperature of the engine very well and controls the water temperature within a comfortable working range.
When it comes to pure electric vehicles, thermal management control becomes more complicated. The three-electric architecture of pure electric vehicles requires cooling or heating of the entire high-voltage system components, and the comfortable operating temperatures of the components are different. Thermal management protection of motor circuits mainly involves heat dissipation, including motor controllers, motors, DCDC, chargers and other components; thermal management protection of batteries requires heating and cooling. Therefore, the thermal management control of pure electric vehicles needs to distinguish loops and carry out classified control according to the performance characteristics of components. Under normal circumstances, the motor circuit and the battery circuit are distinguished.
