なぜ do 従来型 燃料 車両 および 新 エネルギー 車両 必要性 熱 管理?
従来型 内燃機関 エンジン 車両 熱 管理 システム アーキテクチャ: 従来型 車両 熱 管理 システム また 回転 周り エンジン 冷却. 熱 管理 モジュール is 分割 into 3 sub-sections: engine, air conditioning, and air intake。
thermal management system of new energy vehicles consists of three parts: cabin thermal management, battery system thermal management, and motor electronic control cooling system. new energy vehicles do not have an engine as a source of heat energy, and a new battery thermal management system is added. オン ザ その他 ハンド, ザ パフォーマンス of バッテリー および 電源 コンポーネント is sensitive to temperature, which drives the Chiller heat exchanger, cooling team, electronic expansion valve, electronic water pump, and electronic water. The demand for valves, electric compressors and other parts is also increase, and PTC heaters or heat pump systems are added.
1. The purpose of engine thermal management: smooth cold start and prevent "沸騰"
For the thermal management system of traditional internal combustion engine vehicles, the main purposes of thermal management are two:
(1) In cold weather, quickly warm up the car to achieve a cold start.
(2) In hot weather, prevent the engine from "boiling". When the engine of a traditional internal combustion engine vehicle is turned off for a period of time, the engine has cooled down and its temperature is lower than the normal operating temperature. The engine oil flows back to the oil pan due to gravity. When the vehicle is started again, the oil in the oil pan needs to be transported through the oil pump to various moving parts and friction pairs through the oil passages, and a certain oil pressure must be established and maintained.
で 寒さ 冬 地域, such as the Northeast at -35 degree , the atomization of gasoline is extremely poor. いつ starting, a much higher amount of oil than normal starting must be injected to obtain a conditional combustion mixture, and ignition is difficult and the low temperature starting time is it is obviously longer. generally speaking, it is normal to successfully start within 15 seconds at -35 degree . シリンダー内 direct injection will improve the cold start performance。
以来 オイル 温度 は 非常に 低い および 粘着性 増加, it is difficult に すぐに 潤滑する エンジン 部品 under low temperature conditions, so it takes time to increase the oil temperature. On the other hand, the gaps between the internal parts of the engine are large and it takes time to warm up. , the specified clearance can be gradually reached only after preheating and expansion. If the oil film has not yet formed between the components during the process of oil delivery and oil pressure establishment, especially the valve hydraulic lifters in the cylinder head, they need to undergo an oil filling process. At this time The valve clearance is large, and a normal mechanical "click" sound will be produced when the valve is closed and seated. Mechanical wear caused by difficulty in cold starting has a very serious impact on the engine. more than 80% of engine wear is caused during the cold start stage.
"沸騰" means that the antifreeze coolant is boiling, showing a "water is boiled" state. The coolant will not reach the boiling point under normal conditions. If a "boiling" situation occurs, it means coolant failure, circulation cooling system failure and other thermal management problems.
In recent years, the domestic automobile industry has developed rapidly, with the emergence of many independent brands, and thermal management problems have become increasingly prominent. Arranging cooling modules in the engine compartment with limited space will inevitably cause great obstacles to the flow of cooling air, leading to the possibility of local overheating. , poor air flow on the cold side and other problems. If the OEM selects heat exchangers and fans without reasonable calculation and analysis for the selection of cooling system heat exchangers, this will lead to problems with the matching between cooling modules and between the cooling module and the engine. This causes the coolant temperature to be too high under low-speed conditions or extreme conditions such as climbing, which in turn causes the engine to "boil". This further causes the strength of connecting rods, pistons, piston rings and other components to be reduced or deformed, making it difficult for the car to withstand normal driving loads and destroying the normal operation of various parts, affecting the reliability of the entire vehicle.
2. 目的 の 熱 管理 の 新しい energy vehicles: heating inside the cabin to provide suitable operating temperature for the three power systems
thermal efficiency of traditional internal combustion engines can reach about 40%. Through an effective thermal management system, the waste heat generated by the engine can be recovered and provided to the cockpit for heating. しかし, new energy vehicles cannot utilize the heat generated by combustion. The mainstream heating solutions include air (wind heating) PTC, water heating PTC and heat pump air conditioning. The heating principle of the PTC thermistor type heating system is simple, relying on current to pass through a resistor to generate heat. The PTC used in pure electric vehicles is a semiconductor thermistor.
特性 of PTC is that as the temperature increases, the resistance of the PTC material will also increase. This characteristic determines that under constant voltage conditions, the PTC heater heats faster when the temperature is low, and when the temperature rises, the resistance becomes larger and the current Being smaller, the PTC consumes less energy, which keeps the temperature relatively constant.
PTC クーラント ヒーター は しばしば 組み合わせ モーター 冷却 水 回路; air heating PTC is to install the PTC directly at the heater core of the cab, circulate the air in the car through the blower, and directly heat the air in the cab through the PTC heater. The structure is relatively simple. PTC technology has the advantages of low cost, simple manufacturing process, and rapid heating. しかし, using PTC to heat electric vehicles will seriously reduce the vehicle's cruising range, and the the COP of PTC technology is less than 1 and the efficiency is low. In this context, heat pump technology has attracted more attention.
