Rubber Seals in Thermal Management:Solutions for Combustion Engine vs. Electric Vehicle Cooling Systems
1. Combustion Engine Vehicles: Engine/Transmission Cooling + Cabin HVAC System + Intake Air Management
Engine/Transmission Cooling:
- Engine Cooling: Utilizes a water circulation system. When the temperature is low, the thermostat remains closed, and the coolant follows a small loop. As the temperature rises, the thermostat opens, and the coolant follows a larger loop, cooling down via the radiator and fan to keep the engine at an optimal operating temperature.
- Transmission Cooling: Relies on oil cooling to manage the transmission’s temperature.
OBT Solutions:
Engine Cooling:
1）EPDM seals : resistance to ethylene glycol-based coolants (up to 50% concentration).
2）High-temperature stability (up to 150°C) with low compression set (<25% per ASTM D395).
Transmission Cooling:
1) AEM seals: compatibility with mineral oils and transmission fluids ATF oil
2) METAL to rubber Gaskets: Hybrid designs with integrated rubber for oil sealing and higher stess interfaces.
Cabin HVAC System:
- Heating: Primarily uses the engine’s waste heat. High-temperature coolant transfers heat to the air, which is then blown into the cabin by a fan.
- Cooling: Uses refrigerant evaporation to absorb heat from the surrounding air. The cool air is then blown into the cabin, while the condenser re-liquefies the high-pressure gas for the next cycle.
Intake Air Management:
- Intercooler: Reduces the temperature of the air entering the engine.
- EGR (Exhaust Gas Recirculation): Cools a portion of the exhaust gas before recirculating it back into the engine for another combustion cycle, improving air intake and combustion efficiency.
2. Electric Vehicles: Thermal Management for the Electric System + Cabin HVAC System
Thermal Management for the Electric System:
The cooling system of Electrical vehicle models generally consists of three components: the battery cooling system, the motor and electronic control cooling system, and the air conditioning/heating system.
Key functional components involved include: electronic water pumps,eletrical valves, quick connectors, heat exchangers, liquid-gas separators, radiators, expansion tanks, cooling pipelines, and various sensors.
Using electronic water pumps as power sources and coolant as the medium, with valves controlling flow direction, the coolant circulates through pipelines passing radiators and cooled components. Through heat exchange, it achieves cooling to maintain functional components within their optimal temperature ranges, maximizing performance.
Whether in pure electric or hybrid vehicles, the battery thermal management operates independently from other systems. This isolation is primarily because the normal operating temperature range of battery packs (generally not exceeding 35°C) differs significantly from other systems: drive motors typically operate around 55°C, while engines function at approximately 95°C. Therefore, each system must operate independently to ensure optimal performance.
OBT Solutions:
Peroxide vulcanization formula to improve : the rebound performance of materials and Ethylene glycol resistence
Improved low temperature resistance: TR10 = -48℃. It means that the seal could work under -50℃ for static sealing application.
Cabin HVAC System:
- Cooling: Similar to conventional vehicles.
- Heating: Lacks an engine, so it requires an additional heating system, typically using PTC heaters or heat pump air conditioning.
- PTC Heating: Uses a thermistor to heat the surrounding air, which is then blown into the cabin.
- Heat Pump Air Conditioning: Changes the direction of the refrigerant flow via a four-way valve, using the heat generated by the condenser’s high-pressure gas to warm the air, which is then blown into the cabin. Compared to PTC heating, heat pumps are more energy-efficient and can extend the vehicle’s range.
3. Plug-in Hybrid Vehicles: Engine Cooling + Thermal Management for the Electric System + Cabin HVAC System
Plug-in hybrid vehicles combine the thermal management systems of both conventional internal combustion engine vehicles and electric vehicles.
Engine/Transmission Cooling:
- Engine/Transmission Cooling: Similar to internal combustion engine vehicles, relying on liquid and oil cooling.
Thermal Management for the Electric System:
- Electric System: Similar to electric vehicles, with efficient thermal management for the battery, motor, and power electronics.
Cabin HVAC System:
- Heating: Can use both engine waste heat and heat pump air conditioning.
- Cooling: Similar to internal combustion engine vehicles.
The thermal management systems of different vehicle models collectively reflect the following development trends:
1. Highly integrated system design;
2.Intelligent control strategies;
3.Adaptability to extreme environments;
4.Environmental protection concepts of energy conservation and emission reduction.
Looking ahead, the thermal management system of electric vehicles will continue to develop for greater efficiency, intelligence, and environmental-friendly.
It may integrate more sensors and algorithms to achieve more precise thermal management.
While exploring new heat exchange materials and designs to further enhance the overall performance and driving experience of electric vehicles.
Reference Reading:
How to measure the hardness: shore A,B,C,D?
How to measure the density of rubber material?
How to Evaluate the Resistance of Rubber to Oils and Other Solvents？
How to Evaluate the Low-Temperature Performance of Rubber?
How to Evaluate the Resistance of Rubber to Oils and Other Solvents？
How to choose between HNBR and AEM?
How to choose between HNBR and FKM(Viton) for O-Ring/gasket?
How choose Between FKM vs FVMQ?
When to use HNBR and Low Temperature HNBR(LT HNBR)?
Low Temperature FKM Rubber: Ideal for Automotive, Aerospace, and Chemical Processing
