In modern vehicles, electronics and advanced features generate significant heat that must be removed to ensure optimal performance and reliability. As cars become more complex with the addition of advanced driver-assistance systems, infotainment screens and electric powertrains, effective thermal management is critical.

Automotive Thermal Management Cooling System Design

The primary method for removing heat from a vehicle is the cooling system. Heat from the engine, transmission and other components is transferred to the coolant, a mixture of water and antifreeze. A water pump circulates the coolant through small channels in critical components and then to the radiator.

The radiator is a heat exchanger that uses airflow from the vehicle's forward motion or an electric fan to dissipate heat from the coolant into the ambient air. Radiator design has evolved significantly, with materials like aluminum allowing for more compact cores that are also more durable. Advanced radiator designs can optimize airflow under different operating conditions.

Automotive Thermal Management: Coolant Flow Control

Precise temperature control of the coolant is vital to ensuring components operate within a safe temperature window. Automotive Thermal Management used to control the flow of coolant through the radiator based on temperature. Wax-pellet thermostats open to allow coolant flow once the engine reaches operating temperature. More advanced electric thermostats provide variable control of coolant flow for optimal efficiency.

Auxiliary Cooling Systems

As electronics proliferate in vehicles, dedicated cooling systems are required. Sensitive components like power electronics and battery management systems use coolant loops isolated from the main engine system. Pumps, heat exchangers and controls tailored for lower temperature operation keep electronics from overheating. For electric vehicles, additional cooling is required for high-voltage components and battery packs.

Cabin Climate Control

Modern cars incorporate sophisticated climate control systems to heat and cool the passenger cabin. Heat from the engine or an electric heater warm the cabin on cold days. Air conditioning uses a refrigerant loop, with a compressor driven by the engine or electric motor. Heat is absorbed by the refrigerant in an evaporator inside the car and rejected to the outside air in a condenser.

Thermal Management Challenges from Electrification

The transition to electrified powertrains like hybrids, plug-in hybrids and EVs introduces new thermal management challenges. Batteries generate significant heat that must be carefully controlled to ensure safety and performance over many charge cycles. Coolant loops integrated with the vehicle cooling system keep batteries within an optimal temperature window.

Thermal loads from high-voltage drive motors and power electronics require dedicated liquid cooling circuits. Coolant flow must be actively managed with valves and pumps. Compact heat exchanger designs optimize heat rejection while minimizing size and weight penalties. Sophisticated control algorithms precisely coordinate thermal management with driving conditions and charge state.