Thermal Management in Internal Combustion Engines

Thermal management in internal combustion engines encompasses the control and optimisation of heat generation, dissipation and retention within engine components. Effective management of in-cylinder temperatures and heat transfer to structural parts is essential for maximising efficiency, reducing mechanical stresses and curbing pollutant emissions. Traditional approaches rely on water-cooled jackets, oil circuits and thermostatic valves to maintain an optimal operating window, while advanced strategies include variable coolant flow, exhaust heat recovery and adaptive control of coolant temperature. Materials science has delivered thermal barrier coatings and surface treatments that locally reduce heat loss to metal substrates, thereby promoting higher combustion temperatures and improved fuel conversion. Computational techniques such as coupled computational fluid dynamics and finite-element analysis have become indispensable for predicting transient thermal behaviour and guiding the design of cooling passages, coatings and novel combustion concepts. As emissions regulations tighten and hybridisation accelerates, refined thermal management remains pivotal for prolonging component life, enhancing brake thermal efficiency and minimising the carbon footprint of legacy powertrains.

Research from Nature Portfolio

Recent studies have employed finite-element simulation combined with engine testing to assess yttria-stabilised zirconia thermal barrier coatings on aluminium alloy pistons. Under both rated power and maximum torque conditions, coated pistons exhibited surface temperature reductions of up to 13 %, with corresponding decreases in thermal stress of approximately 26 %. Models resolved the spatial distribution of temperature, stress and deformation, revealing that radial thermal deformations of coated pistons were consistently lower than those of uncoated counterparts. These findings demonstrate the potential of low-conductivity coatings to enhance knock resistance, reduce heat rejection and extend component durability, thus offering a route to higher cycle efficiency in high-pressure common-rail diesel engines.

Thermal Management in Internal Combustion Engines publication trend

The graph below shows the total number of articles in thermal management in internal combustion engines across all publications each year (not limited to Nature Index journals).

Technical terms

Brake thermal efficiency: The ratio of useful work output to the chemical energy input of the fuel, indicating engine efficiency.

Thermal barrier coating (TBC): A low-conductivity ceramic layer applied to hot-section components to reduce heat transfer to the underlying metal.

Quenching distance: The minimum gap between the flame front and the wall at which the flame is extinguished by heat loss.

Thermal swing: The rapid oscillation of wall temperature following the in-cylinder gas temperature during combustion.

Finite-element analysis (FEA): A numerical method for predicting temperature, stress and deformation distributions in complex geometries.

Heat flux: The rate of thermal energy transfer per unit area, crucial for characterising local cooling or heating effects.

References

1. Influence of Yttria-Stabilized Zirconium Oxide Thermal Swing Coating on the Flame-Wall Interaction in Spark Ignition Engines. Energies (2023).
2. Experimental and simulation study on aluminium alloy piston based on thermal barrier coating. Scientific Reports (2022).
3. Effects of thermal barrier coating porosity on combustion and heat losses in a light duty diesel engine. International Journal of Engine Research (2024).