Silent flight inspires quieter cooling fans

The ability of owls to glide silently makes them a formidable predator, which inspired automotive supplier Mahle to design a ‘bionic’ cooling fan for electrified vehicles that is quieter and more efficient, using artificial intelligence to develop fan blades that mimic the wings of nocturnal birds of prey.

Mahle analysed parts of the animal kingdom with artificial intelligence to come up with ways of improving products in ways that would help the automotive industry decarbonise. 

“We learn from nature. It inspires us in many areas,” said Mahle head of thermal management development Dr Uli Christian Blessing at the IAA Transportation 2024 exhibition in Hannover, Germany.

“We analysed the characteristic features of bats, swordfish, and many other inspirations from nature. We finally ended up with the owl, the silent hunter, as the main template for our new fan.”

By utilising AI, Mahle was able to design ventilation blades that mimic the noise-reducing properties of an owl’s plumage, minimising turbulence, resulting in a more efficient design that offered a 4 dB(A) noise reduction. 

This halving of sound levels, which can often be disruptive at full load or during night-time EV charging, was likened by Dr Blessing as “turning off one of the speakers on a stereo system”.

Electrification hinges on efficient thermal management, and Mahle’s bionic fan is engineered to excel in this area. 

Specifically designed for demanding electric and fuel cell vehicles, Mahle claims the ‘bionic’ fan has a 10 per cent performance advantage over conventional products, which translates to enhanced battery or tank range and improved passenger comfort.

Further optimising efficiency, Mahle applied its bionic design principles to the fan cover and carrier, resulting in both a 10 per cent weight reduction and higher structural integrity.

Vehicle manufacturers are currently testing prototypes of the fan, which features a scalable design accommodating 300W units for passenger cars to 35kW for large trucks.

“With this new product, Mahle continues to pave the way for the electrification of mobility – and contributes to making it more attractive for customers,” said Dr Blessing.

In addition to the bionic fan, Mahle also debuted its new evaporative cooling system at the IAA, showcasing its systems approach to fuel cell truck technology. 

This innovative system leverages the time-honoured power of water evaporation to efficiently cool fuel cells by spraying water onto the coolant cooler through a specialised grating, ensuring optimal temperature control and a claimed 50kW increase in cooling performance when compared to a traditional setup.

This enhanced cooling capability translates to reduced fan usage, leading to a smaller fan motor and a significant boost in propulsion power, providing an additional 25 kW (or eight per cent) of propulsion power for a 300kW fuel cell truck.

With forecasts predicting 30 per cent of global truck production to be battery and fuel cell electric by 2035, the company plans to continue tackling electrification challenges from multiple angles, developing both next-generation electric drives and optimised components.