KEEPING IT COOL

We investigate the function of modern vehicle cooling systems and their role in ensuring reliability and operating efficiency

- Graham Eagle

In internal combustion engines, the conversion of the chemical energy of fuel into kinetic energy creates heat as a waste product. This heat, along with the heat created by the friction of various moving components, needs to be reliably controlled and dissipated to protect the engine and its components.

AIR COOLING OR WATER COOLING?

The earliest motor vehicles featured simple air-cooled engines, but it wasn't long before a switch to water cooling began. Early water-cooling systems were not reliable in extreme conditions. Engine damage owing to coolant water freezing, or overheating under high load conditions was the norm. While water-cooling systems were being further developed to improve their reliability and efficiency, several manufacturers continued with air-cooled engines, enjoying the benefits of simplicity, cost, reliability, and lower weight. The most well-known were the Volkswagen Beetle - which was produced until 2003 - and the Porsche 356/911 models, the air-cooled 993 version in production until 1998. Other manufacturers of air-cooled cars included Chevrolet, Citroën, Fiat, Honda, and Tatra but over time, the disadvantages of their higher engine noise levels - no water jackets to absorb the mechanical noise-and cooling difficulties at high specific power outputs, led to a decline in their usage. Ultimately, the challenge of compliance with exhaust emission standards effectively ended the use of air-cooled engines in cars, and usage is now generally limited to aircraft, motorcycles, and special applications.