In many ways, a racecar is simply an energy conversion mechanism. The combustion engine converts chemical energy in fuel to rotational kinetic energy in a crankshaft; the braking system converts kinetic energy to heat energy; the springs in a suspension system convert kinetic energy into elastic energy and, with more recent hardware, power electronics systems around a car convert chemical energy stored in batteries to electrical energy, which subsequently undergoes another conversion to kinetic energy in the moving vehicle.
These are all ideal cases, however. In reality, the process of converting energy from one format to another always incurs losses. These losses are inefficiencies that manifest themselves as large proportions of energy being dissipated as heat, sound and sometimes even light energy.
In the majority of automotive scenarios, heat losses are most prevalent. A reasonably efficient internal combustion engine only makes useable work from around 40 per cent of the energy contained in the fuel, the other 60 per cent is lost as heat and sound energy, into the cooling system and exhaust gases.
You know that sound your favourite racecar makes? As wonderful as it might be, it’s also a signal of inefficiency. It’s why today’s generation of turbocharged engines are noticeably quieter than their naturally aspirated predecessors. They utilise this lost exhaust energy to drive their turbochargers.
Heat, on the other hand, is an inescapable reality, and engines are designed to operate under these conditions, but there are limits. Excess heat causes increased friction within the engine and a reduction in service life as piston rings and bearings see higher contact loads from reduced clearances.
Hot spots around combustion chamber walls lead to pre-ignition, while high thermal stresses can cause cracking, fatigue and distortion, in particular with mating components fabricated from different metals.
With powerful race engines rejecting hundreds of kW of heat out of combustion chambers and into the block and head(s), cooling systems working to transfer this heat into the atmosphere must be robust and fit for purpose. It’s a very important job.
Heat exchangers
Traditionally, in automotive applications, heat rejection is facilitated by heat exchangers in the form of liquid-to-air, liquid-to-liquid or air-to-air.
The block and cylinder head are designed such that a jacket of water circulates around key areas and is pumped into a liquid-to-air
