FUEL AND LUBRICANTS | SHELL TECHNOLOGY
A word in your Shell-like Racecar investigates the highly complex world of Formula 1 fuels and lubricants
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he evolution of fuels and lubricants in Formula 1 is one of the most critical and untold stories of the sport in the current era. The introduction of the hybrid regulations in 2014 changed the engineering formula for the internal combustion powertrain from an air-limited, mechanically-restricted formula to an energy-limited one. This shift in concept altered the engineering approach, and set the road map to the world’s most efficient race powertrains, now producing over 1000bhp from the combination of 1.6-litre, turbocharged V6 internal combustion engine (ICE) and energy recovery system (ERS) at a thermal efficiency of over 50 per cent. For the current turbocharged V6 formula, the restricting element is no
18 F1 2021 • Racecar Engineering
By Stewart Mitchell longer the oxidising component of the combustion, it is the hydrocarbon element. This forces engineers to think completely differently about the whole process of combustion. The absolute power of the engine derives from its ability to transfer the joules of energy stored in chemical form into kinetic energy. The challenge is to adapt the airto-fuel ratio and combustion parameters to extract the most energy out of each fuel droplet, rather than simply adding more. The number of joules of energy entering a contemporary F1 engine can be considered a constant as the regulations fix a fuel mass flow rate of 100kg/h. The ratio of energy entering the engine in fuel form to that turned into useable kinetic energy is the primary target for the fuel engineers.
‘The 50 per cent plus thermal efficiency of the current crop of Formula 1 engines is extremely impressive, and most of that is attributed to the mechanical design of the engines,’ explains Benoit Poulet, Formula 1 fuel development manager and trackside team leader at Shell. ‘However, the fuel contributes 25 per cent of the functional thermal efficiency of the engine. ‘Of course, the engines were not at 50 per cent thermal efficiency on day one of these regulations in 2014, so this journey has been ongoing for the last seven years.’
Fuel evolution The limiting factor of the naturally aspirated, fixed displacement, air-limited engines was how high they could rev, which is a function of combustion speed and mechanical stress.
