They dictate that the PUs must be based around a 1.6-litre V6 turbocharged petrol engine coupled to two electric motors. One of these converts heat, that would otherwise be wasted, into power; the second performs a similar miracle on kinetic energy from braking.
Only 105 liters of fuel can be burned per race, and the rate at which it can be pumped into the V6 (the fuel-flow rate) is limited to 100kg/hr. That tightly enforced restriction has promoted engineers to look for other sources of concentrated energy that might be stored on board. It has led them, in fact, to explore whether some quantity of the oils and lubricants carried primarily to ensure PUs operate reliably under extreme race conditions could be burned as fuel (oil burning), thereby enriching the engine’s ‘diet’ and boosting power, thanks to an increased amount of chemical energy being available.
The standard ‘pump fuel’ gasoline used in Formula 1 has 43 megajoules of energy per kilo; how might this be enhanced? The loophole exploited has been to divert some of the PU’s lubricant supply into the fuel mix of the V6 internal combustion engine (ICE), with a few burn-friendly additives having been added along the way.
Formula 1 engine manufacturers are highly protective of any information relating to the inner working of their motors, as they contain many proprietary, sometimes experimental, technologies. These are deep trade secrets, often fundamental to their competitive advantage and therefore reliant on the highest levels of data protection.
Nonetheless, it is believed that methods have been established whereby controlled amounts of additives were introduced to the combustion cycle via the airbox and engine breather. These, combined with redirected quantities of lubricating oil, have significantly ‘fattened’ the fuel on which the engine feeds. Hence ‘oil burning’.
Limiting oil consumption to monitor oil burning
Suspicions that these practices were being exploited in Formula 1 prompted the sport’s governing body, the FIA, to limit oil consumption of any power unit to 1.2 liters per 100 km – 0.06 liters a lap.
That limit was halved for 2018 and oil consumption is now being closely monitored by the FIA, underlining suspicions that something very cunning indeed had been taking place. Active valves in air intakes, which could have been used to control the supply of fuel additives, have also been banned. Furthermore, for 2018 engine oil has been more tightly defined as a substance that must be readily identifiable as a lubricant.
Perhaps reassuringly this area of exploitative advantage-seeking is nothing new in motorsport – indeed fuel boosting dates back at least as far as the second world war, when aircraft engineers sought ways of helping their fighter pilots gain an advantage over the enemy. One substance discovered to be of particular value was toluene, thanks to its octane rating around 20 percent higher than that of standard aviation fuel.
Those lessons learned in WWII would prove useful when F1 last used turbo engines extensively during the 1980s. BMW, in particular, whose four-cylinder motors were among the most powerful of the era, were active in researching enhanced fuel blends during a period when the practice was legal.