Mercedes/Ferrari: Pouring oil on the fire

© F1i


Ever since 2014 and the introduction of the current breed of 1.6-litre V6-turbocharged power units, F1 teams have been looking for ways to generate more power amid mandated fuel and fuel flow restrictions. In order to improve the performance of the internal combustion engine (ICE), they have been working on several parameters, including the richness of the air-fuel mixture, mostly thanks to the pre-chamber technology, known as Turbulent Jet Ignition.

There are other methods, not always lawful though. One can remember for instance that in 2015 the FIA was suspecting several teams to bypass the fuel flow limit with an accumulator placed between the fuel flow sensor and the injectors. At the time, the ruling body had already released a directive to remind that “any device, system or procedure the purpose and/or effect of which is to increase the flow rate after the measurement point is prohibited”.

The oil burn tactic consists of adding oil, which is also a hydrocarbon, to the fuel in the cylinders. Burning oil as fuel requires the addition of chemical additives to reach an octane rating similar to that of fuel, so as to avoid the risk of knock (uncontrolled explosions), which is quite high in a lean-burn engine.

Knock disturbs the combustion process, which affects performance, and can also damage the inside of the piston. A turbocharged engine is even more prone to knocking due to higher thermal loads than on a normally-aspirated engine. In order to prevent this risk, oil manufacturers involved in grand prix racing increased the octane rating of the mixture as early as 2014 in order to make it less reactive. Engine suppliers, for their part, have looked for ways to improve the ignition process and have better control of how the flame propagates.

© F1i


Burning oil as fuel means there would be two specs of oil, hence the doubts raised after Ferrari asked the FIA whether these would be compliant with the technical regulations. Hence also the FIA referring to the “permitted characteristics of engine oil used in F1” in its latest note.

Let’s make it clear: the inner workings of the oil burn process are not known. One may surmise that the combustion oil is pumped, at high pressure, in the injection system, where it would mix with fuel. The injectors would then spray the higher density mixture into the cylinders.

"One could be looking at a 20% power increase from the ICE over a lap".

What is tangible however is the theoretical gains that could be reaped, especially in qualifying, from the oil-as-fuel ploy.

“Formula 1 has a fuel flow limit of 100kg/hour, i.e. 27.7g per second,” explained an F1 engine engineer. “If you add, let’s say, 5.5g of combustion oil per second (that’s 443g on an 80-second qualifying lap), one could be looking at a 20% power increase from the ICE over a lap. That said, it’s a rough estimate that should be taken with a pinch of salt.”