Revealed: The secrets behind Ferrari’s latest weapon to beat Mercedes

Ferrari will field its third power unit of the season in Austria,
equipped with the first ADUO upgrade in a bid to catch up to the
benchmark, which has been deemed to be Red Bull. The choice to
bring the evolved power unit to Austria has strategic relevance,
both linked to circuit layout in Spielberg and the run of four
grand prix events in five weeks. The team received a boost last
time out in Spain as Lewis Hamilton climbed to the top step of the
podium, thanks in part to the aerodynamic developments brought to
the event. Ferrari is seeking to recover the ground lost in the
early races as quickly as possible as it looks to inject itself
into the title fight, and has thus far been lacking when it comes
to its PU. A key feature of the Ferrari internal combustion engine
is steel cylinder heads, a choice that has prompted discussion
among insiders due to the significantly higher weight compared to
the aluminium alloys that are common among rival power units.  The
root of Ferrari’s choice is steel’s ability to withstand very high
temperatures, having a significantly lower coefficient of expansion
compared to aluminium. This characteristic is extremely functional
to the basic choice of the project, namely that of a «hot» power
unit, where the intake air also reaches temperatures above 100
degrees.  This choice, which effectively reduces the density of the
incoming air, thus theoretically reducing the oxygen available for
triggering combustion, instead has a very favourable effect in
terms of better combustion of the mixture. What this means is that,
inside the combustion chamber, with higher intake air temperatures,
better atomization of the mixture is achieved, which in this way
instantly increases the flame front, thereby increasing the power
generated. In practice, while the fuel flow rate established by the
regulations remains unchanged and is controlled by means of the FIA
flow meters, the result is that, for the same potential energy —
that is, the same fuel volume — a higher energy balance is
achieved, meaning greater power output. As far as the evolution of
the PU introduced in Austria is concerned, this involves an
increase in the intake temperature to between 114°C and 116°C,
alongside the adoption of a new fuel specification.  Its fuel
partner, Shell, has developed a fuel made up of a different
molecular chain compared to the one used up to the previous race,
specifically designed to increase the flame front following the
variation in intake air temperature. Essentially, the new formula,
according to some reports, would allow an improvement in thermal
efficiency of around 2–3%. This means lower consumption, which can
be interpreted in two ways. With the same amount of fuel carried
and burned, it delivers greater power, for the reasons explained
previously; or, on circuits where power is less relevant, it allows
a lower quantity of fuel to be carried, thereby helping to reduce
the car’s weight when running with a full fuel tank. This could
further lend itself to Ferrari’s advantage in the initial phase of
the race, where even a minimal upper hand becomes crucial for the
strategy that follows.  At Ferrari, there is confidence that the
evolution of the PU can reduce the gap compared to those built at
Mercedes, who has won six out of the opening seven races. A rumour
coming from Mercedes is that the Brixworth technicians have
identified what triggered the recent battery failures within the
PU, and are studying definitive countermeasures to the problem,
linked to a sudden increase in the temperature of some battery
elements. However, the solution cannot be immediately implemented,
so its temporary fix revolves around less extreme energy charging
and deployment routines compared to those used up to Barcelona. 
But as a consequence, this results in slightly lower performance
and could bring others, including Ferrari, into play.