Tech Analysis: Ferrari PU design

Tech Analysis: Ferrari PU design

The Monaco GP weekend finally revealed one of F1′s biggest recent tech secrets. William Tyson takes a look at Ferrari’s power unit.

I distinctly remember reading Shell’s (fuel supplier for Ferrari) Twitter account one January morning with the suggestion that the new Ferrari power unit would be unveiled to the world over the coming hours. Did we catch a glimpse of it? Yes, but it was under a large red blanket. And nothing more. Since then there have only been rumours as to how Ferrari have built their V6 turbo hybrid – until the Monaco GP weekend.

Ferrari pride themselves in their engine building and whilst Mercedes’s true PU layout surfaced very early this season, the Scuderia have been very careful in covering theirs up as the cars are built/stripped during the Grand Prix weekend. On Thursday practice last week Kimi Raikkonen suffered gearbox problems so his car had to be taken apart to discover the issue. In doing so, TV broadcasting cameras were on site to take a look and their images finally revealed what had been suspected about the Ferrari PU design.

Ferrari PU
It was apparent during the launch period that the Ferrari-powered cars had slimmer sidepods than any other and now we have evidence as to why that is. Similar to the Mercedes solution, Ferrari have packaged the turbo’s intercooler along the centreline of the car to free up space in the sidepods for an aerodynamic benefit. Unlike Mercedes, however, the intercooler is mounted inside the ‘V’ of the engine, submerged within a water jacket to cool the charge air from the compressor.

The diagram above demonstrates this tidy layout.  Sandwiched between the exhaust driven (red) and compressor (blue) sides of the turbo lies the MGU-H (yellow), which is situated in almost identical fashion to the Mercedes PU apart from that its axle does not span the entire length of the engine. The compressor draws in air coming through the airbox, which is then passed on to the uniquely placed intercooler (green). Once cooled the charge air bends up and over the engine and back into the cylinders.

The water inside of the water jacket – surrounding the intercooler – is cooled by a small radiator in the sidepod which is far smaller and lighter solution than placing the intercooler itself in the sidepod. The plumbing network between the turbo, inlet plenums and back into the cylinders is far shorter than the Renault design and slightly less than the Mercedes. This is beneficial because less pipework reduces turbo lag significantly. The MGU-H negotiates turbo lag to a very good effect, but Ferrari’s layout puts less reliance/strain on the latter component to do its job, thus improving reliability to a certain extent.

The downside of this architecture is that the water surrounding the intercooler is inflicted by the high surrounding temperatures caused by the engine, so the water jacket has to be thick which increases weight. The Mercedes PU doesn’t have to deal with this problem as the intercooler is mounted along the centre of the car but away from the engine, whereas Renault have differing solutions from team-to-team. Whilst one could argue that placing the intercooler in the ‘V’ increases centre of gravity, this is in fact negated by Ferrari’s ability to mount the turbo unit lower due to the placement of the MGU-H between the two sides of the turbo.

Overall, Ferrari have produced a beautifully crafted piece of tech and it is perhaps no surprise that they have wanted to keep this so secret. With large software tweaks coming for Canada we could well see a match for Mercedes – in raw power terms at least – for the remainder of the season.


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