Ferrari's Oval-Piston Patent Could Revolutionize The V12

Discovered by the AutoGuide research department via the European Patent Office (Application number: 24197835.2), Ferrari's illustrations depict a V12 configuration with pill-shaped pistons rather than circular. Geometrically, the proper term is stadium-shaped.

Unlike Honda’s oval pistons, which were positioned longitudinally—with their long side parallel to the crankshaft and used two connecting rods per piston—Ferrari has flipped this orientation, positioning the long side of the piston perpendicular to the crank. This naturally makes the engine more compact.

More radically, Ferrari designed a new connecting rod, which is shared by pistons on opposite banks. There's a multi-link system that splits the connecting rod in two—similar in philosophy to Nissan's variable compression engine. It's unclear what kind of balance or thrust issues and limitations this setup could cause.

The potential benefits of this design go beyond novelty. By arranging oval cylinders closer together and requiring less offset between banks, Ferrari could significantly reduce the overall length of a V12 engine, allowing for a more compact powertrain without having to sacrifice piston surface area or displacement. As an additional benefit, Ferrari might be able to increase the valve surface area either through larger valves or by increasing the number of valves per cylinder.

This could be particularly useful in mid-engine applications, where space efficiency is key. It could be important if you're planning to use a V12 engine with a hybrid MGU inserted between the engine and the transaxle. This theory would apply to both road cars and race cars. All the same benefits apply to a front-engine application like the 12Clinidri as well.

Additionally, recesses along the longitudinal skirt of each piston could help reduce friction against the cylinder walls, reducing internal friction and increasing efficiency, potentially helping the engine spin faster. While recessing piston skirts around the wrist pin bores is nothing new when it comes to high-performance rotating assemblies, the increased length of the pill-shaped pistons could net a greater effect.

Whether this patent leads to a production engine remains to be seen, but it suggests that Ferrari is actively exploring ways to push the boundaries of internal combustion technology—even as its chief rivals try to excite with software-defined performance cars—looking at you, Porsche.

However, it's important to keep in mind that Honda struggled to get its oval pistons to properly seal with the cylinder wall. There were numerous difficulties in designing and producing oval piston rings—circles are easy to machine, ovals are not. Granted, there have been leaps and bounds made in matching technology since Honda first tried this. Ferrari is also chasing a simpler-to-machine stadium shape, which is just a rectangle with two semi-circles on the end, compared to Honda's ellipse, which has multiple radii.

To this day, Honda isn't sure if its oval-piston NR500 engine was cutting-edge technology or a foolish idea. Hopefully it works out better for Ferrari.

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