Ferrari’s V12 Patent
Ferrari has submitted a patent for a V12 engine with slotted pistons to the European Patent Office. The piston shape, often referred to as "oval," is not a new concept. Honda experimented with oval-piston engines as early as 1979 in racing motorcycles. The motivation at that time was to improve cylinder filling by increasing the number of valves per combustion chamber. Honda’s NR 500 racing bike featured eight valves per cylinder, with an elongated piston shape aligned parallel to the crankshaft, requiring two connecting rods per piston.
Despite the theoretical advantages, issues such as complex piston ring tension, increased engine weight, and higher engine braking effects outweighed the benefits. Honda continued its development, producing the NR 750 in 1987 and launching a limited-production version in 1991. However, the technical drawbacks led to the discontinuation of the oval-piston concept.
Now, Ferrari is reviving the slotted piston concept in a new patent, though it differs significantly from Honda’s approach, aside from the piston shape.
A More Compact V12
In Ferrari’s patent, the slotted pistons are rotated 90 degrees relative to the crankshaft. Geometrically, the pistons are composed of two identical semicircles connected by two tangential straight lines. The orientation of the slots perpendicular to the crankshaft suggests a key advantage: a more compact engine design with shorter combustion chambers.
A significant benefit of this design is that each cylinder still requires only one connecting rod. However, Ferrari engineers will need to address the challenges associated with piston ring tension.
Use of Articulated Connecting Rods
To further reduce the engine’s size, Ferrari employs articulated connecting rods, consisting of a primary and secondary rod. In most V-engines, two connecting rods share a crankpin, creating a small offset between the cylinder banks and extending the engine’s length.
With articulated connecting rods, the primary and secondary rods share a single lower connection point, eliminating the offset between cylinder banks and enabling a more compact engine layout. This design was originally patented in 1932 by Swiss engineer Arnold Zoller for use in opposed-piston engines and is commonly used in radial engines.
Potential Applications: Mid-Engine & Hybrid Systems
A highly compact V12 engine could be particularly advantageous for mid-engine layouts, where space is limited. Additionally, a smaller combustion engine could be an ideal component in a hybrid powertrain. However, manufacturing an engine with slotted pistons is significantly more complex than producing one with conventional round pistons.
Whether Ferrari will bring this V12 with slotted pistons into production remains uncertain.
Source: www.auto-motor-und-sport.de
