Aprilia V4 shown in Piaggio variable valve timing patents
Piaggio is developing a variable valve timing system that could be used not only on the high performance models of Aprilia but also smaller bikes.
Piaggio is seemingly preparing a variable valve timing system for its motorcycle engines which could be used in a variety of models, including those of Aprilia.
Variably valve timing (VVT) has been used by motorcycle manufacturers for a while, but not by Piaggio or its associated brands, such as Aprilia or Moto Guzzi.
That seems set to change, though, as Piaggio has posted patent filings regarding a VVT system. The drawings in the filing, reported by Motorrad, show the system used on the V4 engine of Aprilia, used in the Tuono V4 1100 naked and RSV4 1100 sports bike.
VVT is a technology used in internal combustion engines to adjust engine characteristics between high and low speeds. Therefore, the engine can be aggressive at high speeds, but smoother at lower speeds and on the first touch of the throttle.
The Piaggio system is a relatively simple one in that it does not require any electronics to operate. Instead, three balls are placed on the drive wheel of the intake camshaft; when centrifugal force is exerted on the balls, they move outwards, thus varying the simultaneous opening of the intake and exhaust valves.
In these ways - with the lack of electronics and the use of small balls on the intake camshaft’s drive wheel - the Piaggio system is similar to that used by Suzuki in 2017 on the GSX-R 1000. However, Suzuki used 12 balls on its system, whereas Piaggio’s system is only using three, which could reduce friction losses and, perhaps more importantly, lower manufacturing costs.
The latter point there is of particular interest, as it means the Piaggio VVT could be used not only in high-performance sports bikes, but also in lower-capacity motorcycles where costs are a more significant concern.
