Pattakon
Greece

DVVA Click here for more
Desmodromic Variable Valve Actuation,
a further step for VVA systems
from a FVVA to a DVVA system

At left is a FVVA or Fully Variable Valve Actuation mechanism. It needs valve springs to restore the valves at their rest position, it also needs restoring springs for some parts of the FVVA mechanism.

At right is a Desmodromic (from the Greek words "desmos", meaning "tie", and "dromos", meaning "road"/"track"/"path") Fully Variable Valve Actuation system or DVVA.
The DVVA needs neither valve springs, nor other kind of restoring springs.
The DVVA is as Desmodromic as Ducati's valve train systems for normal and racing moto engines.
And, at the same time, the DVVA is infinite times more variable than the state of the art Variable Valve Actuation systems, like BMW's valvetronic, Nissan's VVEL, Honda's A-VTEC etc (see Pattakon's FVVA system).

To learn more and 'play' with DVVA's capabilities, download and run the program 'DVVA.exe' (90 KB) by clicking on the image:
Click on the image to download the DVVA.exe program
The 'DVVA.exe' shows animated a Desmodromic Fully Variable Valve Actuation mechanism, and computes and presents graphically the valve lift profile according the desirable / selected angles of the two control shafts.

Locking at an angle the control shaft that holds the roller, the system "degrades" down to a Desmodromic Constant Duration VVA (suitable for applications where the simplified direct control and the instant response are mandatory, like in motoGP).
Locking at an angle the other control shaft, the system "degrades" down to a Desmodromic Lost Motion VVA.
Locking both control shafts, the system degrades to a Desmodromic valve train.

Without springs of any kind and without camshafts, the DVVA can operate reliably at extreme revs for racing use, like motoGP and Formula1, and at the same time the DVVA, compared to the state of the art VVAs and to the conventional valve train systems, increases fuel economy and reduces pollution, being more driver friendly and pleasant.

Click here for more (GIF anim, single shaft version etc)

mailto:vva@pattakon.com

Pattakon Greece