Pattakon
Greece
VVA “Rod Roller”
version
The "Rod Roller" version of Pattakon VVA on
the intake valves of a Citroen/Peugeot 1600 cc,16 valve:
This design is "universal" (most cylinder heads
"compatible").
The control shaft is directly connected to the gas
pedal by the gas cable. The deeper the gas pedal is pressed, the more the
control shaft rotates increasing the valve stroke. When the gas pedal is
released the normal intake valve springs restore the control shaft to its
“idling” position.
Depending on the control shaft angular position the
valve lift profile varies continuously from zero (for valve deactivation if
desirable), to tiny (for idling), to mild, to medium, to racing (top curve), all
in the same engine, all instantly available:
The following
stereoscopic image illustrates a part of the control shaft with the rollers
(red), the roller pins (blue), the rods (brown), and the actuators / lash
adjusters:
The quick
moving parts are "true" lightweight.
Even with the toughest valve springs,
the engine at normal conditions (i.e. low to medium revs) "feels" (as regards
friction, wear etc) softer valve springs than conventional.
The intake valves
make the "throttling" (ideal for efficient and cheap ITB).
The lash adjusters
- if desirable - can be hydraulic.
With a different control shaft the above "Constant
Duration VVA" changes to a "Lost Motion VVA" as shown below (the axis of
rotation of the control shaft goes from the "top center" to the "bottom center"
of the rods) .
BMW's "Valvetronic" is a "Lost motion VVA": decreasing the
valve stroke, the valve duration - in crankshaft degrees - is also
decreased.
Compare BMW's Valvetronic to Pattakon's Rod Roller Lost Motion VVA
in functionality, simplicity, accuracy (number of "joints" interposed), height,
lightweight, inertia loads, cost and capability for high revs (specific
output).
Click here for more about Lost
Motion version
mailto:vva@pattakon.com