Project Four wrote:Hi, I do believe that the valve train is gear driven by a series of gears from crankshaft.
Pneumatic valves only replace the valve springs.
Pneumatic systems use conventional cams operating the valve (4) via a shim\bucket or finger follower, the valve spring pocket is replaced with a chamber (28) pressurised with nitrogen (held within a cylinder in the sidepods) that runs at a constant pressure to return the valve when the cam timing retards.
What Renault have is an Electro-hydraulic system, where two pressurised circuits operate the valve (16). Valve return is still handled by the pneumatic system (52, 20), but the opening of the valves discards cams for a hydraulic circuit (50) controlled by a electronic valve (58). As this system can use high pressure hydraulics already on the car to operate the valve at the required RPM ceiling, the system seems almost too simple..! Infinitely variable valve timing plus the loss of the reciprocating weight of the cams and drive gears makes this an enticing solution. This solution has yet to race or to my knowledge even be tested in a car, Renault have admitted that as a broader automotive organisation, that this systems has been tried.
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