Ferrari introduced a new engine spec in Spain; this was in order to resolve a problem with the pneumatic valve system. This raises two points; why are they allowed to change a frozen engine specification and what are the pneumatic valves?
Since the end of 2006 F1 engine specs have been frozen, this was a move to further reduce the costs for the engine suppliers. It was introduced even after stringent standard engine specifications and limited engines over season were introduced. Since the first homologation of the engines, teams have been allowed to retune the engine for different RPM limits and also to accommodate KERS. Offsetting this has been the increase to the parts covered by the specification freeze.
Teams are however allowed to make changes to the their engines for reliability reasons, this applies both to resolving issues that have ‘blown up’ engines, as well as impending failures. To request a change, teams have to apply to the FIA outlining the reason for the change and the resulting changes. This information is passed around the other engine suppliers, this transparency helps to reduce excessive changes and reassures teams what their rivals might or might not be getting up to.
While the fundamental reason for this dispensation is to aid teams with reliability problems, any ‘reliability’ change could also bring a performance gain. This could be either as a direct result of the ‘reliability’ change i.e. lighter part making more power, or as a secondary result, i.e. new valve seat material allows a different fuel for more power. Clearly any possible advantage will be taken by the manufacturers when making changes to the engine.
Ferrari had an issue with leaking pneumatic valves; this meant the car may not be able to last a full race distance without the system being topped up. Thus Ferrari asked for and gained approval to make alterations to their valve system to resolve the problem.
Pneumatic valves are universal in F1 and have been for decades, first introduced by Renault on their V6 turbo engine, they replicate the effect of valve spring in closing the poppet valves in the cylinder head. Where as a valve spring could do the job, they are more difficult to manufacture to cope with ever higher RPMs. Although F1 engines are now limited to 18,000rpm, these pneumatic valves have worked on engines revving to over 20,000rpm. Metal coiled valve springs, suffer from harmonic and fatigue problems at higher revs. While still resolvable, these issues are simply cured with a switch to a pneumatic valve return system (PVRS). Instead of a valve being closed against the cam by a coil spring sat in a pocket in the head, the pocket is sealed by a cap and the resulting closed cylinder pressurised with nitrogen gas creating an airspirng. Of course the PVRS set up can lose pressure and F1 cars run with small nitrogen cylinder housed in the sidepod to keep the system pressurised. Sometimes when excessive leaking occurs, the car is topped up at a pitstop by a mechanic with a hand held gas cylinder. In Ferraris case their problem was that their system had always ‘leaked’ to some degree, but with a ban on the longer fuel stops, pit stops are now too short for effective repressurising. Thus they applied to have their system altered. It is understood that the Ferrari solution takes some lessons from the Toyota teams’ experience, possibly through the new Ferrari Engine Head Luca Marmorini, who also ran Toyotas F1 engine operation until the end of 2008. A different PVRS set up, with different seals and revised oil formulation to aid sealing, the engine is now believed to be more powerful by some 12 horse power. Quite a gain from a change in this era of frozen specification.