VarioCam is an

automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

variable valve timing In internal combustion engines, variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with var ...

technology developed by

Porsche Dr. Ing. h.c. F. Porsche AG, usually shortened to Porsche (; see below), is a German automobile manufacturer specializing in high-performance sports cars, SUVs and sedans, headquartered in Stuttgart, Baden-Württemberg, Germany. The company ...

. VarioCam varies the timing of the

intake An intake (also inlet) is an opening, structure or system through which a fluid is admitted to a space or machine as a consequence of a pressure differential between the outside and the inside. The pressure difference may be generated on the ins ...

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

s by adjusting the tension on the timing chain connecting the intake and

exhaust Exhaust, exhaustive, or exhaustion may refer to: Law *Exhaustion of intellectual property rights, limits to intellectual property rights in patent and copyright law ** Exhaustion doctrine, in patent law ** Exhaustion doctrine under U.S. law, in ...

camshaft A camshaft is a shaft that contains a row of pointed cams, in order to convert rotational motion to reciprocating motion. Camshafts are used in piston engines (to operate the intake and exhaust valves), mechanically controlled ignition systems ...

s. VarioCam was first used on the 1992 3.0 L engine in the

Porsche 968 The Porsche 968 is a sports car manufactured by German automobile manufacturer Porsche AG from 1991 until 1995. It was the final evolution of a series of water-cooled front-engine rear wheel drive models begun almost 20 years earlier with the ...

. Porsche's more recent VarioCam Plus combines

with two-stage lift on the intake side. The two-stage valve-lift function is performed by electro-hydraulically operated switchable tappets. Each of these 12 tappets consists of concentric lifters which can be locked together by means of a pin. The inner lifter is actuated by a small cam lobe, while the outer ring element is moved by a pair of larger-profile lobes. The timing of each valve is seamlessly adjusted by means of an electro-hydraulically operated rotary vane adjuster at the head of each intake camshaft. Valve timing and the valve profile are continuously altered according to conditions and engine load. For improved responsiveness on cold starts, VarioCam Plus raises the amount of lift and retards valve timing. At medium revs with minimal loads, the valve lift is lowered and timing advanced to help minimize fuel consumption and emissions. For maximum power and torque, the lift is raised and the timing is advanced. This system debuted on the 1999 Porsche 996 Turbo. A system similar to the VarioCam Plus system was developed by Porsche for

Subaru ( or ; ) is the automobile manufacturing division of Japanese transportation conglomerate Subaru Corporation (formerly known as Fuji Heavy Industries), the twenty-first largest automaker by production worldwide in 2017. Subaru cars are ...

for the redesigned EZ30R H6 engine which debuted in 2003 in the

Legacy In law, a legacy is something held and transferred to someone as their inheritance, as by will and testament. Personal effects, family property, marriage property or collective property gained by will of real property. Legacy or legacies may refer ...

and

Outback The Outback is a remote, vast, sparsely populated area of Australia. The Outback is more remote than the bush. While often envisaged as being arid, the Outback regions extend from the northern to southern Australian coastlines and encompass a ...

References

Porsche Variable valve timing {{automotive-tech-stub