Bueno, después del regaño, lei... y confirme:
VTEC:
Variable Valve Timing and Lift Electronic Control
VVT: Variable Valve Timing, a secas
El VTEC es un tipo de VVT, el primero en ser tan difundido. Después han venido muchos más, utilizando diferentes tecnologías para hacer básicamente lo mismo: variar el tiempo de apertura de las válvulas dependiendo de las RPM (o incluso de la apertura del Throttle Body, etc.). En fin, VVT es sólo una parte del sistema o el concepto básico en las variaciones que sobre el tema existen. El VTEC añade entonces el levante electrónico, pero sigue usando el concepto del VVT como tal.
Donde confirmé?
http://www.carbibles.com/fuel_engine_bible_vvt.html
También, para la muestra un "par"de sistemas VVT, tomados de Wikipedia:
VVT implementations
Aftermarket modifications — Conventional hydraulic tappet can be engineered to rapidly bleed-down for variable reduction of valve opening and duration.
Alfa Romeo
Twin Cam — some versions are equipped with Variable Valve Timing technology.
Twin Spark — is equipped with Variable Valve Timing technology.
JTS — is equipped with Variable Valve Timing technology, both intake and exhaust.
Multiair continuously varies the timing of the inlet valve by changing oil pressure.
BMW
Valvetronic — Provides continuously variable lift for the intake valves; used in conjunction with Double VANOS.
VANOS — Varies intake timing by rotating the camshaft in relation to the gear.
Double VANOS — Continuously varies the timing of the intake and exhaust valves.
Fiat
"StarJet" FIRE-based engine.
Ford
VCT Variable Cam Timing — Varies valve timing by rotating the camshaft.
Ti-VCT Twin Independent Variable Camshaft with two fully variable camshafts used in Ford Sigma engine and Ford Duratec engine.
Chrysler — Varies valve timing through the use of concentric camshafts developed by Mechadyne enabling dual-independent inlet/exhaust valve adjustment on the 2008 Dodge Viper.
General Motors Corporation (GM)
VVT — Varies valve timing continuously throughout the RPM range for both intake and exhaust for improved performance in both overhead valve and overhead cam engine applications.(See also Northstar System).
DCVCP (Double Continuous Variable Cam Phasing) — Varies intake and exhaust camshaft timing continuously with hydraulic vane type phaser (see also Ecotec LE5).
Alloytec — Continuously variable camshaft phasing for inlet cams. Continuously variable camshaft phasing for inlet cams and exhaust cams (High Output Alloytec).
Honda
VTEC — Varies duration, timing and lift by switching between two different sets of cam lobes.
VTEC-E — This system is designed solely for the purpose of improving fuel economy. A variation of the VTEC mechanism is used to create an offset of lift between the two intake valves, one valve opening only slightly to prevent accumulation of fuel in the intake port. The asymmetrical opening of the intake valves creates a powerful swirl in the combustion chamber and allows for a very lean intake charge to be used under certain conditions. Under normal operation the two intake valve rocker arms are locked together and both valves follow the normal lift cam profile.
i-VTEC — In high-output DOHC 4 cylinder engines, the i-VTEC system adds continuous intake cam phasing (timing) to traditional VTEC. In economy-oriented SOHC and DOHC 4-cylinder engines the i-VTEC system increases engine efficiency by delaying the closure of the intake valves under certain conditions and by using an electronically controlled throttle valve to reduce pumping loss. In SOHC V6 engines the i-VTEC system is used to provide variable cylinder management which deactivates one bank of 3 cylinders during low demand operation.
Advanced VTEC — This is the latest Honda VVT system and is the most unique of all the VTEC systems. Rather than switching between cam lobes the Advanced VTEC system uses intermediate rocker arms with a variable fulcrum to continuously vary intake valve timing, duration and lift.
Hyundai MPI CVVT — Varies power, torque, exhaust system, and engine response.
Kawasaki — Varies position of cam by changing oil pressure thereby advancing and retarding the valve timing, 2008 Concours 14.
Lexus VVT-iE — Continuously varies the intake camshaft timing using an electric actuator.
Mazda S-VT — Continually varies intake timing and crank angle using an oil control valve actuated by the ECU to control oil pressure.
Mitsubishi MIVEC — Varies valve timing, duration and lift by switching between two different sets of cam lobes. The 4B1 engine series uses a different variant of MIVEC which varies timing (phase) of both intake and exhaust camshafts continuously.
Nissan
N-VCT — Varies the rotation of the cam(s) only, does not alter lift or duration of the valves.
VVL — Varies timing, duration, and lift of the intake and exhaust valves by using two different sets of cam lobes.
CVTC introduced with the HR15DE, HR16DE, MR18DE and MR20DE new engines in September 2004 on the Nissan Tiida and North American version named Nissan Versa (in 2007); and finally the Nissan Sentra (in 2007).
VVEL introduced with the VQ37VHR Nissan VQ engine engine in 2007 on the Infiniti G37.
Porsche
VarioCam — Varies intake timing by adjusting tension of a cam chain.
VarioCam Plus — Varies intake valve timing by rotating the cam in relation to the cam sprocket as well as duration, timing and lift of the intake and exhaust valves by switching between two different sets of cam lobes.
Proton Campro CPS — Varies intake valve timing and lift by switching between 2 sets of cam lobes without using rocker arms as in most variable valve timing systems. Debuted in the 2008 Proton Gen-2 CPS[5][6] and the 2008 Proton Waja CPS.
PSA Peugeot Citroën CVVT — Continuous variable valve timing.
Renault Clio Renault Sport 172, 172 Cup, 182, 182 Cup, Trophy, 197, 197 Cup, 200, and Clio V6 Mk2 VVT — variable valve timing.
Rover VVC — Varies timing with an eccentric disc.
Suzuki — VVT — Suzuki M engine
Subaru
AVCS — Varies timing (phase) with hydraulic pressure, used on turbocharged and six-cylinder Subaru engines.
AVLS — Varies duration, timing and lift by switching between two different sets of cam lobes (similar to Honda VTEC). Used by non-turbocharged Subaru engines.
Toyota
VVT — Toyota 4A-GE 20-Valve engine introduced VVT in the 1992 Corolla GT-versions.
VVT-i — Continuously varies the timing of the intake camshaft, or both the intake and exhaust camshafts (depending on application).
VVTL-i — Continuously varies the timing of the intake valves. Varies duration, timing and lift of the intake and exhaust valves by switching between two different sets of cam lobes.
Volkswagen Group — VVT introduced with later revisions of the 1.8t engine, and the 30v 2.8l V6. Similar to VarioCam, the intake timing intentionally runs advanced and a retard point is calculated by the ECU. A hydraulic tensioner retards the intake timing. Most modern VW Group petrol engines now include VVT on either the inlet cam, or both inlet and exhaust cams, as in their V6, V8 and V10 engines.
Volvo — CVVT
Yamaha — VCT (Variable Cam Timing) Varies position of cam thereby advancing and retarding the valve timing.
Proton — VVT introduced in the Waja 1.8's F4P renault engine (Toyota supplies the VVT to renault)
