VVT-i

"Valvematic" redirects here. Not to be confused withValvetronic.

Cutaway view of Variable Valve Timing with intelligence on aZRengine inTechniquest Glyndŵr

VVT-i,orVariable Valve Timing with intelligence,is anautomobilevariable valve timingpetrol enginetechnologymanufactured byToyota Groupand used bybrandsGroupe PSA(PeugeotandCitroen),Toyota,Lexus,Scion,Daihatsu,Subaru,Aston Martin,PontiacandLotus Cars.It was introduced in 1995 with the2JZ-GEengine found in theJZS155 Toyota CrownandCrown Majesta.

The VVT-i system replaces the previous ToyotaVVTsystem introduced in 1991 with the five-valve per cylinder4A-GE"Silver Top" engine found in theAE101 Corolla LevinandSprinter Trueno.The VVT system is a 2-stage hydraulically controlled cam phasing system.

VVT-i varies the timing of theintakevalvesby adjusting the relationship between thecamshaftdrive (belt or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. Adjustments in the overlap time between the exhaust valve closing and intake valve opening result in improved engine efficiency.

Variants of the system, includingVVTL-i,Dual VVT-i,VVT-iE,VVT-iW,Valvematic,D-4 (VVT-i D-4)andD-4Shave followed.

VVTL-i

The 2ZZ-GE engine, the first and only engine to feature VVTL-i

VVTL-i(Variable Valve Timing and Lift intelligent system) (also sometimes denoted as VVT-iL or Variable Valve Timing and Intelligence with Lift) is an enhanced version of VVT-i that can alter valvelift(andduration) as well as valve timing. It was introduced with the2ZZ-GEfound in the 1999Toyota Celica.In the case of the 16-valve2ZZ-GE,the engine head resembles a typicalDOHCdesign, featuring separate cams for intake and exhaust and featuring two intake and two exhaust valves (four total) per cylinder. Unlike a conventional design, each camshaft has two lobes per cylinder, one optimized for lower rpm operation and one optimized for high rpm operation, with higher lift and longer duration. Each valve pair is controlled by one rocker arm, which is operated by the camshaft. Each rocker arm has a slipper follower mounted to the rocker arm with a spring, allowing the slipper-follower to freely move up and down with the high lobe without affecting the rocker arm. When the engine is operating below 6000-7000 rpm (dependent on year, car, and ECU installed), the lower lobe is operating the rocker arm and thus the valves, and the slipper-follower is freewheeling next to the rocker arm. When the engine is operating above the lift engagement point, theECUactivates an oil pressure switch which pushes a sliding pin under the slipper-follower on each rocker arm. The rocker arm is now locked into the slipper-follower's movements and thus follows the movement of the high rpm cam lobe and will operate with the high rpm cam profile until the pin is disengaged by the ECU. The lift system is similar in principle toHonda'sVTECoperation. Toyota has ceased production of its VVTL-i engines in most markets, because it does not meetEuro IVspecifications for emissions regulations. This includes theCorolla T-Sport(Europe),Corolla Sportivo(Australia),Celica,Corolla XRS,Matrix XRS,and thePontiac Vibe GT,all of which had the2ZZ-GEengine fitted. TheLotus EliseandExigecontinued to offer the2ZZ-GEengine until 2011, with the Exige offering the engine with asupercharger.

Dual VVT-i

The BEAMS 3S-GE 5th-generation engine ( "Black Top" ), the first to feature Dual VVT-i

TheDual VVT-isystem adjusts timing on both the intake and exhaust camshafts. It was introduced in 1998, on theAltezza RS200's3S-GEengine. Dual VVT-i is also found in Toyota's 3.5-litre2GR-FEV6 engine, first appearing on the 2005Avalon.This engine can be found on numerous Toyota and Lexus models. By adjusting the valve timing, engine start and stop occurs almost unnoticeably at minimum compression. Fast heating of the catalytic converter to its light-off temperature is possible, thereby reducing hydrocarbon emissions considerably. Most Toyota engines including the1LR-GUE(V10,used in theLexus LFA),UR engines(V8),GR engines(V6),AR engines(largeI4),ZR engines(mediumI4), andNR engines(smallI4) use this technology.

VVT-iE

The 1UR-FSE engine, the first to feature VVT-iE

VVT-iE(Variable Valve Timing - intelligent by Electric motor) is a version of Dual VVT-i that uses an electrically operated actuator to adjust and maintain intakecamshafttiming.The exhaust camshaft timing is still controlled using a hydraulic actuator. This form of variable valve timing technology was developed initially forLexusvehicles. This system was introduced on the1UR-FSEengine in the 2007Lexus LS 460.The electric motor in the actuator spins together with the intake camshaft as the engine runs. To maintain camshaft timing, the actuator motor will operate at the same speed as the camshaft. To advance the camshaft timing, the actuator motor will rotate slightly faster than the camshaft speed. To retard camshaft timing, the actuator motor will rotate slightly slower than camshaft speed. The speed difference between the actuator motor and camshaft timing is used to operate a mechanism that varies the camshaft timing. The benefit of the electric actuation is enhanced response and accuracy at low engine speeds and at lower temperatures as well as a greater total range of adjustment. The combination of these factors allows more precise control, resulting in an improvement of both fuel economy, engine output and emissions performance.

VVT-iW

The 8AR-FTS engine, the first to feature VVT-iW

VVT-iW(Variable Valve Timing - intelligent Wide) was introduced with the 2.0Lturbochargeddirect-injected8AR-FTSfitted to theLexus NX 200t.VVT-iW uses VVT-iW on the intake valves and VVT-i on the exhaust valves. The intake cam has mid-position cam lock mechanism that retards the continuously variable timing. It offers expanded valve opening angles (Wide) which enables the engine to operate in a modified-Atkinson cycleat low rpm for improved economy and lower emissions, and in theOtto cycleat high rpm for better performance, while delivering high torque throughout the rpm band.

Valvematic

The 3ZR-FAE engine, the first to feature the Valvematic system

TheValvematicsystem offers continuous adjustment to valve lift and timing and improvesfuel efficiencyby controlling the fuel/air intake using valve control rather than conventional throttle plate control.The technology made its first appearance in 2007 with the3ZR-FAEengine in theNoahand later in early-2009 in theAvensis.This system is simpler in design compared toValvetronicandVVEL,allowing the cylinder head to remain at the same height.

D-4

D-4(standing for Direct Four Line) is adirect injectionsystem used in a number of Toyota engines, sometimes referred to asVVT-i D-4.It appeared on the1JZ-FSEand2JZ-FSEengines found in some models of theToyota CrownandToyota Crown Majesta.It can also be found in several engines in theToyota AvensisandToyota RAV4.

D-4S

The 2GR-FSE engine, the first to use D-4S

D-4Sis a twin injection fuel system combining both indirect and direct injection, using a traditional manifold fuel injector on one end for low pressure and a direct injector on the other for high pressure. It works in conjunction with VVT-i. This system debuted in the2GR-FSEengine used in theToyota Crown Athleteand theLexus IS 350.This system was also used in the4U-GSE(FA20) engine found in the 2012–2021Toyota 86andSubaru BRZworking in conjuction with Subaru'sAVCSsystem, as well as theFA24Dengine used in the 2022–presentToyota GR86and Subaru BRZ, also working in conjunction with the AVCS system.

It is important to note that the "S" in the D-4S name doesnotsignify a supercharged engine, as engines using the D-4S system such as the 4U-GSE and the 2GR-FSE do not have superchargers.

VVT-i oil supply hose issues

In 2010, Toyota USA announced aLimited Service Campaign (LSC 90K)to replace the rubber portion of the oil supply hose for the VVT-i actuator on the 2GR-FE (V6) engine, which were found to be defective. In all, approximately 1.6 million vehicles manufactured prior to 2008 were affected. The defective oil supply hoses were prone to degradation and eventual rupture, causing oil to rapidly leak and resulting in permanent engine damage. In 2014, the LSC 90K Campaign was extended to 31 December 2021on 117,500 Toyota brand vehicles that were "missed" during the initial campaign.

See also

• Variable valve timing
• Variable valve lift
• Petrol direct injection(Toyota D-4 and D-4S)
• Variable-length intake manifold
• List of Toyota engines
  • Toyota AR engine
  • Toyota AZ engine
  • Toyota FZ engine
  • Toyota GR engine
  • Toyota JZ engine
  • Toyota LR engine
  • Toyota MZ engine
  • Toyota NZ engine
  • Toyota NR engine
  • Toyota UR engine
  • Toyota ZR engine
  • Toyota ZZ engine
• VTEC
• S-VT
• MIVEC
• Valvetronic