VVT-i

VVT-i
Company type	Technology
Industry	Automotive
Founded	1995; 31 years ago
Founder	Toyota Group
Products	Variable valve timing systems for petrol engines
Owner	Toyota Group

VVT-i (Variable Valve Timing with intelligence) is a technology for variable valve timing in petrol engines, created by the Toyota Group. It has been implemented by various manufacturers such as Groupe PSA (Peugeot, Citroën), Toyota, Lexus, Scion, Daihatsu, Subaru, Aston Martin, Pontiac, and Lotus Cars. Launched in 1995 with the 2JZ-GE engine found in the JZS155 Toyota Crown and Crown Majesta, VVT-i replaced Toyota's earlier 1991 VVT system that was used in the five-valve-per-cylinder 4A-GE "Silver Top" engine of the AE101 Corolla Levin and Sprinter Trueno. The initial VVT system utilized a two-stage cam phasing mechanism controlled hydraulically.

The VVT-i system improves intake valve timing by modifying the camshaft drive to the intake camshaft through engine oil pressure actuators, resulting in enhanced engine efficiency via variable valve overlap timing. Variations of this technology include VVTL-i, Dual VVT-i, VVT-iE, VVT-iW, and Valvematic. Furthermore, direct injection variants such as D-4 (VVT-i D-4) and D-4S are combined with VVT-i to boost both performance and emission control.

VVTL-i

VVTL-i (Variable Valve Timing and Lift intelligent system), occasionally called VVT-iL, builds upon VVT-i by adjusting valve lift and duration as well as timing. Introduced with the 16-valve 2ZZ-GE engine in the 1999 Toyota Celica, this system features a DOHC layout with two lobes per cylinder on each camshaft—one designed for low rpm and another for high rpm with greater lift and extended duration. Below approximately 6,000–7,000 rpm (depending on the variant), valves follow the low-lobe profile; beyond this rpm range, an ECU-managed oil pressure switch activates a locking pin that engages the rocker arm to track the high-lobe cam profile.

Functionally similar to Honda’s VTEC technology, VVTL-i has largely been discontinued in most regions due to its failure to meet Euro IV emissions standards. Vehicles equipped with the 2ZZ-GE engine include the Corolla T-Sport (Europe), Corolla Sportivo (Australia), Celica, Corolla XRS, Matrix XRS, and Pontiac Vibe GT. The Lotus Elise and Exige models continued to utilize this engine until 2011, with a supercharged option available for the Exige.

Dual VVT-i

Dual VVT-i enables adjustment of valve timing on both intake and exhaust camshafts. This system first appeared on the 3S-GE engine of the Altezza RS200 in 1998 and was subsequently incorporated into Toyota’s 3.5-litre 2GR-FE V6 engine, debuting on the 2005 Avalon. Dual VVT-i is now widely adopted across numerous Toyota and Lexus vehicles. By optimizing valve timing on both cams, it facilitates smoother engine restarts and accelerates catalytic converter warm-up times, significantly lowering hydrocarbon emissions. This technology is integrated into many Toyota engines including the 1LR-GUE (the V10 powering the Lexus LFA), UR series V8s, GR series V6s, AR inline-4s, ZR inline-4s, and NR inline-4s.

VVT-iE

VVT-iE (Variable Valve Timing - intelligent by Electric motor) advances Dual VVT-i by employing an electric motor actuator for controlling intake camshaft timing while retaining hydraulic control for exhaust timing. Initially developed for Lexus, it made its first appearance on the 1UR-FSE powering the 2007 Lexus LS 460. The electric actuator adjusts intake timing with high precision by modulating motor speed relative to camshaft position, enabling quicker and more accurate responses especially at low speeds and cooler temperatures. This enhanced control contributes to improved fuel efficiency, performance output, and emissions reduction.

VVT-iW

VVT-iW (Variable Valve Timing - intelligent Wide) was first introduced with the 2.0L turbocharged direct-injection 8AR-FTS powering the Lexus NX 200t. This system integrates VVT-iW on the intake valves alongside VVT-i on the exhaust valves. By utilizing a mid-position cam lock, it delays intake valve timing to widen valve opening angles, allowing the engine to operate on a modified-Atkinson cycle at low engine speeds for enhanced fuel economy and reduced emissions. At higher rpm, it switches to the Otto cycle to deliver improved performance and maintain strong torque throughout the rev range.

Valvematic

The Valvematic technology continuously varies both valve lift and timing, improving fuel efficiency by managing air and fuel intake through valve adjustments rather than a traditional throttle plate. Launched in 2007 with the 3ZR-FAE engine in the Noah, it was subsequently incorporated into the 2009 Avensis. Compared to systems like Valvetronic and VVEL, Valvematic features a more straightforward design that keeps the cylinder head height fixed.

Direct injection systems

Since 1996, Toyota has paired its VVT-i technology with gasoline direct injection (GDI) systems, including D-4 and D-4S variants.

Engines equipped with direct injection are identified by an "S" suffix in Toyota's engine codes (for example, 2JZ-FSE, 2GR-FSE, and 4U-GSE). Historically, this suffix denoted swirl intake ports (such as in 3A-SU).

D-4

D-4 (Direct Four Line) represents Toyota’s direct injection technology, occasionally referred to as VVT-i D-4. Developed in 1996, it made its debut around 2000 on engines like the 1JZ-FSE and 2JZ-FSE, which powered vehicles such as the Toyota Crown and Crown Majesta. The system is also found in engines used by the Toyota Avensis and Toyota RAV4. It employs high-pressure swirl control valves to enhance combustion efficiency, complemented by a three-way catalytic converter. Integrated with VVT-i, D-4 achieves ultra-lean fuel consumption alongside cleaner emissions while boosting power, torque, and throttle response. All engines featuring D-4 utilize electronic throttle control (drive-by-wire) rather than mechanical throttle cables.

D-4S

D-4S (Direct Four Line Superior) is an advanced dual-injection fuel system combining both indirect port injection and direct injection. It operates with a conventional low-pressure manifold injector alongside a high-pressure direct injector, coordinated with VVT-i and its derivatives. This system first appeared in the 2GR-FSE powering the Toyota Crown Athlete and Lexus IS 350, marking Toyota’s initial fusion of traditional and direct fuel injection methods. Additionally, D-4S is utilized in the 4U-GSE (FA20) engine found in the 2012–2021 Toyota 86 and Subaru BRZ, as well as in Subaru's FA24D powering the current-generation (2022–present) Toyota GR86 and Subaru BRZ models, integrating with Subaru's AVCS. Compared to D-4, D-4S offers cleaner exhaust emissions and increased peak power at elevated rpm.

It is important to note that the "S" designation in D-4S does not signify supercharging; engines such as the 4U-GSE and 2GR-FSE are naturally aspirated. Toyota uses "Z" within its naming conventions to indicate supercharged engines—for instance, 4A-GZE, 1G-GZE, and 2TZ-FZE.

VVT-i oil supply hose concerns

In 2010, Toyota USA initiated a Limited Service Campaign (LSC 90K) aimed at replacing faulty rubber oil supply hoses connected to the VVT-i actuator on the 2GR-FE V6 engine. This recall impacted roughly 1.6 million vehicles manufactured before 2008, as hose deterioration caused oil leaks that could result in engine damage. The campaign's coverage was extended until December 31, 2021, to include 117,500 Toyota units that were initially overlooked.

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