VVT-i
Encyclopedia
Automobile
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
variable valve timing
Variable valve timing
In internal combustion engines, variable valve timing , also known as Variable valve actuation , is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine...
technology developed by Toyota, similar in performance to the BMW's VANOS
VANOS
VANOS is an automobile variable valve timing technology developed by BMW in close collaboration with Continental Teves. VANOS varies the timing of the valves by moving the position of the camshafts in relation to the drive gear...
. The Toyota VVT-i system replaces the Toyota VVT offered starting in 24 December 1991 on the 5-valve per cylinder 4A-GE engine. The VVT system is a 2-stage hydraulically controlled cam phasing system. The Toyota motors CEO has been reported to have said, "VVT is the heart of every modern Toyota!"
VVT-i, introduced in 1996, varies the timing of the intake
Intake
An intake , or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power...
valve
Poppet valve
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...
s by adjusting the relationship between the camshaft
Camshaft
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...
drive (belt, scissor-gear 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, including VVTL-i, Dual VVT-i, Triple VVT-iE, and Valvematic, have followed.
VVTL-i
Engine Control Unit
An engine control unit is a type of electronic control unit that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to keep running...
activates an oil pressure switch which pushes a sliding pin under the slipper follower on each rocker arm. The rocker arm is now locked into 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 to Honda
Honda
is a Japanese public multinational corporation primarily known as a manufacturer of automobiles and motorcycles.Honda has been the world's largest motorcycle manufacturer since 1959, as well as the world's largest manufacturer of internal combustion engines measured by volume, producing more than...
VTEC
VTEC
VTEC is a valvetrain system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine. The VTEC system uses two camshaft profiles and electronically selects between the profiles. It was invented by Honda R&D engineer Ikuo Kajitani, and was the first system...
operation.
The system was first used in 2000 Toyota Celica
Toyota Celica
The Toyota Celica name has been applied to a series of coupes made by the Japanese company Toyota. The name is ultimately derived from the Latin word coelica meaning "heavenly" or "celestial"....
with 2ZZ-GE. Toyota has now ceased production of its VVTL-i engines for most markets, because the engine does not meet Euro IV specifications for emissions. As a result, this engine has been discontinued on some Toyota models, including that of the Corolla
Toyota Corolla
The Toyota Corolla is a line of subcompact and compact cars manufactured by the Japanese automaker Toyota, which has become very popular throughout the world since the nameplate was first introduced in 1966. In 1997, the Corolla became the best selling nameplate in the world, with over 35 million...
T-Sport (Europe), Corolla
Toyota Corolla
The Toyota Corolla is a line of subcompact and compact cars manufactured by the Japanese automaker Toyota, which has become very popular throughout the world since the nameplate was first introduced in 1966. In 1997, the Corolla became the best selling nameplate in the world, with over 35 million...
Sportivo (Australia), Celica, Corolla XRS
Toyota Corolla
The Toyota Corolla is a line of subcompact and compact cars manufactured by the Japanese automaker Toyota, which has become very popular throughout the world since the nameplate was first introduced in 1966. In 1997, the Corolla became the best selling nameplate in the world, with over 35 million...
, Toyota Matrix
Toyota Matrix
The Toyota Matrix, sometimes officially referred to as the Toyota Corolla Matrix, is a compact hatchback manufactured by the Toyota Motor Corporation in Canada, to be sold in the United States, Canada, and Mexico...
XRS, and the Pontiac Vibe
Pontiac Vibe
The Pontiac Vibe is a compact hatchback car that was produced in Fremont, California, in the United States by NUMMI , a joint venture between General Motors and Toyota, and marketed under General Motors' Pontiac brand...
GT, all of which had the 2ZZ-GE engine fitted. The Lotus Elise continues to offer the 2ZZ-GE and the 1ZZ-FE engine, while the Exige
Lotus Exige
The Lotus Exige is a two-door, two-seat sports car made by Lotus Cars. It is essentially a coupé version of the Lotus Elise, a mid-engined roadster in production since 1996....
offers the engine with a supercharger
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
.
Dual VVT-i
Dual VVT-i is also found in Toyota's new generation V6 engine, the 3.5-liter 2GR-FE first appearing on the 2005 Avalon
Toyota Avalon
The Toyota Avalon is a full-size car produced by Toyota in the United States, and is the flagship sedan of Toyota in the United States, Canada, Puerto Rico and the Middle East. It was also produced in Australia from 2000 until July 2005 when it was replaced in November 2006 by the Toyota Aurion...
. This engine can now 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 the UR engines
Toyota UR engine
The Toyota UR engine family is a 32-valve quad-camshaft V8 piston engine series which was first introduced in 2006 as the UZ series it replaced began phasing out. Production started with the 1UR-FSE engine with D4-S direct injection for the 2007 Lexus LS. The series launched with a die-cast...
(V8), GR engines
Toyota GR engine
The Toyota GR engine family is an open-deck, V6 piston engine series. The GR series has a 60° die-cast aluminum block and aluminum DOHC cylinder heads. This engine series also features 4 valves per cylinder, forged steel connecting rods, one-piece cast camshafts, and a cast aluminum lower intake...
(V6), AR engines
Toyota AR engine
The AR engine family is a straight-4 piston engine series by Toyota, first introduced in 2008 for the RAV4, and subsequently for the Highlander, Venza, and Camry.The AR series uses a die-cast aluminium engine block and aluminium DOHC cylinder head...
(Large I4
I4
I4, i4, I 4 or I-4 may be:* iPhone 4, a popular mobile device from Apple* I4 , a Japanese video game developer and publisher...
), and ZR engines
Toyota ZR engine
The ZR engine family, introduced in 2007 by Toyota Motor Corporation, uses a DOHC 16-valve cylinder head with a 4-cylinder die-cast block. Engines displace either 1.6 liters, 1.8-liters or 2.0-liters. All engines in this family are equipped with Toyota's dual VVT-i technology that optimizes both...
(Small I4
I4
I4, i4, I 4 or I-4 may be:* iPhone 4, a popular mobile device from Apple* I4 , a Japanese video game developer and publisher...
) now use this technology.
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 intake camshaftCamshaft
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...
timing. The exhaust camshaft timing is still controlled using a hydraulic actuator. This form of variable valve timing technology was developed initially for Lexus
Lexus
is the luxury vehicle division of Japanese automaker Toyota Motor Corporation. First introduced in 1989 in the United States, Lexus is now sold globally and has become Japan's largest-selling make of premium cars. The Lexus marque is marketed in over 70 countries and territories worldwide, and has...
vehicles. This system was first introduced on the 2007MY Lexus LS 460
Lexus LS
The Lexus LS is a full-size luxury sedan that serves as the flagship model of Lexus, the luxury division of Toyota. Four generations of the sedan have been produced, all equipped with V8 engines and rear-wheel drive, although since 2006 all-wheel drive, hybrid, and long-wheelbase variants have also...
as 1UR
Toyota UR engine
The Toyota UR engine family is a 32-valve quad-camshaft V8 piston engine series which was first introduced in 2006 as the UZ series it replaced began phasing out. Production started with the 1UR-FSE engine with D4-S direct injection for the 2007 Lexus LS. The series launched with a die-cast...
engine.
Valvematic
The Valvematic system offers continuous adjustment to lift volume and timing, and improves fuel efficiency by controlling the fuel/air mixture using valve control rather than conventional throttle plate control. The technology made its first appearance in 2007 in the NoahToyota Noah
The Toyota Noah is an eight-seater MPV with two rear sliding doors built by Toyota Motor Company and sold only in Asia. A five-seater version without the third seat row is available . Its predecessor was the Toyota Liteace Noah...
and later in early-2009 in the ZR engine family
Toyota ZR engine
The ZR engine family, introduced in 2007 by Toyota Motor Corporation, uses a DOHC 16-valve cylinder head with a 4-cylinder die-cast block. Engines displace either 1.6 liters, 1.8-liters or 2.0-liters. All engines in this family are equipped with Toyota's dual VVT-i technology that optimizes both...
used on the Avensis
Toyota Avensis
The Toyota Avensis is a large family car built in Derbyshire, United Kingdom by Japanese carmaker Toyota since 1997. It is the direct successor to the Carina E and is available as a four-door saloon, five-door liftback and estate...
. This system is simpler in design compared to Valvetronic
Valvetronic
The Valvetronic system is a variable valve timing system to offer continuous and precisely variable intake valve lift, from ~0 to 10 mm, and duration. It typically works in conjunction with the independent Double VANOS system that continuously varies the timing...
and VVEL, allowing the cylinder head to remain at the same height.
See also
- Variable valve timingVariable valve timingIn internal combustion engines, variable valve timing , also known as Variable valve actuation , is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine...
- Gasoline Direct InjectionGasoline direct injectionIn internal combustion engines, gasoline direct injection , also known as petrol direct injection or direct petrol injection, is a variant of fuel injection employed in modern two-stroke and four-stroke gasoline engines...
(Toyota D4 and D4-S) - Variable Length Intake ManifoldVariable Length Intake ManifoldIn internal combustion engines, a variable length intake manifold , or variable intake manifold is an automobile internal combustion engine manifold technology...
- List of Toyota engines
External links
- VVT-i video animation
- Video animation of VVT-i can be found here (courtesy of PT. Toyota Astra Motor, Indonesia)