computer science crazy
Guest
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.
VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. In 1998, 'Dual' VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza's 3S-GE engine. Dual VVT-i is also found in Toyota's new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Other Dual VVT-i engines will be seen in upcoming Toyota models, including a new 4 cylinder Dual VVT-i engine for the new generation 2007/2008 Corolla. Another notable implementation of the Dual VVT-i is the 2GR-FSE D-4S engine of the Lexus GS450h. By adjusting the valve timing, engine start and stop occur virtually unnoticable at minimum compression, and fast heating of the catalytic converter to its light-off temperature is possible, thereby reducing HC emissions considerably.
Posts: 4
Threads: 0
Joined: Jul 2009
Posts: 3
Threads: 0
Joined: Jul 2009
can i get the full report please.
Posts: 226
Threads: 187
Joined: Jul 2009
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota, similar in performance to the BMW's VANOS. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 5-valve per cylinder 4A-GE engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.
VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position.
VVTL-i
In 1998, Toyota began offering a new technology, VVTL-i, which can alter valve lift (and duration) as well as valve timing. In the case of the 16 valve 2ZZ-GE, the engine has 2 camshafts, one operating intake valves and one operating exhaust valves. Each camshaft has two lobes per cylinder, one low rpm lobe and one high rpm, high lift, long duration lobe. Each cylinder has two intake valves and two exhaust valves. Each set of two valves are 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 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 low lobe is operating the rocker arm and thus the valves. When the engine is operating above the lift engagement point, the ECU activates an oil pressure switch which pushes a sliding pin under the slipper follower on each rocker arm. This in effect, switches to the high lobe causing high lift and longer duration
http://en.wikipediawiki/VVT-i
http://images.googleimages?client=opera&rls=en&q=VVT-i&sourceid=opera&oe=utf-8&um=1&ie=UTF-8&ei=3RqXSovaBMmDkAXBz6WZDA&sa=X&oi=image_result_group&ct=title&resnum=4
http://kereta.info/how-toyota-vvti-engin...telligent/
Posts: 4,190
Threads: 817
Joined: Feb 2012
to get information about the topic VVT-i full report ,ppt and related topic refer the page link bellow
http://studentbank.in/report-vvt-i-or-va...telligence
http://studentbank.in/report-vvt-i--2151