11-02-2012, 01:21 PM
VTEC
Variable valve timing and lift
Electronically controlled
INTRODUCTION
WHAT THE WORD VTEC MEANS :
The word VTEC means “ Variable valve Timing and lift, Electronically Controlled”
The technology dynamically adjusts valve timing and also valve lift (or amount of opening) while driving.
When you are cruising around town or on the highway with
little throttle the engine control unit deactivates one bank of three
cylinders, reducing the engine capacity from 3.5 litres to 1.75
litres. With light to moderate acceleration the engine will change
to four cylinders, with one cylinder in each bank deactivated
and creating a 2.3-litre engine, both scenarios that improve fuel
economy.
Honda invented VTEC which allows it to extract turbo level
specific output from its engines without having to suffer from
the disadvantages of turbo charging
allows the engine to effectively have multiple camshafts.
As the engine moves into different rpm ranges, the engine's
computer can activate alternate lobes on the camshaft and
change the cam's timing. In this way, the engine gets the best
features of low-speed and high-speed camshafts in the same engine.
ADVANTAGES
Why we should prefer VTEC :
Higher Efficiency
Lower Emission
Greater Performance
Why it is fuel efficient
The diagrams below shows the valve positions at higher and lower speeds
VTEC constitutes
VCM – VARIABLE CYLINDER MANAGEMENT
“Ample power with fuel efficiency”
CVT – CONTINUOSLY VARIABLE TRANSMISSION
“Smooth and Seamless acceleration”
