VTEC is a system of variable valves designed by Honda to control the gas engines in its car models. These days, the system is the market leader in this industry even though most automobile manufacturers have begun to develop their own similar machine. In addition, VTEC system also achieves the most striking success and becomes a famous trademark all over the world, which plays a really important part in Honda’s brand identity.
Since the 80s, due to the increasing demand for sports engines with high power, Honda has started their mission to attempt and develop a type of engine that could provide both drive ability and high power. And the solution achieved through a new system called REV or revolution-modulated valve control. Its main purpose is to stop various valves forcibly if necessary to get the optimal flow of air, provide a steady idling as well as improved smoothness for medium to low engine performance.
From a REV system applied in the engine of motorcycle, Honda has manufactured the VTEC system for cars based on the concept of having both 2 camshaft profiles and variable opening times of valve: for high to middle as well as middle to low engine speeds.
How Does a VTEC System Work?
At first, VTEC is made for DOHC gas engines so that it would switch between operating mode of gas saving and performance. In general, this would be achieved by operating with a valve timing in low pace and minor cam profile with the aim of improving the consumption of gas and burning of leaner gas. In addition, when the motor requires more energy, the VTEC will speed the valve timing up and switch to bigger cam profile, thereby getting a better output.
Switching from the cams with low profile for better consumption of gas to the cams with high profile for better output of power is achieved through a locked pin, which helps to connect 2 separate lobes of cam at a couple of motor speed.
In fact, a VTEC system operates rather similarly to a turbocharger or mechanical compressor by generating a great swirl output and perfect filling feature, which is materialized in better output of power. When it comes to reliability, Honda, the second biggest car manufacturer in Japan, has a perfectly positive record all over the world and VTEC unit is not an exception.
Models of VTEC
For the past few years, Honda has created a couple of VTEC models, which are different in terms of valve system to meet various gas consumption or engine output requirements. Moreover, a VTEC system could also be used to SOHC motors.
This is a system of valve train, which is made with 2 standard cam profiles to start the valves in different forms. In general, the smaller one would allow a valve to open a little bit, thereby getting better consumption of fuel. Similar to the initial VTEC system, if the motor reaches higher RPM, the pin would lock the cams with high profile and the valve timing would increase to achieve better output of power.
This model applies 3 independent cam profiles, which basically run in 3 stages. Every of them will manage a different lift pattern and valve timing.
i-VTEC or intelligent VTEC
This is the most successful VTEC model since its firs introduction in 2001, which is applied broadly in a wide range of car models. An i-VTEC system uses a valve timing with constantly variable intake and computer control to maximize gas efficiency and torque output.
AVTEC or Advanced VTEC
It was first introduced in 2006. With a combination between constantly variable phase management and the advantages of i-VTEC system, AVTEC is used to respond to the needs of a driver in power, which is free from the speed of engine.
In general, Honda introduces that AVTEC system would achieve 75 per cent lower gas emissions than the standards in 2005 and 13 per cent better gas economy than i-VTEC system.