Gandhi Institute of Engineering and Technology,

Gunupur Presentation on VTEC Engine

By: Rahul Bhoi11ME034Mechanical Engineering

INTRODUCTION

VTEC (Variable Valve Timing and Lift Electronic Control)

is a valve train system developed by Honda

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 engineer Ikuo Kajitani.

This was the first system of its kind.

HISTORY

Originated from REV (Revolution-modulated valve

control) introduced on the CRB400 in 1983 known as

HYPER VTEC.

The earliest VTEC-E implementation is a variation of

SOHC VTEC.

Its introduction in usage was to enhance the output

power .

BASIC MECHANISMS

The basic mechanism used by the vtec technology is

hydraulically actuated pin.

Pin reached to rocker arms.

A spring mechanism used to return

the pin back.

Comprises of two camshaft

lobes.

PRINCIPALS

One of the cam lobes on the left hand have a widerprofile , opens its valve earlier.

For more time and close it later in compare to the other.

The fuel is allowed to enter through one valvecompletely , while other valve opens partly.

SERIES OF VTEC ENGINES

SOHC VTEC

VTEC –E

3 STAGE VTEC

I- VTEC

VTEC-E

Vtec E implementation is for the economy.

Uses swirling to promote more

efficient air fuel mixing in engine chamber.

Only one intake cam lobe used.

Making engine to operate in 16

valve working mode.

I-VTEC

The intake camshaft is now capable of advancing between

25 and 50 degrees.

Phasing is implemented by a computer-controlled, oil-

driven adjustable cam gear.

I-VTEC V6 that includes Honda's cylinder deactivation

technology.

VTEC IN MOTORCYCLES

Firstly used in 2003 in sports bikes.

One intake valve remains closed until a threshold of 7000

rpm is reached.

Second valve is opened by an oil-pressure actuated pin.

Uses a single camshaft to provide two timing routines for

the intake .

ADVANTAGES

Better fuel efficiency.

High initial torque with relevant high power.

Lower emission.

Strong performance.

LIMITATIONS

Higher cost of engine.

More complex mechanism.

Wear and Tear problems.

Failed to overcome turbo charging.

Decreased engine life.

FUTURE OF VTEC

Implementation on performance engines.

Better opportunities of higher petroleum prices.

Consideration on its disadvantages gives improvement in

it.

Economy and satisfaction to be estimated.