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VTEC Engines
1. Gandhi Institute of Engineering and
Technology,
Gunupur
Presentation on VTEC Engine
By: Rahul Bhoi
11ME034
Mechanical Engineering
2. 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.
3. 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 .
4. 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.
5. PRINCIPALS
One of the cam lobes on the left hand have a wider
profile , opens its valve earlier.
For more time and close it later in compare to the other.
The fuel is allowed to enter through one valve
completely , while other valve opens partly.
6. SERIES OF VTEC ENGINES
SOHC VTEC
VTEC –E
3 STAGE VTEC
I- VTEC
7. 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.
8. 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.
9. 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 .
10. ADVANTAGES
Better fuel efficiency.
High initial torque with relevant high power.
Lower emission.
Strong performance.
11. LIMITATIONS
Higher cost of engine.
More complex mechanism.
Wear and Tear problems.
Failed to overcome turbo charging.
Decreased engine life.
12. 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.