The way of VTEC engine work

How VTEC engine work??

VTEC is a short name for Variable Valve Timing and lift Electronic Control introduced by Honda to improve the volumetric efficiency of the engine, and the VTEC system is a variable valve timing system is the first commercially used in the automotive industry. VTEC system was invented by Honda R & D engineers, Ikuo Kajitani. Here I'll tell you a little about this VTEC engine.

In an engine, cam not only determines the size of the valve opening, but also determine the timing and duration of input / output. When increasing engine speed, the inlet air-fuel mixture as well as the exhaust gas output is becoming increasingly limited. However, the fixed size of the valve opening to prevent more air-fuel mixture to enter during high speed, thus limiting the maximum power of the engine. Thus, the variable valve timing system was created to allow for more air-fuel mixture into the combustion chamber during high engine speeds, thereby increasing engine power.


Types of VTEC system in Honda


Conventional VTEC (SOHC and DOHC)

The most basic VTEC system is DOHC VTEC. In this system, the VTEC system controls the opening timing and valve for both inlet and exhaust valves. Each has 2 cam camshaft per cylinder - small aperture cam and cam large aperture. During low speed, small aperture cam used by default for fuel savings. During a high-speed, electronic solenoid open oil route to large aperture cam locking pins and locking pin cam oil pressure large aperture. As a result, large aperture cam used for maximum power. When the engine speed back down, the solenoid is switched off and the locking pin is released, causing a small aperture cam used again.

For SOHC VTEC, the mechanism used is the same but the single camshaft can only control the timing and inlet valve opening only.


VTEC-E

VTEC-E works in a different way, if the conventional VTEC is used to increase the power of the engine, VTEC-E is designed for maximum fuel economy. In the VTEC-E system, only one inlet valve that opens by default on low speed for maximum fuel economy. At high speed, oil pressure pushes the locking pin to lock the second inlet valve, allowing both inlet valve used.


3 Stage VTEC

3 Stage VTEC combines both VTEC-E technology and conventional VTEC. At low speeds, only one inlet valve opened by default. First locking pin to lock the second inlet valve during moderate engine speeds while the second locking pin is moved to allow large aperture cam used at high speeds. With this, the engine uses 3 Stage VTEC benefit of both fuel economy and increased engine power.


i-VTEC

i-VTEC engine that combines technologies used by pemfasaan cam variable valve timing system to another with VTEC technology in place to reduce the "shock force" during VTEC mechanism works.


VTEC in motorcycles

Besides the engine, Honda's VTEC technology also used on some motorcycle models. It was first used on Honda motorcycles CBR400F Super Four HYPER VTEC, and so on motorcycle Honda VFR800.