What Is a VTEC?

VTEC is an engine system developed by the Honda Motor Company. It was developed by Honda engineer Ikuo Kajitani, and uses technology that dates back to the early 1980s. VTEC engines use electronic controls to maximize their output and efficiency.

The VTEC Acronym

The VTEC system is a follow-up to Honda's REV system (revolution modulated valve control) which was introduced in 1983.
VTEC is an acronym for Variable Valve Timing and Lift Electronic Control. VTEC engines use two different camshaft profiles with one of the profiles selected electronically to maximize the engine's efficiency. Today, VTEC-like systems for variable valve timing are offered under other names by several automakers, though Honda's system was the first of its kind.

Operation

The VTEC system uses an electronic control unit (ECU) to select between two different camshaft profiles, one of which is designed to maximize fuel efficiency when the engine is running at low RPMs, and the other meant to maximize engine output at high-RPM operation. The ECU chooses between the two profiles based on input from various sensors that monitor oil pressure, vehicle speed, engine RPM and throttle position.

Introduction

Honda first made the VTEC system available on its dual overhead cam (DOHC) engines. The first models to feature a VTEC engine were the European models of the Integra and Civic in 1989. The first appearance of the VTEC in the United States was the 1990 Acura NSX sports car. The NSX was unusual for being a sports car powered by a V6 engine, but the VTEC system allowed for a maximum output of 270 horsepower.

Expansion

As competing automakers began to introduce VTEC-like systems, Honda turned its status as an originator of the technology into an important marketing tool. VTEC was soon offered on vehicles with large and small engines alike, including the Honda Prelude and Honda Del Sol, as well as later editions of the Integra and Civic.
A single overhead cam (SOHC) version of the VTEC was also developed. Initially, this system suffered from engineering problems, and performance was poor, but engineering refinements made the SOHC VTEC as reliable as the trusted DOHC version. In 2002, Honda began offering VTEC-equipped motorcycles.

Variations

Honda also capitalized on the popularity of VTEC by developing several variants with specific applications. VTEC-E was designed with an emphasis on fuel economy at the expense of power output. This was accomplished by using the car's ECU to control the ratio of fuel and air entering the engine.
Introduced in 2001, iVTEC ("intelligent VTEC") featured a continuously variable camshaft profile, instead of the earlier system which featured only two fixed profiles.

Resources

• Honda Worldwide