![]() ![]() VTEC made its commercial debut on the 1989 Honda Integra XSi in Japan, with stunning results. This forced the two outer arms to act upon the center cam, which featured a longer duration, higher lift, and timing optimized for high-end horsepower. However, as revs increased, the engine computer signaled a spool valve to direct oil pressure to activate a pin that locked the two outer rocker arms to the arm in the center. Each cam had its own rocker arm, but only the outer two actually pressed against the valves, with the central rocker arm assigned only to the center cam.Īt low engine speeds, the two outer cams were used to open and close the valves, with the center cam inactive, since its rocker arm wasn’t directly attached to the valvetrain. The two outer cams were tuned for low-end torque and smooth idle, while the center cam was tuned for high-revving horsepower. This led to the development of Variable Valve Timing and Lift Electronic Control, or VTEC.Īt the core of early VTEC engines was a camshaft featuring three different cam lobes for each pair of valves. Ikuo Kajitani, a Honda engineer at Honda's Tochigi R&D Center, recognized that the solution to this problem was to create a mechanism that could alter the timing and lift of the valves so low-end torque wouldn’t be sacrificed for high-end power, or vice versa. Resetting the valvetrain and retuning an engine for low-end torque would do so at the expense of high-end horsepower. The intricate relationship between the timing, lift, and duration of intake and exhaust valves set to produce high-revving horsepower generally hurts low-end torque. Traditionally, high-revving four-valve-per-cylinder engines sacrificed low-end torque to produce high-revving horsepower. The program led to the development of 4-valve per cylinder double overhead cam (DOHC) engines that debuted in Honda and Acura automobiles at the time, including the 1986 Acura Integra in the U.S ![]() In 1984, Honda launched the New Concept Engine (NCE) program to increase the horsepower and torque produced from its small displacement engines. Originally an alternative to turbochargers, today VTEC is used in conjunction with turbos for maximum responsiveness and power, all while helping vehicles meet strict emissions and fuel economy standards in the U.S. Today, VTEC has evolved to include specialized applications designed to improve fuel efficiency and emissions, as well as add power. As the first practical, reliable and commercially successful variable valve timing and lift technology, VTEC spurred an industry-wide movement to use variable valve timing in engines. Variable Valve Timing and Lift Electronic Control, or VTEC ®, debuted in the late 1980s as a way to extract maximum horsepower and torque from smaller displacement engines without using turbocharging. The technology remains a key component to Honda’s enthusiast appeal.VTEC has evolved over the past 30+ years to provide multiple benefits, including increasing horsepower and torque, and improving fuel efficiency.VTEC ® was the first commercially successful variable valve timing and lift technology used in a production car.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |