The active valve control system (AVCS) is an automobile variable valve timing technology used by Subaru. It varies the timing of the intake valves by using hydraulic oil pressure to rotate the camshaft in order to provide optimal air flow in and out of the engine. The system is closed loop using camshaft sensors, crankshaft sensors, air flow meter, throttle position as well as oxygen sensors and/or Air-Fuel ratio sensors in order to calculate engine load. The ECU is programmed to operate control valves that adjust the delivery of the hydraulic pressure in order to move the camshaft into the position that will provide the engine with the best performance while minding emissions standards.
AVCS is used on the Version 7 and up EJ207 engines, the EJ255 and EJ257, the second generation EZ30D (2005+ in the USA Market) found in the Legacy Outback, Legacy 3.0R and the B9 Tribeca. A Dual AVCS system utilizes both the intake and exhaust camshafts on the EZ36 found in the 2008 Tribeca. Dual AVCS is also found on Japanese Spec engines, although a complete list of the engines with Dual AVCS has yet to be compiled.
Read more about Active Valve Control System: AVCS
Famous quotes containing the words active, control and/or system:
“Things happen to us, all the time. It was like that for a century, and it is again. It’s not like here: People always do things, because you are born with it; you are brought up in this spirit, the active approach to life: “Stand up and go.” We were not. We were always passive in our lives.”
—Natasha Dudinska (b. c. 1967)
“In Vietnam, some of us lost control of our lives. I want my life back. I almost feel like I’ve been missing in action for twenty-two years.”
—Wanda Sparks, U.S. nurse. As quoted in the New York Times Magazine, p. 72 (November 7, 1993)
“The human body is not a thing or substance, given, but a continuous creation. The human body is an energy system ... which is never a complete structure; never static; is in perpetual inner self-construction and self-destruction; we destroy in order to make it new.”
—Norman O. Brown (b. 1913)