Editing VTEC (section)

=== Patent ===
A related U.S. patent (6,968,819) was filed on January 5, 2005.<ref>{{cite web|last=Tan|first=Paul|date=2007-04-17|title=Honda Files Advanced VTEC Patent|url=http://paultan.org/2007/04/17/honda-files-advanced-vtec-patent/|access-date=2010-12-04|publisher=Paultan.org}}</ref><ref>{{cite web|url=http://www.vtec.net/news/news-item?news_item_id=659664 |title=A-VTEC Details Break Cover at USPTO; TOV Analyzes |publisher=Vtec.net |access-date=2010-12-04}}</ref>

Advanced VTEC has a standard camshaft and rocker arms, attached as they normally are with camshaft overhead, and rocker arms pushing down on the [[poppet valve]]s. The camshaft is surrounded by a partially open drum which has secondary rocker arms attached to it via a pivoting point. These secondary rocker arms, which have a varying depth profile (similar to cams), are directly actuated by the camshaft, in a scissor-like manner. The primary rocker arms are actuated by the secondary (drum attached) rocker arms. The drum will only rotate to advance or retard the position of the secondary rocker arms, to take advantage of their varying profiles. Thus, through varying the position of the drum about its axis, each cam profile is changed to an optimal height for maximum [[Engine tuning|engine performance]] without sacrificing fuel efficiency at lower speeds.<ref>[https://archive.today/20120713023510/http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/PTO/srchnum.htm&r=1&f=G&l=50&s1=6968819.PN.&OS=PN/6968819&RS=PN/6968819 "U.S. Patent Application # 11/028,608"]</ref>