Editing Multi-valve (section)

{{short description|Type of car engine}}
[[File:Nissan VQ35DE 005.jpg|250px|thumb|A [[cylinder head]] of a four-[[poppet valve|valve]] [[Nissan VQ engine]] engine]]

A '''multi-valve''' or '''multivalve''' [[Four-stroke engine|four-stroke]] [[internal combustion engine]] is one where each [[Cylinder (engine)|cylinder]] has ''more than two'' [[poppet valve|valves]] – more than the minimum required of one of each, for the purposes of air and fuel [[intake]], and [[Exhaust system|venting exhaust gases]]. Multi-valve engines were conceived to improve one or both of these, often called "better breathing", and with the added benefit of more valves that are smaller, thus having less mass in motion (per individual valve and spring), may also be able to operate at higher [[revolutions per minute]] (RPM) than a two-valve engine, delivering even more intake an/or exhaust per unit of time, thus potentially more [[power (physics)|power]].<ref name="KevinClemensDOHC">{{cite web |url=http://www.europeancarweb.com/features/0209ec_twin_cam_analysis/index.html |title=An Echo of the Past: The history and evolution of twin-cam engines (European Car, February, 2009) |first=Kevin |last=Clemens |access-date=2011-12-23 |url-status=dead |archive-url=https://web.archive.org/web/20140111045642/http://www.europeancarweb.com/features/0209ec_twin_cam_analysis/ |archive-date=2014-01-11 }}</ref><ref name="DanMcCosh4valves">{{cite web |url=http://www.popsci.com/archive-viewer?id=1QAAAAAAMBAJ&pg=37&query=Quad+4 |title=Auto Tech 88: 4-valves (Popular Science, May 1988, pp. 24, 37-40) |first=Dan |last=McCosh |access-date=2011-12-23 |archive-date=2013-06-02 |archive-url=https://web.archive.org/web/20130602151732/http://www.popsci.com/archive-viewer?id=1QAAAAAAMBAJ&pg=37&query=Quad+4 |url-status=dead }}</ref>