In automotive engineering a multi-valve or multivalve engine is one where each cylinder has more than two valves. A multi-valve engine has better breathing and may be able to operate at higher revolutions per minute (RPM) than a two-valve engine, delivering more power.
A cylinder head of a four valve engine. ( Nissan VQ engine )
Cutaway model of Subaru's i-AVLS variable valve timing system on SOHC 4-valve-per-cylinder EJ25 boxer engine at Tokyo Motor Show 2007.
Combustion chamber of a 2009 Ford Ecoboost 3.5-liter turbocharged V6 petrol engine (77.8 kW/liter) showing two intake valves (right), two exhaust valves (left), centrally placed spark plug, and direct fuel injector (right).
A cylinder head from a 1987 Honda CRX Si showing SOHC, rocker arms, valve springs, and other components. This is a multi-valve configuration with two intake valves and one exhaust valve for each cylinder.
The Mazda B-series is a small-sized, iron-block, inline four-cylinder engine with belt-driven SOHC and DOHC valvetrain ranging in displacement from 1.1 to 1.8 litres. It was used in a wide variety of applications, from front-wheel drive economy vehicles to the turbocharged full-time 4WD 323 GTX and rear-wheel drive Miata.
Mazda B3E
Mazda B6D, 3rd generation
B6ZE(RS)
Mazda BPT - Turbocharged 1.8L