Search results
Results from the WOW.Com Content Network
Endobronchial valves are medical devices that allow air to exit these sections but not to re-enter. The valves, in effect, cause damaged lung tissue to deflate, thereby reducing the excessive lung volume (hyperinflation) caused by emphysema. Two endobronchial valves have been approved by the FDA for BLVR: Zephyr and Spiration. [citation needed]
Endobronchial valve. An endobronchial valve (EBV) is a small, one-way valve, which may be implanted in an airway feeding the lung or part of lung. The valve allows air to be breathed out of the section of lung supplied, and prevents air from being breathed in. This leaves the rest of the lung to expand more normally and avoid air-trapping.
A hemispherical head ("hemi-head") gives an efficient combustion chamber with minimal heat loss to the head, and allows for two large valves.However, a hemi-head usually allows no more than two valves per cylinder due to the difficulty in arranging the valve gear for four valves at diverging angles, and these large valves are necessarily heavier than those in a multi-valve engine of similar ...
Choke valve, Butterfly valve used to limit air intake in internal combustion engine. (Not to be confused with choke valves used in industrial flow control, above.) Clapper valve: a type of check valve used in the Siamese fire appliance to allow only one hose to be connected instead of two (the clapper valve blocks the other side from leaking out)
A cylinder head of a four valve Nissan VQ engine engine. A multi-valve or multivalve engine is one where each cylinder has more than two valves (an intake, and an exhaust).A multi-valve engine has better breathing, and with more smaller valves (having less mass in motion) may be able to operate at higher revolutions per minute (RPM) than a two-valve engine, delivering more power.
A crossflow T-head sidevalve engine The usual L-head arrangement Pop-up pistons may be used to increase compression ratio Flathead with Ricardo's turbulent head. A flathead engine, also known as a sidevalve engine [1] [2] or valve-in-block engine, is an internal combustion engine with its poppet valves contained within the engine block, instead of in the cylinder head, as in an overhead valve ...
Late intake valve closing (LIVC) The first variation of continuous variable valve timing involves holding the intake valve open slightly longer than a traditional engine. This results in the piston actually pushing air out of the cylinder and back into the intake manifold during the compression stroke.
A desmodromic valve is a reciprocating engine poppet valve that is positively closed by a cam and leverage system, rather than by a more conventional spring. The valves in a typical four-stroke engine allow the air/fuel mixture into the cylinder at the beginning of the cycle and exhaust spent gases at the end of the cycle. In a conventional ...