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A valvetrain is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. [1] The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) into the combustion chamber, while the exhaust valves control the flow of spent exhaust gases out of the ...
The anti dribble function or 'pressure pipe release' [5] is achieved by not only stopping fuel flow after the main delivery phase, but also by lowering the pressure in the pipe at this point. Together with the pop valve in the fuel injector, this ensures that fuel flow stops abruptly when it needs to.
Desmodromic poppet valve in a Ducati engine. 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 ...
The location of the valves is broadly the same between OHV and OHC engines, however OHC engines saw the camshaft located to the top of the engine with the valves and OHC engines often have more valves per cylinder. Most OHC engines have an extra intake and an extra exhaust valve per cylinder (four-valve cylinder head), compared with the design ...
The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engines are often categorized by the number of rotors present. Gas turbine engines are often categorized into turbojets ...
Swirl flap principle in a four-valve engine. A swirl flap is a small butterfly valve fitted to four-stroke internal combustion engines with at least two intake valves.It is installed inside or just before one of a cylinder's two intake ports, allowing to throttle its intake port's air flow, causing a swirl in the other intake port not fitted with a swirl flap.
Reed valves are commonly used in high-performance versions of the two-stroke engine, where they control the fuel-air mixture admitted to the cylinder. As the piston rises in the cylinder a vacuum is created in the crankcase beneath the piston. The resulting pressure differential opens the valve and the fuel-air mixture flows into the crankcase.
If an engine spins too quickly, valve springs cannot act quickly enough to close the valves. This is commonly referred to as 'valve float', and it can result in piston to valve contact, severely damaging the engine. At high speeds the lubrication of piston cylinder wall interface tends to break down.