Search results
Results From The WOW.Com Content Network
Cutaway of a dual overhead camshaft engine 1969 AMC V8 overhead valve engine. The rocker cover has been removed, so elements of the pushrods, rocker arms, valve springs, and valves are visible. A valvetrain is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. [1]
Pneumatic valve springs are also found in several Moto GP motorcycle engines, debuting in 2002 with the Aprilia RS Cube. In 2005, Team Roberts was the first to use pneumatic valves full-time in their uncompetitive KTM powered bike. Today, almost all of the MotoGP teams use pneumatic valve technology on their bikes, including Yamaha, Suzuki and ...
The trip point of the valve mechanism, and therefore the cut-off, would be adjusted either manually or automatically by the governor. The valve is opened by the mechanical valve gear mechanism, and when the trip gear trigger releases the mechanism the valve is snapped closed, usually by a spring acting against a dashpot .
A hydraulic tappet, also known as a hydraulic valve lifter or hydraulic lash adjuster, is a device for maintaining zero valve clearance in an internal combustion engine. Conventional solid valve lifters require regular adjusting to maintain a small clearance between the valve and its rocker or cam follower .
Stiffer valve springs can help prevent valve float and valve bounce but at the expense of increased friction losses, higher stresses, and more rapid wear in the valvetrain. Various techniques have been used to offset the effect of stiffer springs, such as dual-spring and progressive-sprung valves, roller-tipped tappets, and pneumatic valve ...
The common valve spring system is satisfactory for traditional mass-produced engines that do not rev highly and are of a design that requires low maintenance. [1] At the period of initial desmodromic development, valve springs were a major limitation on engine performance because they would break from metal fatigue.
The Schrader valve consists of a valve stem into which a valve core is threaded. The valve core is a poppet valve assisted by a spring. A small rubber seal located on the core keeps the fluid from escaping through the threads. Using the appropriate tools, a faulty valve core can be immediately extracted from the valve stem and replaced with a ...
With traditional fixed valve timing, an engine will have a period of "valve overlap" at the end of the exhaust stroke, when both the intake and exhaust valves are open. The intake valve is opened before the exhaust gases have completely left the cylinder, and their considerable velocity assists in drawing in the fresh charge. Engine designers ...