Search results
Results from the WOW.Com Content Network
The upper part of the valve stem, within the rocker box, is lubricated by oil. If this oil travels unchecked along the valve stem, engine HC emissions will become excessive. To control this, an elastomeric seal is fitted over the top of the valve guide. These may wear or stiffen with age, so are usually replaced whenever valves are removed for ...
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 ...
Valve float is an adverse condition which can occur at high engine speeds [1] when the poppet valves in an internal combustion engine valvetrain do not properly follow the closure phase of the cam lobe profile. This reduces engine efficiency and performance.
In an overhead valve engine the tappets (on right) are sandwiched between pushrods and the camshaft. In an internal combustion engine, a tappet (also called a 'valve lifter' or 'cam follower') [3] [4] [5] is the component which converts the rotation of the camshaft into vertical motion to open and close an intake or exhaust valve.
1919 Napier Lion II aircraft engine with three cylinder banks. Any design of motor/engine,be it a V or a boxer can be called an "in-line" if it's mounted in-line with the frame/chassis and in-line with the direction of travel of the vehicle.When the motor/engine is across the frame/chassis this is called a TRANSVERSE motor.Cylinder arrangement is not in the description of how the motor/engine ...
The common valvetrain configurations for piston engines, in order from oldest to newest, are: Flathead engine: The camshaft and the valves are located in the engine block below the combustion chamber. Overhead valve engine: The camshaft remains in the block, however the valves are located in the cylinder head above the combustion chamber.
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 ...
In most steam engine designs there is a short time at the end of the return stroke of the piston when all the valves are shut and it is compressing any remaining steam. Water can be introduced from the boiler or in a cold engine, steam will condense to water on the cool walls of the cylinders and can potentially hydrolock an engine.