( E ) exhaust camshaft, ( I ) intake camshaft, ( S ) spark plug, ( V ) poppet valve | valve s, ( P ) piston, ( R ) connecting rod, ( C ) crankshaft, ( W ) water jacket for coolant flow.

Another heat transfer application is in high-performance internal combustion engines with poppet valves, where valve stems partially filled with sodium are used as a heat pipe to cool the valves.

A pipe leads from the tank to a poppet valve, and then to the decomposition chamber of the rocket motor.

The rocket is fired when the computer sends direct current through a small electromagnet that opens the poppet valve.

* Tappet, part of an internal combustion engine that actuates a poppet valve through rocker arms and pushrods

A uniflow diesel engine takes in air via scavenge ports, and exhaust gases exit through an overhead poppet valve.

( E ) Exhaust camshaft, ( I ) Intake camshaft, ( S ) Spark plug, ( V ) poppet valve | Valves, ( P ) Piston, ( R ) Connecting rod, ( C ) Crankshaft, ( W ) Water jacket for coolant flow.

The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve.

A small number of designs used a " cuff " sleeve in the cylinder head instead of the cylinder proper, providing a more " classic " layout compared to traditional poppet valve engines.

In other words, at higher RPM the engine typically requires larger ports that remain open for a greater proportion of the cycle, which is fairly easy to achieve with sleeve valves, but difficult in a poppet valve system.

This helps scavenging when exhaust / inlet timing overlap is used and a wide speed range required, whereas poor poppet valve exhaust scavenging can dilute the fresh air / fuel mixture intake to a greater degree, being more speed dependent ( relying principally on exhaust / inlet system resonant tuning to separate the two streams ).

Greater freedom of combustion chamber design ( few constraints other than the spark plug positioning ) means that fuel / air mixture swirl at TDC can also be more controlled allowing improved ignition and flame travel which as demonstrated by Ricardo, at least one extra unit of compression ratio before detonation compared with the poppet valve engine.

A problem with high-speed engines that use poppet valves is that as engine speed increases, the speed at which the valve moves also has to increase.

Sleeve valves did not suffer from the wear and recession caused by the repetitive impact of the poppet valve against its seat.

In the Knight engine, carbon build-up actually helped to improve the sealing of the sleeves, the engines said to " improve with use ", in contrast to poppet valve engines, which lose compression and power as valves and valve stems and guides wear.

In a poppet valve engine, the piston possesses piston rings ( at least three and sometimes as many as eight ) which form a seal with the cylinder bore.

In the 1940s this was not a major concern because the poppet valve stems of the time typically leaked appreciably more than they do today, so that oil consumption was significant in either case.

This paper outlined the advantages of the sleeve valve and suggested that poppet valve engines would not be able to offer power outputs much beyond 1500 hp ( 1, 100 kW ).

Following World War II, the sleeve valve disappeared from use, as the previous problems with sealing and wear on poppet valves had been remedied by the use of better materials and the inertia problems with the use of large valves were reduced by using several smaller valves instead, giving increased flow area and reduced mass.

Up to that point, the single sleeve valve had won every contest against the poppet valve in comparison of power to displacement.

Jan refers to everyone as " poppet " and " darling " and has extravagantly camp mannerisms, but is in fact practical and efficient.

Steam engines are usually double-acting ( i. e. steam pressure acts alternately on each side of the piston ) and the admission and release of steam is controlled by slide valves, piston valves or poppet valves.

Most radial engines use overhead poppet valves driven by pushrods and lifters on a cam plate which is concentric with the crankshaft, with a few smaller radials, like the Kinner B-5 and Russian Shvetsov M-11, using individual camshafts within the crankcase for each cylinder.

* The combustion chamber formed with the sleeve at the top of its stroke is ideal for complete, detonation-free combustion of the charge, as it does not have to contend with compromised chamber shape and hot exhaust ( poppet ) valves.

A poppet valve ( also called mushroom valve ) is a valve typically used to control the timing and quantity of gas or vapour flow into an engine.

The word poppet shares etymology with " puppet ": it is from the Middle English popet (" youth " or " doll "), from Middle French poupette, which is a diminutive of poupe.

In the past, " puppet valve " was a synonym for poppet valve ; however, this usage of " puppet " is now obsolete.

The main advantage of the poppet valve is that it has no movement on the seat, thus requiring no lubrication.

The operating principle of poppet valves is described in the online article " How Poppet Valves Work ".

In most cases it is beneficial to have a " balanced poppet " in a direct-acting valve.

Less force is needed to move the poppet because all forces on the poppet are nullified by equal and opposite forces.

A sectional illustration of Watt's beam engine of 1774 using the device is found in Thurston 1878: 98, and Lardner ( 1840 ) provides an illustrated description of Watt's use of the poppet valve.

In internal combustion engines with pistons, the camshaft is used to operate poppet valves.

Likely the voodoo doll concept in popular culture is influenced by the European poppet dolls.

A kitchen witch is a poppet originating in Northern Europe.

While the Pro-am was like the 68 Special in layout, being an inline poppet valve design, it was a major change in design, with a different body, valve, breech, hammer, hammer to bolt linkage, and sear arrangements.

The use of the word poppet to describe a valve comes from the same word applied to marionettes, which – like the poppet valve – move bodily in response to remote motion transmitted linearly.

One of the designers in the engine department was Samuel Heron, who later went on to invent the sodium-filled poppet valve, instrumental in achieving greater powers from piston engines.

At the pull of the trigger, an electronic impulse trips the four-way valve, pushing compressed gas through the ram from behind, forcing the ram and bolt assembly to move towards the valve, impacting the poppet and releasing gas to the chamber.

The word poppet is an older spelling of puppet, from the Middle English popet, meaning a small child or doll.

When he soon improved the device by removing the poppet valve action, these three components became the piston valve, the slide valve, and the graduating valve.

They can be divided into those that drove the standard reciprocating valves ( whether piston valves or slide valves ), those used with poppet valves, and stationary engine trip gears used with semi-rotary Corliss valves or drop valves.

Steam locomotives may have slide valves, piston valves or poppet valves.