Hydraulic Valve Lifter
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Hydraulic Valve Lifter
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. This space prevents the parts from binding as they expand with the engine's heat, but can also lead to noisy operation and increased wear as the parts rattle against one another until they reach operating temperature. The hydraulic lifter was designed to compensate for this small tolerance, allowing the valve train to operate with zero clearance—leading to quieter operation, longer engine life, and eliminating the need for periodic adjustment of valve clearance. The hydraulic lifter, situated between the camshaft and each engine's valve, is a hollow steel cylinder encasing an internal piston. This piston is held at the outer limit of its travel with a strong spring. The l ...
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Internal Combustion Engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons ( piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle ( jet engine). This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known ...
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Tappet
A tappet is most commonly a component in an internal combustion engine which converts the rotating motion of the camshaft into linear motion of the valves, either directly or indirectly. An earlier use of the term was for part of the valve gear in beam engines beginning in 1715. The term is also used for components in pneumatic cylinders and weaving loom. __TOC__ Beam engines The first recorded use of the term tappet is as part of the valve gear in the 1715 Newcomen engine, an early form of steam engine. Early versions of the Newcomen engines from 1712 had manually operated valves, but by 1715 this repetitive task had been automated through the use of tappets. The beam of the engine had a vertical 'plug rod' hung from it, alongside the cylinder. Adjustable blocks or 'tappets' were attached to this rod and as the beam moved up and down, the tappets pressed against long levers or 'horns' attached to the engine's valves, working the cycle of steam and injection water valves ...
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Rocker Arm
In the context of an internal combustion engine, a rocker arm is a valvetrain component that typically transfers the motion of a pushrod to the corresponding intake/exhaust valve. Rocker arms in automobiles are typically made from stamped steel, or aluminum in higher-revving applications. Some rocker arms (called ''roller rockers'') include a bearing at the contact point, to reduce wear and friction at the contact point. Overview In the typical use-case of an overhead valve (pushrod) engine, the camshaft at the bottom of the engine pushes the pushrod upwards. The top of the pushrod presses upwards on one side of the rocker arm (located at the top of the engine), which causes the rocker arm to rotate. This rotation causes the other end of the rocker arm to press downwards on the top of the valve, which opens the valve by moving it downwards. A ''roller rocker'' is a rocker arm that uses needle bearings (or a single bearing ball in older engines) at the contact point between the ...
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Cam Follower
In mechanical engineering, a cam follower, also known as a track follower, is a specialized type of roller or needle bearing designed to follow cam lobe profiles. Cam followers come in a vast array of different configurations, however the most defining characteristic is how the cam follower mounts to its mating part; ''stud'' style cam followers use a stud while the ''yoke'' style has a hole through the middle. Construction The modern stud type follower was invented and patented in 1937 by Thomas L. Robinson of the McGill Manufacturing Company. It replaced using a standard bearing and bolt. The new cam followers were easier to use because the stud was already included and they could also handle higher loads. While roller cam followers are similar to roller bearings, there are quite a few differences. Standard ball and roller bearings are designed to be pressed into a rigid housing, which provides circumferential support. This keeps the outer race from deforming, so the race cr ...
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Backlash (engineering)
In mechanical engineering, backlash, sometimes called lash, play, or slop, is a clearance or lost motion in a mechanism caused by gaps between the parts. It can be defined as "the maximum distance or angle through which any part of a mechanical system may be moved in one direction without applying appreciable force or motion to the next part in mechanical sequence."p. 1-8 An example, in the context of gears and gear trains, is the amount of clearance between mated gear teeth. It can be seen when the direction of movement is reversed and the slack or lost motion is taken up before the reversal of motion is complete. It can be heard from the railway couplings when a train reverses direction. Another example is in a valve train with mechanical tappets, where a certain range of lash is necessary for the valves to work properly. Depending on the application, backlash may or may not be desirable. Some amount of backlash is unavoidable in nearly all reversing mechanical couplings, ...
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Tappet
A tappet is most commonly a component in an internal combustion engine which converts the rotating motion of the camshaft into linear motion of the valves, either directly or indirectly. An earlier use of the term was for part of the valve gear in beam engines beginning in 1715. The term is also used for components in pneumatic cylinders and weaving loom. __TOC__ Beam engines The first recorded use of the term tappet is as part of the valve gear in the 1715 Newcomen engine, an early form of steam engine. Early versions of the Newcomen engines from 1712 had manually operated valves, but by 1715 this repetitive task had been automated through the use of tappets. The beam of the engine had a vertical 'plug rod' hung from it, alongside the cylinder. Adjustable blocks or 'tappets' were attached to this rod and as the beam moved up and down, the tappets pressed against long levers or 'horns' attached to the engine's valves, working the cycle of steam and injection water valves ...
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Valvetrain
A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. 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 gasses out of the combustion chamber once combustion is completed. Layout The valvetrain layout is largely dependent on the location of the camshaft. 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. * Overhead camshaft engine: The valves and camshaft(s) are in the cylinder head above the combustion chamber. Components The valvetrain consists of all the compo ...
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Cylinder Head
In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern overhead valve and overhead camshaft engines, the cylinder head is a more complicated block often containing inlet and exhaust passages, coolant passages, valves, camshafts, spark plugs and fuel injectors. Most straight engines have a single cylinder head shared by all of the cylinders and most V engines have two cylinder heads (one per bank of cylinders). Design A summary of engine designs is shown below, in chronological order for automobile usage. Sidevalve engines In a flathead (''sidevalve'') engine, all of the valvetrain components are contained within the block, therefore the head is usually a simple sheet of metal bolted to the top of the engine block. Sidevalve engines were once universal in automobiles but are now lar ...
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Valvetrain
A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. 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 gasses out of the combustion chamber once combustion is completed. Layout The valvetrain layout is largely dependent on the location of the camshaft. 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. * Overhead camshaft engine: The valves and camshaft(s) are in the cylinder head above the combustion chamber. Components The valvetrain consists of all the compo ...
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Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder. __TOC__ Piston engines Internal combustion engines An internal combustion engine is acted upon by the pressure of the expanding combustion gases in the combustion chamber space at the top of the cylinder. This force then acts downwards through the connecting rod and onto the crankshaft. The connecting rod is att ...
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Engine Valves
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power generation), heat energy (e.g. geothermal), chemical energy, electric potential and nuclear energy (from nuclear fission or nuclear fusion). Many of these processes generate heat as an intermediate energy form, so heat engines have special importance. Some natural processes, such as atmospheric convection cells convert environmental heat into motion (e.g. in the form of rising air currents). Mechanical energy is of particular importance in transportation, but also plays a role in many industrial processes such as cutting, grinding, crushing, and mixing. Mechanical heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a mechanical heat engine, in which hea ...
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Engine Components
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power generation), heat energy (e.g. geothermal), chemical energy, electric potential and nuclear energy (from nuclear fission or nuclear fusion). Many of these processes generate heat as an intermediate energy form, so heat engines have special importance. Some natural processes, such as atmospheric convection cells convert environmental heat into motion (e.g. in the form of rising air currents). Mechanical energy is of particular importance in transportation, but also plays a role in many industrial processes such as cutting, grinding, crushing, and mixing. Mechanical heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a mechanical heat engine, in whi ...
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