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Retarder (mechanical Engineering)
A retarder is a device used to augment or replace some of the functions of primary friction-based braking systems, usually on heavy vehicles. Retarders serve to slow vehicles, or maintain a steady speed while traveling down a hill, and help prevent the vehicle from unintentional or uncontrolled acceleration when travelling on a road surface with an uneven grade. They are not usually capable of bringing vehicles to a standstill, as their effectiveness diminishes as a vehicle's speed lowers. Instead, they are typically used as an additional aid to slow vehicles, with the final braking done by a conventional friction braking system. An additional benefit retarders are capable of providing is an increase in the service life of the friction brake, as it is subsequently used less frequently, particularly at higher speeds. Additionally, air actuated brakes serve a dual role in conserving air pressure. Friction-based braking systems are susceptible to brake fade when used extensivel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Engine Braking
Engine braking occurs when the retarding forces within an internal combustion engine are used to slow down a motor vehicle, as opposed to using additional external braking mechanisms such as friction brakes or magnetic brakes. The term is often confused with several other types of braking, most notably compression-release braking or "jake braking" which uses a different mechanism. Traffic regulations in many countries require trucks to always drive with an engaged gear, which in turn provides a certain amount of engine braking (viscous losses to the engine oil and air pumped through the engine and friction losses to the cylinder walls and bearings) when no accelerator pedal is applied. Engine braking in different engine types Gasoline engines The term "engine braking" refers to the braking effect that occurs in gasoline engines when the accelerator pedal is released. This causes fuel injection to cease and the throttle valve to close almost completely, greatly restricting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Viscosity
Viscosity is a measure of a fluid's rate-dependent drag (physics), resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per metre squared, or pascal-seconds. Viscosity quantifies the internal friction, frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's center line than near its walls. Experiments show that some stress (physics), stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Valve
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or Slurry, slurries) by opening, closing, or partially obstructing various passageways. Valves are technically Piping and plumbing fitting, fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure. The word is derived from the Latin ''valva'', the moving part of a door, in turn from ''volvere'', to turn, roll. The simplest, and very ancient, valve is simply a freely hinged flap which swings down to obstruct fluid (gas or liquid) flow in one direction, but is pushed up by the flow itself when the flow is moving in the opposite direction. This is called a check valve, as it prevents or "checks" the flow in one direction. Modern control valves may regulate pressure or Fluid dynamics, flow downstream and operate on sophisticated Automation#Industrial automation, automat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Exhaust System
An exhaust system is used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes. Depending on the overall system design, the exhaust gas may flow through one or more of the following: * Cylinder head and exhaust manifold *A turbocharger to increase engine power. *A catalytic converter to reduce air pollution. *A muffler (North America) / silencer (UK/India), to reduce noise. Design criteria An exhaust pipe must be carefully designed to carry toxic and noxious gases away from the users of the machine. Indoor generators and furnaces can quickly fill an enclosed space with poisonous exhaust gases such as hydrocarbons, carbon monoxide and nitrogen oxides, if they are not properly vented to the outdoors. Also, the gases from most machines are scorching; the pipe must be heat-resistant and not pass through or near anything that can burn or be da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Exhaust Brakes
Exhaust, exhaustive, or exhaustion may refer to: Law *Exhaustion of intellectual property rights, limits to intellectual property rights in patent and copyright law **Exhaustion doctrine, in patent law ** Exhaustion doctrine under U.S. law, in patent law *Exhaustion of remedies, restrictions on opening a new lawsuit while an original suit is pending Mathematics *Brute-force attack, a cryptanalytic attack, also known as exhaustive key search *Collectively exhaustive, in probability and set theory, a collection of sets whose union equals the complete space *Exhaustion by compact sets, in analysis, a sequence of compact sets that converges on a given set *Method of exhaustion, in geometry, finding the area of a shape by approximating it with polygons *Proof by exhaustion, proof by examining all individual cases Medicine *Fatigue, a weariness caused by exertion * Adrenal exhaustion or hypoadrenia, a hypothesized maladaption of the adrenal glands *Heat exhaustion or hyperthermia, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Compression Release Engine Brake
A compression release engine brake, compression brake, or decompression brake is an engine braking mechanism installed on some diesel engines. When activated, it opens exhaust valves to the cylinders, right before the compression stroke ends, releasing the compressed gas trapped in the cylinders. The compression followed by the "wasteful" release consumes great amount of energy, effectively slowing the vehicle. Clessie Cummins was granted a patent for the engine compression brake in 1965, and the first company to manufacture them was Jacobs Vehicle Systems. Therefore, the brakes are commonly known as Jake brakes. Function When the driver releases the accelerator on a moving vehicle powered by an internal combustion engine, the vehicle's forward momentum continues to turn the engine's crankshaft. Most diesel engines do not have a throttle body, so regardless of the throttle setting, air is always drawn into the cylinders (excluding the valve fitted to certain diesels, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Turbocharger
In an internal combustion engine, a turbocharger (also known as a turbo or a turbosupercharger) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into the engine in order to produce more power for a given displacement. Turbochargers are distinguished from superchargers in that a turbocharger is powered by the kinetic energy of the exhaust gases, whereas a is mechanically powered (usually by a belt from the engine's crankshaft). However, up until the mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. History Prior to the inv ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Transmission (mechanics)
A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (industrialist), Louis Renault (who founded Renault, Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/reduction in a machine. Transmissions can have a single fixed-gear ratio, multiple distinct gear ratios, or continuously variable ratios. Variable-ratio transmissions are used in all sorts of machinery, especially vehicles. Applications Early uses Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engine, steam-powered devices. Applications of these devices included pumps, mill (grinding), mills and Hoist (device), hoists. Bicycles Bicycles traditionally have used hub gear or Derailleur gear transmissions, but there are other more recent design innovations. Automobiles Since the torque and Horsepower, power output of an interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Air Compressor
An air compressor is a machine that takes ambient air from the surroundings and discharges it at a higher pressure. It is an application of a gas compressor and a Pneumatics, pneumatic device that energy conversion, converts mechanical power (from an electric motor, Diesel engine, diesel or gasoline engine, etc.) into potential energy stored in compressed air, which has many uses. A common application is to compress air into a storage tank, for immediate or later use. When the delivery pressure reaches its set upper limit, the compressor is shut off, or the excess air is released through an overpressure valve. The compressed air is stored in the tank until it is needed. The pressure energy provided by the compressed air can be used for a variety of applications such as pneumatic tools as it is released. When tank pressure reaches its lower limit, the air compressor turns on again and re-pressurizes the tank. A compressor is different from a pump because it works on a gas, while pum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cylinder (engine)
In an engine, the cylinder is the space in which a piston travels. The inner surface of the cylinder is formed from either a thin metallic liner (also called "sleeve") or a surface coating applied to the engine block. A piston is seated inside each cylinder by several metal piston rings, which also provide seals for compression and the lubricating oil. The piston rings do not actually touch the cylinder walls, instead they ride on a thin layer of lubricating oil. Steam engines The cylinder in a steam engine is made pressure-tight with end covers and a piston; a valve distributes the steam to the ends of the cylinder. Cylinders were cast in cast iron and later in steel. The cylinder casting can include other features such as valve ports and mounting feet. Internal combustion engines The cylinder is the space through which the piston travels, propelled by the energy generated from the combustion of the air/fuel mixture in the combustion chamber. In an air-cooled e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Dead Centre (engineering)
In a reciprocating engine, the dead centre is the position of a piston in which it is either furthest from, or nearest to, the crankshaft. The former is known as top dead centre (TDC) while the latter is known as bottom dead centre (BDC). More generally, the dead centre is any position of a crank where the applied force is straight along its axis, meaning no turning force can be applied. Many sorts of machines are crank driven, including unicycles, bicycles, tricycles, various types of machine presses, gasoline engines, diesel engines, steam locomotives, and other steam engines. Crank-driven machines rely on the energy stored in a flywheel to overcome the dead centre, or are designed, in the case of multi-cylinder engines, so that dead centres can never exist on all cranks at the same time. A steam locomotive is an example of the latter, the connecting rods being arranged such that the dead centre for each cylinder occurs out of phase with the other one (or more) cylinders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
