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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] |
Four Stroke Cycle Start
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is a square number, the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures. Evolution of the Hindu-Arabic digit Brahmic numerals represented 1, 2, and 3 with as many lines. 4 was simplified by joining its four lines into a cross that looks like the modern plus sign. The Shunga would add a horizontal line on top of the digit, and the Kshatrapa and Pallava evolved the digit to a point where the speed of writing was a secondary concern. The Arabs' 4 still had the early concept of the cross, but for the sake of efficiency, was made in one stroke by connecting the "western" end to the "northern" end; the "eastern" end was finished off with a curve. The Europeans dropped the finishing curve and gradually made the digit less cursive, ending up with a digit very close to the original Brahmin cross. While the shape of the character for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chainwheel
The crankset (in the US) or chainset (in the UK) is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called ''chainrings'' or ''chainwheels'' attached to the '' cranks'', ''arms'', or ''crankarms'' to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain. Parts Cranks The two ''cranks'', one on each side and usually mounted 180° apart, connect the bottom bracket axle to the pedals. Lengths Bicycle cranks can vary in length to accommodate different sized riders and different types of cycling. Crank length is measured from the center of the pedal spindle to the center of the bottom bracket spindle or axle. The larger bicycle component manufacturers typically offe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributor
A distributor is an electric and mechanical device used in the ignition system of older spark-ignition engines. The distributor's main function is to route electricity from the ignition coil to each spark plug at the correct time. Design A distributor consists of a rotating arm ('rotor') that is attached to the top of a rotating 'distributor shaft'. The rotor constantly receives high-voltage electricity from an ignition coil via brushes at the centre of the rotor. As the rotor spins, its tip passes close to (but does not touch) the output contacts for each cylinder. As the electrified tip passes each output contact, the high-voltage electricity is able to 'jump' across the small gap. This burst of electricity then travels to the spark plug (via high tension leads), where it ignites the air-fuel mixture in the combustion chamber. On most overhead valve engines, the distributor shaft is driven by a gear on the camshaft, often shared with the oil pump; on most overh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timing Light
A timing light is a stroboscope used to dynamically set the ignition timing of an Otto cycle or similar internal combustion engine equipped with a distributor. Modern electronically controlled passenger vehicle engines require use of a scan tool to display ignition timing. The timing light is connected to the ignition circuit and used to illuminate the timing marks on the engine's crankshaft pulley or flywheel, with the engine running. The apparent position of the marks, frozen by the stroboscopic effect, indicates the current timing of the spark in relation to piston position. A reference pointer is attached to the flywheel housing or other fixed point, and an engraved scale gives the offset between the spark time and the top dead centre position of the piston in the cylinder. The distributor can be rotated slightly until the reference pointer aligns with the specified point on the timing scale. Fuel-injected engines, or engines with microprocessor controls may require specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timing Mark
A timing mark is an indicator used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel. These have the largest radius rotating at crankshaft speed and therefore are the place where marks at one degree intervals will be farthest apart. On older engines it is common to set the ignition timing using a timing light, which flashes in time with the ignition system (and hence engine rotation). Shining the light on the timing marks makes them appear stationary due to the stroboscopic effect. The ignition timing can then be adjusted to fire at the correct point in the engine's rotation, typically a few degrees before top dead centre and advancing with increasing engine speed. The timing can be adjusted by loosening and slightly rotating the distributor in its seat. Modern engines usually use a crank sensor directly connected to the engine management system. The term can also be used to describe the tick mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmonic Balancer
A harmonic damper is a device fitted to the free (accessory drive) end of the crankshaft of an internal combustion engine to counter torsional and resonance vibrations from the crankshaft. This device must be an interference fit to the crankshaft in order to operate in an effective manner. An interference fit ensures the device moves in perfect step with the crankshaft. It is essential on engines with long crankshafts (such as straight-six or straight-eight engines) and V8 engines with cross plane cranks, or V6 and straight-three engines with uneven firing order. Harmonics and torsional vibrations can greatly reduce crankshaft life, or cause instantaneous failure if the crankshaft runs at or through an amplified resonance. Dampers are designed with a specific weight (mass) and diameter, which are dependent on the damping material/method used, to reduce mechanical Q factor, or damp, crankshaft resonances. A harmonic balancer (sometimes called crankshaft damper, torsional damper, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Vehicle
A hydrogen vehicle is a vehicle that uses hydrogen to move. Hydrogen vehicles include some road vehicles, rail vehicles, space rockets, forklifts, ships and aircraft. Motive power is generated by converting the chemical energy of hydrogen to mechanical energy, either by reacting hydrogen with oxygen in a fuel cell to power electric motors or, less commonly, by hydrogen internal combustion. Hydrogen burns cleaner than fuels such as gasoline or methane but is more difficult to store and transport because of the small size of the molecule. As of the 2020s hydrogen light duty vehicles, including passenger cars, have been sold in small numbers due to competition with battery electric vehicles. , there were two models of hydrogen cars publicly available in select markets: the Toyota Mirai (2014–), the first commercially produced dedicated fuel cell electric vehicle (FCEV), and the Hyundai Nexo (2018–). The Honda CR-V e:FCEV became available, for lease only, in very limited q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While activation energy must be supplied to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. The study of combustion is known as combustion science. Combustion is often a complicated sequence of elementary reaction, elementary Radical (chemistry), radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nissan MA Engine
The MA is a straight-4 Single overhead cam, SOHC 0.9 L, 1.0 L, or 1.2 L engine first introduced in 1982 by Nissan Motors, Nissan, intended primarily for the K10 series Nissan Micra, Micra/March model. It shares design similarities with the older Nissan E engine, E engine, with an 8-valve hemispherical cylinder head but differs in that it uses an aluminium cylinder block. Unusually, the specified ignition timing for the MA10 running on the specified 90 RON gasoline was 2 degrees after top dead centre, reflecting a very high flame speed in the compact combustion chambers. MA09ERT The MA09ERT is a Twincharger, twin-charged design (possessing both a turbocharger and a supercharger), an unusual design, particularly for Japanese vehicles. It powered the March Superturbo, March R, and the March Superturbo R. The "Nissan PLASMA" (Powerful & Economic, Light, Accurate, Silent, Mighty, Advanced) improved performance and response by adding a supercharger to the (already turbocharged) Nissan MA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignition Timing
In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke. The need for advancing (or retarding) the timing of the spark is because fuel does not completely burn the instant the spark fires. The combustion gases take a period of time to expand and the angular or rotational speed of the engine can lengthen or shorten the time frame in which the burning and expansion should occur. In a vast majority of cases, the angle will be described as a certain angle advanced ''before top dead center'' (BTDC). Advancing the spark BTDC means that the spark is energized prior to the point where the combustion chamber reaches its minimum size, since the purpose of the power stroke in the engine is to force the combustion chamber to expand. Sparks occurring after top dead center (ATDC) are usually counter-productive (pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firing Order
The firing order of an internal combustion engine is the sequence of ignition for the cylinders. In a spark ignition (e.g. gasoline/petrol) engine, the firing order corresponds to the order in which the spark plugs are operated. In a diesel engine, the firing order corresponds to the order in which fuel is injected into each cylinder. Four-stroke engines must also time the valve openings relative to the firing order, as the valves do not open and close on every stroke. Firing order affects the vibration, sound and evenness of power output from the engine and heavily influences crankshaft design. Cylinder numbering Numbering systems for car engines The numbering system for cylinders is generally based on the cylinder numbers increasing from the front to the rear of an engine (See engine orientation below). However, there are differences between manufacturers in how this is applied; some commonly used systems are as listed below. Straight engine In a straight engine the cylin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignition System
Ignition systems are used by heat engines to initiate combustion by igniting the fuel-air mixture. In a spark ignition versions of the internal combustion engine (such as petrol engines), the ignition system creates a spark to ignite the fuel-air mixture just before each ''combustion'' stroke. Gas turbine engines and rocket engines normally use an ignition system only during start-up. Diesel engines use ''compression ignition'' to ignite the fuel-air mixture using the heat of compression and therefore do not use an ignition system. They usually have glowplugs that preheat the combustion chamber to aid starting in cold weather. Early cars used ignition magneto and trembler coil systems, which were superseded by Distributor-based systems (first used in 1912). Electronic ignition systems (first used in 1968) became common towards the end of the 20th century, with coil-on-plug versions of these systems becoming widespread since the 1990s. Magneto and mechanical systems Ig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
