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Balance Shaft
Balance shafts are used in piston engines to reduce vibration by cancelling out unbalanced dynamic forces. The counter balance shafts have eccentric weights and rotate in opposite direction to each other, which generates a net vertical force. The balance shaft was invented and patented by British engineer Frederick W. Lanchester in 1907. It is most commonly used in inline-four and V6 engines used in automobiles and motorcycles. Overview The operating principle of a balance shaft system is that two shafts carrying identical eccentric weights rotate in opposite directions at twice the engine speed. The phasing of the shafts is such that the centrifugal forces produced by the weights cancel the vertical second-order forces (at twice the engine RPM) produced by the engine. The horizontal forces produced by the balance shafts are equal and opposite, and so cancel each other. The balance shafts do not reduce the vibrations experienced by the crankshaft. Applications Two-cylinder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engine Balance
Engine balance refers to how the forces (resulting from combustion or rotating/reciprocating components) are balanced within an internal combustion engine or steam engine. The most commonly used terms are ''primary balance'' and ''secondary balance''. ''First-order balance'' and ''second-order balance'' are also used. Unbalanced forces within the engine can lead to vibrations. Causes of imbalance Although some components within the engine (such as the connecting rods) have complex motions, all motions can be separated into reciprocating and rotating components, which assists in the analysis of imbalances. Using the example of an inline engine (where the pistons are vertical), the main reciprocating motions are: * Pistons moving upwards/downwards * Connecting rods moving upwards/downwards * Connecting rods moving left/right as they rotate around the crankshaft, however the lateral vibrations caused by these movements are much smaller than the up–down vibrations caused by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balancing Machine
A balancing machine is a measuring tool used for balancing rotating machine parts such as rotors for electric motors, Fan (mechanical), fans, turbines, disc brakes, disk storage, disc drives, propellers and pumps. The machine usually consists of two rigid pedestals, with suspension and Bearing (mechanical), bearings on top supporting a mounting platform. The unit under test is bolted to the platform and is rotated either with a belt-, air-, or end-drive. As the part is rotated, the vibration in the suspension is detected with sensors and that information is used to determine the amount of unbalance in the part. Along with phase information, the machine can determine how much and where to add or remove weights to balance the part. Hard-bearing vs. soft-bearing There are two main types of balancing machines, hard-bearing and soft-bearing. The difference between them, however, is in the suspension and not the bearings. In a hard-bearing machine, balancing is done at a frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat-six Engine
A flat-six engine, also known as a horizontally opposed-six, is a six-cylinder piston engine with three cylinders on each side of a central crankshaft. The most common type of flat-six engine is the boxer-six engine, where each pair of opposed cylinders moves inwards and outwards at the same time. The advantages of the flat-six layout are good engine balance (for reduced vibration), a low center of gravity, short length (compared with an inline-six engine) and being well suited to air-cooling. The disadvantages are a large width (which can limit the maximum steering angle when used in a front-engined car), a large intake manifold being required when a central carburetor is used, and duplication of the inlet and outlet connections for water-cooled engines. The first production flat-six engine was in the 1904 ''Wilson-Pilcher 18/24 HP'' car. The most notable use of flat-six engines is the Porsche 911 sports car, which has used flat-six engines continuously since 1963. Several o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Straight-six Engine
The straight-six engine (also referred to as an inline-six engine; abbreviated I6 or L6) is a piston engine with six cylinders arranged in a straight line along the crankshaft. A straight-six engine has perfect primary and secondary engine balance, resulting in fewer vibrations than other designs of six or less cylinders. Until the mid-20th century, the straight-six layout was the most common design for engines with six cylinders. However, V6 engines became more common from the 1960s and by the 2000s most straight-six engines had been replaced by V6 engines. An exception to this trend is BMW which has produced automotive straight-six engines from 1933 to the present day. Characteristics In terms of packaging, straight-six engines are almost always narrower than a V6 engine or V8 engine, but longer than straight-four engines, V6s, and most V8s. Straight-six engines are typically produced in displacements ranging from , however engines ranging in size from the Benelli 750 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Motors Atlas Engine
Atlas is a name for a family of modern inline piston engines for trucks from General Motors, used in the GMT355 and GMT360 platforms. The series debuted in 2002 with the Oldsmobile Bravada, and is also used in the Buick Rainier, the Chevrolet TrailBlazer and Colorado, the GMC Envoy and Canyon, the Hummer H3, Isuzu Ascender and i-370, and the Saab 9-7X. The engines use GM's Vortec name, and Straight-4, Straight-5, and Straight-6 engines are all part of the same family, sharing the same manufacturing equipment, rods, pistons, valves, and other parts. They feature coil-on-plug ignition systems, variable valve timing on the exhaust side, electronic throttle control, and a special oil pan with a pass-through for the half shafts in four-wheel drive vehicles. The inclusion of VVT on the exhaust camshaft side allows the Atlas series to meet emissions standards without the use of EGR, simplifying the engine design and increasing power for a broad power curve. The LL8 shares 75% of it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Straight-five Engine
The straight-five engine (also referred to as an inline-five engine; abbreviated I5 or L5) is a piston engine with five cylinders mounted in a straight line along the crankshaft. Although less common than straight-four engines and straight-six engines, straight-five engines have occasionally been used by automobile manufacturers since the late 1930s, particularly the Mercedes Benz's diesel engines from 1974 to 2006 and Audi's petrol engines from 1979 to the present. Straight-five engines are smoother running than straight-four engines and shorter than straight-six engines. However, achieving consistent fuelling across all cylinders was problematic prior to the adoption of fuel injection. Characteristics Straight-five engines are typically shorter than straight-six engines, making them easier to fit transversely in an engine bay. They are also smoother than straight-four engines, and are narrower than V engines and flat engines. Engine balance and vibration Five-cylinder e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat-four Engine
A flat-four engine, also known as a horizontally opposed-four engine, is a four-cylinder piston engine with two banks of cylinders lying on opposite sides of a common crankshaft. The most common type of flat-four engine is the boxer-four engine, each pair of opposed pistons moves inwards and outwards at the same time. A boxer-four engine has perfect primary and secondary balance, however, the two cylinder heads means the design is more expensive to produce than an inline-four engine. Boxer-four engines have been used in cars since 1897, especially by Volkswagen and Subaru. They have also occasionally been used in motorcycles and frequently in aircraft. Cessna and Piper use flat four engines from Lycoming and Continental in the most common civil aircraft in the world - the Cessna 172, and Piper Cherokee, while many ultralight and LSA planes use versions of the Rotax 912. Design Most flat-four engines are designed so that each pair of opposing pistons moves inwards and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitsubishi Astron Engine
The Mitsubishi Astron or 4G5/4D5 engine, is a series of straight-four internal combustion engines first built by Mitsubishi Motors in 1972. Engine displacement ranged from 1.8 to 2.6 litres, making it one of the largest four-cylinder engines of its time. Design It employed a hemispherical cylinder head, chain-driven single overhead camshaft (SOHC) and eight valves (two per cylinder). United States passenger car versions had a small secondary intake valve referred to as the "Jet Valve". This valve induced swirl in the intake charge, enabling the use of leaner fuel/air mixtures for lower emissions. It was designed as a cartridge containing the valve spring and seat which simply screwed into a threaded hole in the head, similar to a spark plug but inside the cam cover. The rocker arms for the intake valve were widened on the valve end to accommodate the cartridge, which was equipped with a very soft valve spring in order to avoid wear on the camshaft intake lobe. Modifications to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bore (engine)
In a piston engine, the bore (or cylinder bore) is the diameter of each cylinder. Engine displacement is calculated based on bore, stroke length and the number of cylinders: displacement = The stroke ratio, determined by dividing the bore by the stroke, traditionally indicated whether an engine was designed for power at high engine speeds (rpm) or torque at lower engine speeds. The term "bore" can also be applied to the bore of a locomotive cylinder or steam engine pistons. Steam locomotive The term bore also applies to the cylinder of a steam locomotive or steam engine. See also * Bore pitch * Compression ratio * Engine displacement Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. It is commonly used as an expression of an engine's size, and by extension as a loose indicator of the ... References {{Steam engine configurations Engine technology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroke (engine)
In the context of an internal combustion engine, the term stroke has the following related meanings: * A phase of the engine's cycle (e.g. compression stroke, exhaust stroke), during which the piston travels from top to bottom or vice versa. * The type of power cycle used by a piston engine (e.g. two-stroke engine, four-stroke engine). * "Stroke length", the distance travelled by the piston during each cycle. The stroke length––along with bore diameter––determines the engine's displacement. Phases in the power cycle Commonly used engine phases or strokes (i.e. those used in a four-stroke engine) are described below. Other types of engines can have very different phases. Induction-intake stroke The induction stroke is the first phase in a four-stroke (e.g. Otto cycle or Diesel cycle) engine. It involves the downward movement of the piston, creating a partial vacuum that draws a air-fuel mixture (or air alone, in the case of a direct injection engine) into the combus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadratic Growth
In mathematics, a function or sequence is said to exhibit quadratic growth when its values are proportional to the square of the function argument or sequence position. "Quadratic growth" often means more generally "quadratic growth in the limit", as the argument or sequence position goes to infinity – in big Theta notation, f(x)=\Theta(x^2). This can be defined both continuously (for a real-valued function of a real variable) or discretely (for a sequence of real numbers, i.e., real-valued function of an integer or natural number variable). Examples Examples of quadratic growth include: *Any quadratic polynomial. *Certain integer sequences such as the triangular numbers. The nth triangular number has value n(n+1)/2, approximately n^2/2. For a real function of a real variable, quadratic growth is equivalent to the second derivative being constant (i.e., the third derivative being zero), and thus functions with quadratic growth are exactly the quadratic polynomials, as these a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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