Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black)

Continental engine marine crankshafts, 1942

Components of a typical, four stroke cycle, DOHC piston engine. (E) Exhaust camshaft, (I) Intake camshaft, (S) Spark plug, (V) Valves, (P) Piston, (R) Connecting rod, (C) Crankshaft, (W) Water jacket for coolant flow.

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation. It typically connects to a flywheel, to reduce the pulsation characteristic of the four-stroke cycle, and sometimes a torsional or vibrational damper at the opposite end, to reduce the torsion vibrations often caused along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity of the metal. The crankshaft was invented by the inventor Al-Jazari in the 12th century. Image File history File links Cshaft. ... Image File history File links Cshaft. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Continental engines were used in various American cars from independent automobile manufacturers during the early 1900s and into the 1920s. ... Labeled diagram of a four-stroke engine, created by Wapcaplet in Blender. ... Labeled diagram of a four-stroke engine, created by Wapcaplet in Blender. ... The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today (cars and trucks, generators, etc). ... Computer animation of a camshaft The camshaft is an apparatus often used in piston engines to operate poppet valves. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ... piston + connecting rod Components of a typical, four stroke cycle, DOHC piston engine. ... piston (top) and connecting rod from typical automotive engine (scale is in centimetres) Components of a typical, four stroke cycle, DOHC piston engine. ... A crank is a bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it; also used to change circular into reciprocating motion, or reciprocating into circular motion. ... An engine is something that produces an effect from a given input. ... In mathematics, the reciprocal, or multiplicative inverse, of a number x is the number which, when multiplied by x, yields 1. ... The word linear comes from the Latin word linearis, which means created by lines. ... piston + connecting rod Components of a typical, four stroke cycle, DOHC piston engine. ... Spoked flywheel Flywheel from stationary engine. ... Today Internal combustion engines in cars, trucks, motorcycles, construction machinery and many others, most commonly use a four-stroke cycle. ... Look up torsion in Wiktionary, the free dictionary. ... Ibn Ismail Ibn al-Razzaz Al-Jazari (1206 AD) wrote notable books about engineering that are consulted in the history of engineering even today. ...

Design

Large engines are usually multicylinder to reduce pulsations from individual firing strokes, with more than one piston attached to a more complex crankshaft; but many small engines, such as those found in mopeds or garden machinery, are single cylinder and use only a single piston, simplifying crankshaft design. The crankshaft has a linear axis about which it rotates, typically with several bearing journals riding on replaceable bearings held in the engine block, the main bearings. As the crankshaft undergoes a great deal of sideways load from each cylinder in a multicylinder engine, it must be supported by several such bearings, not just one at each end; this was also a factor in the rise of V8 engines with their shorter crankshafts in preference to straight-8 engines, whose long crankshafts suffered from an unacceptable amount of flex when engine designs began using a higher compression ratio and improved-breathing over head valves allowed higher RPM's. High performance engines will often have more main bearings than their lower performance cousins, for this reason. In addition, to convert the reciprocating motion into rotation, the crankshaft has "crank throws" or "crank pins", additional bearing surfaces whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from each cylinder attach. The distance of the axis of the crank throws from the axis of the crankshaft determines the piston stroke measurement, and thus engine displacement; a common way to increase the low-RPM torque of an engine is to increase the stroke. This also increases the reciprocating vibration, however, limiting the high RPM capability of the engine; in compensation, it improves the low speed operation of the engine, as the longer intake stroke through smaller valve(s) results in greater turbulence and mixing of the intake charge. For this reason, even such high speed production engines as current Honda engines are classified as long-stroke, in that the stroke is larger than the diameter of the cylinder bore. In production V or flat engines, neighboring connecting rods attach side by side to the same crank throw, simplifying crank design. Engine configuration is an engineering term for the layout of the major components of an internal combustion engine. ... A stroke is a single action of certain engines. ... A picture of several mopeds from a ride sponsored by the Moped Army. ... The axis of rotation of a rotating body is a line such that the distance between any point on the line and any point of the body remains constant under the rotation. ... It has been suggested that Bushing be merged into this article or section. ... In a piston engine, the main bearings are the bearings on which the crankshaft rotates. ... The Liberty V8 aircraft engine clearly shows the configuration A V8 engine is a V engine with eight cylinders. ... 1933 Bugatti DOHC straight-8 in a Type 59 Grand Prix racer 1940s Oldsmobile Straight-8 engine A Straight-8 is a straight engine with eight cylinders. ... Piston and connecting rod from an automobile engine, showing the big end bearing at the bottom. ... piston (top) and connecting rod from typical automotive engine (scale is in centimetres) Components of a typical, four stroke cycle, DOHC piston engine. ... A stroke is a single action of certain engines. ... One complete cycle of a four cylinder, four stroke engine. ... Engine balance is the design, construction and tuning of an engine to run smoothly. ... rpm or RPM may mean: revolutions per minute RPM Package Manager (originally called Red Hat Package Manager) RPM (movie) RPM (band), a Brazilian rock band RPM (magazine), a former Canadian music industry magazine In firearms, Rounds Per Minute: how many shots an automatic weapon can fire in one minute On... This article or section does not cite its references or sources. ... Bore, when used in the context of piston engines, is a measurement of the diameter of the holes bored into the engine block for use as cylinders. ... A V engine is a common configuration for an internal combustion engine in which the pistons are aligned so that, if viewed along the line of the crankshaft, they appear to be in a V. Usually, two opposing pistons share one crank on the crankshaft. ... The Boxer engine A flat engine is an internal combustion engine with its pistons parallel to the ground. ...

The configuration and number of pistons in relation to each other and the crank leads to straight, V or flat engines. The same basic engine block can be used with different crankshafts, however, to alter the firing order; for instance, the 90 degree V6 engine configuration, usually derived by using six cylinders of a V8 engine with what is basically a shortened version of the V8 crankshaft, produces an engine with an inherent pulsation in the power flow due to the "missing" two cylinders, often reduced by use of balance shafts. The same engine, however, can be made to provide evenly spaced power pulses by using a crankshaft with an individual crank throw for each cylinder, spaced so that the pistons are actually phased 60 degrees apart, as in the GM 3800 engine. Similarly, while production V8 engines use 4 crank throws spaced 90 degrees apart, racing engines often use a "flat" crankshaft with throws spaced 180 degrees apart, accounting for the higher pitched, smoother sound of IRL engines compared to NASCAR engines, for example. In engines other than the flat configuration, it is necessary to provide counterweights for the reciprocating mass of each piston and connecting rod; these are typically cast as part of the crankshaft, but occasionally are bolt-on pieces. This adds considerably to the weight of the crankshaft; crankshafts from Volkswagen, Porsche, and Corvair flat engines, lacking counterweights, are easily carried around by hand, compared to crankshafts for inline or V engines, which need to be handled and transported as heavy chunks of metal. Usually found in 4 and 6 cylinder configurations, the straight engine (often designed as inline engine) is an internal-combustion engine with all cylinders aligned in one row, with no or only minimal offset. ... A V engine is a common configuration for an internal combustion engine in which the pistons are aligned so that, if viewed along the line of the crankshaft, they appear to be in a V. Usually, two opposing pistons share one crank on the crankshaft. ... The Boxer engine A flat engine is an internal combustion engine with its pistons parallel to the ground. ... An engine block is the main part of an internal combustion engine. ... The firing order is the sequence of sparking of the spark plugs in a reciprocating engine, or the sequence of fuel injection in each cylinder in a Diesel engine. ... The Ford Essex V6 engine V6 and V-6 redirect here. ... The Liberty V8 aircraft engine clearly shows the configuration A V8 engine is a V engine with eight cylinders. ... The Ford Essex V6 engine V6 and V-6 redirect here. ... Balance shaft in Ford Taunus V4 engine. ... The 3800 family is a large V6 engine used by General Motors. ... The Indy Racing League, better known as IRL, is the sanctioning body of a predominantly American based open-wheel racing series. ... The National Association for Stock Car Auto Racing (NASCAR) is the largest sanctioning body of motorsports in the United States. ... This article or section does not cite its references or sources. ... Volkswagen AG (ISIN: DE0007664005), or VW, is an automobile manufacturer based in Wolfsburg, Germany. ... This article is about the auto company. ... The Chevrolet Corvair remains one of General Motors most unusual creations. ...

Many early aircraft engines (and a few in other applications) had the crankshaft fixed to the airframe and instead the cylinders rotated, known as a radial engine design. Airframe is a novel by renowned author Michael Crichton first published in hardback edition in 1996 and as a paperback edition in 1997. ...

In the Wankel engine, also called a rotary engine, the rotors drive the eccentric shaft, which can be considered the equivalent of the crankshaft in a piston engine. Wankel Engine in Deutsches Museum Munich, Germany The Wankel rotary engine is a type of internal combustion engine, invented by German engineer Felix Wankel, which uses a rotor instead of reciprocating pistons. ...

Construction

Crankshafts can be forged or cast from iron. They can be machined out of a single billet of forged steel. A disadvantage to billet crankshafts is that the grain structure is uni-directional. The only real advantage to billet crankshafts is its capability to produce very low amounts of custom designed crankshafts. Untreated mild steel is only used for engines in models or other such applications, where the engine runs but does not supply high power. Cast crankshafts are usually found in low cost production engines, where as now more and more automotive manufacturers are using forged crankshafts in need of its durability for todays high powered engines (not just high performance cars, but mid-ranged vehicles). The rough casting or forging is machined to size and shape, the holes are drilled, the main and connecting rod bearing journals are precision ground and case hardened, and the appropriate holes are threaded. A blacksmiths forge For finery forges (making iron) see finery forge. ... This article is about the manufacturing process. ... Billet is a term used in manufacturing to refer to a cast product. ... A replica Colt 1873 revolver, showing case hardening colors on the frame Case hardening or surface hardening is the process of hardening the surface of a metal, often a low carbon steel, by infusing elements into the materials surface, forming a thin layer of a harder alloy. ...

Germany's ThyssenKrupp and India's Bharat Forge Ltd are the largest manufacturers of crankshafts. They use forging to make crankshafts, axle beams, steering knuckles and other automobile components. German industrial company ThyssenKrupp AG, with about 200,000 employees, mainly operates in the steel industry, but also in the automotive, industrial construction, and shipbuilding areas, as well as manufacturing lifts and providing other technologies and services. ... Bharat Forge is the worlds second largest forging company. ...

Stress analysis of crankshaft

The crankshaft is subjected to various forces but it needs to be checked in two positions. First, failure may occur at the position of maximum bending. In such a condition the failure is due to bending and the pressure in the cylinder is maximal. Second, the crank may fail due to twisting, so the crankpin needs to be checked for shear at the position of maximal twisting. The pressure at this position is not the maximal pressure, but a fraction of maximal pressure.

See also

• Crankcase, the housing that surrounds the crankshaft
• Bicycle crankset
• Crank (mechanism)
• Brace (tool)
• Controlled Combustion Engine
• Piston motion equations
• Hudson Motor Car Company, balanced crankshaft in 1916 allowed higher RPM & more power

Image File history File links Commons-logo. ... Wikimedia Commons logo by Reid Beels The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ... Crankshaft Continental engine marine crankshafts, 1942 Crankshaft is also the name of a comic strip about an old, curmudgeonly bus driver. ... A Shimano Deore crankset, drive-side showing crank arm, spider, three chainrings and chainring guard // The crankset, or chainset, is the component of a bicycle drivetrain that converts the reciprocating motion of the riders legs into rotational motion used to drive the chain, which in turn drives the rear... A crank is a bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it; also used to change circular into reciprocating motion, or reciprocating into circular motion. ... A Brace or Brace and bit is a hand tool used to drill holes. ... Controlled Combustion Engine (CCE) is a type of internal combustion engine designed by Brad Howell-Smith in 1995. ... The motion of a non-offset piston connected to a crank through a connecting rod (as would be found in internal combustion engines), can be expressed through several mathematical equations. ... Hudson Logo Hudson Six-40, 1914 1917 Hudson Phaeton The Hudson Motor Car Company made Hudson brand automobiles in Detroit, Michigan, from 1909 to 1957. ...

External links

• Nicely detailed discussion of crankshaft features, from Mustang & Fords magazine, with many photographs
• Animated representations of the vibrations characteristic of various two cylinder engine and crankshaft configurations
• Balancing engines
• An interesting tool used to electrically emulate crankshaft position sensors