NationMaster - Encyclopedia: Undersquare

A piston engine is undersquare or longstroke if its cylinders have a smaller bore (width, diameter) than stroke (length of piston travel). This can be a negative trait, since a longer stroke usually means greater friction, a weaker crankshaft, and a smaller bore means smaller valves which restricts gaseous exchange; however, with the aid of modern technology, these are not the large problems that they used to be. An undersquare engine usually has a lower redline than an oversquare one, but it may generate more low-end torque. In addition, a longstroke or undersquare engine can have a higher compression ratio with the same octane fuel compared to a similar displacement engine with a much shorter stroke ratio. This also equals better fuel economy and somewhat better emissions. An undersquare engine does not overheat as easily as similar oversquare engine. Engines can be modified with a "stroker" crankshaft, which increases an engines stroke from stock, increasing torque. Components of a typical, four stroke cycle, DOHC piston engine. ... A piston and cylinder from a steam engine A cylinder in an internal combustion engine is the space within which a piston travels. ... Bore may refer to: A wave in a river caused by an incoming tide - see tidal bore The diameter of a pipe or tube, or the caliber of a gun The diameter of a cylinder and piston in a piston engine (See also: Stroke) A person who is boring The... Stroke can mean: In medicine, a cerebrovascular accident (or cerebral accident) A sunstroke In writing, a single line without any break such as stroke in graphics or Chinese characters, see stroke order. ... Crankshaft, pistons, and flywheel Continental engine marine crankshafts, 1942 For the comic strip about an old, curmudgeonly bus driver, see Crankshaft (comic strip). ... The tachometer, right, shows red lines above 5700 RPM. Redline refers to the maximum engine speed at which an internal combustion engine and its components are designed to operate without causing damage to the components themselves or other parts of the engine. ... A piston engine is oversquare or shortstroke if its cylinders have a greater bore (width, diameter) than stroke (length of piston travel). ... In physics, torque can be thought of informally as rotational force. The SI units for Torque are newton meters although centinewton meters (cNÂ·m), foot-pounds force (ftÂ·lbf), inch pounds (lbfÂ·in) and inch ounces (ozfÂ·in) are also frequently used expressions of torque. ... The compression ratio is a single number that can be used to predict the performance of any internal-combustion engine. ... R-phrases , , , , S-phrases , , , , , , , Flash point 13 Â°C Autoignition temperature 220 Â°C Explosive limits 1. ... Stroke ratio, bore/stroke ratio and stroke/bore ratio are terms that are used to describe the form of a piston engines cylinder when the piston is at the lowmost point. ...

Undersquare engines are typically shorter in length, but heavier and taller than equivalent oversquare ones, which is one of the reasons why this type of engine is not generally used.

Many British automobile companies used undersquare designs through the 1950s, largely because of a motor tax system that taxed cars by their cylinder bore. Therefore, many of the most famous cars of that era use this design. This includes the Austin A-Series engine and many Nissan derivatives. Austin Motor Companys small straight-4 automobile engine, the A-Series, is one of the most common in the world. ... Nissan Motor Co. ...

The Chrysler Slant-6, in the most common 225 cubic inch version, is a massively undersquare engine (3.40" bore by 4.125" stroke) and, as such, produces most of its power right on the peak of its torque curve. The achilles heel of this engine, otherwise known for its exceptional durability, is being over-revved by inexperienced drivers. Red line for a factory engine is under 4,500RPM; red line with aftermarket connecting rods is about 5,500RPM. On the other hand, a well-maintained Slant-6 can be made to idle as low as 75RPM (though this is *not* a recommended speed, neither the alternator nor the oil pump will function adequately). In some circles, the Slant-6 is nicknamed "The Stump-Puller" for its diesel-like low-speed torque. Appropriate gearing and driving skill is required for performance use. The Chrysler Corporation is a United States-based automobile manufacturer, since 1998 merged with Daimler_Benz into DaimlerChrysler. ... Slant 6 was a punk rock trio based in Washington, D.C.. The group consisted of Christina Billotte (guitar, vocals), Myra Power (bass guitar, vocals), and Marge Marshall (drums, trumpet), and formed in July 1992 following the 1991 breakup of Autoclave, in which Billotte had played. ... This article is about the physical concept. ... In Greek mythology, Achilles is made invulnerable by being dipped in the river Styx by his mother, Thetis. ... piston + connecting rod In a reciprocating piston engine, the connecting rod or con rod connects the piston to the crank or crankshaft. ... Early 20th century Alternator made in Budapest, Hungary, in the power generating hall of a hydroelectric station. ... A Diesel engine built by MAN AG in 1906 Rudolf Diesels 1893 patent on his engine design The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature...

GM's popular 2.5L I4 "Iron Duke" motor, used in cars ranging from the Pontiac Fiero to the Oldsmobile Cutlass and Chevrolet S-10, is also undersquare. In the Fiero, it was a particular issue, since the car's styling tended to attract drivers who would over-rev the motor at stoplight confrontations - a skilled driver would shift around 3,700RPM, just after the engine's peak torque, long before the mellow power gives way to the whine of a high-revving motor. Compounding this, many Iron Dukes had defective connecting rods, leading to several recalls of the Fiero and a few other cars. GM is usually taken to mean General Motors (NYSE: GM), an automobile manufacturing company. ... The Iron Duke (also called the 2500, 151, Pontiac 2. ... This article or section does not cite its references or sources. ... The Oldsmobile Cutlass was an automobile made by the Oldsmobile division of General Motors. ... The Chevrolet S-10 (and similar GMC S-15 and Sonoma) was a compact pickup truck from the GMC marquee of General Motors. ...

Willys also used mostly undersquare engines, in fact the L- and F-134 engines, with their fairly small 3.125 inch bore and outrageous 4.375 inch stroke, are probably the most undersquare engines ever built. 1920 Willys-Knight advertisement Willys (pronounced WILL-iss) was the brand name used by the United States automobile company Willys-Overland Motors, best known for its production of military and civilian Jeeps, during the last century. ...

Nowadays, undersquare engines tend to be quite rare, but this form of engine is still used in some applications. For example, a modern 8.4 liter Valmet 645 inline-6 tractor diesel engine is a longstroke/undersquare engine, but has an output of over 300 horsepower (224 kW) with turbocharger and intercooler. The straight-6 (also inline 6, I-6, or I6) is an internal combustion engine with six cylinders aligned in a single row. ... A Diesel engine built by MAN AG in 1906 Rudolf Diesels 1893 patent on his engine design The diesel engine is a type of internal combustion engine; more specifically, it is a compression ignition engine, in which the fuel is ignited by being suddenly exposed to the high temperature... // Information processing In information processing, output is the process of transmitting information by an object (verb usage). ... The horsepower (hp) is the name of several non-metric units of power. ... Air foil bearing-supported turbocharger cutaway made by Mohawk Innovative Technology Inc. ... A front-mounted intercooler on a Mitsubishi Eclipse An intercooler is a device used on turbocharged and supercharged internal combustion engines to improve the volumetric efficiency, increase the amount of charge in the engine, and lower charge air temperature thereby increasing power and reliability. ...