# Cylinder (engine) > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Cylinder_(engine) > Markdown URL: https://mediated.wiki/source/Cylinder_(engine).md > Source: https://en.wikipedia.org/wiki/Cylinder_(engine) > Source revision: 1338210007 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Combustion engine block tube in which a piston operates For other uses, see [Cylinder (disambiguation)](/source/Cylinder_(disambiguation)). In an engine, the **cylinder** is the space in which a [piston](/source/Piston) travels.[1] 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](/source/Piston_ring),[1] 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 Cylinder (and piston) in a double-acting steam engine Main article: [Cylinder (locomotive)](/source/Cylinder_(locomotive)) The cylinder in a [steam engine](/source/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 Cross-section of a cylinder, along with the valves, spark plug, piston and connecting rod See also: [Internal combustion engine](/source/Internal_combustion_engine) The cylinder is the space through which the [piston](/source/Piston) travels, propelled by the energy generated from the combustion of the air/fuel mixture in the combustion chamber.[2] In an [air-cooled engine](/source/Air-cooled_engine), the walls of the cylinders are exposed to the airflow, to provide the primary method of cooling to the engine. Most air-cooled engines have cooling fins on the cylinders and each cylinder has a separate case in order to maximise the surface area available for cooling. In engines where the cylinders are removable from the engine block, a removable single cylinder is called a jug. For motorcycle engines, a "reverse cylinder engine" is where the intake ports are on the front side of each cylinder, and the exhaust ports are on the rear side of each cylinder.[3] ### Cylinder liners/sleeves [PSA TU engine](/source/PSA_TU_engine) block with wet liners. Cylinder liners (also known as sleeves) are thin metal cylinder-shaped parts which are inserted into the [engine block](/source/Engine_block) to form the inner wall of the cylinder.[4][5] Alternatively, an engine can be 'sleeveless', where the cylinder walls are formed by the engine block with a wear-resistant coating, such as [Nikasil](/source/Nikasil) or plasma-sprayed bores. During use, the cylinder liner is subject to wear from the rubbing action of the [piston rings](/source/Piston_ring) and piston skirt. This wear is minimized by the thin oil film which coats the cylinder walls and also by a layer of [glaze](/source/Glaze_(metallurgy)) which naturally forms as the engine is run-in. On some engines, the cylinder liner is replaceable, in case it becomes worn or damaged. On engines without replaceable sleeves, the cylinder can sometimes be repaired by boring out the existing liner to produce a new smooth and round surface (although the diameter of the cylinder is slightly increased). Another repair technique is 'sleeving' the cylinder— boring it and then installing a sleeve in the extra space created by the boring. Most engines use 'dry liners', where the liner is surrounded by the engine block and does not make contact with the coolant.[6] However, cylinders with 'wet liners' are used in some water-cooled engines, especially French designs. The wet liners are formed separately from the main casting so that liquid coolant is free to flow around their outsides. The advantage of wet liners is better cooling and a more even temperature distribution; however, this design reduces the rigidity of the engine. ## See also - [Bore (engine)](/source/Bore_(engine)) - [Cylinder (locomotive)](/source/Cylinder_(locomotive)) - [Engine displacement](/source/Engine_displacement) - [Internal combustion engine](/source/Internal_combustion_engine) - [Steam engine](/source/Steam_engine) - [Stroke (engine)](/source/Stroke_(engine)) ## References 1. ^ [***a***](#cite_ref-hsw_1-0) [***b***](#cite_ref-hsw_1-1) Brain, Marshall (5 April 2000). ["HowStuffWorks "Basic Engine Parts""](http://www.howstuffworks.com/engine2.htm). HowStuffWorks, Inc. Retrieved 3 May 2012. 1. **[^](#cite_ref-2)** ["Internal Combustion Engine"](https://web.archive.org/web/20130512211634/http://www.highbeam.com/doc/1G2-3418501239.html). *The Gale Encyclopedia of Science*. Gale Group. Archived from [the original](http://www.highbeam.com/doc/1G2-3418501239.html) on 12 May 2013. Retrieved 3 May 2012. 1. **[^](#cite_ref-3)** ["The long history of reverse-cylinder engine designs"](https://web.archive.org/web/20140222152949/http://motocrossactionmag.com/Main/News/THE-LONG-HISTORY-OF-REVERSECYLINDER-ENGINE-DESIGNS-7056.aspx). *www.motocrossactionmag.com*. Archived from [the original](http://motocrossactionmag.com/Main/News/THE-LONG-HISTORY-OF-REVERSECYLINDER-ENGINE-DESIGNS-7056.aspx) on 22 February 2014. 1. **[^](#cite_ref-4)** ["What is a cylinder liner?"](https://www.tpr.co.jp/tp_e/products/cylinderliners/about.html). *www.tpr.co.jp*. Retrieved 9 November 2019. 1. **[^](#cite_ref-5)** ["What is a Cylinder Liner?"](https://www.wisegeek.com/what-is-a-cylinder-liner.htm). *www.wisegeek.com*. Retrieved 10 November 2019. 1. **[^](#cite_ref-6)** ["Types of Cylinder Liners"](https://itstillruns.com/types-cylinder-liners-6938044.html). *www.itstillruns.com*. Retrieved 10 November 2019. v t e Internal combustion engine Part of the Automobile series Engine block and rotating assembly Balance shaft Block heater Bore Connecting rod Crankcase Crankcase ventilation system (PCV valve) Crankpin Crankshaft Core plug (freeze plug) Cylinder (bank, layout) Displacement Flywheel Firing order Stroke Main bearing Piston Piston ring Starter ring gear Valvetrain and Cylinder head Flathead layout Overhead camshaft layout Overhead valve (pushrod) layout Tappet / lifter Camshaft Chest Combustion chamber Compression ratio Head gasket Rocker arm Timing belt Valve Forced induction Blowoff valve Boost controller Intercooler Supercharger Turbocharger Fuel system Diesel engine Petrol engine Carburetor Fuel filter Fuel injection Fuel pump Fuel tank Ignition Magneto Compression ignition Coil-on-plug Distributor Glow plug Ignition coil Spark plug Spark plug wires Capacitor discharge ignition Engine management Engine control unit (ECU) Electrical system Alternator Battery Dynamo Starter motor Intake system Airbox Air filter Idle air control actuator Inlet manifold MAP sensor MAF sensor Throttle Throttle position sensor Exhaust system Catalytic converter Diesel particulate filter Gasoline particulate filter EGT sensor Exhaust manifold Muffler Oxygen sensor Cooling system Air cooling Water cooling Electric fan Radiator Thermostat Viscous fan (fan clutch) Lubrication Oil Oil filter Oil pump Sump (wet, dry) Other Knocking / pinging Power band Redline Stratified charge Top dead centre Portal Category --- Adapted from the Wikipedia article [Cylinder (engine)](https://en.wikipedia.org/wiki/Cylinder_(engine)) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Cylinder_(engine)?action=history)). 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