Stroke ( engine ) - wikipedia 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 ( eg 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 ( eg two - stroke engine, four - stroke engine ). `` Stroke length '', the distance travelled by the piston in each cycle. The stroke length - along with bore diameter - determines the engine 's displacement. Contents 1 Phases in the power cycle 1.1 Induction / Intake stroke 1.2 Compression stroke 1.3 Combustion / Power / Expansion stroke 1.4 Exhaust stroke 2 Types of power cycles 2.1 Two - stroke engine 2.2 Four - strokes engine 3 Stroke length Phases in the power cycle The phases / strokes of a four - stroke engine. 1 : intake 2 : compression 3 : power 4 : exhaust Commonly - used engine phases / strokes ( ie 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 stroke in a four - stroke internal combustion engine cycle. It involves the downward movement of the piston, creating a partial vacuum that draws a fuel / air mixture ( or air alone, in the case of a direct injection engine ) into the combustion chamber. In a reciprocating engine, it is that portion of the cycle when the pistons move from TDC ( top dead center ) to BDC ( bottom dead center ) and the fuel - air mixture is drawn into the cylinders... This is a cylinder for a 4 - stroke Petrol / Gasoline engine. The first step is to get the air - fuel mixture into the chamber. Mixture enters through an inlet port that is opened and closed by an inlet valve. This is called the Intake Manifold. Compression stroke The compression stroke is the second of four stages in an otto cycle or diesel cycle internal combustion engine. In this stage, the mixture ( in the case of an Otto engine ) or air ( in the case of a Diesel engine ) is compressed to the top of the cylinder by the piston until it is either ignited by a spark plug in an Otto engine or, in the case of a Diesel engine, by the fuel being injected into the compressed ( and thereby heated ) air, forcing the piston back down. In a Diesel engine, the injection of fuel usually leads top dead center by about 4 mechanical degrees, this `` lead '' being intended to allow complete fuel ignition to occur slightly after top dead center. Compression serves to increase the proportion of energy which can be extracted from the hot gas and should be optimised for a given application. Too high a compression can cause detonation, which is undesirable compared with a smooth, controlled burn. Too low a compression may result in the fuel / air mixture still burning when the piston reaches the bottom of the stroke and the exhaust valve opens. Combustion / power / expansion stroke A power stroke is, in general, the stroke or movement of a cyclic motor while generating force and thus power. It is used in describing mechanical engines. This force is the result of the spark plug igniting the compressed fuel - air mixture ( in Petrol Engines ). Exhaust stroke The exhaust stroke is the fourth of four stages in a four stroke internal combustion engine cycle. In this stage gases remaining in the cylinder from the fuel ignited during the compression step are removed from the cylinder through an exhaust valve at the top of the cylinder. The gases are forced up to the top of the cylinder as the piston rises and are pushed through the opening, which then closes to allow a fresh air / fuel mixture into the cylinder so the process can repeat itself. Types of power cycles The thermodynamic cycle used by a piston engine is often described by the number of strokes to complete a cycle. The most common designs of for engines are two - stroke and four - stroke. Less common designs include five - stroke engines, six - stroke engines and two - and - four stroke engines. Two - stroke engine Two - stroke engines complete a power cycle every two strokes, which means a power cycle is completed with every crankshaft revolution. Two - stroke engines are commonly used in outdoor power tools ( eg lawnmowers and chainsaws ) and motorcycles. Four - strokes engine Four - stroke engines complete a power cycle every four strokes, which means a power cycle is completed every two crankshaft revolutions. Most automotive engines are a four - stroke design. Stroke length The stroke length is how far the piston travels in the cylinder, which is determined by the cranks on the crankshaft. Engine displacement is calculated by multiplying the cross-section area of the cylinder ( determined by the bore ) by the stroke length. This number is multiplied by the number of cylinders in the engine, to determine the total displacement. Reciprocating engines and configurations Type Bourke Orbital Piston Pistonless ( Wankel ) Radial Rotary Split cycle Stelzer Tschudi Stroke cycles Two - stroke Four - stroke Five - stroke Six - stroke Two - and four - stroke Configurations & number of cylinders Single cylinder Single Two cylinders Split - single I2 V2 F2 Inline / straight I2 I3 I4 I5 I6 I7 I8 I9 I10 I12 I14 Flat F2 F4 F6 F8 F10 F12 F16 V / Vee V2 V3 V4 V5 V6 V8 V10 V12 V14 V16 V18 V20 V24 W8 W12 W16 W18 Other inline U Square four VR Opposed X X24 Junkers Jumo 222 Components Valves Cylinder head porting Corliss Intake Exhaust Multi Overhead Piston Poppet Side Sleeve Slide Rotary valve Variable valve timing Camless Desmodromic Hydraulic tappet Fuel supplies Carburetor Gasoline direct injection Common rail Mechanisms Cam Camshaft Overhead camshaft Connecting rod Crank Crankshaft Scotch yoke Swashplate Rhombic drive Linkages Peaucellier -- Lipkin Watt 's ( parallel ) Other Hemi Recuperator Turbo - compounding Automotive engine Part of the Automobile series Basic terminology Bore Compression ratio Crank Cylinder Dead centre Diesel engine Dry sump Engine balance Engine configuration Engine displacement Engine knocking Firing order Hydrolock Petrol engine Power band Redline Spark - ignition engine Stroke Stroke ratio Wet sump Main components Connecting rod Crankcase Crankpin Crankshaft Crossplane Cylinder bank Cylinder block Cylinder head ( crossflow, reverse - flow ) Flywheel Head gasket Hypereutectic piston Main bearing Piston Piston ring Starter ring gear Sump Valvetrain Cam Cam follower Camshaft Desmodromic valve Hydraulic tappet Multi-valve Overhead camshaft Overhead valve Pneumatic valve springs Poppet valve Pushrod Rocker arm Sleeve valve Tappet Timing belt Timing mark Valve float Variable valve timing Aspiration Air filter Blowoff valve Boost controller Butterfly valve Centrifugal - type supercharger Cold air intake Dump valve Electronic throttle control Forced induction Inlet manifold Intake Intercooler Manifold vacuum Naturally aspirated engine Ram - air intake Scroll - type supercharger Short ram air intake Supercharger Throttle Throttle body Turbocharger Twin - turbo Variable - geometry turbocharger Variable - length intake manifold Warm air intake Fuel system Carburetor Common rail Direct injection Fuel filter Fuel injection Fuel pump Fuel tank Gasoline direct injection Indirect injection Injection pump Lean - burn Stratified charge engine Turbo fuel stratified injection Unit injector Ignition Contact breaker Magneto Distributor Electrical ballast High tension leads Ignition coil Spark plug Wasted spark Electrics and engine management Air -- fuel ratio meter Alternator Automatic Performance Control Car battery ( lead -- acid battery ) Crankshaft position sensor Dynamo Drive by wire Electronic control unit Engine control unit Engine coolant temperature sensor Glow plug Idle air control actuator MAP sensor Mass flow sensor Oxygen sensor Starter motor Throttle position sensor Exhaust system Automobile emissions control Catalytic converter Diesel particulate filter Exhaust manifold Glasspack Muffler Engine cooling Air cooling Antifreeze ( ethylene glycol ) Core plug Electric fan Fan belt Radiator Thermostat Water cooling Viscous fan ( fan clutch ) Other components Balance shaft Block heater Combustion chamber Cylinder head porting Gasket Motor oil Oil filter Oil pump Oil sludge PCV valve Seal Synthetic oil Underdrive pulleys Portal Aircraft piston engine components, systems and terminology Piston engines Mechanical components Camshaft Connecting rod Crankpin Crankshaft Cylinder Cylinder head Gudgeon pin Hydraulic tappet Main bearing Obturator ring Oil pump Piston Piston ring Poppet valve Pushrod Rocker arm Sleeve valve Tappet Electrical components Alternator Capacitor discharge ignition Dual ignition Electronic fuel injection Generator Ignition system Magneto Spark plug Starter Terminology Air - cooled Aircraft engine starting Bore Compression ratio Dead centre Engine displacement Four - stroke engine Horsepower Ignition timing Manifold pressure Mean effective pressure Naturally aspirated Monosoupape Overhead camshaft Overhead valve engine Rotary engine Shock cooling Stroke Time between overhaul Two - stroke engine Valve timing Volumetric efficiency Propellers Components Propeller governor Propeller speed reduction unit Spinner Terminology Autofeather Blade pitch Constant - speed Contra - rotating Counter-rotating Scimitar Single - blade Variable - pitch Engine instruments Annunciator panel EFIS EICAS Flight data recorder Glass cockpit Hobbs meter Tachometer Engine controls Carburetor heat Throttle Fuel and induction system Avgas Carburetor Fuel injection Gascolator Inlet manifold Intercooler Pressure carburetor Supercharger Turbocharger Updraft carburetor Other systems Auxiliary power unit Coffman starter Hydraulic system Ice protection system Recoil start Steam engines Operating cycle Atmospheric Watt Cornish Compound Uniflow Valves Valves Slide D slide Piston Drop Corliss Poppet Sleeve Bash Valve gear Gab Stephenson link Joy Walschaerts Allan Baker Corliss Lentz Caprotti Gresley conjugated Southern Mechanisms Beam Cataract Centrifugal governor Connecting rod Crank Crankshaft Hypocycloidal gear Link chain Parallel motion Plate chain Rotative beam Sun and planet gear Watt 's linkage Boilers Simple boilers Haystack Wagon Egg - ended Box Flued Cornish Lancashire Fire - tube boilers Locomotive Scotch Launch Water - tube boilers Babcock & Wilcox Field - tube Sentinel Stirling Thimble tube Three - drum Yarrow Boiler feed Feedwater heater Feedwater pump Injector Cylinder Locomotive Oscillating Single - and double - acting Condenser Condensing steam locomotive Jet Kirchweger Watt 's separate `` Pickle - pot '' Surface Other Crosshead Cutoff Expansion valve Hydrolock Piston Reciprocating engine Return connecting rod engine Six - column beam engine Steeple engine Safety valve Steeple compound engine Stroke Working fluid History Precursors Savery Engine ( 1698 ) Newcomen engine Newcomen Memorial Engine ( 1725 ) Fairbottom Bobs ( 1760 ) Elsecar Engine ( 1795 ) Watt engine Beam Kinneil Engine ( 1768 ) Old Bess ( 1777 ) Chacewater Mine engine ( 1778 ) Smethwick Engine ( 1779 ) Resolution ( 1781 ) Rotative beam Soho Manufactory engine ( 1782 ) Bradley Works engine ( 1783 ) Whitbread Engine ( 1785 ) National Museum of Scotland engine ( 1786 ) Lap Engine ( 1788 ) High - pressure Richard Trevithick Puffing Devil ( 1801 ) London Steam Carriage ( 1803 ) `` Coalbrookdale Locomotive '' ( 1803 ) `` Pen - y - Darren '' locomotive ( 1804 ) Compound Woolf 's compound engine ( 1803 ) Murray Murray 's Hypocycloidal Engine ( 1805 ) Salamanca ( 1812 ) High - speed Porter - Allen ( 1862 ) Ljungström ( 1908 ) See also Glossary of steam locomotive components History of steam road vehicles Cugnot 's fardier à vapeur ( 1769 ) Murdoch 's model steam carriage ( 1784 ) Lean 's Engine Reporter List of steam technology patents Modern steam Stationary steam engine Timeline of steam power Water - returning engine Retrieved from `` https://en.wikipedia.org/w/index.php?title=Stroke_(engine)&oldid=811229271 '' Categories : Engine technology Talk Contents About Wikipedia Čeština Deutsch Español Français Hrvatski Italiano Nederlands Norsk Simple English Slovenčina Slovenščina Svenska 中文 Edit links This page was last edited on 20 November 2017, at 08 : 47. 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Question: what component of the engine determines the stroke
Answer: phase of the engine's cycle