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The Info List - Stroke (engine)


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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
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[edit]

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
Intake
stroke[edit] 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
Intake
Manifold. Compression stroke[edit] 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[edit] 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[edit] 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[edit] 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[edit] 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 (typically large) marine engines, outdoor power tools (e.g. lawnmowers and chainsaws) and motorcycles. Four-strokes engine[edit] 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[edit] 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.

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Reciprocating engines and configurations

Type

Bourke Orbital (Sarich) Piston Pistonless (Wankel) Radial Axial 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

W

W8 W12 W16 W18

Other inline

H U Square four VR Opposed X X24 Junkers Jumo 222

Components

Valves

Cylinder head
Cylinder head
porting Corliss Intake Exhaust Multi Overhead Piston Poppet Side Sleeve Slide Rotary valve Variable valve timing Camless Desmodromic Hydraulic tappet

Fuel
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

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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
Cylinder head
(crossflow, reverse-flow) Flywheel Head gasket Hypereutectic piston Main bearing Piston Piston
Piston
ring Starter ring gear Sump

Valvetrain

Cam 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
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
Throttle
body Turbocharger Twin-turbo Variable-geometry turbocharger Variable-length intake manifold Warm air intake

Fuel
Fuel
system

Carburetor Common rail Direct injection Fuel
Fuel
filter Fuel
Fuel
injection Fuel
Fuel
pump Fuel
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
Car
battery (lead–acid battery) Crankshaft
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
Throttle
position sensor

Exhaust system

Automobile emissions control Catalytic converter Diesel particulate filter Exhaust manifold Glasspack Muffler

Engine cooling

Air cooling Antifreeze
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
Cylinder head
porting Gasket Motor oil Oil filter Oil pump Oil sludge PCV valve Seal Synthetic oil Underdrive pulleys

Portal Category

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Aircraft piston engine components, systems and terminology

Piston
Piston
engines

Mechanical components

Camshaft Connecting rod Crankpin Crankshaft Cylinder Cylinder head Gudgeon pin Hydraulic tappet Main bearing Obturator ring Oil pump Piston 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
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
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
Carburetor
heat Throttle

Fuel
Fuel
and induction system

Avgas Carburetor Fuel
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

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Steam engines

Operating cycle

Atmospheric Watt Cornish Compound Uniflow

Valves

Valves

Slide

D slide

Piston Drop Corliss Poppet Sleeve Bash

Valve
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
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
Newcomen Memorial Engine
(1725) Fairbottom Bobs
Fairbottom Bobs
(1760) Elsecar Engine
Elsecar Engine
(1795)

Watt engine

Beam

Kinneil Engine
Kinneil Engine
(1768) Old Bess (1777) Chacewater Mine engine (1778) Smethwick Engine
Smethwick Engine
(1779) Resolution (1781)

Rotative beam

Soho Manufactory engine (1782) Bradley Works engine (1783) Whitbread Engine
Whitbread Engine
(1785) National Museum of Scotland engine (1786) Lap Engine
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
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 Wate

.