- Stroke (engine)
Reciprocating motion, used in reciprocating engines and other mechanisms, is back-and-forth motion. Each cycle of reciprocation consists of two opposite motions: there is a motion in one direction, and then a motion back in the opposite direction. Each of these is called a stroke. The term is also used to mean the length of the stroke.
The stroke length is determined by the cranks on the crankshaft. Stroke can also refer to the distance the piston travels. Bore is the diameter of the cylinder, which means that engine displacement is dependent on both the bore and the stroke of the cylinder.
Four-stroke internal combustion engine
Most modern internal combustion engines work on a four-stroke cycle; that is, a complete cylinder cycle consists of four discrete strokes, as described below. Other types of engines can have very different stroke cycles.
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 (allows atmospheric pressure to push) a fuel/air mixture into the combustion chamber.
In a reciprocating engine, 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.
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, reaches the point at which the fuel which has been injected spontaneously combusts, forcing the piston back down.
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.
Solve for variable
A power stroke is, in general, the stroke of a cyclic motor which generates force. It is used in describing mechanical engines. This force is the result of the spark plug igniting the compressed fuel-air mixture.
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 fresh air/fuel mixture into the cylinder so the process can repeat itself.
Reciprocating engines and configurations Type Stroke cycles Engine
configurationsI2 · I3 · I4 · I5 · I6 · I7 · I8 · I9 · I10 · I12 · I14F2 · F4 · F6 · F8 · F12 · F16Other inline
ComponentsEvans · Peaucellier–Lipkin · Sector straight-line · Watt's (parallel)Other 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
Air-cooled · 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 · Rotary engine · Shock-cooling · Stroke · Time between overhaul · Two-stroke engine · Valve timing · Volumetric efficiency
Propellers Engine instruments Engine controls Fuel and induction system Other systems
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Look at other dictionaries:
stroke engine — See long stroke engine short stroke engine … Dictionary of automotive terms
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long stroke engine — An engine where the length of the piston stroke is greater than the diameter of the bore of a cylinder. A relatively long stroke produces higher low end torque at the cost of increased piston speeds and reduced revving ability. The opposite is… … Dictionary of automotive terms
two-stroke engine — noun An engine in which the pistons perform two strokes per engine cycle (i.e., intake/compression and combustion/exhaust). See Also: four stroke engine … Wiktionary
four-stroke engine — noun An engine in which the pistons perform four strokes per engine cycle (i.e. intake, compression, power, exhaust). See Also: two stroke engine … Wiktionary
four-stroke engine — n an engine that works with two up and down movements of a ↑piston … Dictionary of contemporary English
two-stroke engine — dvitaktis variklis statusas T sritis fizika atitikmenys: angl. two cycle engine; two stroke engine vok. Zweitaktmotor, m rus. двухтактный двигатель, m pranc. moteur à deux temps, m … Fizikos terminų žodynas