A combustion chamber is the part of an engine in which fuel is burned. An engine is a mechanical device that produces some form of output from a given input Fuel is any material that is burned or altered in order to obtain energy
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Internal Combustion Engine
The leftover hot gases produced by this combustion tend to occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber. This page is about the physical properties of gas as a state of matter Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface This pressure can be used to do work, for example, to move a piston on a crankshaft. A piston is a component of Reciprocating engines Pumps and Gas compressors It is located in a cylinder and is made gas-tight by Piston The crankshaft, sometimes casually abbreviated to crank, is the part of an Engine which translates reciprocating Linear The energy can be converted to various types of motion or to produce thrust when directed out of a nozzle as in a rocket or jet engine. Thrust is a reaction force described quantitatively by Newton 's Second and Third Laws. A nozzle is a mechanical device or Orifice designed to control the characteristics of a Fluid flow as it exits (or enters an enclosed chamber or Pipe. A rocket or rocket vehicle is a Missile, Aircraft or other Vehicle which obtains Thrust by the reaction of the specific --->A jet engine is a Reaction engine that discharges a fast moving jet of Fluid to
Petrol or Gasoline engine
A reciprocating engine is often designed so that the moving pistons are flush with the top of the cylinder block at top dead centre. A reciprocating engine, also often known as a piston engine, is a Heat engine that uses one or more reciprocating Pistons to convert A piston is a component of Reciprocating engines Pumps and Gas compressors It is located in a cylinder and is made gas-tight by Piston The cylinder block or engine block is a machined casting (or sometimes an assembly of modules containing cylindrically bored holes for the Pistons of a multi-cylinder In a Reciprocating engine, the dead center is the position of a piston in which it is farthest from or nearest to the Crankshaft. The combustion chamber is recessed in the cylinder head and commonly contains a single intake valve and a single exhaust valve. In an Internal combustion engine, the cylinder head sits atop the cylinders and consists of a platform containing part of the Combustion chamber and the Some engines use a dished piston and in this case the combustion chamber can be considered as partly within the cylinder. Various shapes of combustion chamber have been used, such as L-head (or flathead) for side-valve engines;"bathtub", "hemispherical" and "wedge" for overhead valve engines; and "pent-roof" for engines having 3, 4 or 5 valves per cylinder. A flathead engine or sidevalve engine (sometimes called a flatty) is an Internal combustion engine with valves placed in the engine block The shape of the chamber has a marked effect on power output, efficiency and harmful emissions; the designer's objectives are to burn all of the mixture as completely as possible while avoiding excessive temperatures (which create NOx). The term nitrogen oxide typically refers to any Binary compound of Oxygen and Nitrogen, or to a mixture of such compounds Nitric This is best achieved with a compact rather than elongated chamber. The intake valve/port is usually placed to give the mixture a pronounced "swirl" (the term is preferred to "turbulence" which implies uncontrolled movement) above the rising piston, improving mixing and combustion. Cylinder head porting refers to the process of modifying the intake and exhaust ports of an Internal combustion engine to improve the quality and quantity of the gas flow The shape of the piston top also effects the amount of "swirl. " Finally, the spark plug must be situated in a position from which the flame front can reach all parts of the chamber at the desired point, usually around 15 degrees after top dead centre. In a Reciprocating engine, the dead center is the position of a piston in which it is farthest from or nearest to the Crankshaft. It is strongly desirable to avoid narrow crevices where stagnant "end gas" can become trapped, as this tends to detonate violently after the main charge, adding little useful work and potentially damaging the engine. Knocking (also called knock, detonation or spark knock, pinking in UK English or pinging in US English in spark-ignition Also, the residual gasses displace room for fresh air/fuel mixture and will thus reduce the power potential of each firing stroke.
Diesel engine
Diesel engines fall into two broad classes:
- Direct injection, where the combustion chamber consists of a dished piston
- Indirect injection, where the combustion chamber is in the cylinder head
Direct injection engines usually give better fuel economy but indirect injection engines can use a lower grade of fuel. A diesel engine is an Internal combustion engine which operates using the Diesel cycle (named after Dr In an Internal combustion engine, the term indirect injection refers to a Fuel injection where fuel is not directly injected into the Combustion chamber
Harry Ricardo was prominent in developing combustion chambers for diesel engines. Sir Harry Ricardo ( 26 January 1885 – 18 May 1974) was one of the foremost engine designers and researchers in the early years of the development
Steam Engine
The term combustion chamber is also used to refer to an additional space between the firebox and boiler in a steam locomotive. A boiler is a closed vessel in which Water or other Fluid is heated A steam locomotive is a Locomotive powered by Steam. The term usually refers to its use on Railways but can also refer to a "road locomotive" This space is used to allow further combustion of the fuel, providing greater heat to the boiler.
Large steam locomotives usually have a combustion chamber in the boiler to allow the use of shorter firetubes. A fire-tube boiler is a type of boiler in which hot gases from the fire pass through one or more tubes within the boiler This is because:
- Long firetubes have a theoretical advantage in providing a large heating surface but, beyond a certain length, this is subject to diminishing returns. In Economics, diminishing returns is also called diminishing marginal returns or the law of diminishing returns.
- Very long firetubes are prone to sagging in the middle.
See also
Dictionary
combustion chamber
-noun
- An enclosed space, within a heat engine, in which the fuel is mixed and reacted with air or other oxidizing agent in a controlled manner
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