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Gasoline or petrol is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When formulated as a fuel for engines, gasoline is chemically composed of organic compounds derived from the fractional distillation of petroleum and later chemically enhanced with gasoline additives. It is a high-volume profitable product produced in crude oil refineries.
Specific impulse is a measure of how efficiently a reaction mass engine, such as a rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the impulse, i.e. change in momentum, per mass of propellant. This is equivalent to "thrust per massflow". The resulting unit is equivalent to velocity, although it doesn't represent any physical velocity ; it is more properly thought of in terms of momentum per mass, since this represents a physical momentum and physical mass.
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without causing engine knocking. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates the resistance to detonating under pressure without a spark.
A stratified charge engine describes a certain type of internal combustion engine, usually spark ignition (SI) engine that can be used in trucks, automobiles, portable and stationary equipment. The term "stratified charge" refers to the working fluids and fuel vapors entering the cylinder. Usually the fuel is injected into the cylinder or enters as a fuel rich vapor where a spark or other means are used to initiate ignition where the fuel rich zone interacts with the air to promote complete combustion. A stratified charge can allow for slightly higher compression ratios without "knock," and leaner air/fuel ratio than in conventional internal combustion engines.
A flame is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction made in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density, they are then considered plasma.
In spark-ignition internal combustion engines, knocking occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but when one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel–air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive.
Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula CH
3NO
2. It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent. As an intermediate in organic synthesis, it is used widely in the manufacture of pesticides, explosives, fibers, and coatings. Nitromethane is used as a fuel additive in various motorsports and hobbies, e.g. Top Fuel drag racing and miniature internal combustion engines in radio control, control line and free flight model aircraft.
A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed jet of high-temperature gas produced by the combustion of rocket propellants stored inside the rocket. However, non-combusting forms such as cold gas thrusters and nuclear thermal rockets also exist. Rocket vehicles carry their own oxidiser, unlike most combustion engines, so rocket engines can be used in a vacuum, and they can achieve great speed, beyond escape velocity. Vehicles commonly propelled by rocket engines include missiles, artillery shells, ballistic missiles and rockets of any size, from tiny fireworks to man-sized weapons to huge spaceships.
Deflagration is subsonic combustion in which a pre-mixed flame propagates through an explosive or a mixture of fuel and oxidizer. Deflagrations in high and low explosives or fuel–oxidizer mixtures may transition to a detonation depending upon confinement and other factors. Most fires found in daily life are diffusion flames. Deflagrations with flame speeds in the range of 1 m/s differ from detonations which propagate supersonically with detonation velocities in the range of km/s.
Detonation is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with speeds about 1 km/sec and differ from deflagrations which have subsonic flame speeds about 1 m/sec. Detonation is an explosion of fuel-air mixture. Compared to deflagration, detonation doesn't need to have an external oxidizer. Oxidizers and fuel mix when deflagration occurs. Detonation is more destructive than deflagrations. In detonation, the flame front travels through the air-fuel faster than sound; while in deflagration, the flame front travels through the air-fuel slower than sound.
Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process.
Methanol fuel is an alternative biofuel for internal combustion and other engines, either in combination with gasoline or independently. Methanol (CH3OH) is less expensive to sustainably produce than ethanol fuel, although it is more toxic than ethanol and has a lower energy density than gasoline. Methanol is safer for the environment than gasoline, is an anti-freeze agent, prevents dirt and grime buildup within the engine, has a higher ignition temperature and can withstand compression equivalent to that of super high-octane gasoline. It can readily be used in most modern engines. To prevent vapor lock due to being a simple, pure fuel, a small percentage of other fuel or certain additives can be included. Methanol may be made from fossil fuels or renewable resources, in particular natural gas and coal, or biomass respectively. In the case of the latter, it can be synthesized from CO2 (carbon dioxide) and hydrogen. The vast majority of methanol produced globally is currently made with gas and coal. However, projects, investments, and the production of green-methanol has risen steadily into 2023. Methanol fuel is currently used by racing cars in many countries and has seen increasing adoption by the maritime industry.
The heating value of a substance, usually a fuel or food, is the amount of heat released during the combustion of a specified amount of it.
Air–fuel ratio (AFR) is the mass ratio of air to a solid, liquid, or gaseous fuel present in a combustion process. The combustion may take place in a controlled manner such as in an internal combustion engine or industrial furnace, or may result in an explosion. The air–fuel ratio determines whether a mixture is combustible at all, how much energy is being released, and how much unwanted pollutants are produced in the reaction. Typically a range of air to fuel ratios exists, outside of which ignition will not occur. These are known as the lower and upper explosive limits.
Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always higher than the local speed of sound in the material.
A premixed flame is a flame formed under certain conditions during the combustion of a premixed charge of fuel and oxidiser. Since the fuel and oxidiser—the key chemical reactants of combustion—are available throughout a homogeneous stoichiometric premixed charge, the combustion process once initiated sustains itself by way of its own heat release. The majority of the chemical transformation in such a combustion process occurs primarily in a thin interfacial region which separates the unburned and the burned gases. The premixed flame interface propagates through the mixture until the entire charge is depleted. The propagation speed of a premixed flame is known as the flame speed which depends on the convection-diffusion-reaction balance within the flame, i.e. on its inner chemical structure. The premixed flame is characterised as laminar or turbulent depending on the velocity distribution in the unburned pre-mixture.
Thermal spraying techniques are coating processes in which melted materials are sprayed onto a surface. The "feedstock" is heated by electrical or chemical means.
A hydrogen internal combustion engine vehicle (HICEV) is a type of hydrogen vehicle using an internal combustion engine that burns hydrogen fuel. Hydrogen internal combustion engine vehicles are different from hydrogen fuel cell vehicles. Instead, the hydrogen internal combustion engine is simply a modified version of the traditional gasoline-powered internal combustion engine. The absence of carbon means that no CO2 is produced, which eliminates the main greenhouse gas emission of a conventional petroleum engine.
The Sugden Award is an annual award for contributions to combustion research. The prize is awarded by the British Section of The Combustion Institute for the published paper with at least one British Section member as author, which makes the most significant contribution to combustion research. The prize is named after Sir Morris Sugden.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
References
- ↑ Griffiths, J.F.; Barnard, J.A. (1995). Flame and Combustion. Springer. ISBN 978-94-011-0619-1.
- ↑ Jarosinski, J.; Veyssiere, B. (2009). Combustion phenomena: selected mechanisms of flame formation, propagation, and extinction. CRC. ISBN 9780849384097.
- ↑ Keating, E.L. (2007). Applied Combustion. CRC Press/Taylor & Francis. ISBN 9781420017489.
- ↑ NASA Technical Note, May 1977, "Emissions and Total Energy Consumption of a Multicylinder Piston Engine Running on Gasoline and a Hydrogen-Gasoline Mixture"
- ↑ "Gasoline FAQ - Part 3 of 4Section - 7. What parameters determine octane requirement?".
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