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Ignition and fuel
Published in Andrew Livesey, Motorcycle Engineering, 2021
Servicing spark plugs is limited to cleaning and gapping between replacements. If cleaning is needed, then a special machine is needed. Gapping the plug means setting the size of the gap between the fixed and the side electrode. Spark plug gaps are usually between 0.020 and 0.040 in (0.5 and 1 mm). New spark plugs are usually already gapped from the factory, but it is worth checking them before fitting. Plug condition is usually indicated by the engine analyzer test.
Ignition and fuel
Published in Andrew Livesey, Practical Motorsport Engineering, 2019
Servicing spark plugs is limited to cleaning and gapping between replacements. If cleaning is needed then a special machine is needed. Gapping the plug means setting the size of the gap between the fixed and the side electrode. Spark plug gaps are usually between 0.020 and 0.040 inch (0.5 and 1 mm). New spark plugs are usually ready gapped from the factory; but it is worth checking them before fitting. Plug condition is usually indicated by the engine analyser test.
Engineering Thermodynamics
Published in Raj P. Chhabra, CRC Handbook of Thermal Engineering Second Edition, 2017
Michael J. Moran, George Tsatsaronis
Although most gas turbines are also internal combustion engines, the name is usually reserved to reciprocating internal combustion engines of the type commonly used in automobiles, trucks, and buses. Two principal types of reciprocating internal combustion engines are the spark-ignition engine and the compression-ignition engine. In a spark-ignition engine, a mixture of fuel and air is ignited by a spark plug. In a compression ignition engine, air is compressed to a high enough pressure and temperature that combustion occurs spontaneously when fuel is injected.
Characterisation of spark plug deposits of an SI engine fuelled with gasoline-ethanol blends
Published in International Journal of Ambient Energy, 2022
Garima Kushwaha, Samir Saraswati, Bireswar Paul
The spark plug is one of the key components of the SI engine with its primary function to ignite air–fuel mixture within the combustion chamber under all operating conditions. A sufficient amount of voltage is supplied to spark plug central electrode to generate an intensely localised spark across the spark plug gap. The combustible gas between the electrodes is then ionised and excited by the high plasma energy, forming the initial spark kernel (Duan et al. 2021). The central electrode is insulated from the other components at ground potential. Inside the combustion chamber, the spark plug is exposed to combustion products that promote the formation of carbon deposits on the insulator. If the deposits, which are conductive in nature, connect insulator and central electrode, an additional shunt path is available for the spark to occur. When the resistance across the shunt path gets lower than the resistance of air gap between centre and ground electrode, a diffused side spark occurs between insulator nose and spark plug metal housing (Figure 1). The side sparking results in lower plug voltage, unstable ignition and misfire (Anand et al. 2020). The misfiring in an engine can lead to a loss in efficiency and an increase in fuel consumption and emissions like hydrocarbon (HC) and carbon monoxide (CO) (Kushwaha and Saraswati 2016; Kushwaha, Saraswati, and Paul 2017). Several factors influence the characteristics of the deposits that adhere to the spark plug insulator, including engine operating conditions, the spatial and temporal history of cylinder temperature, boundary conditions, and the physiochemical properties of the mixture. Many of these variables are influenced by the type and composition of fuel used. Nowadays, much attention is paid in the field of internal combustion engines to the search for environmentally friendly fuels derived from renewable sources. Among the various alternative fuels, the use of alcohols is actively pursued in many parts of the world because they are simple to produce, transport, and incorporate into internal combustion engines without requiring significant changes in engine design. In India, ethanol is the most widely used and promoted alcohol. When ethanol is blended with gasoline in the proper ratio, it improves many of its properties. Table 1 shows the major properties of ethanol in comparison to gasoline.