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Power unit – engine
Published in Andrew Livesey, Motorcycle Engineering, 2021
Pre-ignition, post-ignition, pinking, and detonation are often confused, as their symptoms and effects are almost identical; that is, the air and fuel are burned in a noisy manner, usually a knocking noise, and there is a loss of power or uneven running. Running-on is associated with these symptoms too. Pre-ignition is when the fuel is ignited before the spark occurs; this is usually by something burning or becoming overheated in the combustion chamber. Often this is the spark plug insulator, a carbon deposit, or a section of damaged cylinder head gasket. Post-ignition is when the fuel burns late, or more likely, combustion continues after the engine is switched off. When the engine continues to run for a while when the ignition is switched off, this is called running-on. Pinking, also called knock, is the noise made by the mixture burning too quickly or on two flame fronts and is caused by the ignition timing being too advanced or too low-octane-rated fuel being used. Detonation is when pockets of fuel burn in an irregular way, usually because of poor air–fuel mixing, incorrect ignition timing, or poor combustion chamber design.
Power unit – engine
Published in Andrew Livesey, Practical Motorsport Engineering, 2019
Pre-ignition, post ignition, pinking and detonation are often confused as their symptoms and effects are almost identical; that is the air and fuel are burnt in a noisy manner, there is usually a knocking noise and there is a loss of power or uneven running. Running-on is associated with these symptoms too. Pre-ignition is when the fuel is ignited before the spark occurs – this is usually caused by something burning, or overheated in the combustion chamber. Often this is the spark plug insulator, a carbon deposit or a section of damaged cylinder head gasket. Post-ignition is when the fuel burns late, or more likely combustion continues after the engine is switched off – the engine continues to run for a while when the ignition is switched off – this is running-on. Pinking, also called knock, is the noise made by the mixture burning too quickly, or on two flame fronts, caused by the ignition timing being too advanced or too low octane rating fuel being used. Detonation is when pockets of fuel burn in an irregular way, usually because of poor air–fuel mixing, incorrect ignition timing or poor combustion chamber design.
Engine
Published in Andrew Livesey, Advanced Motorsport Engineering, 2012
Pre-ignition, Post-ignition, Pinking and Detonation are often confused as their symptoms and effects are almost identical; that is the air and fuel are burnt in a noisy manner, usually a knocking noise, and there is a loss of power or uneven running. Running-on is associated with these symptoms too. Pre-ignition is when the fuel is ignited before the spark occurs, this is usually by something burning, or overheating in the combustion chamber. Often this is the spark plug insulator, a carbon deposit or a section of damaged cylinder head gasket. Post-ignition is when the fuel burns late, or more likely combustion continues after the engine is switched off – the engine continues to run for a while when the ignition is switched off, this is running-on. Pinking, also called knock, is the noise made by the mixture burning too quickly, or on two flame fronts, caused by the ignition timing being too advanced or too low octane rating fuel being used. Detonation is when pockets of fuel burn in an irregular way, usually because of poor air fuel mixing, incorrect ignition timing or poor combustion chamber design.
Impact of fueling methods on the combustion and cyclic variability in a compression ignition engine
Published in International Journal of Green Energy, 2021
Meisam Ahmadi Ghadikolaei, Chun Shun Cheung, Ka-Fu Yung, Pak Kin Wong
Pre-ignition is one the main reasons to initiate abnormal combustion in the engines causing a rapid in-cylinder pressure rise along with a large amount of heat release in the cylinder, therefore, analysis on the in-cylinder pressure (especially peak in-cylinder pressure) or heat release rate based on crank angle degree can show the pre-ignition (Zhou et al. 2016). The pre-ignition analysis in this study was obtained from the peak in-cylinder pressure of 500 working cycles. If a peak in-cylinder pressure is observed before the main fuel injection time (8° BTDC for the engine tested in this study), a pre-ignition occurs, otherwise, there is no pre-ignition. The fumigating fuel might have an effect on the pre-ignition in the engine cylinders due to the injection of fumigated fuel into the cylinders before the main fuel injection; therefore, a pre-ignition analysis for all the tested loads and speeds was conducted in this research. Only the results of the highest engine load (228 Nm) and speed (2200 rpm) are presented in Figure 3 due to the highest combustion temperatures at these conditions which might be favorable for pre-ignition. It is found that all the tested fueling methods, even the fumigating method, have no pre-ignition at all the tested loads and speeds (Figure 3 is only shown as an example). Since ethanol has lower cetane number and also higher heat of evaporation, which leads to decline in combustion temperature; therefore, it prevents the early combustion (pre-ignition) in the fumigating method.
A comparative study of performance and combustion characteristics of a CI diesel engine fuelled with B20 biodiesel blends
Published in International Journal of Ambient Energy, 2019
Figure 7 shows HRR as a function of crank angle for the modified test fuel blends and diesel fuel. HRR analysis is the best method to analyse the combustion behaviour inside the cylinder. This combustion parameter analyses the start of combustion and combustion rate behaviour for each test fuel blend. The SOC for test fuel blends increased significantly and occurred earlier than that of diesel fuel at the end of compression stroke. This is due to the accessibility of free oxygen molecules in test fuel blends which results in the pre-ignition process inside the combustion chamber (Tompkins et al. 2012). The modified test fuel blends exhibit lower viscosity, lower cetane number and higher latent heat of evaporation which are responsible for better-premixed combustion resulting in higher HRR.
An overview of development and challenges in hydrogen powered vehicles
Published in International Journal of Green Energy, 2020
Seyed Ehsan Hosseini, Brayden Butler
Due to wide flammability range of hydrogen and its low ignition energy, fast combustion of hydrogen–air mixture in ICEs is unavoidable; therefore, undesired backfiring and pre-ignition should be controlled (Duan, Liu, and Sun 2014). Engine malfunctions like sudden increases in pressure, high engine temperature, acoustic oscillations, and high waste heat release are the results of pre-ignition (Ferguson and Kirkpatrick n.d.). Moreover, pre-ignition reduces the peak power output of the system and consequently decreases the efficiencies of H2ICEs (Das 2016).