Pre-ignition Pre-ignition Pre-ignition (or preignition) in a spark-ignition engine is a technically different phenomenon from engine knocking, and describes the event wherein the air/fuel mixture in the cylinder ignites before the spark plug fires. Pre-ignition is initiated by an ignition source other than the spark, such as hot spots in the combustion chamber, a spark plug that runs too hot for the application, or carbonaceous deposits in the combustion chamber heated to incandescence by previous engine combustion events. The phenomenon is also referred to as 'after-run', or 'run-on' or sometimes dieseling, when it causes the engine to carry on running after
Michaelmas term the next academic year but one are published by the Registrar in the University Gazette during each Hilary Term. Schools in the United Kingdom and Ireland which use the name 'Michaelmas term' include: Schools in the United States which use the name 'Michaelmas term' include: Michaelmas term Michaelmas term is the first academic term of the academic year in a number of English-speaking universities and schools in the northern hemisphere, especially in the United Kingdom. Michaelmas term derives its name from the Feast of St Michael and All Angels, which falls on 29 September. The term runs from September or