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The reduced engine speeds allow more time for autoignition chemistry to complete thus promoting the possibility of pre-ignition and so called "mega-knock". Under these circumstances, there is still significant debate as to the sources of the pre-ignition event. [3] Pre-ignition and engine knock both sharply increase combustion chamber temperatures.
Low-speed pre-ignition (LSPI), also known as stochastic pre-ignition (SPI), [1] is a pre-ignition event that occurs in gasoline vehicle engines when there is a premature ignition of the main fuel charge. [2] LSPI is most common in certain turbocharged direct-injection vehicles operating in low-speed and high-load driving conditions. [3]
In spark-ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) 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.
If the ignition spark occurs at a position that is too advanced relative to piston position, the rapidly combusting mixture can actually push against the piston still moving up in its compression stroke, causing knocking (pinking or pinging) and possible engine damage, this usually occurs at low RPM and is known as pre-ignition or in severe ...
Equally, as the engine's load increases, so does the temperature of the bulb. This causes the start of combustion to advance (occurring earlier in the cycle) which reduces power and efficiency. If combustion is allowed to advance too much then damaging pre-ignition can occur. This was a limiting factor on the power output of hot-bulb engines ...
CBS is once again testing out new ingredients for one of its oldest, most recognizable programs, “The CBS Evening News.” On Monday, CBS News jettisoned many of the signature elements of the ...
A problem with compressed charge engines is that the temperature rise of the compressed charge can cause pre-ignition. If this occurs at the wrong time and is too energetic, it can damage the engine. Different fractions of petroleum have widely varying flash points (the temperatures at which the fuel may self-ignite).
"The pre-deployment is very, ... which already warns of critical fire weather and the rapid spread of fire should an ignition occur. To add to the danger, the region has had negligible rain since ...