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The autoignition temperature or self-ignition temperature, often called spontaneous ignition temperature or minimum ignition temperature (or shortly ignition temperature) and formerly also known as kindling point, of a substance is the lowest temperature at which it spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark. [1]
Homogeneous charge compression ignition (HCCI) is a form of internal combustion in which well-mixed fuel and oxidizer (typically air) are compressed to the point of auto-ignition. As in other forms of combustion , this exothermic reaction produces heat that can be transformed into work in a heat engine .
Auto-ignite, need some standard, is it 2 minutes, or what. Put paper in oven at 451F, it takes 10 minutes to brown up, that is not auto-ignition. This is science, not cut and paste from sources. In fact, was it a standard day, etc. etc. etc. After 15 minutes at 451 my paper was browning up like my french fries, not auto-ignition burnt, on fire.
"Rollover" or tongues of fire appear (known as "angel fingers" to firefighters) as gases reach their auto-ignition temperatures. There is a rapid build-up (or "spike") in temperature due to the compound effect of rapidly burning (i.e., deflagrating) gases and the thermal cycle they produce. This is generally the best indication of a flashover. [2]
The earliest electronic systems available as factory installations were vacuum tube car radios, starting in the early 1930s.The development of semiconductors after World War II greatly expanded the use of electronics in automobiles, with solid-state diodes making the automotive alternator the standard after about 1960, and the first transistorized ignition systems appearing in 1963.
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.
Auto-ignition can be mitigated by using fuels with high auto-ignition resistance (octane rating), however it still puts an upper bound on the allowable peak cylinder temperature. The thermodynamic limits assume that the engine is operating under ideal conditions: a frictionless world, ideal gases, perfect insulators, and operation for infinite ...
Pressure in cylinder pattern in dependence on ignition timing: (a) - misfire, (b) too soon, (c) optimal, (d) too late. In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke.