Ignitability

The ignition readiness of a fuel provides information about the period between injection and self-ignition ( ignition delay ). With diesel fuel, this measured value is called the cetane number . Today, minimum values ​​of CZ 50 are a prerequisite for the diesel principle . Combustion only takes place if the fuel ignites itself after being injected into the compressed hot air.

There is a connection with the flammability limit . This is defined as the lower and upper volume percent of the gaseous fuel in the air, where ignition and subsequent combustion can take place at all. The best air ratio is usually lambda 1 . The minimum ignition temperature of the gas mixture to cause it to explode is also important . In this context, the term "explosion" does not mean explosiveness, as is the case with explosives, but rather a moderate burning rate of the flame front after the start of burning due to minimum ignition energy (and ignition power) or self-ignition (temperature and pressure).

literature

• Karl-Heinz Dietsche, Thomas Jäger, Robert Bosch GmbH: Automotive pocket book. 25th edition, Friedr. Vieweg & Sohn Verlag, Wiesbaden, 2003, ISBN 3-528-23876-3