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daveyjones97
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can you delay autoignition of petrol air mixture by preventing it from heating above 20 degree celsius as its compressed. how high pressure could be reached before autoignition? assume 10 to 1 (10:1) air to petrol mix.
daveyjones97 said:can you delay autoignition of petrol air mixture by preventing it from heating above 20 degree celsius as its compressed. how high pressure could be reached before autoignition? assume 10 to 1 (10:1) air to petrol mix.
mrspeedybob said:Yes. Heat from compression is what causes autoignition, If you keep the heat down you could probably compress the mixture all the way to a liquid without igniting it.
Diesel engines rely on autoignition, they have no spark plugs. Older diesels were hard to start in cold weather because the air started out too cold to get hot enough during compression to ignite the fuel. That is why modern diesels have glow-plugs and intake air heaters.
rcgldr said:I doubt it's possible to extract a significant amount of heat from the fuel-air mixture during the short time of a compression cycle in an engine. Water vapor injection can be used to cool the intake air.
http://en.wikipedia.org/wiki/Water_injection_(engines)
daveyjones97 said:thanks guys, was daydreaming about compressed air energy storage with the ability to ignite the mix as a power boost. Lots of time to daydream as I am a trucker. Thanks
Autoignition is the spontaneous ignition of a fuel-air mixture without the presence of an external spark or flame. It is important to delay autoignition because it can lead to engine knocking, which can cause damage to the engine and decrease its efficiency.
A 10:1 air-petrol mix refers to the ratio of air to petrol in the fuel-air mixture. At 20°C, this ratio is able to delay the autoignition of the mixture, providing a more controlled and efficient combustion process.
There are several factors that can affect the delay of autoignition, including the temperature, pressure, and chemical composition of the fuel-air mixture. Other factors such as the presence of additives or contaminants can also play a role.
The delay of autoignition can be measured using methods such as the ignition delay time test, in which the time between fuel injection and the start of ignition is recorded. This can be done in a controlled laboratory setting or in real-world engine tests.
Delaying autoignition has numerous applications in the automotive and aerospace industries, as well as in power generation. It can help improve engine performance, reduce emissions, and increase fuel efficiency. It can also be used in the development of new fuels and engines with improved combustion processes.