Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - --- When will gas self ignite?? --- Temp?

RustyLugNut · 06-10-2019, 01:15 PM

is what you need to look for.

Gasoline is a variable mixture so the 280 degC auto-ignition temperature (AIT) is variable. The AIT must be tested for each gasoline mixture and plotted.

In general, the higher the pressure, the lower the AIT.

The higher the mixture turbulence the lower the AIT.

This is why a homogeneous gasoline mixture is compression limited. It is also the principle used in Homogeneous Charge Compression Ignition (HCCI) engines. HCCI engines will vary fuel lamda from stoichiometric to lean to vary the AIT. Mixture temperature is also a variable. So is mixture turbulence.

Again, duel to the complexity of gasoline mixtures, there is no simple equation. Testing and plotting is the usual procedure. Powerful computing is making combustion modelling a viable tool, however.

06-10-2019, 01:15 PM	#18 (permalink)
RustyLugNut Master EcoModder Join Date: Nov 2012 Location: San Diego, California Posts: 982 Thanks: 271 Thanked 385 Times in 259 Posts	Semenoff plots, is what you need to look for. Gasoline is a variable mixture so the 280 degC auto-ignition temperature (AIT) is variable. The AIT must be tested for each gasoline mixture and plotted. In general, the higher the pressure, the lower the AIT. The higher the mixture turbulence the lower the AIT. This is why a homogeneous gasoline mixture is compression limited. It is also the principle used in Homogeneous Charge Compression Ignition (HCCI) engines. HCCI engines will vary fuel lamda from stoichiometric to lean to vary the AIT. Mixture temperature is also a variable. So is mixture turbulence. Again, duel to the complexity of gasoline mixtures, there is no simple equation. Testing and plotting is the usual procedure. Powerful computing is making combustion modelling a viable tool, however.