HCs generally 500s ppm.
the Gasoline and methane mix are less stable than the gasoline alone. as the mixture evaps into a "vacuum" of whatever level it begins to expand the mollecular chain leaving more actual space between the bonded surrounding carbons.as does happen a molecular sieve vacuum generator which tears apart atoms by heat and enpansion then cooling and heavy molecules drop out into the diffusion oil boiling below.
like decrease air pressure allows water to boil or channge state and asorb energy to do so and vise versa a pressure cooker is higher press and requires more input energy (>212) to boil and push the atoms apart.


see any good or industrial evaporator or sputtering or implanter or particle accelerator.
(as in atom smasher) these "spaces" get larger and the coheasive effect between the 8 outer electrons is weaker and vulnerable to attack from a "friendly lookind free electron or carbon looking to ozidize as every thing on the perodic table likes O2 to stabilize (well most cept for inerts at netural state)then it totally breaks open in the combustion compression. thats why aediabatic heat of compression can ignignt low octane gas cause its broken open and most vulnerable to the rapid combination of the entered oxygen with little energy as it looking to satisfy its "dangling bonds" of Hs and Cs with O2 produccing HC+NOX (Nitrogen from atmosphere 80%+ 1 oxygen )
kinda like we ram electrons into Lead to increase outer shell by to and its now Gold in an implanter with high voltade, huge magetic field to steer it and ultra high vac in a few Millitorr. to keep unwanted molecules out of the way.
as I type im running 10 Pure Hydrogen reactors to create different elemential propeties of basic chemicals O2,Ar,H2,N2,HCL,HF,KOH,HN03,and all kinds of metal dopants too.