Interesting subject. Petrol companies try to get the maximum calorific value into their petrol formulation. More calories per unit volume means less volume for the same horsepower, alternatively more horsepower for the same fuel volume, provided there is enough oxygen to burn it in!
There are also additives to lubricate the valve gear, help prevent engine knock - allowing the use of higher compression ratios – keep everything clean and some compounds that liberate oxygen during their combustion, which then helps all those calories in the fuel to burn a little more completely.
Petrol is also used to cool the inlet charge, as the fuel is atomised it also starts to evaporate. Evaporation requires heat energy, which is taken from the surrounding air, as the air cools it becomes denser, which means more oxygen, so you can burn more fuel and make more power.
Need a cool drink and don't have a fridge? Wrap it in a wet towel and leave it to stand and it will cool as the water evaporates, just like the water in a clay pot wine chiller works.
Running the engine's fuel air mixture richer than necessary can cause a drop in combustion temperature to. This was used quite extensively in the turbo era until the fuel efficiency formula was introduced. I don't think it is used in this way in modern engines, as they require maximum efficiency as well as maximum power to be competitive.
Super brewing of fuel reached its peak during the early years of the turbo era when the fuel used was virtually unrecognisable when compared to the petrol you and I use. There were some pretty lethal additives, such as Benzene, which is something you do not want to get on your person! More recently the FIA has gone much further than before to level the feild, they now specify the legal make up much more closely than ever before, seriously limiting the petrol supplier’s operational window, so that the fuel is pretty close to what you and I buy. Even so there is a window and it is being exploited to the full by the manufactures and engine builders.
Monstrobolaxa – hope you had a good exam, I am sure you will have passed with flying colours.
One thing is to supply products to a F1 Team, another thing is to put a sticker on the rear wing (Liqui-Moly)
