Time for some ad-related myth busting. The claim that a fuel derived from crude oil cleans your engine as you drive is utterly absurd. In fact, without an asterisk to explain that all the supplier has done is add a small quantity of injector cleaner that also happens to reduce the build-up on the port side of intake valves, this claim is just not true. Actually, the very opposite is true. Crude oil fuels are the primary reason internal combustion engines get dirty on the inside. To see how badly, you don't even need to take an engine apart or service one to observe how black the sump oil gets as a result of carbon build up. All you have to do is look inside the tailpipe of any crude-oil powered vehicle and you'll find an accumulation of carbon-based crud, and that's just what managed to stick to the sides. Most of it made it out into the lower atmosphere that you're breathing right now. Moreover, the reason engines need a filter on the fuel line is to remove dirt or other solid contaminants. And it's actually the crude oil fuel itself causing the injectors to gum up. Sure, before they get burned, petrol is a type of solvent (but that use is definitely not recommended), and diesel is a very thin lubricant. However, after they are burned they become various gasses (including noxious and greenhouse) and soot. Crude oil fuels are basically just liquid coal. Crude oil even forms in a very similar way (accumulated organic matter is subjected to heat and pressure in the earth's ever-changing crust over millions of years; for coal the source of this matter is usually plants and for oil it's often zooplankton and algae). Falsely suggesting that a crude oil fuel cleans your engine is also about the oldest advertising trick there is. I could point to print ads in the 1950s and even then it was old. But the reason for continuing with it into an era where developed nations are aiming for net-zero on carbon-dioxide and growing ever-more conscious of other noxious emissions seems far more nefarious to me. The reason I say that is the suggestion of a crude oil fuel doing any cleaning at all implies that using it isn't also dirtying the air. Another tactic of inference used is a fuel retailer saying they can get you anywhere in Australia, implying other energy sources can't. But if you stick to just one brand, you actually can't get everywhere. So far as I can tell, it's an anti-electric campaign thinly-disguised as ads for a retail network. Beyond that, performance wise petrol is actually a rather crap energy source. Even the special high-octane blend used in piston-powered aircraft (smaller planes and helicopters) is still so crap that tetraethyl lead is added to reduce wear on parts like valve seats and to reduce pre-detonation (which is the fuel burning under heat and pressure before the spark source has ignited, often causing fatigue and damage). Yes, even today, long after lead was phased out of road vehicle fuels from 1986 because of how disastrous it is for our health, 100LL (low lead) is used in Australia and many other countries. All the while, some operators whinge that insufficient levels of lead are causing their engines to wear and fail sooner (seriously, some older aircraft like those used to muster on cattle stations have fallen from the sky, killing their pilots, and the lowered levels of lead gets the blame from some people, not the age of the aircraft or the lack of changes to engine maintenance nor failing to give it a basic rebuild to suit the available fuel). So petrol is a woeful fuel source. It's just that people are so used to it they placidly accept it and its toxic unburned vapours that are allowed into the atmosphere anywhere it's stored. Consider this. When you fill up you're inhaling the same poisonous chemicals that cause long-term damage to the brain, heart, lungs, immune system, liver and kidneys of petrol sniffers. We haven't even discussed the epic environmental disasters that are oil spills, sometimes directly killing people and ruining marine waters for many years, as was the case with the Deepwater Horizon oil spill of 2010. So what is the potentially-sustainable alternative? As I discussed on a previous occasion, for internal combustion engines it's biofuels, which do have a few of their own issues but they are nowhere near the problems caused by crude oil fuels.