Which Fuels Can Be Used in an Internal Combustion Engine?
Petrol, diesel, CNG, LPG, ethanol and hydrogen all work in an IC engine. Coal does not — and why explains what these engines need from a fuel.
The fuels that move aircraft, rockets, trains and power stations, and why each application picks the fuel it does.
Aircraft burn kerosene, rockets carry their own oxygen, power stations grind coal to a powder finer than face powder, and trains increasingly burn nothing at all. Each of those choices follows from a constraint, and the constraints are what this section explains.
Aviation runs on kerosene rather than petrol mainly for safety: a flash point above 38 °C against petrol's −43 °C means the tanks are not carrying an ignitable vapour space, which matters when you are carrying tonnes of fuel in the wings. Rockets carry an oxidiser because there is no air in space, which is why propellant is roughly 90% of a launch vehicle's mass. Pulverised coal exists because combustion happens at surfaces, and grinding multiplies surface area enormously.
The recurring theme is that no fuel is best in the abstract. Energy density by mass decides aircraft, energy density by volume decides cars, and controllability decides power stations.
Petrol, diesel, CNG, LPG, ethanol and hydrogen all work in an IC engine. Coal does not — and why explains what these engines need from a fuel.
Grinding coal to powder gives faster, more complete, more controllable combustion — but costs grinding power and makes far more fly ash.
Indian Railways runs mostly on electricity now, with diesel for unelectrified lines. How the split works and why the switch happened fast.
Most thermal power stations burn pulverised coal, some natural gas or lignite. What happens between the coal wagon and your light switch.
Rockets burn liquid hydrogen, refined kerosene (RP-1) or solid composite propellants — and must carry their own oxidiser, because there is no air in space.
Jets burn aviation turbine fuel, a kerosene grade sold as Jet A-1. Small piston aircraft use avgas. Here is why kerosene beats petrol.