Petroleum fuel starts off as crude oil that’s naturally found in the Earth. When crude oil is processed at refineries, it can be separated into several different kinds of fuels, including petrol, jet fuel, kerosene and, of course, diesel.

Diesel fuel is heavier and oilier. It evaporates much more slowly than gasoline — its boiling point is actually higher than the boiling point of water. You will often hear diesel fuel referred to as “diesel oil” because it’s so oily.

Both diesel and petrol engines are similar in that they convert fuel into energy through a series of small combustions or explosions. The difference is in the way these explosions happen.

In petrol engines the fuel is mixed with air, compressed by pistons and then ignited by sparks from spark plugs.

In diesel engine the fuel is first compressed before it gets injected. Because air heats up when it is compressed, the fuel then ignites.

Diesel engines does not have spark plugs but some may contain a glow plug. The compression process itself may not raise the air to a high enough temperature for fuel ignition. The glow plug help to raise the air temperature in the combustion chambers when the engine is cold much like the hot wires you see in a toaster.

What should you do if you put in the wrong fuel in your vehicle?

Putting the wrong fuel into your vehicle can cause havoc to your journey and potentially cause extensive damage to your car engine.

If you have realised your mistake before you started driving out of the petrol station – do not start your engine. If you have already started the engine, pull over somewhere safe and turn off your engine.

Starting your engine will circulate the mixed fuel around your engine, which can cause more damage. You want to make sure that the fuel is drained so that you can be on your way.

There are services such as Wrong Fuel Rescue that you can call to help you drain the fuel. You may think that these fuel rescue services are costly but the cost of letting the mixed fuel circulate around your engine is even greater! If you let the mixed fuel contaminate other parts of your car engine, it could mean that the entire fuel system requires costly repairs, or replacing completely.