Now, this is a question for a curious mind, What will happen if I fill up a diesel engine with petrol or a petrol engine with diesel? Will it run or will it not? In order to get to the bottom of this curious question, let us first try to understand the basic differences between the two engine types.

Petrol engines use a carburettor to feed the engine with a mixture of petrol and air which is then ignited by a spark from the spark-plugs mounted on every cylinder. In simpler terms the gaseous mixture of fuel is ignited in the cylinder with help of a spark, this explosive mixture then powers the vehicles. A noticeable thing here is that petrol engines are designed to operate at a lower pressure in comparison to their diesel counterparts.Reason being the volatility and combustibility of the fuel utilized.

Also Read: Why Diesel Engines Are Heavier Than Petrol Engines 

Petrol by its nature is a volatile fuel and does not need high pressures for ignition. Whereas a diesel engine owing to the nature of the fuel used has to operate at high pressures in order to achieve combustion of fuel.

Diesel being a thicker and heavier fuel is also non-volatile in nature. Diesel engines utilize an array of fuel injectors which spray the fuel into the cylinder at a high pressure, this pressurized fuel then comes in contact with the hot pressurized air in the cylinder and ignites generating power for the engine. 

Now coming to the point!

Petrol engine

what will happen if we use the wrong fuel ? There are two scenarios that we need to deal with while answering this question-