Using wrong fuels in your car is called as a process of misfuelling. The fuels most used these days are petrol and diesel. No other fuels are in use as much as these fuels are used. It is because of the efficiency of these fuels. These two fuels give away more combustion energy with less amount of fuel used than any other fuel available.
Also, lorries and load trucks use different oils like kerosene oil in the diesel engine because, during extraction of petroleum, kerosene comes between crude oil and diesel i.e., it comes up after crude oil and before diesel and further petrol and other oils. So, kerosene is also a fuel and many of its properties are similar to diesel, so it is used as fuel. But there’s a vast difference between both fuels that is why it is not recommended to use kerosene oil in diesel engines.
Diesel In Petrol Engine:
Using Diesel in Petrol engine will lead engine knocking to take place. This will happen because initially, diesel and air will come inside with the help of the carburetor in 1st stroke. Further, in 2nd stroke, the cycle will get over because combustion will take place only when the diesel is compressed because the diesel has a high flash point and it won’t burn until it is compressed or sprayed as a mist. In more simple language, diesel will not catch enough fire and engine may fail. In 3rd and 4th stroke, nothing will be there as the cycle has already been ended in the 1st and 2nd stroke. Some cars may be able to run if some combustion is there. This will be called as irregular combustion. And it will cause no profit to the engine.
Petrol in Diesel Engine:
Using Petrol in 4 stroke diesel engine, the case will be better than the previous one. In the 1st stroke, only air intake will be there. In the 2nd stroke, air will be compressed to the required ratio, generally 22 times less volume than its original volume. In the 3rd stroke, with the help of fuel injector, petrol will be sprayed instead of diesel and being a different case from previous one, petrol will burn. This will lead the car to run and this will happen because petrol will be in mist form when sprayed. And in mist form combustible properties of fuels change and its ignition temp will be much less since the volume of each mist droplet is very less and pressure is high.
Long story, in short, use of petrol in a diesel engine will cause the fuel pump to fail after some use and it will completely stop working because of the requirement of lubrication in case of petrol.
Hence, in both cases, the driver is gonna stay in loss because the car is sure to require a visit to the mechanic after you do so but petrol in diesel engine may get the vehicle to some point on road but the path covered using diesel in petrol engine will not gonna be easy.