Today in this article, we are going to discuss the major points of differences between, a petrol engine and a diesel engine, and their characteristics which make them suited for different purposes. Before discussing the differences between the construction of the two engines, let's begin with differentiating the fuel driving them. Petrol Petrol is a highly volatile fuel consisting mostly of the organic compounds, which is the end result of fractional distillation of petroleum. It is blended with additives, so as to enhance the quality of the fuel and increasing its performance characteristics, anti-corrosive nature, chemical stability, and also acts as a cleaning agent that keeps the fuel system clean and in good health. Petrol and air mixture inside the engine, requires an agent to ignite itself, that is, a "spark". Petrol may contain oxygen compounds, like Ethanol, to increase its combustibility. Petrol is also offered in various grades, usually called Octanes, which de