So in petrol engine, the air fuel mixture is sent into the engine cylinder and the mixture is ignited by the spark generated by the spark plug. Whereas in diesel engine the air is compressed initially then the fuel i. e. , diesel is injected into the cylinder. read more
Diesel Engines we dont need the Spark Plug the Calorific value of the Diesel is more when compared with petrol Engine. For less colorific value we do not get more horse power. But diesel natually have more heat developed during combustion thus developing more power than petrol engines. read more
Best Answer: Diesel engines compress the air in the cylinders so much that the heat from compression ignites the fuel. A glow plug is just an electric heater that sticks into the cylinder to warm things up when it is cold. read more