97 Do you know who invented the diesel engine? If you don t, search the Internet. Older diesel engines are very polluting because they produce smoke and harmful gases like nitrogen oxides and particulates. THE DIESEL ENGINE A diesel engine is a type of internal combustion engine that runs on diesel fuel. It is widely used in trucks, buses, ships, trains, and some cars because of its efficiency and durability. Diesel engines work on the compression ignition principle, by which air inside the cylinder is compressed to very high pressure, raising its temperature. When diesel fuel is injected into this hot, compressed air, it ignites automatically, producing power. Types of diesel engines There are different ways to classify diesel engines. Commonly, they are categorised by how much power they can produce (small, medium, and large). However, another way to classify them is by the number of strokes used to complete an engine cycle. The two-stroke diesel engine produces power once every revolution of the crankshaft, making it lighter and more powerful for its size. to add: aggiungere spin: rotazione torque: coppia (motrice) 228 MECHANICS At the start of the cycle, fresh air enters the cylinder and pushes out the old air. Then the piston compresses the air. When the piston reaches the top, diesel fuel is added, which catches fire and produces energy. This energy pushes the piston down, sending power to the wheels. It is often used in big machines, ships, and trains because it generates a lot of power. The four-stroke diesel engine produces power every two spins of the engine, so it uses less fuel and lasts longer. It is used in cars, buses, lorries and construction vehicles. Pros and cons of diesel engines Diesel engines are more fuel-efficient than petrol engines, which means they use less fuel to produce the same amount of power. Besides, they are very durable and can last for hundreds of thousands of kilometres if properly maintained. On the other hand, they are usually heavier and noisier than petrol engines, which can make vehicles less smooth to drive, and they are also slower in acceleration.