1. Air Intake: The engine's piston moves downward during the intake stroke, drawing in air through an intake valve.
2. Compression: As the piston moves back up, it compresses the air in the cylinder. This compression significantly increases its temperature and pressure.
3. Fuel Injection: At a precisely determined moment before the piston reaches the top of its stroke (known as the injection timing), a fuel injector sprays a finely atomized mist of diesel fuel directly into the highly compressed and heated air within the cylinder. This is in contrast to gasoline engines, where fuel is mixed with air before entering the cylinder.
4. Ignition: The intense heat and pressure in the cylinder cause the diesel fuel to spontaneously ignite without the need for an electric spark plug. This process is called auto-ignition or compression ignition. The high pressure in the cylinder ensures that the fuel droplets vaporize rapidly, facilitating the ignition process.
5. Combustion: The diesel fuel burns rapidly, releasing a significant amount of heat and energy. This expansion of gases pushes the piston downward with great force, generating power for the engine.
It's important to note that the fuel injection system in a diesel engine is precisely controlled to deliver the right amount of fuel at the appropriate moment. Modern diesel engines often use electronic fuel injection systems with high-pressure injectors to ensure accurate and efficient fuel delivery, leading to improved engine performance and fuel economy.
