1. Air Intake: The process starts with the intake stroke. The piston inside the engine moves downwards, creating a low-pressure area within the cylinder. As the piston moves down, it opens an intake valve, allowing fresh air to be drawn into the cylinder from the atmosphere.
2. Compression: Once the intake stroke is complete, the intake valve closes, and the piston starts moving upwards, compressing the air trapped inside the cylinder. This compression increases the air pressure and temperature significantly.
3. Fuel Injection: Just before the piston reaches the top of the compression stroke, a precisely controlled amount of diesel fuel is injected directly into the highly compressed and heated air within the cylinder. Diesel fuel does not require a spark plug for ignition, unlike gasoline engines. Instead, the high temperature and pressure inside the cylinder cause the diesel fuel to ignite spontaneously, leading to combustion.
4. Power Stroke: The combustion of the fuel mixture generates a tremendous amount of heat and pressure within the cylinder. This high pressure forces the piston downwards, generating power. The expansion of gases during the power stroke provides the force required to move the vehicle or generate electricity.
5. Exhaust Stroke: After combustion, the piston moves upwards again, pushing the exhaust gases created during the power stroke out of the cylinder through an exhaust valve. These exhaust gases are then expelled from the engine through the exhaust system.
6. Repeat: The four strokes—intake, compression, power, and exhaust—form one complete operating cycle of the diesel engine. These strokes continuously repeat to keep the engine running.
Diesel engines typically operate at higher compression ratios compared to gasoline engines, allowing for better fuel efficiency. Additionally, diesel fuel contains more energy per gallon compared to gasoline, contributing to the improved efficiency of diesel engines. However, diesel engines emit higher levels of nitrogen oxides and particulate matter than gasoline engines, which is why emission control systems are crucial for reducing harmful emissions.
Advancements in diesel engine technology have focused on improving fuel efficiency, reducing emissions, and increasing performance to meet environmental regulations and consumer demand for cleaner and more efficient vehicles and equipment.
