The single-cylinder air-cooled diesel engine is a common internal combustion engine and is widely used in various light machinery and agricultural machinery. This article will analyze in detail the working principle of a single-cylinder air-cooled diesel engine, including its structure, working cycle and combustion process, to help readers better understand this key power device.
1. Structural composition
A single-cylinder air-cooled diesel engine is composed of multiple important components, including cylinder block, piston, connecting rod, crankshaft, cylinder head, valves and injectors. Among them, the cylinder block is the main part of the diesel engine. There is a piston and a cylinder head inside, forming a closed working room. The piston is connected to the crankshaft through a connecting rod, converting reciprocating motion into rotational motion to drive mechanical equipment.
2. Work cycle
The working cycle used by the single-cylinder air-cooled diesel engine is a four-stroke cycle, including the intake stroke, compression stroke, combustion stroke and exhaust stroke.
2.1 Intake stroke: When the crankshaft rotates, the piston moves downward, a negative pressure is formed in the cylinder, the intake valve opens, fresh air enters the cylinder through the intake passage, and the fuel injector is closed at the same time.
2.2 Compression stroke: The piston moves upward, compressing the air entering the cylinder, and at the same time the valve closes, forming high-pressure and high-temperature compressed air.
2.3 Combustion stroke: When the piston approaches top dead center, the injector injects high-pressure fuel into the cylinder. The fuel mixes with the compressed air and ignites spontaneously, producing high-temperature and high-pressure combustion gas, thereby pushing the piston downward.
2.4 Exhaust stroke: The piston moves upward again, pushing out the burned exhaust gas. At the same time, the exhaust valve opens to discharge the exhaust gas out of the cylinder to prepare for the next intake cycle.
3. Combustion process
The combustion process of a single-cylinder air-cooled diesel engine is relatively complex and mainly includes three stages: mixing, ignition and combustion.
3.1 Mixing stage: Fuel is injected into the cylinder through the injector and mixed with the incoming compressed air to form a combustible mixture. Diesel engines use compression ignition combustion, and fuel can spontaneously ignite under high temperature and high pressure conditions.
3.2 Ignition stage: When the piston approaches top dead center, the fuel injected by the injector is heated by the compressed air to a high temperature and high pressure state, reaching autoignition conditions and combustion begins. Ignition is ignited by a spark formed by high-pressure fuel atomization provided by an injector.
3.3 Combustion stage: The combustion gas expands rapidly, generating huge heat energy, pushing the piston downward, and at the same time driving the crankshaft to rotate and output power. After combustion is completed, the remaining exhaust gas is discharged from the cylinder through the exhaust stroke.
Through the above analysis of the working principle of a single-cylinder air-cooled diesel engine, we can see that a single-cylinder air-cooled diesel engine converts chemical energy into mechanical energy through the cyclic intake, compression, combustion and exhaust processes to provide power for various light-duty vehicles. Mechanical equipment and agricultural machinery. It has a simple structure, reliable operation, high power output and fuel economy performance. However, in practical applications, we also need to pay attention to the maintenance of diesel engines to ensure their normal operation and extend their service life. With the continuous advancement of technology, the combustion efficiency and environmental protection performance of diesel engines are also constantly improving, providing reliable power support for the development of all walks of life.