Uncovering the inner workings of diesel engines

When delving into the internal working principles of diesel engines, we can elaborate on the following aspects:

1、 Basic concepts of diesel engines
Diesel engine, also known as compression ignition engine, is a type of internal combustion engine. It generates a high-temperature and high-pressure environment by compressing air, which then ignites the diesel fuel injected into the cylinder, causing the fuel to burn inside the cylinder and push the piston to do work, thereby converting the chemical energy of the fuel into mechanical energy. Diesel engines are widely used in fields such as trucks, tractors, locomotives, and ships due to their high efficiency and economy.

2、 Working principle of diesel engine
The working principle of diesel engines is based on the Diesel cycle, which mainly includes four strokes: intake stroke, compression stroke, power stroke, and exhaust stroke.
Inhalation stroke: During the inhalation stroke, the intake valve opens, the exhaust valve closes, the piston moves downward, and fresh air is drawn into the cylinder.
Compression stroke: As the piston moves upward, the air inside the cylinder is compressed, and the temperature and pressure gradually increase. During this process, the air is compressed to a sufficiently high temperature and pressure to prepare for the subsequent combustion process.
Power stroke: At the end of the compression stroke, when the pressure and temperature inside the cylinder reach a certain level, the fuel injector sprays diesel fuel into the cylinder in a high-pressure mist. Due to the high temperature and high pressure environment inside the cylinder at this time, diesel quickly mixes with air and self ignites, producing high-temperature and high-pressure gas. These gases rapidly expand, pushing the piston downwards, thereby driving the crankshaft to rotate and achieve external work.
Exhaust stroke: After the power stroke is completed, the exhaust valve opens and the piston moves upward to discharge the burned exhaust gas from the cylinder.

3、 Characteristics of diesel engines
Efficient and economical: Diesel engines have high thermal efficiency and fuel economy, thanks to their compression ignition working principle and high compression ratio.
High torque: Diesel engines can provide significant torque output at low to medium speeds, which gives them a significant advantage in situations that require high torque, such as trucks, ships, etc.
Emission issues: Traditional diesel engines have some emission problems, such as high emissions of particulate matter (PM) and nitrogen oxides (NOx). But with the development of technology, modern diesel engines have been able to significantly reduce the emissions of these harmful substances by adopting advanced emission control technologies such as SCR, DPF, etc.
Noise and vibration: Diesel engines generate significant noise and vibration during operation, which to some extent limits their application in certain situations. However, these issues have been effectively improved through optimized design and the adoption of advanced noise reduction and vibration reduction technologies.

4、 The Development Trend of Diesel Engines
With the increasingly strict environmental regulations and continuous technological progress, diesel engines are developing towards greater efficiency, environmental friendliness, and intelligence. For example, by increasing fuel injection pressure, optimizing combustion chamber shape, and adopting advanced exhaust aftertreatment technology, the thermal efficiency and emissions of diesel engines can be further improved; At the same time, by introducing advanced technologies such as electronic control systems and intelligent diagnostic systems, precise control and fault warning of diesel engines can be achieved, improving their reliability and service life.

In summary, diesel engines, as an important type of internal combustion engine, play a significant role in transportation and other fields. By gaining a deeper understanding of its internal working principles and characteristics, we can better recognize and apply this technological achievement.