What are the common technical methods and optimization measures for diesel engines?

There are various common technical methods and optimization measures for diesel engines, which are detailed below:

1、 Optimization of fuel injection system

High voltage common rail technology

This is an advanced fuel injection technology. The traditional diesel injection system has low and unstable pressure, while the high-pressure common rail system can increase the fuel pressure to a very high level, generally reaching around 1600-2000 bar.

High pressure common rail technology can achieve precise fuel injection, with precise control of injection time, injection quantity, and injection rate through an electronic control unit (ECU). For example, during engine start-up, multiple pre injections can be achieved to better mix fuel and air, thereby reducing noise and vibration during start-up and reducing harmful gas emissions.

Improvement of fuel injector design

Using porous fuel injectors allows fuel to be sprayed into the combustion chamber in a finer mist. This can increase the contact area between fuel and air, allowing fuel to burn more fully. For example, the number of orifices of some new fuel injection nozzles has increased from 4-6 to 8-10, and the fuel spray angle has also been optimized, so that the fuel can be evenly distributed in the combustion chamber.

2、 Optimization of intake system

Turbocharging technology

Turbocharging is a commonly used technical means for diesel engines. The turbocharger uses the exhaust gas emitted by the engine to drive the turbine to rotate, which in turn drives a coaxial compressor to compress more air and send it into the engine cylinder.

This can increase the amount of air entering the cylinder, making fuel combustion more complete. For example, in high-altitude areas, due to the thin air, the power of naturally aspirated engines will decrease, while turbocharged diesel engines can ensure the normal power output of the engine by compressing air, improving the power and economy of the engine.

Variable intake duct technology

By changing the length and cross-sectional area of the intake duct, the intake volume can be optimized according to the engine speed and load. At low speeds, use a longer intake duct to increase the inertia of the intake and improve intake efficiency; At high speeds, switch to a shorter intake duct to meet the engine's demand for large air intake.

3、 Optimization of combustion process

Optimization of combustion chamber shape

A well-designed combustion chamber shape can improve the mixing effect of fuel and air. For example, an omega shaped combustion chamber can create a good vortex of fuel inside the combustion chamber, promote the mixing of fuel and air, accelerate combustion speed, and improve combustion efficiency.

Adopting exhaust gas recirculation (EGR) system

The EGR system reintroduces a portion of the exhaust gas into the intake system, reducing the oxygen content in the combustion chamber. This can lower the combustion temperature and reduce the generation of nitrogen oxides (NOx). Meanwhile, proper exhaust gas recirculation can also improve the stability of the combustion process.

4、 Optimization of post-processing technology

Particulate Filter (DPF)

Used to capture particulate matter in diesel engine exhaust and reduce air pollution. DPF can filter out most of the carbon smoke particles in the exhaust gas. When the particles accumulate to a certain extent, they are burned off through the regeneration process, allowing the filter to restore its filtering function.

Selective Catalytic Reduction (SCR) System

The SCR system is mainly used to reduce nitrogen oxides in exhaust gas. By injecting urea solution into the exhaust gas, under the action of a catalyst, the ammonia produced by urea decomposition reacts chemically with nitrogen oxides, converting them into nitrogen and water, effectively reducing the emission of harmful gases.