The application principle of turbocharging technology in diesel engines and its impact on power?

1、 The core principle of turbocharging technology

Turbocharging technology improves engine performance by recovering energy from diesel engine exhaust gas and achieving intake turbocharging. Its core principles are based on energy conservation and thermodynamic cycles:

Exhaust gas driven turbine: The high-temperature and high-pressure exhaust gas emitted by the engine impacts the turbine blades, driving the turbine to rotate at high speed (with a speed of over 100000 revolutions per minute).

Compressed fresh air: The turbine drives the compressor impeller through a coaxial connection, compressing the external air and sending it into the combustion chamber.

Increase intake density: The compressed air density significantly increases (usually by 30% -50%), resulting in a higher oxygen content per unit volume and providing conditions for full combustion of the fuel.

Combined with the compression ignition characteristics of diesel engines, turbocharging technology solves the problem of limited combustion efficiency caused by insufficient intake in naturally aspirated engines. Due to the high compression ratio of diesel engines (usually 16:1 to 22:1), turbocharging can further increase the density of the mixture and optimize the combustion process.

2、 The Influence of Turbocharging on the Power Performance of Diesel Engines

Significantly increase power and torque

Turbocharging allows diesel engines to increase power by 30% -100% and torque by 50% -80% without increasing displacement. For example, after installing turbocharging on a 2.0L diesel engine, the maximum power increased from 100kW to 140kW, and the peak torque increased from 300N · m to 400N · m. This characteristic makes it indispensable in fields such as heavy trucks and construction machinery, especially in high-altitude areas where turbocharging can compensate for power attenuation caused by thin air.

Improve fuel economy

After turbocharging, the engine can output high torque at lower speeds, reducing friction losses caused by high speeds. At the same time, more thorough combustion improves fuel efficiency, and some models can reduce fuel consumption by 10% -15%. For example, a heavy-duty truck equipped with a turbocharged diesel engine reduced its fuel consumption from 35L to 30L per 100 kilometers.

Optimize emission performance

Boosting technology promotes the oxidation of particulate matter (PM) and reduces particulate emissions by increasing combustion temperature and pressure. However, it should be noted that turbocharging may lead to an increase in the generation of nitrogen oxides (NOx), which requires the use of post-treatment technologies such as SCR (selective catalytic reduction) to control emissions.

3、 Technical Challenges and Solutions

Turbo Lag

Insufficient exhaust energy at low speeds results in delayed boost response (usually 0.5-2 seconds), affecting driving smoothness. The solution includes:

Variable cross-section turbine (VGT): optimizes low-speed turbocharging efficiency by adjusting the angle of the turbine blades.

Electric assisted turbine: Start the motor to assist the turbine in acceleration at low speeds, reducing response time.

Thermal load and mechanical stress

After turbocharging, the temperature and pressure in the combustion chamber increase, which puts higher demands on engine materials such as cylinder blocks and pistons. The use of high-strength alloys, ceramic coatings, and optimized cooling systems can alleviate this problem.

Reliability and maintenance costs

Turbochargers have extremely high rotational speeds and require high-precision bearings and high-temperature resistant lubricating oil. Regularly replacing the oil filter and avoiding sudden acceleration/deceleration can extend its service life.

4、 Future Development Trends

Intelligent control: Real time monitoring of intake pressure, temperature, and other parameters through an electronic control unit (ECU), dynamically adjusting the boost strategy to achieve more accurate power output.

Hybrid synergy: In the field of commercial vehicles, turbocharged diesel engines can be combined with electric motors to form a "diesel electric hybrid" system, further improving energy efficiency.

Hydrogen fuel adaptation: Some turbocharging technologies have been modified for hydrogen fuel engines, improving hydrogen combustion efficiency through turbocharging and exploring zero carbon power paths.

conclusion

Turbocharging technology is a key means for diesel engines to break through physical limits, which significantly improves power, economy, and environmental friendliness through energy recovery and thermodynamic optimization. Despite facing challenges such as lag and reliability, with the advancement of materials science and intelligent control technology, turbocharging will still be one of the core directions for the future development of diesel engines. In the context of the transition to new energy, this technology will also collaborate with other forms of power to provide diversified solutions for the transportation and industrial sectors.