Diesel Engine Emissions Reduction through Urea Injection Optimization

A new study from Shandong University in China has reported significant progress in reducing diesel engine emissions through the optimization of urea injection. The research, published in Applied Sciences, utilized a Support Vector Machine (SVM) to predict nitric oxide (NOx) conversion efficiency and ammonia (NH3) slip in diesel engines. The optimized urea injection volume was found to maximize NOx conversion efficiency while controlling NH3 slip within 10 ppm, resulting in a 7.5% reduction in NOx accumulation during the World Harmonized Transient Cycle (WHTC).

Key Takeaways:

• The research identified urea injection strategies as a key factor in reducing NOx emissions and NH3 slips in diesel engines.
• The SVM model developed in the study was optimized using the Crested Porcupine Optimizer (CPO) to improve its prediction accuracy.
• The optimized urea injection volume maximized NOx conversion efficiency while controlling NH3 slip within 10 ppm.
• The optimized urea injection amount resulted in a 7.5% reduction in NOx accumulation during the WHTC cycle.
• The research concluded that the proposed method could be used to optimize urea injection volume for all conditions in diesel engines.
• The study was funded by the Shandong Province Key R&D Program and the National Engineering Laboratory of Mobile Source Pollution Control Technology of China.

Statistics:

• 7.5% reduction in NOx accumulation during the WHTC cycle.
• 10 ppm NH3 slip control threshold.
• 2025: Publication year of the study.
• 15(9):5195: Volume and page number of the study in Applied Sciences.

Sources:

• Applied Sciences, 2025, 15(9):5195.
• Xu Chen et al. Diesel Engine Urea Injection Optimization Based on the Crested Porcupine Optimizer and Genetic Algorithm. Applied Sciences, 2025, 15(9):5195.
• Shandong Province Key R&D Program, China.
• National Engineering Laboratory of Mobile Source Pollution Control Technology of China.
• Shandong University.