Research on real-world emission characteristics based on the Symmetry Solid SCR system

Area of Science:

• Environmental Science
• Mechanical Engineering
• Chemical Engineering

Background:

• Diesel engines face challenges with high NOx emissions, particularly in urban, low-temperature conditions, impacting the effectiveness of Urea Selective Catalytic Reduction (SCR) technology.
• Urea SCR systems suffer from low-temperature issues like freezing and urea crystallization, hindering performance in real-world urban driving.

Purpose of the Study:

• To compare the real-world emission characteristics of Solid SCR and Urea SCR systems in a China VI compliant diesel truck.
• To evaluate the effectiveness of Solid SCR technology in mitigating low-temperature operational defects associated with Urea SCR systems.

Main Methods:

• Utilized a Portable Emission Measurement System (PEMS) for real-world vehicle testing.
• Compared a SAIC Hongyan Dump truck equipped with both Solid SCR and Urea SCR systems under actual operating conditions.

Main Results:

• Solid SCR systems, using solid ammonium, reduce urea-related issues like icing and crystallization at low temperatures.
• Under real-world conditions, Solid SCR showed a slight increase in NOx conversion efficiency (0.5%) and an 8.9% reduction in NOx emissions compared to Urea SCR at specific average window temperatures.
• Particulate Number (PN) emissions showed minimal influence from either SCR system. CO, HC, NO, and NOx emissions decreased with increasing vehicle speed when using the Solid SCR system.

Conclusions:

• Solid SCR technology presents a more reliable and efficient solution for diesel exhaust treatment, particularly in cold environments.
• Solid SCR offers improved system operation and adaptability, contributing to reduced diesel vehicle emissions and environmental pollution.
• Solid SCR is a promising technology for controlling NOx emissions in diesel engines.