Simplified Modeling and Analysis of Surface Temperature Distribution in Electrically Heated Catalyst for Diesel Urea-SCR Systems

• Published in: Energies (Basel) Vol. 15; no. 17; p. 6406
• Main Authors: Moon, Seoksu, Park, Sunhong, Son, Jihyun, Oh, Kwangchul, Jang, Sungwook
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2022
• Subjects: 1D modeling; Air quality management; Catalysts; Chemical reduction; Cold; Convection; convective heat transfer; Decomposition; Diesel; Diesel engines; Diesel motor; Dimensional analysis; Electric power; electrically heated catalyst (EHC); Emission measurements; Emissions; Energy conservation; Engines; Environmental regulations; Evaporation; Exhaust gases; Flow rates; Flow velocity; forced internal convection; Gas flow; Heat transfer; Internal combustion engines; Laws, regulations and rules; Nitrogen oxide; Nitrogen oxides; Parameters; Photochemicals; Regulations; Selective catalytic reduction; selective catalytic reduction (SCR); Surface temperature; Temperature distribution; Temperature measurement; Thermal decomposition; United States; Urea; United States
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en15176406

Impending emission regulations of diesel engines for construction machineries would regulate nitrogen oxide emissions strictly in cold operating conditions. The urea-based selective catalytic reduction (urea-SCR) system coupled with the electrically heated catalyst (EHC) has been considered as a potential measure to meet the strict emission regulations by promoting evaporation and thermal decomposition of urea–water solution in cold operating conditions. Analyzing the thermal conditions in the EHC is crucial for the optimized operation and control of EHC-based urea-SCR systems under various engine operating conditions. In the current study, we introduce a simple one-dimensional analysis scheme to characterize the surface temperature distribution in the EHC based on energy conservation and the theories of forced internal convection. Since the EHC has a complicated internal structure with fine flow cells inside it, a flow cell in the EHC is extracted for the one-dimensional heat transfer analysis. EHC operation parameters such as exhaust gas flow rate and supplied electric power to the EHC are scaled to be applied for the flow cell analysis. The adequacy of the analysis scheme is then validated by surface temperature measurement results at the EHC outlet. The validation results showed over 95% prediction accuracy of the 1D analysis scheme in the operating conditions of a heavy-duty diesel engine. Based on proven reliability, the effects of geometric and operation parameters on the surface temperature distribution in the EHC were analyzed and discussed using the analysis results.