## 5 Conclusions  
To further decrease the nitrogen oxide emission of diesel engines, electrical heating is applied for better EAT system performance at mid- to low working points. The effect of exhaust parameter and DOC on NO\({}_{\text{x}}\) conversion is investigated to further decrease the NO\({}_{\text{x}}\) emission during the cold-start WHTC cycle. 1. At lower exhaust temperatures, the NH\({}_{3}\)-NO\({}_{\text{x}}\) reactions were hindered by the low temperature, which is consistent with the article mentioned in [8]. As exhaust temperature increases, the NO\({}_{\text{x}}\) conversion rate gradually increases from 87.07% at 200 \({}^{\circ}\)C to 97.81% at 260 \({}^{\circ}\)C. Longer SCR carriers can also increase the NH\({}_{3}\)-NO\({}_{\text{x}}\) reaction rate at steady working points at the cost of higher capital cost and ammonia chemical loss, as mentioned in [10]. 2. A separate LO-SCR coupled with an upstream electrical heater can effectively increase the NO\({}_{\text{x}}\) conversion rate at lower exhaust temperatures. With a 7.2 kW electrical heater, the NO\({}_{\text{x}}\) emission at the LO-SCR outlet decreased by 45% during the 200-500 s of the WHTC cycle. 3. The effect of DOC on the NH\({}_{3}\)-NO\({}_{\text{x}}\) reactions is twofold. At lower working points, partially oxidized NO into NO\({}_{2}\) increases the proportion of fast reaction in LO-SCR, while, at higher load working points, the high NO\({}_{2}\) proportion may increase N\({}_{2}\)O generation and the proportion of slow reaction, similar to those mentioned in [21; 22]. The upstream DOC decreased the LO-SCR outlet NO\({}_{\text{x}}\) emission by 63% during the 200-500 s of the WHTC cycle at the cost of worse cold-start performance and higher N\({}_{2}\)O emission. 4. The application of thermal management increased the average exhaust temperature, which increased the NH\({}_{3}\)-O\({}_{2}\) reaction rate in SCR. The urea input shall be adjusted properly to avoid NO\({}_{\text{x}}\) emission during the latter part of WHTC, as mentioned in [10]. Conceptualization, K.S. and S.B. ; methodology, K.S. and D.L. ; software, Z.W. ; validation, Z.W. and D.L. ; formal analysis, D.L. and G.Z. ; investigation, K.S., D.L. and G.Z. ; resources, S.B. and C.L. ; data curation, K.S. and G.Z. ; writing--original draft preparation, K.S., Z.W. and D.L. ; writing--review and editing, D.L., G.Z. and H.C.; visualization, G.Z. and Z.W. ; supervision, G.L., S.B. and C.L. ; project administration, K.S. ; funding acquisition, G.L. and S.B. All authors have read and agreed to the published version of the manuscript. Figure 13: Effect of thermal management on NO\({}_{\text{x}}\) conversion. **Funding:** This research was funded by Construction Machinery Intelligent Equipment Innovation and Entrepreneurship Community of Shandong, China (grant numbers GTT2021105), Department of Science & Technology of Shandong Province, China (grant numbers 2021T5 GC1334), Asset & Laboratory Management Department of Shandong University, China (grant numbers sy20232305), and the Undergraduate School of Shandong University, China (grant numbers 2022Y155). **Institutional Review Board Statement:** Institutional review is not applicable as the paper did not involve humans or animals. **Informed Consent Statement:** Informed consent is not applicable as the paper did not involve humans. **Data Availability Statement:** All data and models used in the study appear in the submitted article. **Acknowledgments:** We appreciate the editors and reviewers for their constructive and detailed critiques that contributed to the quality of this paper, and all individuals have confirmed this acknowledgment. **Conflicts of Interest:** The authors declare no conflict of interest. **Nomenclature**