Development of a NOx Calculation Model for Low-Speed Marine Diesel Engines Based on Soft Measurement Technology

Round 1

Reviewer 1 Report

 

Title: Development of a NOx computational model for low-speed marine engines based on soft measurement technology The article focuses on the development of a NOx simulation model that can calculate and predict NOx emissions based on current operating parameters of low-speed two-stroke diesel engines. The authors undertake this task by analyzing correlations, analyzing principal components and optimizing the structure of neural networks of the BPNN type (Back Propagation Neural Network) using the group data processing (GMDH) method. The article is well written and presents an interesting approach to the problem of NOx emissions in low speed marine engines. The authors focus on the study of simulation models that rely on correlation analysis and principal component analysis to reduce the dimensionality of the input parameters, which leads to lower model complexity. As a result, the GMDH-BP model was developed and compared with the BPNN model and model BPNN with an optimized genetic algorithm (GA). As a result of these comparisons, the GMDH-BP model showed the highest prediction accuracy. The article also presents potential further research directions, such as: a) Increasing the amount of sample data, which may lead to a better understanding of the performance of the model under target operating conditions. (b) Selection of further control parameters and readily available as input parameters to facilitate the application of the NOx calculation model to a real diesel engine. (c) Integration of the NOx calculation model with the hardware, which will allow the achievement of NOx values ​​without the use of NOx sensors and optimizing the accuracy and speed of calculations of the model integrated with the hardware. The figures and tables presented in the article are correct and adequate for the presentation of research results. The drawings are clear, well organized and contain appropriate labels, which makes it easier to understand the data presented. The tables are also organized and show the essentials information in a transparent way. Both figures and tables contribute significantly to a better understanding of the topic and help the reader understand the results and achievements presented in the article more quickly. In conclusion, the article presents an innovative approach to the problem of NOx emissions in low-speed marine engines and presents solid research to develop a model with high prediction accuracy. The authors successfully developed the GMDH-BP model, which can be used for real-time monitoring of NOx emissions without the use of NOx sensors. Further research should consider using more data samples and integrating the model with real hardware. I would suggest adding a reference to other research in this area based on simulation models. https://doi.org/10.1016/j.seta.2023.103045; https://doi.org/10.1016/j.energy.2023.126974; https://doi.org/10.1016/j.applthermaleng.2023.120236

Author Response

Dear Reviewers
Thank you for your comments on my article, I have added references to the additional text.

I added references on the classification of soft measurement modeling, references related to soft measurement modeling using physical and data-driven models, and also references on the main types of NOx formation in low-speed engine.

Reviewer 2 Report

In this paper, the authors presented a method for NOx calculation based on virtual measurement technology. Please find below my minor suggestions:

- the authors should expand the context into the introduction section. The journal readership is broad and this could be helpful to non experts in the field

- I suggest the authors to specify all the acronyms within the text (several are missing like NOx, SRC, etc.).

- page 4 line 140 the authors refer to Table 2 which is missing in the text

- in page 5 line 176 the authors state: "Since this paper takes 6EX340EF as the research object, its relevant structural parameters will not change during use, so the correlation with NOx is not considered". Could the authors give more insight about this aspect? How their analysis is differentiated if a different research object is considered?

- the discussion section should be expanded highlighting the advantages and drawbacks of the proposed method compared to similar approaches already presented in the literature.

The authors should check the manuscript English with a proofreader since several typos are present within the text.

Author Response

Dear Reviewers
I have made changes in the text to address the issues you raised, and I have explained them in the attached document, so please check it in time.

Author Response File: Author Response.pdf