Development Process of TGDI SI Engine Combustion Simulation Model Using Ethanol–Gasoline Blends as Fuel

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper can be accepted if the following revisions are taken into account:

• Numerical methods: please specify if the 3D CFD simulation are performed over the complete engine cycle or just on the closed valve period (reviewer is aware that probably the second option is true, however it must be clearly pointed out in the paper);
• authors introduce the first simulation model set, based on the 1D simulation data, at page 3. However, neither main results of this study, nor any reference is provided in order to support the subsequent studies;
• Again, please clearly state that the results from section 3.2 are related to the 3D CFD model and not from the 1D model;
• Please provide some detail about the reaction mechanism employed, beside the number of species and reactions. Morever, a full point is missing at line 134;
• in Table 4, LHV of surrogate fuels is lower than the original one: did authors adjust injection profile or mass flowrate accordingly?
• Title of section 3.1, indipendece instead of indipendence;
• It is not clear what are the varied parameters on which the mesh sensitivity analysis performed in section 3.1 is based, nor Figure 1 gives further clear information about this;
• Results of E10 and E20: there is no ROHR comparison? It is not possible to retrieve the experimental ROHR from experimental measurements, or at least, from the experimental pressure cycle? Indeed, the cumulative ROHR could give great information about the combustion efficiency as well as about the correct injected fuel mass;
• Caption of Figure 2, peration instead of operation;
• Results of Figure 3: as concerns the difference in numerical-experimental HC, the amount of injected fuel also should be investigated, as well as the definition of experimental HC species and the one retrieved from the detailed mechanism;
• Figure 7, wrong Figure and caption are reported.

Author Response

Dear Reviewer,
I have uploaded my responses to the reviews in a Word document.
Best regards,
Bence Zsoldos.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract should be carefully reviewed for clarity, structure, and precision.

Ensure that all abbreviations are either avoided in the abstract or clearly defined upon first use.

The abstract should briefly state the methodology, key results (with numerical values if possible), and main conclusions.

Introduce all abbreviations upon first mention in the introduction and maintain consistency throughout the manuscript.

Include a Literature Review subsection within the introduction.

Summarize and systematize the authors’ previous research related to this topic, highlighting their contribution to the field.

Reference should be made to recent and high-impact studies that provide context for the current work.

The manuscript similarity index (“percent match”) should be reduced to 10–15%, or according to the editorial board’s specific guidelines. This may require paraphrasing or replacing non-original text with original interpretation and referencing.

Include a clear schematic of the experimental setup (e.g., block diagram or test bench layout).

Provide a comprehensive table with technical data of the tested engine, including: Manufacturer, Engine type/model, key technical parameters (e.g., displacement, number of cylinders, compression ratio, fuel system)

Clarify whether the testing methodology is universal or application-specific. If universal, provide justification or references. If specific, explain limitations.

Explain how the testing conditions were selected, including load levels, speed ranges, and ambient conditions. Were these based on standards, prior research, or application relevance?

Provide a table with all measurement devices and software.

Include detailed information about the mixture formation system (fuel system: injection/carburetor) and ignition system (type, control parameters, timing).

Clearly explain the difference in system behavior or efficiency when using two different fuels (e.g., gasoline vs. ethanol blend, etc.).

Discuss how these differences affect combustion, ignition timing, and overall efficiency.

Describe how emissions and fuel consumption were measured (e.g., gravimetric method, flow sensors, exhaust gas analysis).

Reference the use of standard testing procedures or norms (e.g., ISO, ASTM, or specific national standards).

All measured quantities must be presented using the SI unit system (e.g., g/kWh, g/s, kg/h, ppm, kPa, °C, etc.).

Cite appropriate references where applicable, especially for methodology (e.g., DOI: 10.18485/aeletters.2020.5.3.2).

The title of Table 3 should be revised to more accurately reflect its content.

Review the titles and captions of all tables and figures to ensure clarity, precision, and alignment with their content.

Each table and figure must be self-explanatory, with sufficient description in the caption and defined units.

 

All diagrams, graphs, and images must be reviewed for resolution and legibility. Ensure Minimum resolution of 300 dpi for printed figures (as per journal guidelines).

Add a clear “Future Work” or “Directions for Further Research” subsection. Suggested topics include:

-Fuel Variants: Testing with other alternative fuels (e.g., hydrogen, bio-ethanol, synthetic fuels) and their impact on combustion behavior and emissions.

-Hybrid Systems: Investigating ignition system behavior in hybrid power-trains (engine + electric motor).

-Real-World Conditions: Expansion of testing protocols to include transient driving cycles and start-stop regimes-propose this in conclusions.

-Thermal Analysis

Expand the conclusion section by integrating key insights from the discussion of results.

How the results align or contrast with findings from previous literature.

Practical implications of using the tested ignition system with different fuels.

Observed advantages or limitations in terms of efficiency, emissions, or system responsiveness.

Include comparative analysis with cited studies where possible. Proofread for language clarity and technical accuracy.

Author Response

Dear Reviewer,
I have uploaded my responses to the reviews in a Word document.
Best regards,
Bence Zsoldos.

Author Response File: Author Response.pdf