Analysis of the Impact of Split Injection on Fuel Consumption and NO_x Emissions of Marine Medium-Speed Diesel Engine

Round 1

Reviewer 1 Report

The paper represents a  lot of work and is very interesting. It would benefit greatly from some pictorial representation of all the interactions. This could be a bond graph or a block diagram. It is difficult to see the interactions of all the components from the equations alone.

The one technical aspect that is not clear is the mixing of gases in the cylinder. There are 2 extreme models of this mixing. One extreme is no mixing as though there is a barrier between the fresh air and combusted gas products such that the new charge ideally pushes the combustion products out the exhaust.

The other extreme is that there is perfect mixing and the fresh air instantly mixes with the combustion products and some amount of the mixture is pushed out the exhaust. It is not clear how the mixing of fresh and combusted products is done in the model.

Finally, it should be made clear why the model was undertaken in the first place. When one is able to perform experiments then why make a model? Does the model give insights that the experiment does not? Is it justified to extend the model to bigger engines and trust the predictions of combustion products? Does the model allow outputs of signals that are important but not measurable? The paper would benefit from more justification for the undertaking.  

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

I read your paper and from my point of view a major revision is necessary. Details are presented below:

1. Your work doesn't contain literature review section/chapter. A problem of NOx emission from diesels is well known. An impact of the fuel injection strategy on emissions of harmful exhaust components is also know. A new knowledge from your research is not expressed well in relation to the state of the art. 
2. The paper doesn't contain test stand/methodology/methods section. Details on the measurement equipment are not given. Question is how the emission of NOx was measured. The emission or concentration of NOx has been analyzed? 
3. We know nothing about accuracy of measurement equipment, as well as  figures 7-10 present data without of any statistical markings such as standard deviation. 
4. Data points visible in figures 7-10 are connected with lines (regressions?) however it is unknown how these lines where selected.
5. Finally, a lot of references in your work are really old. Some positions were published in 1956, 1938, 1963. Only 10/33 references cited in your work were published in XXI century. It shows that literature review is not the best and it should be revised.

Thank you and good luck.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Authors,

The paper has been revised well. Thank you for your work.