Experimental Study on the Performance-Influencing Factors of an Aviation Heavy-Oil Two-Stroke Direct-Injection Ignition Engine

Round 1

Reviewer 1 Report

The research focuses on the performance-influencing factors of an aviation heavy oil ignition two-stroke direct injection engine. Under cold start conditions, the effects of concentration factors and oil-air interval and ignition energy are studied by experimental methods. Under small load conditions, the effects of ignition advance angle, ignition energy and ignition advance angle are studied by experimental methods. The manuscript can be useful for the research community, while the discussion and conclusions in this research are generally consistent with what was expected, so further discussion should be made innovatively. Here, it is suggested to revise the current manuscript based on the comments below. 1. Some more significance of the research to application should be introduced and summarized in the introduction part. 2. Engine model used in the test should be illustrated in Test System Construction. 3. In line 176, “The concentration coefficients are set to 1, 1.5, 2, 3.5, and 4.5.”, but in line 190, “..., the recommended concentration coefficient is set to 3.” So the speed curve during the cold start process and the engine cold start timing, which are corresponding to the concentration coefficient of 3, should be given to get the recommendation verified.

 

Author Response

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Reviewer 2 Report

1. In line 185, ‘the flameout is finally caused by an insufficient oil supply’. Please explain that when controlling the concentration coefficient, is the overall injection quantity consistent or only the injection quantity at the stable stage consistent?

2. In line 190, why is the concentration coefficient determined to be 3? The author did not have this working condition during the research.

3. In line 235, ‘The reason is that when the ignition advance angle is small, the ignition time is also relatively delayed’? The ignition time affects the ignition delay period and CA50. CA50 is close to TDC, and the cylinder pressure is higher. It is not that the later ignition time, the lower cylinder pressure.

4. In line 239, ‘mainly because the ignition energy generated by the smaller magnetization pulse width is small, and kerosene ignition becomes difficult’. Emission is related to the whole combustion state in the cylinder, and ignition only affects the ignition delay. Please explain in depth.

5. Figures 22 and 23 are wrongly marked, please correct them.

6. Please polish your article.

Author Response

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Reviewer 3 Report

1. The literature review is not sufficient, and the novelty of the research is not fully demonstrated. 

2.Some description of the parameters should be added, such as concentration factors, discharge temperature, etc. Formula is recommended. 

3. Some words are not professional, such as rotating speed, advance angle...

4. The expression is poor. It is not attractive to simply show the solo effects of the parameters on the performance. 

 

Author Response

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Reviewer 4 Report

The authors performed an experimental Study on the Performance-influencing Factors of an Aviation Heavy Oil Ignition Two-Stroke Direct Injection Engine

The paper is very interesting and can be accepted after minor revisions:

-        The introduction is very short and should be extended.

-        More details on the measurement techniques and data acquisition systems are to be provided.

-        An experimental uncertainty study is to be performed.

-        How is the start time evaluated?

-        Are the ambient temperature and relative humidity constant during all the performed experiments?

-        The paper is to be checked against misprints and grammatical mistakes.

-        A nomenclature is to be added.

Author Response

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Round 2

Reviewer 2 Report

1. Line 279, for CO and HC emissions, the author should further explain, and refer to the following two articles:

1) Influence of n-butanol-diesel-PODE3-4 fuels coupled pilot injection strategy on combustion and emission characteristics of diesel engine, Fuel, 2019, 236: 313-324.

2) Study of injection pressure couple with EGR on combustion performance and emissions of natural gas-diesel dual-fuel engine, Fuel, 2020, 261: 116409.

2. In Fig.22 and Fig.23, the author has not modified the label, which is still 2mg. What does this mean?

Author Response

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Reviewer 3 Report

Ignition Advance Angle is not a proper expression.

Author Response

请参阅附件。

Author Response File: Author Response.pdf