Experimental Research on the Energy Efficiency of a Parallel Hybrid Drive for an Inland Ship
Round 1
Reviewer 1 Report
The authors need to address the following comments before the publication of this study.
Please add an acronym and nomenclature for better readability.
Please improve literature review by involving more recently reported works.
"The use of electric propulsion may also result from the expected limitations on the acceptable emissions of harmful substances in urban areas. However, outside densely populated areas, when the ship is moving at the cruising speed due to the limited capacity of current energy storage technologies and the higher power demand, it is necessary to use an internal combustion engine." looks lean without supporting materials on hybrids and energy storage, like IEEE Transactions on Transportation electrification 2, no. 2 (2016): 140-149; IEEE Transactions on Vehicular Technology 66, no. 6 (2017): 4534-4549.
Any comparative results?
Author Response
22th April 2019
Dear Reviewer (no.1),
Thank you very much for valuable comments. All the comments were included in the manuscript. Detailed answers are listed below.
Kind regards,
Wojciech Litwin
comment 1- Please add an acronym and nomenclature for better readability.
Answer to the comment1:
Nomenclature list was added; I can’t find an Energies journal standard for Nomenclature table so typical standard was used (like in Applied Energies) – page 2
comment 2- Please improve literature review by involving more recently reported works.
Answer to the comment2:
New literature was added like suggested – [25] – in red “Energy Management in Plug-in Hybrid Electric Vehicles: Recent Progress and a Connected Vehicles Perspective
comment 3- Any comparative results?
Answer to the comment3:
We are working now on similar propulsion system based on different – DC electric motor and other combustion engine. We was looking for similar size hybrid unit experimental results in literature but I was not able to find anything.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper focused on a very hot and interesting topic in the energy and hybrid propulsion fields. Respect to the future energy regulations, this kind of studies are very productive and helpful. The topic is very interesting and the results of the paper would be very useful for researchers and readers in the field. The paper is also well-organized and the results are novel and interesting. There are some minor rooms in the manuscript that should be addressed by authors in order to enhance the impact and effectiveness of the paper.
1- In the introduction chapter: is there any specific emission regulations for marine transportations that should be met in the future? If so, please add it for clarification.
2- If possible, more details about the case study (characteristics, design point, level of power, the architecture of hybrid system, hybridization procedure and data) would be very helpful.
3- There are some minor typos in the main body and figures (e.g. figure 3). So, please review the paper once again from English language point of view.
4- The conclusion chapter should be edited to cover all achievements of the paper.
5- Some figures are hard to read and should be replaced by higher quality versions (e.g. figures 11 and 12)
Author Response
22th April 2019
Dear Reviewer (no.2),
Thank you very much for valuable comments. All the comments were included in the manuscript. Detailed answers are listed below.
Kind regards,
Wojciech Litwin
comment 1- In the introduction chapter: is there any specific emission regulations for marine transportations that should be met in the future? If so, please add it for clarification.
Answer to the comment1:
The description of upcoming emission regulations were added to Section 1, line 64-74 (in red):
‘From 1 January 2020, in accordance with MARPOL Annex VI [10], the Sulphur content of fuel oil used on board commercial ships trading outside Sulphur Emission Control Areas (ECAs) must not exceed 0.50%. This is a significant reduction from the current global limit of 3.50% which has been in place since 2012. The guidance on the development of a Ship Implementation Plans (SIP) was issued [11]. Special guideline was also prepared by International Chamber of Shipping [12]. Moreover, new regulations are going to take into force on the Emission Control Areas (ECA). The resolution MEPC.286(71) will covet the limit of NOx in addition to SOx [13]. Engines having power above 130kW installed on vessels constructed on or after 01 January 2021 must be Tier III certified. The regulation also applies to non-identical replacement engines or additional engines installed on existing ships on or after 1st January 2021.’
comment 2- If possible, more details about the case study (characteristics, design point, level of power, the architecture of hybrid system, hybridization procedure and data) would be very helpful.
Answer to the comment2:
Dear reviewer, thank you for this suggestion. I was trying to describe clearly the towing model characteristic (fig.3), placed the design points – loads level on the figure. For the better presenting of the hybrid propulsion system the schematic of the test rig was presented – figure 4. I was trying to do my best.
comment 3- There are some minor typos in the main body and figures (e.g. figure 3). So, please review the paper once again from English language point of view.
Answer to the comment3:
English was corrected by professional proofreading service (www.proof-reading-service.com). Description of Fig 3 (jpg file) was corrected.
comment 4- The conclusion chapter should be edited to cover all achievements of the paper.
Answer to the comment4:
Section 7 (Conclusions) was edited to include the most important findings (additional description – in red).
comment 5- Some figures are hard to read and should be replaced by higher quality versions (e.g. figures 11 and 12)
Answer to the comment5:
Figures 11 and 12 were corrected.
