A performance degradation evaluation method for a turbocharger in a diesel engine

As one of the key systems of the marine power plant diesel engine, the turbocharger directly affects whether the diesel engine can continuously and stably provide the power required for the ship. Owing to a number of uncontrollable factors, such as harsh working conditions and complex structures, the turbocharger may have various failures, causing it to lose its intended function. At present, the fault diagnosis of the marine turbocharger has not been paid enough attention yet and in most cases, the method of ‘ex post diagnosis’ is still adopted. When analysing the nonlinear correspondence between the failure symptoms and failure causes, it is difficult for the existing theories to meet the actual diagnostic requirements. This paper introduces the concept of gas-path diagnosis into the condition monitoring for a marine turbocharger for the first time and proposes the flow capacity index which characterizes the flow capacity of the component and the isentropic efficiency index which characterizes the operating efficiency of the component as two dimensionless evaluation indicators for turbocharger health status. Moreover, the nonlinear mapping relationship between these two health parameters and the gas-path measurable parameters of the turbocharger is studied, and a novel performance degradation evaluation method for a turbocharger is established. The proposed method has been tested in three test cases where the degradation of a model turbocharger has been analysed. These case studies have illustrated that the proposed method can accurately isolate the degraded components and further quantify the degradation of the components.

capacity of the proposed model to be used in real time condition monitoring since its necessary execution time is adequate for such applications. The discussion and explanations provided by the authors about the findings are quite analytical and sufficient, stand in the appropriate level and do not extend into useless details. Quality of graphs is very good and the reader of the paper obtains easily and quickly an overview of the findings of the investigation performed. The subject of this investigation is quite important for the present status of technological development in the area of turbochargers and falls inside the scope of the journal. Therefore the paper is suggested for publication without any modification. The editors assigned to your paper ("A perfomance degradation evaluation method for turbocharger in a diesel engine") have now received comments from reviewers. We would like you to revise your paper in accordance with the referee and Associate Editor suggestions which can be found below (not including confidential reports to the Editor). Please note this decision does not guarantee eventual acceptance.
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Comments to Author:
Reviewers' Comments to Author: Reviewer: 1 Comments to the Author(s) The authors proposed a performance degradation evaluation method for turbocharger in a diesel engine from the perspective of "gas-path diagnosis", and the flow capacity index and the isentropic efficiency index as two dimensionless evaluation indicators for the turbocharger health status were firstly proposed. The case studies have illustrated that the method can accurately isolate the degraded components, and quantify the degradation for the components. The method proposed by the author has great potential application value for turbocharger diesel engine industry. The manuscript is well organized and is ready for publication with modification of written English throughout the paper to avoid grammatical errors.

Reviewer: 2
Comments to the Author(s) The paper introduces for the first time the concept of gas-path diagnosis into the condition monitoring of marine turbocharger, and proposes two dimensionless evaluation indicators (i.e., the flow capacity index and the isentropic efficiency index) as turbocharger health parameters. The nonlinear mapping relationship between these health parameters and the gas-path measurable parameters of the turbocharger is studied, and a performance evaluation method of the turbocharger is developed. The proposed model is described and analyzed in detail and all the relevant equations are explained in clear inside the paper. The effectiveness of the proposed model is tested for three diagnostic cases for which experimental data are available in the literature. The results are very promising and reveal the capacity of the proposed model to be used in real time condition monitoring since its necessary execution time is adequate for such applications.
The discussion and explanations provided by the authors about the findings are quite analytical and sufficient, stand in the appropriate level and do not extend into useless details. Quality of graphs is very good and the reader of the paper obtains easily and quickly an overview of the findings of the investigation performed. The subject of this investigation is quite important for the present status of technological development in the area of turbochargers and falls inside the scope of the journal. Therefore the paper is suggested for publication without any modification.
Dr.-Ing. Georgios Mavropoulos Senior Research Associate National Technical Univ. of Athens Greece status were firstly proposed. The case studies have illustrated that the method can accurately isolate the degraded components, and quantify the degradation for the components. The method proposed by the author has great potential application value for turbocharger diesel engine industry. The manuscript is well organized and is ready for publication without any modification.

Recommendation?
Accept as is

Comments to the Author(s)
The paper in its present form is suggested for publication.

18-Oct-2018
Dear Dr Yang, I am pleased to inform you that your manuscript entitled "A performance degradation evaluation method for turbocharger in a diesel engine" is now accepted for publication in Royal Society Open Science.
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