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This text describes the data presented in the paper: <insert paper title> 

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Introductory information
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Files included in the data deposit (include a short description of what data are contained): 

1) Frictional loss comparison of crankshaft engine and free-piston engine.
2) Piston ring fricion of crankshaft engine and free-piston engine.
3)


Explain the relationship between multiple data sets, if required:



Key words used to describe the data:

fricion force, fricional loss, free-piston engine.

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Methodological information
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A brief method description – what the data is, how and why it was collected or created, and how it was processed:
The data is obtained by solving numerical equations of friciton force shown in the paper. The equations were solved in Matlab software.


Instruments, hardware and software used: 

Matlab software

Date(s) of data collection: 

05/2017

Geographic coverage of data:

N/A

Data validation (how was the data checked, proofed and cleaned):
N/A


Overview of secondary data, if used:



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Data-specific information
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Definitions of names, labels, acronyms or specialist terminology uses for variables, records and their values: 

CSE:crankshaft engine
FPE:Free-piston engine
F_pr: Piston ring fricion force	
f_pr: Coefficient of piston ring friction force	
h_oil: Oil film thickness	
f_ps: Coefficient of piston skirt friction force	
F_ps: Piston skirt friction force	
P_fr: Frictional loss of piston ring	
P_fs: Fricional loss of piston skirt



Explanation of weighting and grossing variables: 
N/A


Outline any missing data:
N/A


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Contact
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Please contact rdm@ncl.ac.uk for further information