TY - JOUR
T1 - A study and comparison of frictional losses in free-piston engine and crankshaft engines
AU - Jia, Boru
AU - Mikalsen, Rikard
AU - Smallbone, Andrew
AU - Roskilly, Anthony Paul
N1 - Publisher Copyright:
© 2018 The Authors
PY - 2018/7/25
Y1 - 2018/7/25
N2 - Friction work in free-piston engines is expected to be lower than in crankshaft engines due to the elimination of the crank mechanism. In this paper, friction mechanisms were reviewed and compared between a free-piston and crankshaft engine of similar size. The main friction mechanisms were identified to be the piston assembly including piston rings and piston skirt, valve train system, the crank and bearing system for the CSE, and the linear electric generator for the FPE. The frictional loss of each friction mechanism was estimated and discussed. A Stribeck diagram was used to simulate the piston ring friction during hydrodynamic lubrication, mixed lubrication, and boundary condition. It is found that the FPE doesn't show advantage on piston ring friction force over the CSE, and the frictional loss from the piston ring is even higher. While the elimination of the crankshaft system reduces the frictional loss of the FPE, and the total friction loss of the FPE is nearly half of the CSE.
AB - Friction work in free-piston engines is expected to be lower than in crankshaft engines due to the elimination of the crank mechanism. In this paper, friction mechanisms were reviewed and compared between a free-piston and crankshaft engine of similar size. The main friction mechanisms were identified to be the piston assembly including piston rings and piston skirt, valve train system, the crank and bearing system for the CSE, and the linear electric generator for the FPE. The frictional loss of each friction mechanism was estimated and discussed. A Stribeck diagram was used to simulate the piston ring friction during hydrodynamic lubrication, mixed lubrication, and boundary condition. It is found that the FPE doesn't show advantage on piston ring friction force over the CSE, and the frictional loss from the piston ring is even higher. While the elimination of the crankshaft system reduces the frictional loss of the FPE, and the total friction loss of the FPE is nearly half of the CSE.
KW - Free-piston engine
KW - Friction force
KW - Piston assembly friction
KW - Skirt friction
UR - http://www.scopus.com/inward/record.url?scp=85047085305&partnerID=8YFLogxK
U2 - 10.1016/j.applthermaleng.2018.05.018
DO - 10.1016/j.applthermaleng.2018.05.018
M3 - Article
AN - SCOPUS:85047085305
SN - 1359-4311
VL - 140
SP - 217
EP - 224
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
ER -