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Evaluation of performance characteristics of a novel hydrogen-fuelled free-piston engine generator

Lookup NU author(s): Ugo Ngwaka, Dr Andrew Smallbone, Boru Jia, Chris Lawrence, Ben Towell, Dr Sam Roy, Professor Tony Roskilly



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2020 The Authors. In this work, we present the experimental results obtained from hydrogen fuelled spark-ignited dual piston free-piston engine generator (FPEG) prototype operated in two-stroke and four-stroke mode. The FPEG testing was successfully conducted at 3.7 compression ratio, engine speed between 5 Hz and 11 Hz and with different equivalence ratios. The FPEG technical details, experimental set-up and operational control are explained in detail. Performance indicators show that both equivalence ratio and engine speed affect the engine operation characteristics. For every set of specified FPEG parameters, appropriate range of equivalence ratio is recommended to prevent unwanted disturbance to electric generator operation. Both two-stroke and four-stroke cycle mode were tested, and the results showed different combustion characteristics with the two thermodynamic cycles. Four-stroke cycle mode could operate with indicated thermal efficiency gain up to 13.2% compared with the two-stroke cycle.

Publication metadata

Author(s): Ngwaka U, Smallbone A, Jia B, Lawrence C, Towell B, Roy S, KV S, Roskilly AP

Publication type: Article

Publication status: Published

Journal: International Journal of Hydrogen Energy

Year: 2021

Volume: 46

Issue: 66

Pages: 33314-33324

Print publication date: 24/09/2021

Online publication date: 12/03/2020

Acceptance date: 09/02/2020

Date deposited: 02/04/2020

ISSN (print): 0360-3199

ISSN (electronic): 1879-3487

Publisher: Elsevier Ltd


DOI: 10.1016/j.ijhydene.2020.02.072


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