Hammam Hasen Aljabri

Dr. Hammam Hasen Aljabri

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2023 in Fuel
Verified
Journal Article
Closed access
XLXinlei Liu
Xinlei Liu
HAHammam Hasen Aljabri
Hammam Hasen Aljabri
NPNiraj Panthi
Niraj Panthi
AAAbdullah S. AlRamadan
Abdullah S. AlRamadan
ECEmre Cenker
Emre Cenker
HIHong G. Im
Hong G. Im

26 November 2022 in Energies
Verified
Journal Article
Open access
PDF file
HAHammam Hasen Aljabri
Hammam Hasen Aljabri
MSMickael Silva
Mickael Silva
MHMoez Ben Houidi
Moez Ben Houidi
XLXinlei Liu
Xinlei Liu
MAMoaz Al-lehaibi
Moaz Al-lehaibi
HIHong G. Im
Hong G. Im
Hydrogen is a promising future fuel to enable the transition of transportation sector toward carbon neutrality. The direct utilization of H2 in internal combustion engines (ICEs) faces three major challenges: high NOx emissions, severe pressure rise rates, and pre-ignition at mid to high loads. In this study, the potential of H2 combustion in a truck-size engine operated in spark ignition (SI) and pre-chamber (PC) mode was investigated. To mitigate the high pressure rise rate with the SI configuration, the effects of three primary parameters on the engine combustion performance and NOx emissions were evaluated, including the compression ratio (CR), the air–fuel ratio, and the spark timing. In the simulations, the severity of the pressure rise was evaluated based on the maximum pressure rise rate (MPRR). Lower compression ratios were assessed as a means to mitigate the auto-ignition while enabling a wider range of engine operation. The study showed that by lowering CR from 16.5:1 to 12.5:1, an indicated thermal efficiency of 47.5% can be achieved at 9.4 bar indicated mean effective pressure (IMEP) conditions. Aiming to restrain the auto-ignition while maintaining good efficiency, growth in λ was examined under different CRs. The simulated data suggested that higher CRs require a higher λ, and due to practical limitations of the boosting system, λ at 4.0 was set as the limit. At a fixed spark timing, using a CR of 13.5 combined with λ at 3.33 resulted in an indicated thermal efficiency of 48.6%. It was found that under such lean conditions, the exhaust losses were high. Thus, advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time where an indicated thermal efficiency exceeding 50% was achieved while maintaining a very low NOx level. Finally, the optimized case in the SI mode was used to investigate the effect of using the PC. For the current design of the PC, the results indicated that even though the mixture is lean, the flame speed of H2 is sufficiently high to burn the lean charge without using a PC. In addition, the PC design used in the current work induced a high MPRR inside the PC and MC, leading to an increased tendency to engine knock. The operation with PC also increased the heat transfer losses in the MC, leading to lower thermal efficiency compared to the SI mode. Consequently, the PC combustion mode needs further optimizations to be employed in hydrogen engine applications.

5 March 2025 in Fuel
Verified
Journal Article
Closed access
HAHammam Hasen Aljabri
Hammam Hasen Aljabri
RMRafael Menaca
Rafael Menaca
NPNiraj Panthi
Niraj Panthi
KMKevin Moreno-Cabezas
Kevin Moreno-Cabezas
FAFahad Almatrafi
Fahad Almatrafi
HIHong G. Im
Hong G. Im