In the current study energy and exergy analyses of a hydrogen fueled four-stroke spark ignition engine are presented. The energy and exergy analyses are performed based on experimental results conducted on single cylinder, air cooled SI engine which is operated four different compression ratios (epsilon = 6.6, 7.1 7.6 and 8.1) seven different spark ignition timing, 1600 rpm constant engine speed, lean mixture (phi = 0.6) and wide-open throttle conditions. The experimental results, energy and exergy analyses showed that the increase in compression ratio yields an increase in indicated and effective performance parameters of the engine while decrease in exergy destruction is observed. However, the move away of the ignition timing from the optimum value (over or retarded ignition timing) leads to a reduction in engine performance parameters and rise in exergy destruction. Another noteworthy result of this study is that the values of both indicated and effective thermal efficiencies obtained based on experimental studies and the values of both indicated and effective exergy efficiencies obtained by thermodynamic analyses are very close to each other. (C) 2019 Elsevier Ltd. All rights reserved.