Synthesis gas (syngas) is considered an intermediate step between conventional carbon-based fuels and future hydrogen-based fuels. Spark-ignition (SI) engines are suitable for converting the chemical energy of syngas for small-scale electrical power generation. However, syngas-fueled SI engines have lower power outputs and thermal efficiencies than SI engines fueled with conventional fuels such as gasoline and natural gas do. The objective of this study was to compare the stoichiometric and lean combustion modes in a single-cylinder SI engine to determine the optimal combustion mode for the development of a syngas engine generator with high power and high efficiency. A high gross indicate power was achieved in the stoichiometric combustion mode by increasing the intake pressure, owing to the increase in the volumetric efficiency and syngas fuel input. The gross indicated thermal efficiency (ITE) improved as the compression ratio was increased from 10:1 to 17.1:1, owing to the high peak heat release rate and short combustion duration. In the lean combustion mode, high gross ITEs were achieved by increasing the excess air ratio to 2.5, but the additional increase led to low combustion efficiencies. However, the gross indicated power decreased with an increase in the excess air ratio. The low gross indicated power was increased through intake boosting. Based on a parametric study, the optimal compression ratio for the stoichiometric combustion mode was selected to be 15:1. Pre-ignition occurred in the stoichiometric combustion mode at a compression ratio of 17.1:1 and an intake pressure of 0.16 MPa. Engine operation with a high compression ratio of 17.1:1 was possible in the lean combustion mode owing to the low combustion temperature. The gross ITE in the lean combustion mode was 18.4% higher than that in the stoichiometric combustion mode, mainly because of a significant reduction in the heat transfer loss. However, the gross indicated power in the lean combustion mode was 25.6% lower than that in the stoichiometric combustion mode.

合成气（合成气）被认为是常规碳基燃料和未来氢基燃料之间的中间步骤。火花点火（SI）发动机适用于转换合成气的化学能以进行小规模发电。但是，以合成气为燃料的SI发动机比以汽油和天然气等常规燃料为燃料的SI发动机具有更低的功率输出和热效率。这项研究的目的是比较单缸SI发动机的化学计量和稀薄燃烧模式，以确定开发高功率，高效率的合成气发动机发电机的最佳燃烧模式。通过增加进气压力，在化学计量燃烧模式下获得了很高的总指示功率，由于体积效率和合成气燃料输入的增加。压缩比从10：1增加到17.1：1时，总指示热效率（ITE）有所提高，这归因于峰值放热率高和燃烧持续时间短。在稀薄燃烧模式下，通过将过量空气比率提高到2.5，可以实现高的总ITE排放量，但是额外的增加导致燃烧效率降低。但是，总指示功率随着过量空气比的增加而降低。低的总指示功率通过增加进气量而增加。根据参数研究，化学计量燃烧模式的最佳压缩比选择为15：1。在化学计量燃烧模式下以17：1：1的压缩比和0.16 MPa的进气压力进行预点火。由于燃烧温度低，因此在稀薄燃烧模式下可以以17.1：1的高压缩比运行发动机。稀薄燃烧模式下的总ITE比化学计量燃烧模式下的总ITE高18.4％，这主要是因为传热损失显着降低。然而，稀薄燃烧模式下的总指示功率比化学计量燃烧模式下的总指示功率低25.6％。