A Novel Onboard Syngas-Assisted Cold-Start Strategy for Methanol-Fueled Spark Ignition Engines

Abstract Alternative fuels are emerging as promising energy sources for the power and transportation sectors due to their potential for high performance and lower emissions. The growing demand for clean energy and the need to reduce dependence on fossil fuels in the automotive sector have increased the utilization of alternative fuels. However, cold-start challenges associated with alternative fuels, especially methanol, remain a serious limitation. The onboard production of syngas, consisting mainly of hydrogen and carbon monoxide, can help overcome these cold-start issues. Methanol-derived syngas can be utilized in onboard automotive applications to address cold-start problems at ambient temperatures below 15°C. Due to its high energy content, low ignition energy requirement, and cleaner combustion characteristics, hydrogen plays an important role in overcoming cold-start challenges, even at extremely low ambient temperatures down to − 50°C. Carbon monoxide also possesses favorable combustion properties, which assist in achieving stable and efficient combustion of the fuel-air mixture. The introduction of syngas (H₂/CO ratio of 67/33 by mole fraction) during the initial few minutes of engine operation, particularly for the first 3–4 minutes, can help achieve the required in-cylinder pressure of more than 6 MPa and an in-cylinder temperature of approximately 2400 K. These conditions promote proper combustion and enable the engine to reach stable operating temperatures within a short time. Subsequently, methanol fuel can be introduced together with syngas for a few additional minutes, after which the engine can transition to fully methanol-fueled operation.