Numerical study of a cold start at the ambient temperature of 243 K on methanol engine with coolant heating

Abstract

Misfire during cold starts limits the application of methanol engines. This study proposes a coolant heating method to establish suitable conditions for ignition. Numerical simulations were conducted on a water-cooled, spark-ignition methanol engine to investigate methanol distribution, performance and emissions during cold starts. The results indicate that high-temperature coolant can transfer heat into the cylinder at a high heat flux, providing a methanol-air mixture suitable for flame formation and propagation. Coolant heating enables the methanol engine to start at the ambient temperature of 243 K within the coolant operational temperature range. The main emissions are HC and CO, with minimal emissions of NO_x and soot. As the coolant temperature increases, the engine exhibits an increased cylinder pressure and a shorter ignition delay due to the increased cylinder temperature and richer mixture. NO_x, CO, and SOOT emissions increase while HC emission decreases. Considering the high temperature engine coolant required, this heating method is more suitable for hybrid vehicles.