Numerical simulation of nitric oxide (NO) emission for HCNG fueled SI engine by Zeldovich’, prompt (HCN) and nitrous oxide (N2O) mechanisms along with the error reduction novel sub-models and their classification through machine learning algorithms

•The experiments have been performed under a wide range of operating conditions in HCNG engine.•The NO mechanisms have been coupled with quasi-dimensional combustion model of SI engine.•The improvement in NO emission has been carried out with six different novel sub-models and their combinations.•The best of each combination has been trained through machine learning classifier.