Abstract: This is a system for generating hydrogen on-board the vehicle from compressed natural gas (CNG) in select ratios to create hydrogen-enriched CNG (HCNG) fuel for use in internal combustion engines. The on-board generation of hydrogen is comprised of a reforming system of CNG fuel with direct contact with exhaust gases. The reforming system controls for production of HCNG fuel mixtures is based on specific engine operating conditions. The vehicle's engine controls and operating parameters are modified for combustion of selective ratios of HCNG fuel mixtures throughout engine operating cycle. The reforming system controls and engine controls modifications are also used to minimize combustion emissions and optimize engine performance.