The present work investigates the effect of two-step fuel injection on a four-cylinder engine which has been altered from port injection to direct injection. Hydrogen enriched compressed natural gas (HCNG) blend has been utilized as a substitute in replacement of gasoline. Initially, CNG as a 10 percent of the total fuel mass fraction is injected into the air manifold and the remaining 90 percent fuel is HCNG which is injected into the cylinder by direct injection. Primarily, the CNG was injected at 160° BTDC with 20° stroke duration. HCNG fuel was injected at 130° BTDC with a 50° stroke duration being injected from (0% to 40%) step. AVL software has been utilized for this investigation to inspect the engine performance, efficiency, fuel consumption, and exhaust emissions. The collected data indicates that by injecting 30 percent HCNG blend, the brake power, brake thermal efficiency, and in-cylinder pressure is increased from 8% to 13.64%, and the specific fuel consumption is reduced from 6.2% to 18% due to a rise in flame propagation speed in the combustion chamber. The addition of hydrogen has decreased carbon monoxide and unburned hydrocarbons by up to 14 percent on a complete combustion. NOx has been increased due to the increase in the exhaust gas temperature.

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