This research article mainly focuses on the influence of split injection (split into three injections) technique that was used to improve the ethanol fuel combustion in high compression ignition (CI) mode, with and without zirconia surface coating. This experimental and simulation was used (95% ethanol +5% water) as a fuel in a four‐stroke single‐cylinder variable compression ratio (VCR) engine. The VCR engine was used with optimized compression ratio (28.8:1) and experimental conducted on various load conditions. Performance and exhaust emissions of nitrogen oxides (NOx), carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions of diesel, ethanol fuel single and split injection mode with coating and without coating were compared. The brake thermal efficiency (BTE) of split injection with coating mode was better than single injection mode. The VCR engine operating with ethanol fuel split injection mode showed peak BTE of 29%, which is nearly operating range in the baseline diesel engine. Ethanol fuel was mixed with 3% castorene R40 (lubrication oil) oil by volume due to fully soluble in alcohol fuels. It is used both air and liquid cooled engines running on methanol and ethanol fuel. Ethanol fuel split injection simulation was reduction of NOx compared with single injection simulation mode of operation. In comparison of diesel mode operation with zirconia coating was 3.8% increased than without coating. Ethanol single injection with coating CO emissions various from 0.5 to 3.0 g/kW‐hr. Ethanol split injection with coating mode CO emission various from 0.29 to 2.4 g/kW‐hr. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd