Dataset of numerical study of the impact of two-step injection (direct and port) of hydrogen-enriched and natural gas mixtures on engine efficiency and exhaust emissions

A study was conducted to examine the effects of two-step fuel injection on a modified four-cylinder engine that was converted from port to direct injection. The primary fuel source utilized was hydrogen-enriched compressed natural gas (HCNG), which replaced the conventional gasoline. In the initial phase of the procedure, compressed natural gas (CNG) was introduced into the intake manifold at a concentration of 10 % by mass, relative to the total fuel mixture. The remaining 90 % of the fuel consisted of HCNG, which was injected directly into the cylinders. The injection of compressed natural gas (CNG) commenced at 160 degrees before top dead center (BTDC) with a 20 degrees stroke duration. The HCNG fuel was injected in a two-step process. In the initial phase, HCNG was injected at 130 degrees BTDC with a 50 degrees stroke duration, with a stepwise increase from 0 % to 40 %. The study employed AVL software for the assessment of engine performance, efficiency, fuel consumption, and exhaust emissions. The data collected indicated that the injection of a 30 % HCNG blend resulted in an increase in brake power, brake thermal efficiency, and in-cylinder pressure (from 8 % to 13.64 %), as well as a reduction in specific fuel consumption (by 18 %). This improvement was attributed to an increase in flame propagation speed within the combustion chamber. Additionally, the percentage of excess hydrogen was found to decrease, resulting in a reduction of carbon monoxide and unburned hydrocarbons by up to 14 % due to complete combustion. However, NOx increased due to the rise in exhaust temperature.(c) 2024 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)