International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 09 Issue: 06 | Jun 2022 www.irjet.net p-ISSN: 2395-0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 3446 Advanced fuel injector design and modelling in IC engines to reduce exhaust gas emissions Shubham Shrivastava 1* , Anirban Ghosh 1 , Aviraj Singh 1 1* Senior Engineer, Thermal Business Unit, L&T Technology Services Ltd., India 1 Assistant Manager, Product Development, CEAT Tyre, India 1 Aviraj Singh, L&T Technology Services Ltd., India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - An idea of fuel injector is proposed that can improve the air-fuel mixing capability by spreading it more and creating swirl action without any modification in air flow manifold. For CI engine direct injection engine, fuel doesn’t reach every region of combustion chamber injected by normal fuel injector. These left out regions have low air-fuel mixing velocity and hence are not mixed properly. In new fuel injector the motion of plunger is converted into rotational motion that spreads the fuel throughout in the combustion chamber. The related numerical research of the in-cylinder velocity, fuel/air mixing process, and emission characteristics of a diesel engine was performed. The numerical results showed that the new fuel injector had a positive effect on improving fuel/air mixing process by spreading the fuel more compared to normal fuel injector, which could improve the fuel utilization and reducing its consumption leading to reduction in harmful emissions such as NOx, CO and HC. The improvement in air-fuel mixing showed favorable reduction in NOx by 8.44%, reduction in CO by 8.69% and reduction in HC by 8.56%, showing that it has better performance than normal fuel injector. Key Words: Fuel injector, emission, IC engine, equivalence ratio 1.INTRODUCTION Since pollution is caused by various sources, it requires an integrated and multi-disciplinary approach. The different sources of pollution have to be addressed in an integrated approach to achieve the objective of a cleaner environment. Air pollutants such as carbon monoxide, nitrogen oxides, particulate matter, volatile organic compounds, and benzene are emitted into the environment by motor vehicles. Air pollutants can contribute to urban air quality problems, such as photochemical smog and adversely affect human health. Incomplete combustion leads to high emissions, which is a substantial source of air pollution, especially for the soot. Due to the impact on air pollution, the government introduced several emission regulations [1]. Incomplete combustion leads to high emissions, which is a substantial source of air pollution, especially for the soot [2]. In- complete combustion is generally due to poor mixing of the air and fuel, insufficient residence time, insufficient temperature and low total excess air [3]. After-treatment devices can reduce the harmful emissions to meet the stringent emission regulations. For example, the diesel particulate filter (DPF) is an effective soot post-processing equipment, followed by SCR towards reducing NOx. Improving air fuel mixing efficiency is the key area to reduce shoot and NOx. To achieve better air fuel mixing, swirl flow is generated that enhances turbulence intensity which controls cycle-to-cycle variation, combustion efficiency and exhaust emission in internal combustion engines. Swirl is used to speed up the combustion process in SI engines and to increase faster mixing between air and fuel in CI and some stratified charge engines [4-7]. Extensive research has been conducted to improve fuel air mixing capability. For example, to improve the in-cylinder fuel/air mixing process of heavy-duty diesel engines, optimize the combustion process and reduce the soot emissions, a new device named fuel split device was proposed. This device had a positive effect on improving fuel/air mixing process by splitting the fuel spray, which could in-crease air utilisation and lead to efficient combustion, multi-vortex structure could be formed during the fuel injection process, which could greatly improve the fuel/air mixing process that ultimately reduced HC, CO and soot emissions [8]. In another study, a bump combustion chamber was designed, which was characterized by some rings on the combustion chamber wall. With the bump ring, the spray generates a secondary jet after impinging the bump ring that decreases the wetting and rich mixture layer region on the wall, which led to the reduction of both NOx and soot emissions at low load [9]. In determining the effect of air fuel mixture on emission equivalence ratio becomes a major parameter. Higher equivalence ratios tend to result in less NO2, maybe because of lower concentrations of O2 for oxidising NO to NO2. A higher over-all equivalence ratio than the stoichiometric value results in lower NOx emissions. For all the overall equivalence ratios tested here, the NOx emissions tend to decrease around the richer-mixture equivalence ratio [10]. The optimization of the fuel/air mixing process on diesel engines is still of great interest. To improve the fuel/air mixing process, a new design of fuel injector is pro-posed in this study. In this concept of fuel injector, fuel is sprinkled throughout the engine as explained in Fig.1. With normal injection there are many areas left unaffected leading to less equivalence ratio, whereas in new fuel injector as fuel leaves orifice, it reaches more volume compared to normal injection. Followed by maximum volume coverage, new fuel