The automotive industry is under increasing pressure to reduce the environmental impact of internal combustion (IC) engine emissions. Regulatory bodies worldwide have introduced strict emission standards, prompting automakers to explore innovative solutions. This study focuses on the optimization of in-cylinder measures, specifically dual injection strategies, to address the challenges of diesel engine emissions, including nitrogen oxides (NOx) and particulate matter.
Low Temperature Combustion (LTC) is recognized for its potential to lower emissions and increase efficiency. However, it poses difficulties in controlling combustion timing, handling transient operations, and managing carbon monoxide (CO) and hydrocarbon (HC) emissions. To overcome these challenges, the research investigates the effects of dual injection strategies on engine performance and emissions, with a particular emphasis on the Late Injection Strategy (LIS) during part load conditions.
The study reveals that dual injection techniques can surpass single injection methods in terms of thermal efficiency. The timing of pilot injections and the distribution of fuel mass between injections are identified as key factors in balancing emissions and efficiency. Experimental results demonstrate that by increasing fuel injection pressure, significant improvements in thermal efficiency and NOx reduction can be achieved, along with decreased smoke, CO, and HC emissions. Similarly, higher intake air pressure enhances efficiency and reduces smoke, NOx, HC, and CO emissions.
The research culminates in the identification of optimal parameters for dual injection strategies. A fuel injection pressure of 600 bar, an intake air temperature of 310 K, and an intake air pressure of 107 kPa are found to be the most effective settings. Under these conditions, the study records a maximum indicated thermal efficiency of 38%, representing an 8% improvement over baseline values, and a 68% reduction in NOx emissions to 187 ppm. Additionally, smoke emissions are reduced by 23%, and CO emissions by 75%, with a 4% increase in indicated thermal efficiency compared to baseline readings.
The findings of this study underscore the effectiveness of dual injection strategies in significantly reducing emissions and enhancing the efficiency of diesel engines, offering a promising avenue for meeting future emission standards and improving the environmental footprint of IC engines.