Simulation of the Transient Performance of a Turbocharged Diesel Engine Featuring a Two Point Air Injection Transient Assist System

Growing global concern pertaining to climate change has meant that engine development has become more focused on engine emissions. A method of reducing the emissions of an internal combustion (IC) engine is to use smaller engines but recover power lost due to reduction in size by using a turbocharger or supercharger. Turbocharged vehicles are commonly used but they exhibit a weak point of poor performance under transient running conditions. The phenomenon, known as 'Turbo-lag,' is most noticeable when a sudden load change is applied at lower engine speeds combined with rapid acceleration. The work presented analyzes a novel method of improving the transient performance of turbocharged engines by injecting air into both the compressor of the turbocharger as well as inlet manifold of the engine - known as a two-point air injection system. The effect of two-point air injection on the transient performance of a turbocharged engine as well as on emissions has been examined in the present work. To analyze the effectiveness of the two-point injection system a numerical investigation was carried out on Ricardo WAVE software. The simulation compares engine performance, compressor performance and emission output of the engine. The model has shown that the two-point injection system substantially improves both engine performance and reduces the emissions output from the engine.