| Reducing vehicle fuel consumption and pollutant emissions is one of the most important challenges in the automobile industry.Turbocharging has been considered as the most effective and well-developed technology to reduce engine displacement,improve engine performance and increase fuel efficiency.Turbocharging is achieved by increasing the pressure of the intake air,thus increasing the amount of air forced into the engine.This technology results in larger torque and power,as well as lower fuel consumption by engine downsizing.This thesis studies the matching of a turbocharger with a well-developed 1.5L naturally aspirated engine.The optimization of the engine was achieved by allocating suitably sized exhaust gas turbocharger,adjusting the air intake system and the timing system.Due to the maturity of the technology,the 1.5L naturally aspirated engine is commercially available in large scale,so is the benchmark test results of this type of engine.These test results were employed in the current study to calibrate the numerical model established using GT-power to best simulate the practical conditions of the engine.Based on the basic principles of turbocharging,a simplified method was used to conduct the preliminary screening of the turbocharger,i.e.to select suitable types from a whole range offered by the suppliers.The GT-power model of the turbocharged engine was established by modifying the air intake pipes of,as well as adding turbocharger and intercooler sections to the GT-power model of a 1.5L natural inspiration engine.The final screening of turbochargers was thus performed on the established GT-power model.After that,the engine performance was further optimized to a targeted level by varying the design of the cam shaft and adjusting the timing of the variable valves. |
