Turbocharging

AbstractThe primary purpose of turbocharging is to increase the air mass supplied to an internal combustion engine so that the engine can burn more fuel and generate more power. Turbocharging enables a gasoline engine to be downsized and improves fuel economy significantly. It allows high air–fuel ratios and exhaust gas recirculation (EGR) in diesel engines, which helps control emissions. It was invented in 1905 and the technology has seen continuous improvement to match similar improvements in the technology of internal combustion engines. These improvements include evolutionary but significant improvements in design, materials, and processing such that the same task (airflow and pressure ratio) is performed by a turbocharger with 80% reduction in size compared to early designs. Variable geometry mechanisms, EGR systems, multistage turbocharging in parallel, series, and sequential configurations, and multistage compression packaged on a single shaft have all advanced such that these technologies are now increasingly being applied. The benefits of turbocharging in both gasoline and diesel engines are very significant and there is a marked trend toward increased use of turbocharging worldwide.