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Modern diesel engines for vehicular applications such as buses and other commercial vehicles are increasingly using technological resources in order to meet the pollutant emissions regulations. Among these features, the turbocharger fulfills an essential function of providing a higher air flow to the engine intake, providing a cleaner and more efficient combustion. During the application process of a turbocharger, calculations are performed to estimate the life of the compressor impeller, which takes into account the maximum shaft speed and the number of cycles that cause fatigue damage. Among these parameters, the maximum speed affects directly in the fatigue life of the impeller. Due to the different material options for the compressor impeller, the mass properties of each type of rotor may result in differences in their inertias thus impacting the maximum speed and the fatigue life calculation.

The development of on-highway diesel engines is requiring more resources and technology to comply with ever-stricter emissions regulations. Increased airflow requirements of recently developed engines are not met exclusively with single-stage turbochargers. Two-stage systems have been widely used for off-highway high-horsepower engines and show potential use on smaller output engines. Although turbochargers are used as an exhaust gas energy recovery system, still a great portion of this energy is lost downstream the discharge pipe. The objective of this work is to provide a quantitative comparison of air handling system global efficiency taking into consideration the wasted exhaust gas energy. Experimental data from single-stage and serial two-stage turbocharged engines were compared with theoretical methodology.