Analytical Model for Altitude Adaptability of Turbocharged Heavy-Duty Diesel Engine

Abstract

This paper proposes an analytical model to predict the maximum altitude adaptability of a turbocharging diesel engine. First, the influence of the turbocharging system parameters on the diesel engine performance at different altitudes was analyzed by using an experimental method. The results showed that the engine power decreased dramatically at higher altitude owing to the enlarged energy gap between the available flow energy fed to the turbocharging system and the energy required for the full power recovery. On this basis, an analytical model was established. The model results indicated that the altitude adaptability of the turbocharged diesel engine was determined mainly by three dimensionless parameters, namely the (1) compressor pressure ratio at sea level, (2) turbocharger efficiency multiplied by the ratio of the turbine inlet temperature to the compressor inlet temperature at sea level, and (3) ratio of the turbocharger efficiency at plateau to the turbocharger efficiency at sea level. Next, the maximum altitude adaptability of a turbocharged diesel engine was predicted using these three dimensionless parameters. Finally, the prediction results were validated by comparison with the experimental data. This model can be used to predict whether the engine power can be fully recovered at the studied altitude range before optimizing the turbocharging systems to realize the engine power recovery.