This paper presents a method to predict the transient turbocharger shaft
speed for turbocharged diesel engines based on a dynamic observer. The observer
uses the turbocharger torque balance as a dynamic term and the static turbo map as a
static term. The latter includes the intake and exhaust side together with turbine shaft
speed. The experimental results show that this observer can provide an estimate of
turbocharger shaft speed without introducing large delays in transient operation and
provide a good match with the turbo map data in steady state. However, this method
has to calculate the turbine and compressor torque with a high accuracy which
makes it almost unrealizable because of the complexity of turbine and compressor
torque calculation. A novel method was designed to solve this problem by using an
integral term at steady state to eliminate the torque modelling error.