Transient Turbocharger Shaft Speed Estimation with Steady State Stabilization in a Turbocharged Diesel Engine

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.