An Analysis of the Effects of Torque, Engine Geometry and Speed on Choosing an Engine Inertia Model to Minimize Prediction Errors

Control engineers have typically used constant inertia models to allow real-ime simulation. While this method works well for gross approximation of engine speed, the selection of the constant inertia value is important for minimizing estimation errors. The authors examine the use of a minimum acceleration error methodolgy for selecting the inertia value for the constant inertia model This will help engineers choose an inertia value that provides more accurate engine acceleration estimation. While in some cases, the traditional constant inertia value method will yield better engine velocity estimation. The effects of torque, engine geometry and speed on the calculation of inertia are investigated. Discussions of the advantages and disadvantages of both methods are also included.