Modeling and Calculating Electric Power Consumption of a Diesel Truck Engine

Abstract

In order to dimension alternators and batteries as well as power management control strategies, there is a need to analyse the electrical current consumption in various systems of a diesel truck engine for different modes of operation. The aim of this project is to develop a general way (method and tool support) to calculate and analyse current consumption of the powertrain system. In this work several models with different levels of accuracy have been designed in order to simulate the current consumption of the urea dosing system, which is one of the main systems of the exhaust after treatment system (EATS). The main reason for selecting such a system was its independent characteristics, having its own controller known as the ACM (After treatment Control Module) and as well it is of primary interest of the Volvo system engineering group due to its new developing technology, designed for future Euro VI heavy duty engines. All the models and simulations have been implemented in Matlab®/Simulink®. Moreover the models were compared and verified with measurements that were carried out at Volvo Powertrain test labs. A user friendly graphical interface was also designed as an interface between the user and the Simulink® model. The tool was designed via Matlab®GUI with convenient viewing and post processing capabilities. The results show that the basic model, being a rather simple model with static simulation is sufficient for modeling the air valve, coolant valve and the hose heaters of the Urea dosing system. The accuracy of the implemented basic model structure is found to be 98% of the real measured values. However the urea pump requires a more advanced model due to its complexity, which was implemented in the detailed model. The detailed model, which is based on dynamic simulation and detailed mechanical characteristics in addition to the detailed magnetic characteristics of the pump, produces reasonably good results with an error of 23.8 % in the average coil current. The main contribution to this error is probably the unknown parameters of the electronic control circuit. Finally, the general model is the most suitable model for the urea pump according to the project’s specifications and in comparison with the detailed model, it over predicts the current consumption by 4.3 %.