Model-Based Test Bench Conditioning Systems Control

Engine test benches are crucial instruments to perform tests on internal combustion engines. Possible purposes of these tests are detecting engine performance, checking the reliability of engine components or making a proper calibration of engine control systems managing the actuations. Since many factors affect tests results in terms of performance, emissions and components durability, an engine test bench is equipped with several conditioning systems (oil, water and air temperature, air humidity, etc.), in order to maintain the controlled variables to the target values, throughout the test duration. The conditioning systems are often independently controlled by means of dedicated Programmable Logic Controllers (PLC), but a centralized model-based management approach could offer several advantages in terms of promptness and accuracy. This work presents the application of such control methodology to oil, water and HVAC (Heating, Ventilating and Air Conditioning) conditioning systems, where each actuator is managed coupling model-based open-loop controls to closed-loop actions. The main advantage of integrating the management of several actuators is that the control actions can be coordinated, similarly to what has been achieved in engine management systems with torque-based control: the risk of conflicts in the control actions on different actuators can be reduced, while the introduction in the control loops of other actuators is easier. The control methodology has been validated on an engine test bench where the automation system has been developed on an open software Real-Time compatible platform, allowing the integration of the conditioning system control with all other functionalities concerning the test management. The paper shows the plant layout, details the control strategy and finally analyzes experimental results obtained on the test bench, highlighting the benefits of the proposed management approach.