Development of Hardware-In-Loop Automated Test Bench for Failure Mode Effects Tests and Closed-Loop Feature Tests of Liquid-Assisted After-Treatment Control Systems

Abstract: Air pollution is caused due to harmful exhaust gases comprising of Oxides of Nitrogen (NOx) and Particulate-Matter (PM) coming out from automotive vehicle engines after the fuel is combusted. To meet the statutory Emission Norms and satisfying the required vehicle torque-speed performance, the quantities of these NOx and PM particles going into the environment have to minimised, which can be done by after-treating the exhaust gases upon dosing Urea (AUS-32). The After-Treatment system comprises of various mechanical processors and Urea Dosing Unit along with its set of various sensors and actuators. The dosing action is performed using a control-system, called After- Treatment Control-System. To meet the precise performance, accuracy and system durability, this control-system has to be tested rigorously in the Test-Labs before they are implemented on the Vehicles. The tests carried out include Failure Modes Effects Tests (FMET), Functionality Tests and Closed-Loop Feature-Tests. These tests have to be repeated and reproduced for each regular software releases. Usually, these tests are conducted using a manual-test bench method – which consumes considerable time, prone to manual errors thus increasing overall testing time and programme cost. This paper discusses about the development of automation for these tests using Hardware-In-Loop (HIL) Automated- Test-Bench Technique, using the hardware combination of ACCEPTS (Automated Common Controls Electronic Product Test System), NI hardware and In-house developed Integrated Circuit Logics. The automated test scripts and hardware control logics are developed using automation programming tools like NI-TestStand and NI-LabVIEW. Comparing to the manual test bench method, automated test bench method have reduced the testing time and thus proved to be cost-effective, while increasing the testing efficiency by 23%.

Keywords: After-Treatment Control-System, Electronic-Control-Module, Urea Dosing Unit, Hardware-In-Loop Technique, Closed-Loop Tests Simulation, ACCEPTS, NI-Hardware, NI-TestStand, NI-LabVIEW and MATLAB/Simulink.