Vehicle Simulation for Powertrain System Testing
Examensarbete för masterexamen
Automotive engineering (MPAUT), MSc
Rao, Sudhir Balakrishna
The increase in the extent of vehicles running on internal combustion engines has led to serious concern towards the harmful gasses emitted from them, which affects the balance of natural ecosystem. To reduce the amount of emissions emitted from vehicles, emission regulations are reinforced continuously; which all vehicle manufacturers must fulfil. To meet the emission regulations, powertrain testing has become more important right from the development process of a vehicle. The Hardware-in-Loop is one of the powertrain testing approach which allows testing to be conducted on a test object. The test object can be an engine or any powertrain component without the need for a complete vehicle as in Chassis Dyno testing. Besides the test object which is physical hardware, software components containing all the models to replicate the complete vehicle testing are required. The correct functionality of the software component is vital; if one model produces unwanted behaviour, the whole test can be delayed for days. The objective of the thesis is to create a tool that can be used to check the software components and inform the user if the behaviour of the models varies from what is expected. This testing approach is called Model-in-Loop testing. Engine along with its Electronic Control Module (ECM) was regarded as test objects in our Hardware-in-Loop testing. To convert from Hardware-in-Loop to Model-in-Loop, two new models have been introduced: one for the internal combustion engine and another for the electronic control module of the engine. The remaining software components are retained from Hardware-in-Loop. After the introduction of these two models, the Model-in-Loop was fully functional and the simulation of the complete vehicle was made possible. Once the simulation was possible, the next stage was to create a tool that would perform a check on the models. This tool is referred in this report as Unit Testing. In case the current models are further developed or new models are being introduced, the testing tool will analyse the output and inform the user about the reliability of the models. The user can also use this tool to have an in-depth analysis of the speed of the vehicle, distance travelled and how well it manages to follow the target speed trace, the fuel consumption and CO2 emissions. The final step was to compare the Model-in-Loop testing results across Chassis Dyno testing and Hardware-in-Loop testing to understand the feasibility of further development of the models to capture reliable results. The results obtained from Model-in-Loop was comparable with that of other two testing approaches. The complexity involved in obtaining accurate torque values were realised to implement more models to capture turbocharger, Exhaust Gas Recirculation (EGR), mass airflow effects and possible future work in the development of this testing approach was studied. The thesis is split into three parts; report, appendix and code. The report contains information about the reasoning, objective, methods and findings and is available for public. The appendix and the code, together with the data used in simulation are considered confidential and is only available within Volvo Car Corporation.
Transport , Hållbar utveckling , Teknisk mekanik , Farkostteknik , Transport , Sustainable Development , Applied Mechanics , Vehicle Engineering