Performance based standards for heavy vehicle combinations with electrified dolly
Examensarbete för masterexamen
Mobility engineering (MPMOB), MSc
The need to create environmentally friendly transport solutions has guided research in vehicle engineering over the past few decades. As a result, Battery Electric Powertrains are now in operation in small vehicles like cars. However, these solutions often fall short in terms of providing long mission ranges and high payload capacity. Consequently, implementing them independently in Long Combination Vehicles (LCVs) presents a challenge. This situation creates an opportunity to explore longer and heavier High Capacity Transport (HCT) vehicles, which could reduce the number of trips required. These HCTs could potentially feature hybridized powertrains with multiple propelling units, at least for the time being. However, the use of multiple propelling units is likely to have an impact on vehicle dynamics, particularly in the areas of braking stability and traction capability. This effect could potentially lead to instability issues, such as jack-knifing. Therefore, to ensure their compliance with street regulations, it is imperative to analyze their performance based on the tests outlined in the Performance Based Standards (PBS) framework. The HELPED project has been exploring the integration of electrified dollies in Adouble HCT combinations. This thesis work falls within the scope of this project and seeks to address several questions: How does the performance of an electrified A-double differ from that of a conventional one in terms of vehicle stability and traction when subjected to specific PBS tests? Is the existing PBS framework sufficient to ensure the safe operation of an electrified dolly? If necessary, what additional tests might be required to assess and establish legislation for electrified dolly combinations? To address these questions, this thesis work involves modeling an A-double HCT vehicle combination. The investigation includes modeling specific test cases to study the traction capability and stability of the combination with and without an electrified dolly. The simulations encompass maneuvers such as Startability, Gradability, Single Lane Change, and Deceleration in a curve. The results indicate that in terms of traction, the electrified A-double performs significantly better than a conventional one. However, the results from the stability simulations show that in certain conditions, such as when carrying a lighter payload on low-friction surfaces, it performs worse when subjected to aggressive maneuvers. Hence, the implementation of an A-double may require striking a balance between environmental efficiency and safety considerations.
Battery Electric Powertrian , Performance Based Standards , Long Combination Vehicle , High Capacity Transport , HELPED , Single Lane Change