Eco-optimisation of Goods Supply by Road Transport: From Logistic Requirements Via Freight Transport Cycles to Efficiency-maximised Vehicle Powertrains

摘要

Currently, only a small minority of commercial vehicles on the market are fitted with alternative powertrain systems, and they are mostly of the heavy-duty type. The “alternative” components required (in particular batteries) make these utility vehicles rather expensive for fleet operators. The return on investment seems to be still out of reach. Hence, it is necessary to cut down on operational costs. Given these facts, the starting point was to clarify the criteria of logistic services as needed by the customers. First and foremost this concerns the type of vehicle chosen for a given logistic task. Secondly, concern needs to be given to the factors which influence the dynamics of vehicle movements, such as the load factor in terms of the geographical sequence of the points of deliveries. Thirdly, the time windows available for delivery affect variations in the velocity dependent on the respective level of service of the traffic flow. This opens up some additional potential for optimisation aside from vehicle technology. Road network planning and traffic management can boost low-emission freight services by taking into consideration the performance of different powertrain systems.The object was to quantify effects of innovative powertrain technologies on freight transport fleets with respect to reducing energy consumption and CO2equivalent emissions. We identified representative logistic services as framework conditions of their operations in correlation with vehicle classes (light, medium and heavy). The vehicles use routes from the outskirts to the core of a conurbation and vice versa. The roads used are defined in categories which allow estimates of their capacity to handle variable traffic flows depending on the time of the day. These boundary conditions were used for a comprehensive comparison (based on numerical simulations) of advanced powertrain systems for such commercial vehicles. Particularly, fuel types as well as electricity were taken into account along with some variation in gross vehicle weights and hybrid configurations.The investigations were carried out for 32 different powertrain architectures such as advanced diesel and CNG engines, also as baselines for different hybrid variants and even pure battery-powered commercial vehicles. The results should be of interest for fleet operators, and our interpretations regarding further energy and emission reductions in goods supply processes challenges the entire future system of logistics, traffic management, infrastructure planning and powertrain technologies.