Future Commercial Vehicle Powertrains: Contributions to Sustainable Transportation

Objective Already for many years, fuel consumption and operating cost were the major technology drivers for commercial vehicles. Today, in order to achieve agreed CO₂ goals and to reduce the dependency on crude oil, governments are implementing CO₂ or fuel consumption legislation. Even more, reduction of fuel consumption and consequently low operating costs are continuously an important focus for manufacturers and owners of commercial vehicles. New powertrain technologies, which will further reduce fuel consumption, are able to combine these three drivers, to reduce CO₂ emission, to reduce the dependency on crude oil and to address the need of lower total cost of ownership of the owners of commercial vehicles. Conclusions The efficiency of commercial powertrains can be significantly increased in future. Several potentials for improvement are seen specifically in those technologies, which are able to provide a global optimum of the whole powertrain system, from engine to exhaust aftertreatment to cooling system up to transmission and the final drive. In total a fuel efficiency potential of 20 % is seen for long haul trucks. Results AVL has developed a whole line of technologies, which can be implemented to the commercial powertrain in the future to address the requirements above. The individual measures are the optimization of the balance between engine and aftertreatment systems, reduced engine friction by advanced thermal management systems, reduced parasitic losses of the auxiliaries in real life driving cycles, conversion of exhaust energy in driving power, application of new and advanced transmission technologies and shift strategies as well as degrees of electrification of the powertrain. Additionally, alternative fuels provide another field of CO₂ friendly technologies as well as reduced operating cost. Here specifically, the availability of local resources drive short term applications. This paper will compare the individual saving potentials of these technologies, will rate it against criteria like market readiness, cost efficiency and others. It will be demonstrated that major reductions in CO₂ emissions and operating cost are still possible by commercial vehicle powertrain measures. Methodology To quantify the fuel saving potentials of the individual technologies AVL applied its proven seamless system simulation environment to analyze the whole vehicle system. Interlinked sub-models for all relevant vehicle, respectively engine sub-systems, are the core of this simulation environment. Where necessary, the individual models have been aligned with specific test bed and vehicle measurements. For some of the analyzed technologies the predicted fuel saving potential could already be confirmed by transient operation on test bed using prototype components. To analyze the cost efficiency for the individual technologies the predicted additional product costs have been rated against the saving in operational cost for the final vehicle owner. A return of investment calculation analysis has been made for each individual technology. To predict the market readiness of the individual technology, relevant boundary conditions like estimated development effort, components availability, established supplier base, development risk, etc. have been considered. Limitations Basically the results of this study can be transferred to all commercial powertrain systems. However, the main focus of the study is on the long haul truck application since it has the most significant impact to total CO₂ emissions caused by the high mileage as well as the high absolute fuel consumption level of this vehicle category.