Interest to hybridize mobile work machines has increased substantially during ongoing decade. Reasons for increasing interest are mainly tightening emission regulations and trend of rising fuel prices. To get better understanding for the benefits of hybridization, Helsinki University of Technology (TKK) has started 5 years project to research different aspects, how to improve fuel economy in mobile work machines. For case work machine is chosen an underground mining loader which will be first researched as conventional version and then it will be converted to a hybrid version. The tests for conventional version were done in the early 2009 and for hybridized version till the end of 2010. The results will be then compared to each other.

This paper is part of an ongoing HybLab project funded by the Multidisciplinary Institute of Digitalization and Energy (MIDE) of Aalto University School of Science and Technology. First results and plans were presented in EVS24 [1]. The focus in this paper is to describe what kind requirements must be taken in to account when designing and dimensioning an electromechanical driveline for an underground mining loader. For case work machine is chosen 18t loader which was presented in EVS24 [1]. Also concept for a modular driveline concept will be presented. Basic idea in the concept is to avoid over dimensioning of electric drives by using electromechanically actuated mechanical links between the drive units. The concept gives possibility to optimize dimensioning of each electric drive in driveline so that the best efficiency is in use in normal mean power drive conditions. When one drive needs peak power then mechanical power can be driven via mechanical links from other drives. Disengageable mechanical links gives also possibility to avoid internal counter-torques in driveline caused by steering geometries and differences in tire diameters. The concept will be presented in the EVS25. The first results and experiences from the electromechanical driveline will be presented in EVS26. Copyright EVS25.

The early evaluation of a proposed function structure for a product and also, the possibility to expose the potential failures related to this provides that the design process can be modeled in its entirety. However, so far there are no existed suitable models for the early phase of design process. This article presents an integrated approach aimed to explore the behaviors of concept designs in the early design phase. The approach is founded on a combination of Petri net, π-numbers, qualitative physics principles and Design Structure Matrix. The final aim is to implement this method on the SysML modeling language to integrate a simulation approach that is initially not standardized in the language. A second interest of the approach is to provide a coherent simulation framework that can be used as a reference to verify the coherency of other simulation models further in the design process.

Heavy-duty vehicles OEMs have an increasing interest in alternative power train solutions. To gain benefits of hybrid power train, proper power bus control must be implemented. Control strategy refers to means necessary to meet duty cycle power demands while maintaining vehicle performance. Cascading controlling strategy division is proposed. Control method layering proposition is presented and control methods are divided into two categories, reactive and predictive methods. Finally these methods are implemented in series hybrid energy system model. Implemented reactive methods are load-based control, voltage-based control, voltage/load hybrid control and peak shaving control. Load data is measured data from electrical power train straddle carrier. One vehicle state predictive control method is implemented. Results are evaluated and discussed.

Scientific papers usually do not present 'lessons learnt' results, what comes to engineering aspects in vehicle design. A lot of valuable information is collected during research and prototyping projects, but this is not shared in public often enough. This paper is a general discussion about the engineering matters related to the implementation of hybrid systems in mobile work machines. The target of this paper is to underline the importance of paying attention of these matters already in very beginning of the research and development. The discussed aspects are related to the energy transmission, packaging of components, vehicle assembly and service. The energy transmission section compares benefits and drawbacks of hydraulic and electric transmission implementations. Packaging of components presents some issues to pay attention to when accommodating components into vehicle. Service aspect highlights the benefits and drawbacks of different solutions in maintenance operations. The discussion is limited to explain only differences and analogies between hydraulic and electric components. The cost factors can be estimated only by the reader, because they are very case sensitive. The key factor is number of machines made in serial production. In case of passenger cars the cost structure is very different compared to small series mobile work machines.