Experiences from a Large Scale Software Product Line Merger in the Automotive Domain

Software engineering in the automotive domain faces some outstanding challenges in terms of variability and complexity, specific customer relationship with car manufacturers and quickly and continuously changing requirements. Especially power train control systems currently evolve from classic combustions engine focused concepts towards highly divergent solutions like hybrid systems, range extenders or fully electrically driven vehicles. In this context Bosch's business units Diesel Systems (DS) and Gasoline systems (GS) merged their separated engine control unit development organizations, motivated by a growing portion of functionality independent of the combustion engine type and an increasing synergy potential in hardware and software development. As DS and GS software development evolved independently, they established different technical solutions, organizational structures and development processes - even though both adopted product line engineering principles. Since the official start in 2008, DGS-EC (Diesel Gasoline Systems Engine Control) has installed important prerequisites for common, unified software development and achieved many unification targets. This paper gives an insight to the most important experiences of this large scale product line merger, addressing challenges, enablers and solutions concerning organizational setup, process unification, architecture and product line scope definition as well as software technology harmonization.