Recent Patents on Hybrid Construction Machinery

In recent years, significant patents have been devoted to developing the structure, system and control method of hybrid construction machinery. The focus of this paper is to survey recent patents related to hybrid construction machinery. First, a general overview of hybrid construction machinery is provided, followed by issues related to research in hybrid construction machinery. Various aspects of hybrid construction machinery research are introduced, such as series hybrid power system, parallel hybrid power system and parallel-series hybrid power system. Patents related to hybrid construction machinery, issued since 2007, are selected for the survey. A comparison of these patents is provided, followed by the discussion of future research issues in hybrid construction machinery.