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In the case of parallel hybrid excavator, the internal combustion engine operates the hydraulic pump and generator. The hydraulic pump drives the hydraulic circuit of the device, in a man- ner similar to conventional excavators, while the generator transforms the mechanical energy into electrical power and can operate the electric motor of swing rotation. The hybrid solution in parallel is simpler; however, the fuel consumption is higher, and the return time for these working machines is longer [126]. Hitachi, as shown in Figure 13, proposed a parallel hybrid excavator with the gravitational potential recovery of the boom [113]. Figure 12. Series hybrid configuration of the Kobelco excavator. Figure 11. View of Merlo – TF 40.7 hybrid the hybrid telehandler [106]. Hybrid Electric Vehicles20