Page - 21 - in Hybrid Electric Vehicles

In the series-parallel hybrid power train configuration of an excavator, the engine drives the gen- erator directly. The hydraulic pumps are driven by the generator in series, and the swing elec- tric motor is powered by the generator and the battery or super-capacitor in parallel. Although series-parallel hybrid excavators have higher production costs compared with parallel and series structures, they offer the shortest cost recovery time and efficiency with a fuel consump- tion up to 25% [126]. Series-parallel hybrid excavators are regarded as the most promising solu- tions, and both Komatsu (Figures 14 and 15) and Doosan use similar configurations [128, 129]. Figure 13. Parallel hybrid configuration for working excavator Hitachi [127]. Figure 14. Series-parallel hybrid configuration for working excavator Komatsu [126]. Trends and Hybridization Factor for Heavy-Duty Working Vehicles http://dx.doi.org/10.5772/intechopen.68296 21