Author Description

Hybridization of heavy off-highway working vehicles brings considerable energy savings in form of downsized internal combustion engine (ICE) by means of elimination of no-load losses. In this paper a novel energy saving possibility in working hydraulics at the end of long booms of working vehicles is proposed. In traditional off-highway working vehicles the working hydraulics is supplied through pipes, hoses and valves by a hydraulic pump which is located near the main engine. Significant amount of energy is lost in long pipelines and hoses as well as in valve throttles. A new topology is introduced for supplying the power along the long boom – the power of a hydraulic actuator is supplied by an integrated electro-hydraulic energy converter (IEHEC) which is located at the boom end. The electrical energy to the converter is supplied via electrical cables which have losses negligibly small compared to conventional fluid power supply with long pipelines. The converter transforms the electrical energy into hydraulic energy at the end of the boom, and can recuperate excessive hydraulic energy.