Excavator hydraulic circuit solution to reduce dissipations and fuel consumption

In the field of mobile machine the research is mainly focused on solutions to reduce the energy dissipations and fuel consumptions being these machines mainly equipped with Diesel engines. This paper presents a solution for improving the performance of a traditional Load sensing flow sharing circuit. The solution concerns the insertion of a Load sensing signal conditioner (LSc), developed by Walvoil S.p.A., that permits to dynamically change the pressure drop across the directional valves. A careful control of this new component permits to obtain a reduction of the fuel consumption without changing the performance of the machine taking as reference a JCMAS duty cycle. This paper presents the mathematical model of a 9 ton excavator that was previously validated with tests carried out on both the single hydraulic and the excavator main components like pump and flow sharing valves. The LSc model was developed and added to the traditional hydraulic circuit. The model of the excavator hydraulic circuit with this new component has permitted to simulate the energy saving achievable in comparison with the traditional solution. The paper presents the relevance of a carefully control of this new device in order to maximize the performance. The physical prototyping of this device has been already developed and will be installed in a mobile machine to confirm the simulated performance