MISSION PROFILE FOR AGRICULTURAL TRACTORS: A FOCUS ON HYDRAULIC CIRCUIT

Mission profile for agricultural vehicles aims to define a picture of a typical working condition of the vehicle. The collection of these pictures gives information about the performance, the efficiency, and the eventual critical conditions with reference to the kind of operation and terrain. Unfortunately, to be at the same time quick, easy to be interpreted and effective, this analysis has to neglect the details and to take into consideration the whole situation. However, detailed considerations about the efficiency of the vehicle subsystems and of their components may derive only from a deeper analysis and it is from these information that designers and technicians can derive improvements of the system. A promising way to solve this discrepancy is to integrate experimental analysis with simulation: from experimental test on field is possible to define several duty cycles representing different working conditions on the vehicle. These data can then be used as input in a simulation model representing the system, able to replicate its dynamic behaviour. Finally, possible modifications of the system architecture or components, aimed at the improvement of the performance or efficiency, may be more easily tested on the virtual model. In this paper this methodology is presented with reference to the hydraulic circuit of an agricultural tractor, in particular the portion related to the managing of the auxiliary utilities, showing the capability to represent in detail the behaviour of the system and to explore the critical performances.