Skattning av fordonsmassa med driftstatistik
In the automatic manual transmission system, Opticruise, the choice of gear is based on several parameters such as road incline, driving resistance and vehicle mass. Many different mass estimations are made during driving. A final vehicle mass is then used to determine the current gear. Construction vehicles are often not equipped with air suspension and can therefore not estimate the vehicle mass when standing still. If that sort of vehicle is reloaded while standing still an incorrect mass estimation will be used and as an effect of that also a wrong gear. The solution of this problem is divided into two parts: first to detect the reload and then to estimate the new mass. An accelerometer will be used to detect a reload before start, because it reacts on the gradient change of the vehicle. A force equation will also be used to detect a reload, but only after the start, because it needs access to the vehicle acceleration to make the calculation. After a reload has been detected a new mass can be estimated. The estimation is based on previous vehicle mass estimated during driving. The new mass will be reasonable, if the assumption that the vehicle is mostly driving empty or fully loaded is true, and if it is possible to determine whether the vehicle becomes lighter or heavier at the reload.