چكيده به لاتين
In this thesis, two classes of bulldozers have been simulated in Recurdyn software to examine fuel consumption and dynamic indices. Also, the performance and effectivness of the blade of the bulldozer have been modeled in the software. The Powertrain system were modeled from Caterpillar D6R and D3C specifications and the BSFC lookup table (2D) based on data of Caterpillar C-15’s engine. For the using of that information, torque values and consumption data are scaled to two small and medium-class of vehicles. Based on terramechanics relations, three different well-known terrains are used here to investigate the motion performance of the bulldozer; dry sand, clayey soil, and sandy loam (Michigan). These terrains have a variant of terramechanics specifications (such as cohesion, internal friction angle, cohesive modulus, and friction modulus). A working condition for bulldozer (driving cycle) is considered, and in order to complete this cycle, it is assumed that the end of the vehicle returns to the starting point of the cycle.
In order to reduce fuel consumption, an optimization process for shifting gears for two small and medium-sized vehicles has been done in the Recurdyn / AutoDesign software. The results showed that shifting the gear at the appropriate speed, depending on the type of soil and vehicle weight, reduces fuel consumption for small-class vehicle by 1-3 percent and for the medium-class vehicle by between 1 and 6 percent. The medium-class vehicle has been evaluated with the highest speed approach, focusing on reducing the route's journey time and reducing fuel consumption simultaneously in the new cycle. The results show that with proper speed on the return path, fuel consumption can decrease from 14 to 24 percent, depending on vehicle and soil weight. Subsequently, an optimization of a target with three variables was performed to reduce fuel consumption. The results showed that with proper gear ratios, depending on the type of soil and vehicle weight, the fuel consumption can be reduced from 28 to 36 percent.
