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Operating in an increasingly competitive market, buses and agricultural equipment are facing the changes that passed trucks and commercial vehicles. Those changes are affecting drastically the final cost of the product and consequently its relationship with the costumer. This constant for more competitive prices drives the companies to develop more aggressive strategies of components standardization on a global level, leading to the emergency of global products in regional applications, keeping regional particularity characteristics when operating in the field. In the bus market, it is confirmed that in various media and academic publications there are recurrent complains about driver comfort by several factors related from the ergonomics of the workplace, as well as with operators from agricultural implements.

This paper discusses the benefits of truck simulation for ride and handling tuning at product development. Virtual simulation can guide the conception of new vehicles to a better "first guess" of dynamics characteristics, providing calibrated options to define parameters for springs, dampers and anti-roll bars, closer to the desired condition. TruckSim™, from Mechanical Simulation, was the chosen software due to its user-friendly interface, fast modeling and post-processing that matches with challenging product time-to-market. The scope of analysis is to evaluate/compare virtual results against subjective/objective tests on real prototypes, in order to proof software correlativity. The first step was to develop the vehicle model, using 3D CAD models information, data acquired from real prototypes and product specifications. The chosen vehicle was a 9-ton 4X2 rigid truck.

This paper discusses the importance of vibration transmitted from the ground to the driver from the perspective of human whole-body vibration (WBV). The scope of analysis is to compare the main vehicle frequencies with those important from the human vibration health and comfort point of view. That was performed by mapping the vibration transmissibility present in different sub sections of the vehicle. The first is the transmissibility between the axles and the chassis rail, the following between the chassis rail and the cabin. The last would be between the cabin and the drivers' seat, although that was not possible from the acquisition point of view. The vehicles measured have mechanical suspension and elastomeric cabin coupling. It is known that all suspension systems in vehicle are highly nonlinear, although here linear dynamic analysis methods were used.

Extra heavy vehicles, depending on their application and configuration, demand higher torque, longer drive-off time, many gear shifts, more complex and unusual maneuvers. These situations lead to a high thermal energy applied on the clutch, increasing clutch wear and, in extreme conditions, leading to a thermal destruction. These events demand a technically and economically viable solution as well as a compact layout for easy implementation to increase the clutch performance and life. Since the problem is of thermal nature, without the possibility of forced cooling or the use of a larger clutch assembly to faster dissipate the energy, the proposed improvement has been focused on faster energy absorption in order to minimize peak temperature, both in occurrences and in magnitude.