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Brazil presents a very diverse road and traffic conditions and due to several factors the number of truck accidents is very high. Inside truck accidents group, the one that causes the highest number of losses and fatalities is the rollover crash and understanding rollover dynamics is very important to prevent such events. The diversity of cargo vehicles arrangements requires a detailed study regarding the dynamic behavior these vehicle combinations in order to increase operation safety. The same tractor unit can be used with different types and numbers of trailers and/or semi-trailers, each one with different suspension configurations. These truck combinations have distinct dynamic performances that need evaluation. In this sense, this work presents a first phase study on the dynamic behavior of different types of cargo vehicle configuration. A 6×2 tractor is combined with a two distinct grain semi-trailer with different types of suspension: pneumatic and leaf spring.

The need for braking capacity improvement has a negative impact as it increases the loads acting on the conventional brake system, increasing wear between its components and requiring a more robust design. Looking this scenario, an available option is to use the engine as a source of braking power. Some conventional engine brake systems consume the vehicle/engine inertia power through the exhaust system closing (total or partial). However, the braking efficiency of this version is limited by bouncing occurrence on the exhaust valves, generating stronger impact of valve and valve seat. The developed solution consists in creating an engine brake mechanism acting directly on the exhaust valve, achieving greater efficiency. The mechanism is based on a hydraulic actuator positioned between the exhaust rocker arm and the valve stem top.