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The article presents a heuristic model used to evaluate the level of disorder in the synchronization of airbag operation with a moving phantom head during a frontal collision caused by a change in the longitudinal stiffness. The article describes three areas of research. The first presents the results of the strength tests of longitudinal models: reference and welded joint. Based on these, the relative stiffness decrease coefficient (SDC) of the longitudinal was determined. The second presents an analytical model of the airbag activation algorithm and the impact of SDC on its operation. The third determined the contact time of the phantom head with the airbag, taking into account the SDC. Based on the selected case study, a spatiotemporal analysis was conducted, indicating the level of disorder in the synchronization of the airbag with the moving phantom head due to the change in longitudinal stiffness. [ABSTRACT FROM AUTHOR]

There are many different mathematical models that can be used to describe relations between energy machines in the power-split hybrid drive system. Usually, they are created based on simulations or measurements in bench (laboratory) conditions. In that sense, however, these are the idealized conditions. It is not known how the internal combustion engine and electrical machines work in real road conditions, especially during acceleration. This motivated the authors to set the goal of solving this research problem. The solution was to implement and develop the model predictive control (MPC) method for driving modes (electric, normal) of a hybrid electric vehicle equipped with a power-split drive system. According to the adopted mathematical model, after determining the type of model and its structure, the measurements were performed. There were carried out as road tests in two driving modes of the hybrid electric vehicle: electric and normal. The measurements focused on the internal combustion engine and electrical machines parameters (torque, rotational speed and power), state of charge of electrochemical accumulator system and equivalent fuel consumption (expressed as a cost function). The operating parameters of the internal combustion engine and electric machines during hybrid electric vehicle acceleration assume the maximum values in the entire range (corresponding to the set vehicle speeds). The process of the hybrid electric vehicle acceleration from 0 to 47 km/h in the electric mode lasted for 12 s and was transferred into the equivalent fuel consumption value of 5.03 g. The acceleration of the hybrid electric vehicle from 0 to 47 km/h in the normal mode lasted 4.5 s and was transferred to the value of 4.23 g. The hybrid electric vehicle acceleration from 0 to 90 km/h in the normal mode lasted 11 s and corresponded to the cost function value of 26.43 g. The presented results show how the fundamental importance of the hybrid electric vehicle acceleration process with a fully depressed gas pedal is (in these conditions the selected driving mode is a little importance). [ABSTRACT FROM AUTHOR]