Contribution to the investigation of the influence of tire non-uniformity on the lateral tire characteristics

Tire models are widely used in research in the field of vehicle dynamics and noise, and especially in the simulation of their movement under the action of forces and moments. In general case, we distinguish theoretical models defined on the basis of tire construction and empirical or semi-empirical models based on experimental tests. In addition, a combination of these two types of models can also produce tire models. In practice, there is a very wide range of mathematical tire models defined using finite element analysis, by approximation of polynomials of different degrees, by approximation of magic formula, etc. In this paper, an attempt is made to calculate non-stationary lateral characteristics of tires on the basis of experimental stationary lateral characteristics, using two-parameter higher level polynomials. This polynomials define the tire lateral characteristics, and take into account their non-uniformity. More specifically, the lateral characteristics are approximated as a function of the dynamic change of the slip angle, radial load due to tire non-uniformity and time

Method for acquisition and analysis of operating parameters of a supercapacitor electric bus

Smanjenje emisije štetnih gasova jedan je od glavnih motiva za sve veću zastupljenost električnih autobusa u javnom gradskom prevozu širom sveta. Usled toga, sve veći značaj se pridaje smanjenju potrošnje energije kod elektroautobusa. Jedan od najefikasnijih načina za smanjenje potrošnje energije, odnosno povećanje autonomije kretanja, je odgovarajuća edukacija vozača. Sagledavanjem trenutno dostupnih istraživanja, može se uvideti da se većina istraživanja bavi procenom potrošnje energije elektrovozila na osnovu matematičkih modela i simulacija, dok je veliki deo ispitivanja sproveden u laboratorijskim uslovima, na dinamometrijskim valjcima. Ovim radom je prikazan postupak akvizicije i analize radnih parametara elektroautobusa koji kao izvor energije koristi superkondenzator. Postupak je korišćen pri ispitivanju elektroautobusa, kako u realnim uslovima eksploatacije, tako i na poligonskim ispitivanjima, gde je sprovedeno više različitih voznih ciklusa. Akvizicija podataka je izvršena pomoću postojećih priključaka na CAN magistralu vozila (gde je moguće pratiti različite radne parametre elektroautobusa), merenjem određenih analognih signala i korišćenjem nekoliko davača. Analizom prikupljenih podataka je moguće utvrditi uticaj različitih stilova vožnje na ekonomoičnost elektroautobusa i, na osnovu toga, definisati preporučeni stil vožnje. Takođe, prikupljeni podaci omogućuju utvrđivanje utrošene/rekuperisane energije za različite režime vožnje.Reducing the air pollution is one of the main reasons for increased usage of electric buses in city public transport around the world. As a result, reducing the energy consumption of electric buses is becoming increasingly important. One of the most effective ways to reduce energy consumption, and therefore increase vehicle autonomy, is proper driver education. Based on the conducted analysis, it can be seen that the most of researches deal with the estimation of the energy consumption in electric vehicles with the help of mathematical models and simulations, while, on the other side, majority of testing was conducted in laboratory conditions, on chassis dynamometers. This paper presents the method for acquisition and analysis of operating parameters of the electric bus that uses a supercapacitor as an energy source. This method was used during the testing of electric bus in real operating conditions, and on a test track where different driving cycles were performed. Data acquisition was conducted by using the existing CAN bus data and some additional sensors. By analysing the collected data, it is possible to determine the impact of different driving styles on the efficiency of the electric bus and, based on that, to define the recommended driving style. Also, the collected data can be used for determination of the energy consumed/recuperated during different driving regimes