28,315 research outputs found

    THE STRATEGIC PLANNING WITHIN THE ENTERPRISE PRODUCING ROAD VEHICLES

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    We can look at the planning as the first function of the management because it will take place before the other functions, the avoidance of errors, the economy of resources and the increase of the company activity performances may be achieved through the planning activity. The policy of the organization producing the road vehicles remains the same as long as the organization will carry out its activity or it may be changed when the managerial team will be also changed. As we said before, throughout the whole period of the application of the policy of the organization producing the road vehicles. The main objective of the strategic planning for the companies producing road vehicles is to establish the main objective of activity of the company and that of the organization of the activities in order to obtain the expected results and the achievement of the objectives. The strategic planning has as distinctive element the approach of the content elements of the management and strategic marketing as a process, made up of successive stages (phases), being in interdependent relations. The action carried out by cascade involves the passage of each phase step by step.marketing, strategic planning, road vehicles, management.

    Research on battery-operated electric road vehicles

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    Mathematical analysis of battery-operated electric vehicles is presented. Attention is focused on assessing the influence of the battery on the mechanical and dynamical characteristics of dc electric motors with series and parallel excitation, as well as on evaluating the influence of the excitation mode and speed control system on the performance of the battery. The superiority of series excitation over parallel excitation with respect to vehicle performance is demonstrated. It is also shown that pulsed control of the electric motor, as compared to potentiometric control, provides a more effective use of the battery and decreases the cost of recharging

    Electric road vehicles - overview, concepts and research at Reutlingen university

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    The paper details the architecture of fully electrified vehicles as well as their new electronic systems. Examples of up-to-date electrical passenger cars are given. A very important question, that is the environmental foot-print of electrical vehicles compared to conventional ones, is examined. A research project is introduced where a fleet of two-wheeled vehicles is available for day-to-day use. Research on vehicles, software for fleet management and battery range prediction is described.В данной статье привeдены подробные сведения о принципе работы электрифицированных транспортных средств, а также описаны их новые электрические системы. Показан примеры уже существующих электрических пассажирских транспортных средств. Рассмотрено влияние электрифицированного транспорта на окружающую среду в сравнении с обычными видами транспорта. Приведен проект исследований, в рамках которого для ежедневного использования существует парк двух колесных электрифицированных транспортных средств. Описаны исследования, непосредственно связанные с электрифицированным транспортом, определением точного времени разряда батареи, а также программным обеспечением, позволяющим управлять парком таких транспортных средств.У статті наведено докладні відомості щодо принципів роботи електрифікованих транспортних засобів, а також описано їх нові електричні системи. Показано приклади вже існуючих електричних пасажирських транспортних засобів. Розглянуто вплив електрифікованого транспорту на навколишнє середовище у порівнянні із звичайними видами транспорту. На- ведено проект досліджень, у рамках якого існує парк двоколісних електрифікованих транспортних засобів для щоденного використання. Описано дослідження, безпосередньо пов'язані із електрифікованим транспортом, визначенням точного часу розряду батареї, а також програмним забезпеченням, що дозволяє керувати парком таких транспортних засобів

    Theoretical prediction of ground vibrations generated by road vehicles

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    Ground-borne vibrations represent one of the major adverse environmental impacts of road vehicles, especially of heavy lorries. In the present paper, ground vibrations generated by road vehicles are investigated theoretically. Two main generation mechanisms are considered. The first one is associated with vehicles travelling on rough or bumpy road surfaces, in particular over road humps and speed cushions installed by local authorities at some sensitive road locations. The second mechanism of generation is associated with acceleration and braking of road vehicles. General analytical results are illustrated by numerical examples and are compared with the existing experiments

    Crosswind Sensitivity of Road Vehicles

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    Práce je zaměřena na vytvoření metodiky umožňující spolehlivě hodnotit citlivost vozidel na boční vítr. Součástí práce je vytvoření matematického modelu vozidla zahrnující aerodynamické síly a provedení validace technickým experimentem definovaným v ISO 12021. Na základě modelu je provedena citlivostní analýza jednotlivých vstupů na hodnoticí kritéria citlivosti vozidla na boční vítr, na jejímž základě je určena celková chyba modelu způsobena chybou vstupních parametrů. V závěru práce je popsán vztah mezi bodově měřeným tlakem na povrchu jednotlivých aerodynamických variant vozidla a veličinami popisující jeho samotný pohyb.The aim of the thesis is to devise a methodology which is capable of reliable evaluation of road vehicle’s crosswind sensitivity. The work consists of writing the mathematical model of a vehicle which includes aerodynamic loads and conducting a validation by means of technical experiment as defined by ISO 12021. A sensitivity analysis describing the influence of individual inputs on evaluation criteria of vehicle’s crosswind sensitivity is performed using the model, thereby establishing the overall model error caused by possible inaccuracies of input parameters. At the end, the relationship between discrete pressures on the surface of the vehicle in several aerodynamic configurations and the properties representing the vehicle’s motion is presented.

    Adjustable dampers of road vehicles

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    Tato bakalářská práce se zabývá rozdělením a popisem činnosti konvenčních a regulovatelných tlumičů pérování silničních vozidel. Popisuje dynamiku vozidel při svislém kmitání a vliv tlumení a pérování na chování vozidla. Dále popisuje a rozděluje jednotlivé systémy odpružení podvozků, které využívají regulovatelných tlumičů.This bachelor thesis deals with the distribution and description of the activities of conventional and adjustable shock absorbers of road vehicles. It describes the dynamic of the vehicle in the vertical oscillation and the effect of damping and springs to vehicle behavior. It also describes and classifies individual suspension systems that use adjustable shock absorbers.

    Potential for improvement of comfort parameters in off-road vehicles of Serbian armed forces

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    The paper presents the comparative results of comfort parameter testing inside the cabin of Land Rover Defender off-road vehicles. The measurements were carried out on two vehicle models -110 GS Hard Top and 110 GS Soft Top Heavy Duty. Tests on comfort parameters were performed only on the military off-road vehicles, or to be more precise on the military off-road vehicles used by the Serbian Armed Forces. The results of the performed tests offer some suggestions for the improvement of comfort of military off-road vehicles used by the Serbian Armed Forces. The comfort elements have been compared from the aspect of accommodation of the crew, noise, vibrations and heating efficiency. A part of the experiment was performed by intensive driving of these off-road vehicles in real world conditions, on three pre-selected types of terrain surface, in order to ensure the repeatability of the testing results: heath, gravel and asphalt base (a portion of the Belgrade-Zagreb highway at the territory near Sid was used due to its less frequent traffic and surface quality). Noise and vibration measurements were carried out at the driver's seat, co-driver's seat and other passenger seats under strictly defined vehicle speeds. Testing of the heating efficiency inside the cabin was carried out under laboratory conditions in the cold chamber of the artillery range at Nikinci at a constant ambient temperature of -16 degrees C

    Euromech Colloquium 509: Vehicle Aerodynamics. External Aerodynamics of Railway Vehicles, Trucks, Buses and Cars - Proceedings

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    During the 509th Colloquium of the Euromech society, held from March 24th & 25th at TU Berlin, fifty leading researchers from all over europe discussed various topics affecting both road vehicle as well as railway vehicle aerodynamics, especially drag reduction (with road vehicles), cross wind stability (with trains) and wake analysis (with both). With the increasing service speed of modern high-speed railway traffic, aerodynamic aspects are gaining importance. The aerodynamic research topics comprise both pure performance improvements, such as the continuous lowering of aerodynamic drag for energy efficiency, as well as safety relevant topics, such as cross-wind stability. The latter topic was most recently brought to attention when a swiss narrow-gauge train overturned during the severe storm Kyrill in january 2007. The shape of the train head usually has largest influence on cross wind stability. Slipstream effects of passing trains cause aerodynamic loads on objects and passengers waiting at platforms. The strength of the slipstream is determined by both the boundary layer development along the length of the train and the wake developing behind the tail of the train. Since high-speed trains can be considered to be as smooth as technically possible, attention is drawn to the wake region. The wake of the train again is also one important factor for the total drag of a train. Due to the fact that trains are bidirectional, optimisation of the leading car of a train with respect to drag and cross wind performance while simultaneously minimising the wake of the train for drag and slipstream performance is a great challenge. Modern optimisation tools are used to aid this multi-parameter multi-constraint design optimisation in conjunction with both CFD and wind tunnel investigations. Since many of the aerodynamic effects in the railway sector are of similar importance to road vehicles, the aim of the colloquium is to bridge the application of shape optimisation principles between rail- and road vehicles. Particular topics to be addressed in the colloquium are: Drag, Energy consumption and emissions: Due to increase in energy cost, drag reduction has gained focus in the past years and attention will grow in the future. Pressure induced drag is of common importance for both rail- and road vehicles. The optimisation of head- and tail shape for road vehicles as well as for bi-directional vehicles (trains) is in the focus. Interference drag between adjacent components shall also be treated. Slipstream Effects: Are a safety issue for high-train operation (Prams sucked into track due to train-induced draught flows) when trains passing platforms at high speeds. For Road vehicles, the ride stability of overtaking cars is influenced by the wake of the leading trucks and busses. Common interest is the minimisation of wake effects for both rail and road vehicles. Cross-Wind Safety, Ride stability under strong winds: Both are safety issues for rail- and road vehicles. Aerodynamic forces shall be minimised (roll moment for trains and also yaw moment for road vehicles). Strategies for Vehicle shape optimisation (head, tail and roof shape) in order to minimise aerodynamic moments. Possibilities of Flow control. Optimisation strategies: Parametrisation, analyses (CFD), Optimisation tools and methods, Application to Drag, Cross-Wind, Ride stability and Snow issue
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