Operational conditions of vehicles motion and formation of urban driving cycle in the city of Lviv

Abstract

To the greatest extent, the indicators of the motor vehicles being in the normative technical state are influenced by the operational conditions, which, in turn, are characterized by road, relief (terrain) and transport conditions. The transport conditions of large cities of Ukraine are characterized by the intensive increase of motor transport, especially individual (private) one, on the street-road network of the city caused a number of problems, such as increased waste of time needed for a trip, increased number of forced stops, increased number of emergencies and road-traffic accidents, the occurrence of traffic jams, chemical and noise pollution of the environment. As the special investigations indicated, the volume of traffic has increased by 1.5…1.8 times in comparison with the data of ten years ago [1]. All this caused the necessity to substantiate the rational use of the power of the motor vehicles engines and to control their ecological indexes in order to reduce the negative influence on the environment. While evaluating the toxicity of the motor vehicles engines, two fundamentally different methods of investigations are being used: testing on steady-state operating conditions with constant parameters of the engine and testing on transient operating conditions when the input parameters are being changed. For the transient conditions, the main conditions of the motor vehicles motion have been identified: motion in the conditions of the city and motion out of its borders. Each of the conditions is characterized by the differences in the percentage of toxic components in the exhaust (burnt) gases. While developing the technique of determination of ecological indexes and parameters of fuel economy (saving) for motor vehicles, a large number of factors, which varies depending on the operating conditions, are considered. This is expedient in the case when the operating conditions are very different considering the typical motion conditions in the region and the several aspects that affect the fuel consumption. One of the main reasons for this is the unsatisfactory state of planning, accounting and standardization of the efficiency of the motor vehicles use. In this approach, the operation indexes are estimated based on not always impartial reporting and statistical data, so the standards are not an impartial factor or a model for the motor vehicles operation. These circumstances substantiate the urgency of the subject of research. While carrying out these investigations, the preliminary analysis of the motion conditions of the motor vehicles in different operating conditions is conducted and the peculiarities of the existing driving cycles of different countries of the world are considered. In order to ensure the determination of the motion conditions of motor vehicles in the conditions of the city of Lviv, the technique of investigations carrying out was developed on the basis of available means. The results of changing the conditions of the motor vehicles motion in the conditions of the city of Lviv were obtained taking into account the motion speed of the motor vehicle, the rotation frequency of the engine crankshaft, the instantaneous fuel consumption and the amount of consumed air. According to the results of the experiments carried out, the main features of the operational conditions of motor vehicles motion in Lviv were determined, the driving cycle for testing the motor vehicle in the conditions of Lviv and the method of comparative analysis of existing and improved driving cycles were developed. The analysis of indexes of existing and developed driving cycles is carried out and the expediency of use of the developed driving cycle is substantiated.