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.

The main malfunctions that arise when operating a vehicle in Ukraine are the failure of the suspension elements and vehicle tires due to the poor condition of the most roads [11]. The car suspension elements soften the dynamic load and smooth out the oscillations from the unevenness on the road while riding and provide a good stability and smoothness of the car ride. The car suspension affects not only the handling, stability, stability of the car motion, but also provides comfort and safety of the car, especially, when car is driven on uneven surface of the road and in sharp manoeuvres of the movement. The suspension of the car is a connecting linkage between the wheels and the body of the vehicle through which the forces of the shocks from wheel act on the vehicle body while riding over bumps on the road. Also, especially the front suspension of the car smooths the oscillations from the uneven road and provides the smooth ride. The smoothness of the ride depends on the elasticity of the suspension and car tires, work of shock absorbers and distribution of the vehicle mass. Besides, the smoothness of the ride on the uneven road has the influence on the comfort of the driver and passengers, the average speed of movement (as a consequence it causes the changes in fuel consumption, productivity and cost of transportation), the cargos safety, the reliability of the car. The car suspension is one of the least reliable and durable elements of the car. The work of the faulty suspension reduces the durability of the car in 1,5 times and worsens its steering, thereby reducing its safety [11]. Ultimately, the motion of a car with a faulty suspension can cause an emergency on the road due to possible unpredictable suspension behavior. The analyzing of the typical malfunctions of the car suspension components and its influence on smoothness and safety of motion is provided in the article. The methods of experimental research of the influence of the typical suspension malfunctions on the parameters of the car motion have been developed. The choice of research tools and the mounting place of the sensors on a car suspension is substantiated. On the basis of the experimental research results, the analysis of the influence of the suspension malfunction on the car's condition was performed according to the voltage changing of the sensor-analyzer, and the voltage change was transformed into the linear displacement of the suspension elements. With the use of the MATLAB program in Simulink mode the simulation of the car ride over the typical obstacles with the use of a two-mass structure for sprung and unsprung masses was carried out, the oscillations of the unsprung and sprung masses were obtained in relation to the road with given pressure in the tire and given speed when riding over various types of obstacles with the normal and faulty shock absorbers.

Visual perception plays a crucial role in the safety of road users. However, certain conditions such as twilight, the impact of bad weather, dirty windshields, etc. have a negative impact, which in turn increase the likelihood of traffic accidents (TAs) [1]. The ever increasing number of vehicles on the road is an additional potential danger. In response to these factors work is constantly being done to modernize existing and develop new lighting devices. Vehicular headlights are firstly assigned to optimally illuminate the roadbed in order to ensure safety [2]. For this reason headlights, including their light source, are important safety elements for vehicles, and their application requires official permission. The type and location of vehicular lighting, as well as their design, light source, color and light settings are regulated by law [3]. Automakers pay sufficient attention to the fuel economy and safety of their vehicles. So for this reason automotive light sources, such as incandescent and gas-discharge (HID) bulbs, are increasingly being replaced by LED and laser diode bulbs as they provide superior lighting with lower power consumption. This in turn leads to increased vehicle safety and economy [3].

Індекс рубрикатора НБУВ: О35-082н631

Рубрики:

Автотракторні двигуни (автомобільні та тракторні двигуни)

Шифр НБУВ: Ж44086 Пошук видання у каталогах НБУВ 

Індекс рубрикатора НБУВ: О35-082н631

Рубрики:

Автотракторні двигуни (автомобільні та тракторні двигуни)

Шифр НБУВ: Ж44086 Пошук видання у каталогах НБУВ 

The main system responsible for the safety of the car is its braking system. The efficiency of the braking system is assessed by several parameters, the main of which is the maximum braking force, which is generated in the braking mechanisms, usually it is disc or drum types of brakes. The analysis of peculiarities of designs of existing types of brakes of cars is carried out, advantages and disadvantages of each of them, characteristics of application and maintenance are substantiated. The main factors that have a significant impact on the efficiency of the car's brake system have been identified. It was carried out the research of the influence of the main operational factors on the efficiency of the car's brake system: the pressure in the car's tires, contamination, and friction pairs of the brake mechanisms. The method of conducting experimental test lane and road researches of influence of the chosen factors on indicators of braking efficiency of the car is developed. Test lane experimental studies were performed using the Bosch BSA 4340 brake test equipment, graphs of changes in the braking efficiency of each of the car's wheels based on the researches were built, depending first on the change in tire pressure, then on the presence of rust, grit, and grime and level of wear of mechanisms. The quantity of the maximum braking force of the car depending on three quantities of pressure in tires of wheels was identified: the pressure recommended by the factory of 0,18 MPa, the lowered and increased pressures 0,15 and 0,25 MPa respectively. The influence of motor oil caught in the brake mechanism or treatment with special pastes on the value of the maximum braking force is also determined. The influence of the state of the brake discs and pads on the braking efficiency of the car was also investigated, the braking indicators were measured before and after the replacement of the brake disc and pads. On the basis of the conducted test line and road researches, conclusions are made and practical recommendations on prevention of reduction of brake efficiency of the car in the conditions of operation are offered.