The article presents the results of studies of energy, environmental and fuel efficiency indicators of a passenger car with a gasoline injection system. The engine is equipped with a device additionally supplying liquefied petroleum gas (LPG) and it has an ignition timing variator (ITV). As a result of research, an improvement in the fuel efficiency of a car in thermal equivalent was found when the engine was running on LPG and a slight increase in energy performance was observed. Emissions of pollutants with exhaust gases change in different ways: emissions of carbon monoxide practically do not change, emissions of hydrocarbons and nitrogen oxides are growing, carbon dioxide emissions from LPG operation are reduced, socio-economic damage when the engine is running on LPG is also reduced.

The presented research is focused on the design of a new driving cycle of the Bus Rapid Transit (BRT) for the Kyiv city. This cycle consists of a complex of two types of sections. Each of them includes various phases of the traffic. A mathematical model was specified, which serves for defining the efficiency properties indices and for regimes of bus transport. The BRT are used within the bus lines. It was found, that two articles articulated buses are the most suitable choice, the MAZ-215 among them, for exploitation. At the same time, they provide the smallest fuel consumption together with the shorter operation time on the bus line as well as higher average speed at full and half loading. The optimal driving speeds of the steady traffic are the values of 50 km/h for section up to 1 km and 60 km/h or 70 km/h for section over 1 km. It was evaluated, that depending on the steady motion speed and the load level, the driving time of the BRT on the line varies from 20.1 min to 23.4 min, which is much lower than the driving time of a trolleybus on the same line according to the traffic schedule.

This article deals with the theoretical preconditions for creating a high-performance, universal earthmoving vehicle with continuous motion that can create long grooves of different depths and widths in the soil using a single actuator. For this purpose, a new symmetrical rotor actuator was developed, which operates in translational and rotational modes due to the two-level actuator with a double-swivel mounting on the base chassis, instead of the traditional single-swivel mounting. Its use eliminates the possibility of leveling the thickness of the shavings when digging the soil. The rotor-actuator-movement algorithm at the front part was developed from a combination of vehicle movement and cyclic-lateral-actuator movement. In real practice, this means digging up the soil with even shavings. The implementation of the developed algorithm in the physical model of the symmetrical actuator confirmed the possibility of balancing the thickness of the shavings, which are cut by the rotor buckets with up to 10% accuracy. The difference between the results in determining the thickness of the shavings analytically and experimentally is 12% with a confidence interval of 0.95.

This article considers external loads experienced on the rotor actuator of the universal continuous earthmoving machinery when digging wide excavations (ditches) in the soil and the ways to improve its productivity. Under the condition of translational and rotational supply of the soil-developing actuator to the face, the possibility of minimizing and leveling external loads on the actuator by improving the kinematics of its cyclic movement in the face has been experimentally proved. The actuator should move according to the required trajectory, which corresponds to the curve of the lemniscate of Bernoulli. The load of the UEM soil-developing actuator, operating in the mode of digging the soil, and the effectiveness of the suggested method for leveling the external loads have been experimentally assessed on the current physical model of the operating equipment. Leveling and reducing the absolute values of loads on the UEM operating equipment is achieved by improving the actuator trajectory optimization when digging the soil. It implies the additional rotation of the actuator intermediate frame at the end of each half cycle of the operating process. The required duration of the additional rotation of the intermediate frame is functionally dependent on the actual speed of machinery movement. The additional rotation of the intermediate frame, the duration of which is 1.1 s in the mode of maximum productivity, reduces the maximum load of the operating equipment, namely: torque on the rotor axis M_t-by 19% (up to 60 kN m), the components of the main force vector: vertical force-by 9% (up to 40 kN), and lateral force P_l.m-by 32% (up to 58 kN). The obtained results enable to comprehensively assess the maximum load of the UEM operating equipment under the conditions of changing values of the factors on which it depends and to objectively assess the directional stability of the machinery. Aligning the thickness of the shavings cut by the buckets of the rotor actuator in a half-cycle enables to improve the productivity of the universal earthmoving machinery almost twice.

Результати експериментальних досліджень дизеля Д-243 при додаванні води до повітряного заряду

The presented research is focused on the development of the bus rapid transit (BRT) system, combining the high capacity of rail transport with the flexibility of bus routes. Classic BRT systems have certain limitations, particularly concerning a single rolling stock capacity. The main motivation of the work is to find efficient and cost-effective solutions to increase passenger traffic in the BRT system while optimizing fuel consumption. The main contribution of this study is the comprehensive analysis and optimization of various configurations of trailer bus trains, which represent a flexible and cost-effective alternative to traditional single or articulated buses. Based on two schemes, four possible options for using trailer bus trains are offered, which differ in the number of sections and working engines. Among the suggested schemes of trailer bus trains, the two-section and three-section schemes with all engines running and the three-section scheme with one engine turned off are appropriate for use due to improved fuel efficiency indicators with better or acceptable traction and speed properties. Calculations carried out on a mathematical model show that, for example, a two-section bus train can provide a reduction of specific fuel consumption per passenger by 6.3% compared to a single bus at full load, while a three-section train can provide even greater savings of up to 8.4%. Selective shutdown of one of the engines in a multi-section train can lead to an additional improvement in fuel efficiency by 5–10%, without leading to a critical reduction in the required traction characteristics.