• Energy Research

Problem. The tendency to reduce the working volume of internal combustion engines, which has emerged in recent years in the global automotive industry, is due to the need to improve the environmental situation and energy efficiency of road transport. Goal. The aim of the study is to increase the energy efficiency of vehicles by rationally reducing the maximum effective engine capacity. Methodology. The work uses the method of partial accelerations, implemented in a mobile registration and measurement complex, which allowed the authors to obtain an improved formula for calculating the force of aerodynamic resistance. Experimental studies of car aerodynamics were also carried out. Results. The article presents the results of the authors' research, which made it possible to prove the possibility of reducing the power of the internal combustion engine while maintaining the specified maximum speed and the specified level of indicators of the dynamic properties of cars. Originality. The relationship between the degree of use of the maximum engine power and the relative change in the effective specific fuel consumption of a carburetor gasoline engine with direct injection of gasoline and diesel is determined. Practical value. Calculations performed on the example of the ZAZ-1103 "Slavuta" car showed that a rational reduction in effective power allows for a 9.5% reduction in fuel consumption, and for an engine with direct injection of gasoline and diesel engines, this leads to an increase in fuel consumption by 6.7 % and 20.3%, respectively.

We have developed an energy approach to estimating the dynamics and fuel economy of cars that makes it possible to determine interrelation between consumption of energy and the kinetic energy of a car. We determined coefficients of the specified interrelation for basic and additional (unproductive) consumption of energy. Based on the obtained coefficients, it is possible to rank energy losses, as well as identify the ways to reduce them. As indicators of energy evaluation of the car’s dynamics, we proposed indicators of its dynamics ‒ the level of kinetic energy possessed by a vehicle at full weight and maximal motion speed; energy indicator of the car’s dynamics that can be applied as the unit for measuring energy consumption of engine, employed to move the car. The equations were derived that determine the following: a number of units of energy losses caused by the elastic and dynamic losses of car and transmission (per one meter of the distance); additional consumption of engine energy at fluctuations of the car guide wheels in the horizontal plane are caused by their imbalance. We present dependences that allowed us to do the following: determine maximal total consumption of engine energy while driving; assess a reduction in the additional costs for the motion of hybrid cars under the established mode at an increase in the share of torque generated by electric motors. The interrelations were determined between energy indicators of the dynamics and fuel economy of cars. We found that the smaller the number of units of energy consumption by engine, required to move the car, the higher energy efficiency of the vehicle. Calculation of all types of energy consumption in the units of kinetic energy of the car enables their comparison, analysis of their causes, and the identification of possible ways for their reduction. The proposed dependences could be used to determine engine energy consumption, required for the car motion, taking into account various factors. The equations derived make it possible to assess energy efficiency of the car at the stages of its design and modernization. We have shown the way to improve dynamics and fuel efficiency of a car by reducing additional losses in the vehicle transmission through the use of a combined electromechanical drive of the driving wheels. Applying energy approach allowed us, using hybrid cars as an example, to determine energy saving at their steady motion. This saving for a car with a number of cylinders of 6‒8 can reach 25‒30 %

Problem. There was a need to expand the well-known concept of vehicle operational properties – fuel efficiency arose in connection with the advent of new alternative power plants (electric motors, flywheel engines, hybrid power plants, etc.), which requires the inclusion of not only the thermal energy of the fuel, but also other types of energy (electrical and mechanical). In the paper the research of choice and justification of the vehicle energy efficiency indicators by assessing the energy costs of the engine for its movement was made. The analysis of the relationship between energy characteristics of dynamics and vehicle efficiency was made. Goal. The aim of the study is to analyze methods for assessing the vehicle energy efficiency. To achieve this goal, it is necessary to determine indicators that will allow a comparative analysis of energy efficiency indicators of various vehicles. Methodology. The approaches taken in the work to solve this goal are based on substantiating the indicators of the energy efficiency of the car by assessing the energy consumption of the engine for its movement. Results. In our opinion, in projecting and evaluating the dynamic properties of vehicles, it is rational to use the energy indicators of the vehicle, for which it is necessary to develop appropriate assessment criteria. Analysis of the results of indicators calculation and, in table 1, has shown that the indicator in comparison with has less dispersion. Originality. The obtained results of the influence of the parameters of vehicles on the level of their energy load shows that the indicator has less dispersion than. In addition, the value does not correlate with the year of manufacture of the vehicle, which allows the use of this indicator at the design stage of vehicles. It is only necessary to set the rational normative value of this indicator. Practical value. The results obtained can be recommended to specialists for use in the design, production, certification and operation of automotive vehicles, vehicle energy efficiency, combined power plant.