Tarasov Y. Scientific fundamentals of ensuring the technical level of vehicles in the design and modernization

The dissertation is devoted to the decision of an actual scientific problem - development of theoretical basis for creation of methods and means of maintenance of a high technical level of motor vehicles at a design stage, during tests in the course of commissioning and at long operation. A method for assessing the functional and parametric stability of the dynamic properties of vehicles during long-term operation has been developed. To assess the parametric stability of dynamic properties, an indicator is proposed - the rate of change over the course of the parameters that characterize the dynamic properties. The relationship between the relative increase in the maximum design speed of the car after its modernization in the production process and the required relative increase in the maximum engine power at a variable drag coefficient is determined. The influence of aerodynamic characteristics on the energy efficiency of the car is determined. The method of estimating the change in society's requirements for the braking properties of vehicles with regard to the use of entropy in determining the maximum capabilities of existing methods of braking has been further developed. The method of determining the aerodynamic parameters of the car on the run in road conditions has been improved, which, in contrast to the known ones, allowed to clarify the relationship between the shape of the car body and the coefficient of frontal drag. The probabilistic estimation method at the stage of designing the moment of inertia of the car relative to the vertical axis has been improved, which, in contrast to the known ones, allows to reduce the error of determination. Experimental and theoretical studies of energy and dynamic performance using an improved method for determining the aerodynamic drag of the car.