ОЦІНЮВАННЯ СТІЙКОСТІ РОБОТИ АВТОМОБІЛЬНОГО ДВИГУНА ЗА УМОВИ ПОСТІЙНОЇ КУТОВОЇ ШВИДКОСТІ КОЛІНЧАСТОГО ВАЛА

Abstract

The operation of the automobile engine at a constant angular speed of the crankshaft at an unsteady mode of movement of the car allows increasing its energy and fuel efficiency. It is necessary to use a continuously variable transmission, which allows you to change the speed of the vehicle with infinitely variable gear ratio change transmission without acceleration of the rotating masses of the engine. With a continuously variable automatic change gear ratio of the transmission, it is possible to realize engine operating modes that provide maximum effective engine power, maximum effective engine torque, and also minimum effective specific fuel consumption. It should be noted, that even with perfect management continuously variable transmission fails to obtain the constant value of the angular velocity of the crankshaft, as the internal combustion engine generates oscillations of the indicator torque. As a result of the study, an assessment of the possibility of maintaining a constant angular velocity of the crankshaft at steady and unsteady vehicle motion modes was made. The possibility of transmission operation in the pre-resonance and non-resonance frequency regions has been taken into account. A method has been developed for assessing the stability of an automobile engine with uneven effective torque of an internal combustion engine and a continuously variable transmission. The calculated dependencies are obtained, taking into account the elastic-inertial properties of the transmission and the coefficient of unevenness of the engine's torque, allowing determining the maximum deviations of the angular velocity of the crankshaft in the considered vehicle motion modes. It is shown, that the operation of the transmission in the near- resonance zone not only leads to additional cyclic loads on the parts and components of the transmission itself, but also reduces the energy efficiency of the vehicle power plant. Recommendations to improve the performance of motor-transmission units are formulated.