Підвищення паливної економічності автотранспортного засобу формуванням раціональних законів та алгоритмів перемикання передач трансмісії

Abstract

У дисертаційній роботі розвʼязано науково-практичне завдання раціональної щодо паливоощадності організації процесів перемикання передач за допомогою фрикціонів з відсутністю розриву силового потоку й одночасним автоматичним коригуванням швидкісного і навантажувального режимів роботи двигуна внутрішнього згоряння. Зокрема, детально опрацьовано чотири можливі алгоритми автоматичного коригування режимів роботи двигуна з умов дотримання заданого режиму руху. Доцільність застосування того чи іншого способу керування двигуном у процесі перемикання передач у разі заданих миті його початку та тривалості роботи фрикціонів обґрунтовано витратою палива. Проведені експериментальні дорожні дослідження та імітаційне моделювання цих алгоритмів засвідчили адекватність вибраної математичної моделі. В диссертационной работе решено научно-практическое задание рациональной с точки зрения топливной экономичности организации процессов переключения передач с помощью фрикционов при отсутствии разрыва силового потока и одновременном автоматическом корректировании скоростного и нагрузочного режимов работи двигателя внутреннего сгорания. В частности, подробно разработаны четыре возможных алгоритмы автоматической корректировки режимов работы двигателя при условии соблюдения заданного режима движения. Целесообразность применения того или иного способа управления двигателем в процессе переключения передач при заданных моменте его начала и продолжительности работы фрикционов обоснована расходом топлива. Проведенные экспериментальные дорожные исследования и имитационное моделирование этих алгоритмов подтвердили адекватность выбранной математической модели. The presented dissertation analyzes and estimates the selection of shift points in a stepped mechanic transmission of a vehicle in acceleration and deceleration operating mode under the conditions of fuel efficiency. It presents a comprehensive study of theoretical grounds of gear shift processes organization with the help of clutches under the conditions of continuous power flow transmission (with the closed clutch) and a simultaneous automatic correction of speed and loading modes of the operation of an internal combustion engine. In particular, it has been thoroughly elaborated four possible algorithms of automatic correction of engine operating modes when the driving mode predetermined by the driver is maintained: stabilization of the engine shaft angular velocity (ω- control); transitional mode of engine operation according to the line of minimal fuel loss in the function of engine power (g- control); dynamic transitional mode with short-term shifts to external traction and braking characteristics (the so called forced modes N- control); stabilization of engine turning moment (М- control). The conducted analytical researches proved the lowest indices: the loss of fuel, the deviations from the operating mode determined by the driver and the work of friction clutch skidding (energy losses) during the gear shift in a traction mode (acceleration) occurring just when the work of the engine operation is automatically controlled according to the algorithm of N – control. The application of dynamic transitional mode of engine operation also has an advantage over the other modes of driving (reverse shifts) when the vehicle decelerates. At the same time it should be noted that the possibilities to realize the forced modes of engine operation adjustment proper in the extreme zones of (minimal or maximal) velocity of engine shaft revolution, with the only realizable algorithm М- control (unforced modes of engine operation correction) are limited. It is obvious, that the formation of quantitative characteristics of the algorithms of engine operation modes control (adjustment) and the work of clutches (synchronizers) are influenced to some extend by inertia: the operation of fuel system (injection and the system of burn-down in case of oil engines) and the gyrating mass of the engine proper. The elaborated algorithms of automatic control of the engine operation in the process of the stepped gear transmission shift are also relevant for the mechanical transmissions with dual clutches (of DSG type) which in case of the gear shift by means of synchronizers guarantee the continuity of power flow transmission. The characteristics of automatic correction of engine operation modes in this case are similar to those defined in the analyzed variant of transmission with single clutch and the shift of gears by means of two friction clutches. The process of gears shift is so swift that the linear reproduction of “engine – transmission” system operation modes is quite natural and such that cannot distort the conception of optimal functioning of “engine – transmission” system. The experimental researches carried out on the road and imitating modeling of these algorithms in the program environment MATHCAD and MATLAB (on the example of Toyota Yaris with automated gear case C551A «Multimode») proved the congruence of the results of computer modeling and natural testing within 3-6% and the efficiency of N- and M- engine control algorithms realization in the process of gear shift (which are realized by reprogramming of the electronic block of engine operation control and of the gear case) both in the stage of acceleration and deceleration. The described algorithm of vehicle transmission optimal control also creates the ground for defining motivated instructions concerning the selection of gear shift moments in case of purely manual control over the vehicle. The obtained results are rather generalized, however considerable simplifications have been introduced into the model of the automobile. In particular, the schematically considered very simple gear case in fact completely represents the principles of operations pertain to mechanical stepped transmission of any design. Thus, optimizing the laws of gear shifts, we should consider the program of motion to be predetermined in advance (subjected solely to the driver), whereas the consequences of enforced deviation from this program in the period of transmission control elements operation should be minimized.