Study Of Automatic Shift Modes And Schedule For Tractors

As a power machine,a tractor plays a important role in agriculture, it is useful for plough, seeding, fertilizing, transportation and so on. As tractors’ working condition is complicated, drivers need to shift frequently to adapt to the versatile outside resistance, and adjust the agricultural tools now and then, so it is a tough work for drivers to control the tractor work in optimum condition, especially when it comes to big-power tractors. Automatic shift controlled by computer is helpful to let drivers get rid of frequent shift, focus on manipulate the farm tools, it can also contribute to productivity in the long term.The key points for study automatic transmission are it’s structure, control manner and shift schedule, whereby shift schedule are the core of the shift control part, it determines if a automatic transmission meet with dynamic, financial, safe requirements. As tractors are quite different from cars either in structure or working situation, shift principles of a car can not be directly applied to tractors which has much more complex working condition, so it is vital for studying tractors’ automatic shift modes and schedule. On the base of current technique and tractor’s own characters, this study work out different working modes for various tractors and corresponding shift schedule, determined by different goals, thus it will meet with tractors’ utilization request. The followings are the details and conclusions of this research.(1)By studying the features of velocity, load, and governor control for a tractor’s diesel engine, the optimum working point where the diesel engine works in the most dynamic and economic way was found out; the mathematic function of diesel engine torque to throttle opening and rotating speed was obtained, it can reflect the working situation of a tractor; working resistance as well as its source were analyzed.(2)According to diesel engine torque changing rule with throttle opening and engine speed. tractors’ working features, the best working load section for tractors were set out, certain the foundation for formulate shift rules. And confirmed four significant parameters for automatic shift controlling: speed, the engine throttle opening, engine speed, braking signal parameters.(3)As tractors’ working purpose is different in various operating environment, it is essential to clarify tractor’s working mode and employ relevant shift parameters for different working mode, thus shift rules under unlike working mode would be acquired. And the three mode is heavy load field operation mode, light load operation mode, road transport mode field(4)In accordance with the shift schedule and modes, figure out the optimum working load and speed section for different gears by using a concrete example. As the sake of shifting of every working mode is different from another, the optimal work section and shift point for every gears under various mode is laid down.