The Automatic Control System of the Multistage Manual Transmission

Abstract

The paper represents a multi-stage control system of mechanical transmissions of trucks and buses, it considers the process of the system operation when starting the vehicle and the gear shifting. It represents a general diagram of the control program of the multistage manual transmission, built into the microcontroller unit. It describes a functional diagram of the interaction of the main modules with each other and with the engine control unit. It considers the methods used by the system for automatic transmission control. Keywords-multistage transmission; pneumatic actuator; synchronization process; automatic control; command control I. TOPICABILITY OF THE AUTOMATIC TRANSMISSION CONTROL Improving of the technical level of modern trucks is based on the improvement of operational reliability, competitiveness, increased safety and productivity. Now these tasks are associated with the degree of saturation of the vehicle with microprocessor control. The emergence of the global automobile and tractor automation has led to the restructuring of the system design of the components and units of the vehicles. The strength and benefits of such construction of the units is most clearly visible in the example of transmission. Presence and absence of the automatic control (when other components remain the same) leads to a great contrast of the characteristics of the vehicles. Microprocessor control provides much more favorable properties most characteristics of the vehicles: technical, economic and ergonomic ones. In recent years, there has been an increase in the number of stages in manual transmissions (for example, on road trains up to 16-20). This leads to more frequent gear shifting, which increases physical and psychological stress of the driver. At the same time increase of the speed and amount of road transport requires the driver's attention to the rapidly changing road conditions. Providing of safety and high performance of vehicles in these conditions can be performed by automated control of mechanical multi-stage transmission, in the first place the transmission and the clutch. Microprocessors, capable of operating in complicated environments of the vehicle performance, allow not only improving of the accuracy of control, but also increasing the number of information parameters, thus implementing more flexible control logic. As a result, the automatic transmission control improves efficiency of the engine power, leads to reduction of fuel consumption, and reduces the driver's fatigue. Currently, for creation of semi-automatic and automatic transmissions, along with the use of hydro-mechanical and planetary gearboxes, stage synchronized gearboxes are used. They have such positive qualities as a small weight and size, low cost, high reliability, ease of repair and service and high performance are used. Now electro-pneumatic actuators for the shift control have the increasing development in the synchronized gearboxes. It happens due to the presence of compressors required for the control of brakes, doors and etc. on trucks and buses. When using distance electro-pneumatic actuator, except for facilitating and simplifying of the vehicle control we reduce the vehicle's weight because it eliminates traction, joints, and other units, and expands design possibilities of the vehicle. Furthermore, reducing the time loss for gear shifting we improve the dynamic performance of the vehicle. Due to the widespread use of pneumatic actuators in general engineering their theory and calculation are well developed. In this regard there is a lot of literature.