Research And Development Of Remote-gear Control Of Rear-engine Bus

For big bus , especially for the city buses, rear-engine in the overall arrangement possess varies of advantages, and therefore this kind of layout has been increasingly used in the overall layout of the vehicles. But rear-engine bus has both its engine and transmission system installed at the rear of the bus, and the transmission system is physically quite away from the driver-cabin in distance, therefore a few of assisting levers or mechanism should be incorporated linking the steer handle and gear-shifter, that is the remote-gear control. At the same time, the shifting agencies should be sufficiently rigid, and the connected space can not be too large, otherwise it can not be obviously detected by the drive when shifting. It is really tough to manipulate such kind of operate mechanism, in order to reduce the driver's labor intensity, give the drive more time to pay attention to road conditions and improve traffic safety, it is urgent need to improve the existing institutions of the shift control.This paper is aimed to solve the problem that the driver may get fatigue during the frequently operation of shifting. Through the method of electric control and pneumatic operation, this paper develops a system in terms of electric control unit and pneumatic actuator mechanism to replace the existing rod/cable shifting agency. As a result it solves the problem of difficult to manipulate the remote-rear control of rear-engine bus, reducing the driver's labor intensity and improve traffic safety. At the same time, the system will combine the speed of vehicle and engine speed, gives the driver the best choose of shifting to improve the fuel economic of vehicles.Based on the analysis of the working principle of transmission system, this paper develops a system in terms of electric control unit and pneumatic actuator mechanism based on the traditional mechanical six -election transmission. The main contents include:(1) Analysis the working principle and the institutional of systemBased on the analysis of the working principle of transmission system, combing the experimental data, this paper develops a system in terms of electric control unit and pneumatic actuator mechanism based on the traditional mechanical six -election transmission which can accomplish the shifting operation accurately.(2) The design of implement mechanismThe shifting operation of implementing agencies is mainly finished by the work cylinder, the paper design a series of work cylinder which can accomplish the shifting operation accurately. In addition, the paper analysis and select the solenoid valve which control the work of the cylinder.(3) The design of control systemThe control system detects the current shifting performance requirements of the driver through the sensors and the electric control unit converts the driver's request into shifting command and send it to the implementing agencies. Meantime, it receives the feedback signal from the implementing agencies and feedback to the driver timely. It mainly includes the selection of stall sensor, vehicle speed sensor and engine speed sensor and the design of control circuit.(4) The hardware design and software design of the control system The hardware circuit is the basis of system control functions, while the software is the control center of the hardware and the core of the whole control system. This paper completed the design of hardware circuit and software design.