Research and Implementation of Tractor Power Shift Clutch Control System

Applying power shift control technology on tractor can improve the power, economy and driving comfort of tractor. The separation and engagement control of clutch in tractor power shift transmission system is the key factor to optimize the quality of shift. Through many experiments and tests, an electronic control unit based on MC9S12 was developed, and an effective clutch control strategy was put forward, which improved the jerk of power shift and shortened the gear shift time.

Multi-Plate Shift Clutch Morbidity Index Forecasting Method Study

According to the configuration characteristic of high-power transmissions and working principle of multi-plate shift clutch, the clutch dragging process is analyzed at first in this paper. After introducing the usual monitoring method of clutch dragging process, a portable vibration monitoring method is proposed. And then a GMDH forecast method on the basis of the morbidity index is presented. The practical application of the method can reduce the probability of clutch invalidation, and significantly extend the clutch’s working life.

Research of Gear Shift Control Technology for a New 8-Step Speed Automatic Transmission

For the development research for a new 8 step speed automatic transmission, a simplified dynamic model for this transmission was established. Aimed at four basic shift types, the ideal characteristics of shift clutch and engine control were set up. By using torque estimation method, PI slip control algorithm and engine coordinated control principle, the control model were developed for two main shift phases which are torque phase and inertia phase. The test on the rig and vehicle verified the accuracy and feasibility of this shift control strategy. The development model and algorithm have a high value for engineering application.

The Pressure Design of Wet Shift Clutch Based on Thermoelastic Instability Analysis

This paper investigated the dynamic pressure distribution on the plates within a wet shift clutch in hydrodynamic machineries for one engagement. The perturbation pressure model, heat conduction model and pressure calculation model excited by thermoealstic instability was developed. And wrote calculation programs with Maple 15 to analyze the influence of two kinds of typical friction materials, different thermal conductivity, different initial engagement speed on perturbation pressure amplitude and its impact on the pressure design margin and design radius. The results show that the margin can be decreased and design radius can be reduced, so power density increased. When the slipping speed is controlled within 16m /s, the radius can be reduced to about 1/2 of the original value.

Technique of Digital Electro Hydraulic Automatic Control of Hydro Mechanical Transmission

Based on a high speed electromagnetism valve and a two side throttle slide valve, a digital shift pressure regulation valve was designed. The electromagnetism valve was driven directly by the digital signal of electricity control system, the automatic shifting and the pressure’s real time regulation of shift clutch was achieved. The principle of the electricity control system was stated, based on the characteristic of the electromagnetism valve, the drive circuit was designed. The digital electro hydraulic automatic control system was installed on the heavy vehicle with hydro mechanical transmission, and tested. According to the test data of shift process, the control strategy is analyzed, and the validity and feasibility of the control system is proved.

Fault Diagnosis of Wet-Shift Clutch Based on STFT and Wavelet

The paper analyzes the failure mechanism of the wet shifting clutch, and puts forward the concept that the deformation of the clutch friction plate leads to the irregular collision between the driving and driven sides of disengaged clutch and accordingly forms the transient pulse signal; the short-time Fourier analysis on the vibration signals of failed clutch obtained via test proves such concept. The transient pulse signal in the relatively strong background signal is clearly extracted through the wavelet decomposition after zero setting, and an efficient wet shifting clutch fault diagnosis method is hereby formed.