The Study Of Driving Cycle And Road Load Spectrum Based On The Traffic Characteristics In China

Transmission is a key part of automotive.Its performance is related to the vehicle dynamics, fuel economics and vehicle security. Currently our country mainly draw lessons from foreign countries on the transmission performance appraisal, but the traffic characteristics exist differences in different countries, and some transmission have been broken because of this. The article discusses the loading scheme of transmission performance test based on the traffic characteristics in china.First of all, the road test data includes the speed, the gears and the transmission input torque. Five wheel meter principle is used to collect the speed, and then the ratio relations and wheel rolling radius are used to calculate speed. To get the gear signal, we need to install the gear sensor, and switch the signal to digital signal. Transmission input torque is more difficult to achieve, so it is not able to measure directly. So it is have to analysis the stress model of vehicle to calculate the transmission input torque.Secondly, studied and analyzed the data processing method, mainly used the rain flow count method. The rain flow count method including the equivalent data compression, peak value extraction, remove invalid amplitude and cycle extraction. And since four point method is simple and exact, so the four point method is taken to acquire of rain flow cycle.Based on this, write a MATLAB program, and generate the torque distribution of each gear.In addition, the equivalent damage theory is used to get the transmission loading scheme based on torque and rotational speed.Thirdly, the original data should be filtered by the rain flow count method of the equivalent compression, extraction and remove invalid amplitude peak value to constitute the driving cycle. Then fixed step length truncation method is used to obtain driving pieces samples, from which selected representative fragment with the clustering method.According to the above mentioned, write the MATLAB program to analysis the original data, then obtain three typical fragments, which can constitute the final driving cycle.Finally, summarizing the load spectrum and driving cycle application methods in the field of transmission load, indicate that they’re scientific and feasible in practice.