Speed control strategy for pump-motor hydraulic transmission subsystem in hydro-mechanical continuously variable transmission

2021 ◽  
Vol 35 (12) ◽  
pp. 5665-5679
Author(s):  
Xiaozhao Wei ◽  
Lei Wang ◽  
Xiangdong Ni ◽  
Shuangman Han ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Speed Control ◽  
Continuously Variable Transmission ◽  
Variable Transmission

Improvement of fuel economy by shift speed control for a metal belt continuously variable transmission

2002 ◽  
Vol 216 (9) ◽  
pp. 741-749 ◽  
Author(s):  
H Lee ◽  
H Kim
Keyword(s):  
Fuel Economy ◽  
Dynamic Models ◽  
Control Valve ◽  
Speed Control ◽  
Pressure Control ◽  
Continuously Variable Transmission ◽  
Hydraulic Loss ◽  
Variable Transmission ◽  
Line Pressure ◽  
Shift Speed

In this paper, an algorithm to improve the fuel economy of a metal belt continuously variable transmission (CVT) vehicle by CVT shift speed control is suggested. By rearranging the CVT shift dynamic equation, it is found that the CVT shift speed depends on the line pressure as well as on the primary pressure. CVT shift speed maps are constructed to evaluate the influence of the line pressure on the shift speed. To obtain a target shift speed, an algorithm to calculate the line pressure is presented. In order to estimate the shift speed and the hydraulic loss, dynamic models of the line pressure control valve and the ratio control valve are obtained by considering the CVT shift dynamics and validated by experiments. It is found from the simulation results that fuel economy can be improved by 2 per cent in spite of the increased hydraulic loss due to the increased line pressure.

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